Tag Archives: False Positives

How Common Are Inaccurate Coronary Artery Calcium Scans?

One reason the  skeptical cardiologist has been so enthusiastic about coronary calcium (CAC) scans is that I have found them to be highly reproducible and highly accurate.

Unlike most  imaging tests in cardiology if we perform a CAC on the same individual in the CT scanner of hospital A and then repeat it within a few days in the CT scanner of hospital B we expect the scores to be nearly identical.

Also, unlike most other imaging tests we don’t expect false negatives or false positives. If the CAC score is zero there is no coronary calcification-high sensitivity. If the score is nonzero there is definitively calcium and therefore atherosclerotic plaque in the coronaries-high specificity.

This is  because calcium as defined in the Agatson score is literally black and white-a pixel is either above or below the cut-off. Computer software automatically identifies on the scan. A reasonably trained CT tech should be able to identify the calcium that is residing in the coronary arteries based on his or her knowledge of the coronary anatomy as registered on CT slices. Using software the total Agatson score is calculated.

A physician reader (either cardiologist or radiologist) (who should have a very good understanding of the cardiac and coronary anatomy ) should review the CT techs work and verify accuracy.

A recent case report, however, has demonstrated that the above  assumptions are not always true.

Franz Messerli, a pre-eminent researcher in hypertension and a cardiologist describes in fascinating detail a false-positive CAC scan he underwent in 2013.  He was told he had a score of 804 putting him in a high risk category consistent with extensive plaque formation.

After consulting with cardiologist friends and colleagues he decided to put himself on a statin and aspirin despite having an excellent lipid profile.

Messerli assumed that the CAC score was not a false positive (although later in his article he indicates he had questioned the reading) writing:

“although one can always quibble with ST segments or wall motion abnormalities, on the CAC the evidence is rock-hard, you actually with your own eyes can see the white calcium specks! ‘Individuals with very high Agatston scores (over 1000) have a 20% chance of suffering a myocardial infarction or cardiac death within a year’—although I did not quite classify, this patient information coming from esteemed Harvard cardiology colleagues3 was hardly reassuring.

(His reference 3 for the 20% risk of MI or cardiac death in a year for CAC score >1000 is suspect. It is a 2003 “patient page” on coronary calcium in Circulation which does not have a reference for that statistic.)

A more recent study found patients with extensive CAC (CAC≥1000) represent a unique, very high-risk phenotype with CVD mortality outcomes (0.80%/yr) commensurate with high-risk secondary prevention patients (0.77%/yr) from the FOURIER trial)

Six years after the diagnosis Messerli was at a Picasso exhibition, “leisurely ambling between his Blue and Pink Period “when he developed chest pain.

To further evaluate the chest pain he underwent a coronary CT angiogram and this demonstrated pristine and normal coronary arteries, totally devoid of calcium.

He did have a lot of mitral annular calcification (MAC). The CCTA images below show how close the MAC is to the left circumflex coronary artery (LCX).


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The slice above shows how the MAC would appear on the CT scan designed to assess coronary calcium.  It’s position is very close to that of the circumflex but an experienced reader/tech  should have known this was not coronary calcification.

MAC is a very common finding on echocardiograms, especially in the elderly and it is likely that this error is not an isolated one.

Dr. Messerli writes

After relating these findings to the cardiologist who did the initial CAC, he indicated that most likely someone mistook mitral annular calcification as left circumflex calcium. This was hardly reassuring, since I specifically had asked that obvious question after receiving the initial CAC

Around the time I read Messerli’s case report I encountered a similar, albeit not as drastic case. A CAC scan showed a significant area of calcification near the left circumflex coronary artery which was scored as circumflex coronary calcification.

image001

The  pattern of this calcification is not consistent with the known path of the circumflex coronary in this case. When it was eliminated from the scoring the patient had a zero score. The difference between a nonzero score and a zero score is hugely significant but for patients with scores >100 such errors are less critical.

I have also encountered cases where extracardiac calcium mimics right coronary calcification.

There are some important take-home points from my and Dr. Messerli’s experience.

  1. False positive CAC scans do occur. We don’t know the frequency. If the scans are not overread by a competent cardiologist or radiologist with extensive experience in cardiac CT these mistakes will be more common

When I asked Dr. Messerli about this problem he responded

I am afraid you are correct in that CAC scores are generated by techs and radiologists and cardiologist simply sign the report without verifying the data. Little doubt that MAC is most often missed.
     2. Like other cardiac imaging tests (such as echocardiography) having an expert/experienced/meticulous  tech and reader matters.
    3. Dr. Messerli and I agree that a research project should be done to ascertain how often this happens and to evaluate the process of reading and reporting CAC.
4. Patients should look at the breakdown of the calcium in the CAC by coronary artery. Whereas it is not uncommon to see most of the calcium in the LAD it is rare to see a huge discrepancy in which the circumflex coronary artery score is very high and the LAD score zero. Such a finding should warrant a review of the scan to see if MAC was included in error.
Skeptically Yours
-ACP
N.B. Dr. Messerli’s report can be read for free and makes for entertaining reading.
I was very intrigued by two comments he made at the end:
  1. “Had my CHD been diagnosed a decade earlier, guidelines might well have condemned me to taking beta-blockers for the reminder of my days.6 This, as Philip Roth taught us in ‘The Counterlife’, might have had rather unpleasant repercussions.7

Until recently I had never read anything by Philip Roth but when he died last year I read his Pulitzer Prize winning  1987 novel American Pastoral and liked it. Given this Roth reference involving beta-blockers I felt compelled to get my hands on “The Counterlife.” The book is a good read (much better IMHO than American Pastoral) and one of the main plot points relates to the side effects (see my post on feeling logy) a character suffers from a beta-blocker. Stimulated by a desire to be able to perform sexually if taken of the medication, the character undergoes coronary bypass surgery and dies.

2. “As stated by Mandrola and true in the present case, ‘given the (lucrative) downstream testing that often occurs when coronary calcium is found in asymptomatic people, the biggest winners from CAC screening may be the testers rather than the tested’.”

I feel the CAC in the right hands should not lead to (lucrative or inappropriate) downstream testing in the asymptomatic (see my discussion on this topic here.)

 

 

A Patient’s Confusing Journey Into The Quagmire Of Cardiac Imaging: A Cautionary Tale

Mary-Ann, a reader from the north,  provides today’s post. Her story illustrates how easily medical care can veer off the rails while it is simultaneously railroading patients.  It is a cautionary tale with wisdom that can help most patients.

In this post I’ll just present Mary-Ann’s perspective and solicit responses.  Down the line I’ll provide some perspective on the processes, the problems and the solutions.


It started innocently enough. I showed up for a regular visit with my cardiac provider, a mid-level professional. She noted I was flushed and had a high pulse — about 100. 

Starbucks, I explained, and I flush easily — always have. She looked skeptical.

That is how I went from a half-caf Americano to a 48-hour holter monitor.

I went back for results — the usual ectopic beats but nothing scary or new. But again, she noted I had a fast heart rate and I was flushed.

And once again I explained: Starbucks — it is right down the street and okay, I might have a problem.

That is the short — but highly accurate — version of how I wound up getting a stress echo. 

I showed up for the results of the echo and that is where the runaway train started down the tracks.

“…possible inferoapical wall hypokinesis with lack of augmentation of systolic function, which are abnormal findings and may be indicative of ischemia due to underlying coronary artery disease. EF was 56% at rest and 40-50% at stress.” 

Wait — what?!

I was marched down the hall and scheduled for a cardiac angiography — and told not to run any marathons in the intervening two days. 

Marathon?! I was terrified I was going to drop dead at any moment. I contemplated just sitting the waiting room for 48 hours — just to be safe.

Then I started reading the professional literature and things were not adding up. An EF at stress of 40 – 50% is not good — in fact, it can be heading into heart failure land.

But I was active and fine — it did not make any sense.

I called the office; my provider was not available. I explained that I was worried there was a mistake. Oh no, I was assured, they are very careful to not make mistakes.

I wrote my will. I cried a lot. 

And when the person called to remind me of the procedure (like I could forget!?) I once again explained that I was worried there had been a mistake, and once again — reassurance. No mistake.

Nevertheless, she (aka me) persisted!

I sat on the hospital bed in nothing but a gown and handed the nurse my two-page letter; it started like this:

“I am reminded that what is normal and ordinary for a professional is never that for a patient. I am terrified.

First, I want to be really sure that there is not any chance of a mix-up in the stress echo test results. This is not simple denial or wishful thinking…” 

And that nurse paid attention, which is how I wound up not having a cardiac angiography. 

The cardiologist scheduled to do the procedure — we shall call him Doc #2 — wrote: 

“She has some concerns regarding the results of the stress echo study … I reviewed the most recent stress echo and it appears to me that the results for the resting versus the stress echo ejection fractions have been transposed…”

Translation: A Typo.

I was elated! Jubilant! We went to Starbucks to celebrate.

The giddy joy quickly turned to something along the lines of WTH just happened here? I read the original echo report written by Doc #1 — that lit the tinder. There were two different values for EF at stress documented in the report, and another sentence that was repeated. 

The professorial side of me was deeply affronted — in a subsequent meeting with hospital administrators I confess to saying that someone who is making hundreds of thousands of dollars a year doesn’t get to write such a sloppy ass report — and about someone’s heart, no less! 

But the best part of that meeting was learning that Doc #1 denied there was a typo — he stood by his findings. 

Oh dear.

And Doc #2 stood by his findings as well. And Doc #3 got involved somewhere along the way and he agreed with Doc #2. And the mid-level Provider also agreed with Doc #2.

The majority rule seems like an odd way to make health care decisions — wouldn’t you think all those smart people could talk among themselves and agree?

Apparently not.

That first meeting with the hospital folks included all manner of solicitous apologies and an attitude of collaboration. Of course, they said, we can send the echo to an outside cardiologist — at our expense — and get an answer.

And then I made the unthinkable mistake — and I blame the Skeptical Cardiologist for this — of asking informed questions.

“Are the cardiologists involved in reading my echo Level III echo specialists?”

“I understand that there can be variance in estimated EF between cardiologists — what level of variance is considered acceptable?”

The hospital team responded to my questions by calling a meeting — and the tone had changed considerably (Thanks a lot, Corporate Legal).

The offer to pay for an outside opinion was off the table — after all, they said, you would not have a patient-provider relationship with the cardiologist reading the echo. Ahem, I noted — I have zero relationship with the first cardiologist who read the echo and would not know him if I bumped into him at Starbucks. And you all did offer to pay for that outside opinion…

Oh never mind those minor details. No outside opinion on their dime. They would do a Lexiscan at their expense as a tie breaker. Final Offer.

Tiebreaker — really?! Is this a soccer game?

And seriously — should I have to have an invasive test to settle THEIR disagreement?! [Note: If it involves needles, it is invasive.]

Because there were not enough cardiologists involved already, I saw yet another one — from a different practice. He offered that the EF at stress looked more like 55%, placing his bet smack in the middle, and recommending a CT Angiography Coronary Arteries with Contrast as the tiebreaker.

Tiebreaker. That word implies both sides are equivalent or equal. However, my heart is not actually a game and the two teams cannot both be right — there is no equivalency in play here. What we are really trying to do involves accuracy — not breaking a tie score.

But I digress.

It doesn’t seem like you should have to make a chart to keep track of what cardiologists say about the same echo but in this case, it seemed necessary.

 And in the meantime, yet another cardiologist weighed in that the quality of the echo was poor — and no wonder they could not agree.

Deep breaths.

And so, for the past four months I have tried to navigate all this, and to understand what this actually means about cardiology and medicine and so many things. My confidence and my mind have been blown. Resources – and time – have been wasted. 

Ectopic heartbeats are typically benign in a structurally normal heart — I thought I was safe. But I have not felt safe since that day when I learned that Doc #1 and Docs #2, 3, and so on had decided to have a stand-off at the OK Corral that is my heart.

Except, I do not know if it is okay. And that is the problem. 


Unfortunately, Mary-Anne’s tale is not uncommon. It touches on many of the areas that patient’s should be aware of including

-Undergoing diagnostic imaging testing when you are free of symptoms

-Inadequate quality control in diagnostic imaging and how that leads to false positive results

-Variance in imaging performance and interpretation-how the same test can be read as normal by one doctor and markedly abnormal by another.

-The tendency of some cardiologists to recommend invasive testing when it is inappropriate and likely to cause more harm than good

-The importance of second opinions, especially if invasive testing is recommended

-The importance of patient’s doing their own research and asking good questions based on that research.

Transparently Yours,

-ACP

“Should You Get A Routine Annual Electrocardiogram?”, Revisited

Four years ago the skeptical cardiologist wrote a post which outlined the reasons why most people should avoid getting a routine annual electrocardiogram.

I pointed out that

If you …feel fine (meaning without symptoms or asymptomatic), exercise regularly, have never had heart problems,  and have a pulse between 60 and 90, the value of the routine annual ECG is very questionable. In fact, the United States Preventive Services Task Force (USPFTF)

“recommends against screening with resting or exercise electrocardiography (ECG) for the prediction of coronary heart disease (CHD) events in asymptomatic adults at low risk for CHD events”

(for asymptomatic adults at intermediate or high risk for CHD they deem the evidence insufficient). The USPSTF feels that that the evidence only supports an annual BP screen along with measurement of weight and a PAP smear.

Yesterday, the USPSTF published an updated analysis which confirmed this recommendation:

The U.S. Preventive Services Task Force (USPSTF) recommends against preventative screening with resting or exercise electrocardiography (ECG) in asymptomatic adults at low risk of cardiovascular disease events in an updated recommendation statement published June 12 in the Journal of the American Medical Association (JAMA).

I should point out that I still believe (although some would disagree) screening for atrial fibrillation with methods other than a 12-lead ECG (including taking the pulse or checking a single lead ECG with a Kardia device) is worthwhile.

Below, I’ve reposted relevant sections of my 2014 post which emphasizes the problem of false positives and false negatives which are quite frequent with any screening test but are particularly worrisome with the routine 12-lead ECG.

 


To many, this seems counter-intuitive: how can a totally benign test that has the potential to detect early heart disease or abnormal rhythms not be beneficial?

There is a growing movement calling for restraint and careful analysis of the value of all testing that is done in medicine. Screening tests, in particular are coming under scrutiny.
Even the annual mammogram, considered by most to be an essential tool in the fight against breast cancer, is now being questioned.

My former cardiology partner, Dr. John Mandrola, who writes the excellent blog at www.drjohnm.org, has started an excellent discussion of a recent paper that shows no reduction of mortality with the annual mammogram. He looks at the topic in the context of patient/doctor perception that “doing something” is always better than doing nothing, and the problem of “over-testing.”

In my field of cardiology there is much testing done. It ranges from the (seemingly) benign and (relatively) inexpensive electrocardiogram to the invasive and potentially deadly cardiac catheterization. For the most part, if patients don’t have to pay too much, they won’t question the indication for the tests we cardiologists order. After all, they want to do as much as possible to prevent themselves  from dropping dead from a heart attack and they reason that the more testing that is done, the better, in that regard.

The Problem of False Positives and False Negatives

But all testing has the potential for adverse consequences because of the problem of false positives and negatives. To give just one example: ECGs in people with totally normal hearts are regularly interpreted as showing a prior heart attack. This is a false positive. The test is positive (abnormal) but the person does not have the disease.

12 lead ECG routinely performed prior to surgery and interpreted by computer as ASMI or anteroseptal myocardial infarction ( heart attack).Patient with totally normal heart. Often such false positives are due to poor placement of the ECG leads

False positives lead to unnecessary worry, anxiety, and testing. More testing is highly likely to be ordered; specifically, a stress test. Stress tests in low risk, asymptomatic individuals often result in false positive results. After a false positive stress test, it is highly likely that a catheterization will be ordered. This test carries potential risks of kidney failure, heart attack, stroke and death. It is bad enough that the cascade of testing initiated by an abnormal, false positive,  screening test results in unnecessary radiation, expense and bother but  in some cases it end up killing patients rather than saving lives.

On the other end of the spectrum is the false negative ECG. Most of my patients believe that if their ECG is normal then their heart is OK. Unfortunately the ECG is very insensitive to cardiac problems that are not related to the rhythm of the heart or an acute heart attack.

Patients who have 90% blockage of all 3 of their major coronary arteries and are at high risk for heart attack often have a totally normal ECG. This is a false negative. The patient has the disease (coronary artery disease), but the test is normal. In this situation the patient may be falsely reassured that everything is fine with their heart. The next day when they start experiencing chest pain from an acute heart attack, they may dismiss it as heart burn instead of going to the ER.

More and more, screening tests like the ECG and the mammogram  are rightfully being questioned by patients and payers. For a more extensive discussion about which tests in medicine are appropriate check out the American Board of Internal Medicine’s www.choosingwisely.org.

Keep in mind: not uncommonly,  doing more testing can result in worse outcomes than doing less.

Skeptically Yours,

-ACP

h/t Jerry , the life coach of the skeptical cardiologist , who originally posed this question to me.

 

AfibAlert Versus AliveCor/Kardia: Which Mobile ECG Device Is Best At Accurately Identifying Atrial Fibrillation?

The skeptical cardiologist has been testing the comparative accuracy of two hand-held mobile ECG devices in his office over the last month. I’ve written extensively about my experience with the AliveCor/Kardia (ACK) device here and here. Most recently I described my experience with the Afib Alert (AA) device here.

Over several days I had my office patients utilize both devices to record their cardiac rhythm and I compared the device diagnosis to the patient’s true cardiac rhythm.

Normal/Normal

In 14 patients both devices correctly identified normal sinus rhythm. AFA does this by displaying a green check mark , ACK by displaying the actual recording on a smartphone screen along with the word Normal.

The AFA ECG can subsequently uploaded via USB connection to a PC and reviewed in PDF format. The ACK PDF can be viewed instantaneously and saved or emailed as PDF.

 

Normal by AFA/Unreadable or Unclassified by AliveCor

In 5 patients in normal rhythm (NSR) , AFA correctly identified the rhythm but ACK was either unreadable (3) or unclassified (2). In the not infrequent case of a poor ACK tracing I will spend extra time adjusting the patient’s hand position on the electrodes or stabilizing the hands. With AFA this is rarely necessary.

In this 70 year old man the AFA device recording was very good and the device immediately identified the rhythm as normal.

Chaput AFA SR

ACK recording was good quality but its algorithm could not classify the rhythm.

GC Unclassified

A 68 year old man who had had bypass surgery and aortic valve replacement had a very good quality AFA recording with correct classification as NSRChaput AFA SR

AliveCor/Kardia recordings on the same patient despite considerable and prolonged efforts to improve the recording were poor and were classified as “unreadable”

Scott AC unreadable
Alivecor tracing shows wildly varying baseline with poor definition of p wave

 

False Positives

There were 3 cases were AFA diagnosed atrial fibrillation (AF) and the rhythm was not AF. These are considered false positives and can lead to unncessary concern when the device is being used by patients at home. In 2 of these ACK was unreadable or unclassified and in one ACK also diagnosed AF.

A 90 year old woman with right bundle branch block (RBBBin NSR was classified by AFA as being in AF.

VA AFA read as AF
Slight irregularity of rhythm combined with a wider than normal QRS from right bundle branch block and poor recording of p waves likely caused AFA to call this afib
VA unclassified RBBB
AliveCor tracing calls this unclassified. The algorithm does not attempt to classify patients like this with widened QRS complexes due to bundle branch block.

The ACK algorithm is clearly more conservative than AA. The ACK manual states:

If you have been diagnosed with a condition that affects the shape of your EKG (e.g., intraventricular conduction delay, left or right bundle branch block,Wolff-Parkinson-White Syndrome, etc.), experience a large number of premature ventricular or atrial contractions (PVC and PAC), are experiencing an arrhythmia, or took a poor quality recording it is unlikely that you will be notified that your EKG is normal.

 

One man’s rhythm confounded both AFA and AC. This gentleman has had atrial flutter in the past and records at home his rhythm daily using his own AliveCor device which he uses in conjunction with an iPad.IMG_8399.jpg

During our office visits we review the recordings he has made. He was quite bothered by the fact that he had several that were identified by Alivecor as AF but in fact were normal.

Screen Shot 2017-05-06 at 11.48.47 AM
These are recordings Lawrence made at home that i can pull up on my computer. He makes a daily recording which he repeats if he is diagnosed with atrial fibrillation. In the two cases above of AF a repeat measurement was read as normal. Of the two cases which were unclassified , one was normal with APCs and the other was actually atrial flutter

A recording he made on May 2nd at 845 pm was read as unclassified but with a heart rate of 149 BPM. The rhythm is actually atrial flutter with 2:1 block.

Screen Shot 2017-05-06 at 11.47.37 AM

Sure enough, when I recorded his rhythm with ACK although NSR (with APCS) it was read as unclassified

Screen Shot 2017-05-06 at 11.49.49 AM

AFA classified Lawrence’s rhythm as AF when it was in fact normal sinus with APCs.

AFA Mcgill AF

 

 

One patient a 50 year old woman who has a chronic sinus tachycardia and typically has a heart rate in the 130s, both devices failed.

We could have anticipated that AC would make her unclassified due to a HR over 100 worse than unclassified the tracing obtained on her by AC (on the right)was terrible and unreadable until the last few seconds. On the other hand the AFA tracing was rock solid throughout and clearly shows p waves and a regular tachycardia. For unclear reasons, however the AFA device diagnosed this as AF.

 

 

Accuracy in Patients In Atrial Fibrillation

In 2/4 patients with AF, both devices correctly classified the rhythm..

In one patient AFA correctly diagnosed AF whereas ACK called it unclassified.

This patient was in afib with HR over 100. AFA correctly identified it whereas ACK called in unclassified. The AC was noisy in the beginning but towards the end one can clearly diagnose AFScreen Shot 2017-05-06 at 8.39.06 AMScreen Shot 2017-05-06 at 8.11.53 AM

In one 90 year old man AFA could not make the diagnosis (yellow)

Screen Shot 2017-05-06 at 11.35.40 AM

ACK correctly identified the rhythm as AF

Screen Shot 2017-05-06 at 11.37.51 AM

One patient who I had recently cardioverted from AF was the only false positive ACK. AliveCor tracing is poor quality and was called AF whereas AFA correctly identified NSR>

Screen Shot 2017-05-06 at 8.42.46 AMScreen Shot 2017-05-06 at 8.42.26 AM

 

 

Overall Accuracy

The sensitivity of both devices for detecting atrial fibrillation was 75%.

The specificity of AFA was 86% and that of ACK was 88%.

ACK was unreadable or unclassified 5/26 times or 19% of the time.

 

The sensitivity and specificity I’m reporting is less than reported in other studies but I think it represents more real world experience with these types of devices.

Summary

In a head to head comparison of AFA and ACK mobile ECG devices I found

-Recordings using AfibAlert are usually superior in quality to AliveCor tracings with a minimum of need for adjustment of hand position and instruction.

-This superiority of ease of use and quality mean almost all AfibAlert tracings are interpreted whereas 19% of AliveCor tracings are either unclassified or unreadable.

-Sensitivity is similar. Both devices are highly likely to properly detect and identify atrial fibrillation when it occurs.

-AliveCor specificity is superior to AfibAlert. This means less cases that are not AF will be classified as AF by AliveCor compared to AfibAlert. This is due to a more conservative algorithm in AliveCor which rejects wide QRS complexes, frequent extra-systoles.

Both companies are actively tweaking their algorithms and software to improve real world accuracy and improve user experience but what I report reflects what a patient at home or a physician in office can reasonably expect from these devices right now.

-ACP

Paranoid Rumination From A Freshly-Minted Migraineur

As I sit here writing, I perceive a scintillating band of zig-zags in the shape of a reverse C on the left side of my visual field. I sense the scintillating reverse C with either, or both eyes closed, and I first noted it when the letters in the New Yorker article I was reading became obscured by the C. Attempts to focus on the crescent are futile:  it moves as I move my eyes or head. Within its body are vague browns, blacks and whites, and overall it is reminiscent of an Egyptian or Art Deco piece of art.

I have a friend in Brooklyn, a flaneur, and one in Florida, a raconteur; I have now become a migraineur: one who suffers from migraine headaches or, in my case, the visual or tactile hallucinations known as migraine aura that precede the headaches.

I go to my bookshelf and find Oliver Sacks’ book “Migraine: Understanding a Common Disorder, which I purchased long ago when I was not a migraineur (primarily to complete my collection of Sacks’ unique and brilliant writing).  On page 62, figure 2b, I find a drawing which closely approximates what I’m “seeing.”

An artistic depiction of migraine aura which was similar to mine. Original source is unclear.

I had asked Siri to start the timer on my Apple watch when I first noticed the visual disturbance, and now note that at 16 minutes 32 seconds, my vision was back to normal. At 25 minutes 16 seconds, I experienced a very subtle ache in my left frontal region which persisted for 5 minutes.

I have observed patients with severe migraine headaches: suffering from nausea, intense pain, photosensitivity and requiring dark and sleep and powerful analgesics to cause remission. I am fortunate because my after-aura headaches, if any, are minimal and brief.

The first time I experienced the visual hallucination was five years ago. I was not blogging then, but made a detailed note of the experience, complete with paranoid rumination on brain testing and side effects of MRIs. What follows is the transcript with the comments of the present day skeptical cardiologist in green or red.

“I had a crazy day Thursday. I gave a talk to the echo lab from 7 to 8 AM and then rushed over to the hospital to see the most urgent of the 9 inpatients I had. I had seen 4 patients by the time I got paged to see my first patient in the office. I headed over there and saw 6 patients . Then I hurried back to the hospital to grab the EKGs I was supposed to read that day. I was a little stressed because I needed to read these and try to see more of my inpatients before heading over to the outpatient testing facility which I had to be at by 1230 to supervise stress testing. I sat down in my hospital office and started reading the EKGs. After I had read a few, I became aware of a defect on the left side of my vision. It felt like when you have looked at a bright light and it leaves a residual on your retina.
At first I thought it was due to the fact that i was reading the EKGs with only the desk lamp on my left on. I turned on the overhead light and it didn’t help. I then realized that I had a hockey puck shaped defect in my left visual field in both eyes. When the defect covered key portions of the EKG, I couldn’t read it. It was filled with a jagged, prism like filling. Otherwise I felt fine. My first thought was that I was having a scintillating scotoma and that this was a migraine aura. Other things seemed much less likely-TIA for example. I called Dr S, my favorite neurologist, on his cell phone and told him what was going on. He suggested I visit him in his office right then. His office was in 400 East which would necessitate a right turn from my office. Instead, I took a left turn down to the West office building, took the elevator up to the fourth floor and finally realized my mistake when all I could find were office numbers that ended in W. (At the time young Dr. P felt this disorientation was related to the aura but perhaps it was due to distraction) By the time I reached his office twenty minutes after the visual symptoms started, they had resolved.
Dr. S did a neuro exam and history, and concluded that I most likely had a migraine aura but thought that I should get an MRI to be certain there was no structural brain disease. After I left his office I began feeling slightly nauseated with a slight headache. Over the next two hours the headache became a moderate frontal headache associated with a sense of fatigue.
I got the MRI yesterday and Dr. S thinks it is normal, although the radiologist read it as showing small subcortical defects which could be consistent with “chronic migraine, small vessel disease, or demyelinating process.”
I almost didn’t get the MRI. This is one of the classic situations in medicine where the history and physical alone makes the diagnosis with near certainty (young Dr. P is correct, see what Choosing Wisely says here), but because a very small number of cases might have something more serious (a brain tumor or vascular lesion in this case ), (perhaps also fueled by medical legal concerns and patient’s love of fancy tests) an expensive imaging test is ordered.
If you took 1000 people with my symptoms and the normal neuro exam with low atherosclerotic risk factors, and did brain MRIs on them, the vast majority of findings would be incidental, probably false positives (I believe young Dr. P made up this statistic but the national migraine center in the UK says :

“The main problem with MRI scans is ‘looking for a shilling and finding a sixpence,’ in finding abnormalities that are unrelated to headache, entirely by chance. The risk of a minor abnormality of no medical significance is 1 in 4. The risk of a chance abnormality that might need treatment is about 1 in 40. Once these ‘incidentalomas’ have been found, the patient may then find it difficult to obtain insurance (for example travel) and there is often a temptation to repeat the scan time and time again to check that the ‘incidentaloma’ is not changing..)

False positives lead to unnecessary anxiety in patients and in some cases unnecessary testing (Dr. S told me that he sees tons of patients who have had normal MRIs with readings similar to mine who are convinced they have MS) (MS=multiple sclerosis, a demyelinating process. Although my MRI was read as having abnormalities possibly due to a “demyelinating process” I must not have had one because  6 years later I have had no other symptoms)) and in some cases unnecessary additional testing.

As I was lying in the MRI gantry listening to the “ratatat “of the scanner, I wondered if we really know the consequences of rearranging the molecules of brain tissue with giant magnetic fields.
Dr. S  had ordered the MRI with gadolinium. I recalled seeing adds from law firms seeking “victims” of MRI scans (one man was awarded 5 million dollars after developing nephrogenic systemic fibrosis after one dose of gadolinium (NSF). I knew that gadolinium had been linked to some really serious disorders. The tech had said nothing to me about adverse effects of the “dye” she would be using. My nose began itching like crazy, then my left eyelid. I couldn’t scratch until I emerged from the scanner. After the initial images were done and I was brought out of the scanner, I scratched my face like crazy and asked the tech if there were any side effects from gadolinium.
“Why yes, she said, you can have severe allergic reactions,” but we’ve only had a couple.” Also, she said, there is some disorder… she couldn’t remember the name or what it did but knew that it was only a problem if you had kidney failure or had diabetes and were over the age of 60.
As I was lying in the scanner after receiving the gadolinium, I began trying to estimate what risk I would be willing to assume in this situation. The disease you can get if you have severely impaired kidney function and receive gadolinium is nephrogenic systemic fibrosis.
Would I accept a 1 in 1/1000 chance of NSF in exchange for diagnosing something other than migraine 1/1000 times? I couldn’t and can’t easily and logically make that call. I have no idea how patients can make these decisions.

Cephalgiacally  Yours

-ACP

Here’s a video of an aura similar to mine (one of many posted at visual migraine animation)

Migraine experiences have served as a major source of artistic inspiration in both past and contemporary painters, sculptors, film-makers and other visual artists. Check some of their work out at migraine aura foundation.

 

 

 

Are Your Palpitations Due to Benign PVCs?

If you feel your heart flip-flopping, then you are experiencing palpitations: a sensation that the heart is racing, fluttering, pounding, skipping beats or beating irregularly.

Often, this common symptom is due to an abnormal heart rhythm or arrhythmia.

The arrhythmias that cause palpitations range from common and benign to rare and lethal, and since most individuals cannot easily sort out whether they have a dangerous or a benign problem, they often end up getting cardiac testing or cardiology consultation.

The most common cause of palpitations, in my experience, is the premature ventricular contraction, or PVC (less commonly known as the ventricular ectopic beat or VEB).

Premature Ventricular Contractions-Electrical Tissue Gone Rogue

The PVC occurs when the ventricles of the heart (the muscular chambers responsible for pumping blood out to the body) are activated prematurely.

This video shows the normal sequence of electrical and subsequent mechanical activation of the chambers of the heart.

To get an efficient contraction, the electrical signal and contraction begins in the upper chambers, the atria, and then proceeds through special electrical fibers to activate the left and right ventricles.

Sometimes this normal sequence is disrupted because a rogue cell in one of the ventricles becomes electrically activated prior to getting orders from above. In this situation, the electrical signal spreads out from the rogue cell and the ventricles contract out of sequence or prematurely.

This results in a Premature Ventricle Contraction.

labeled-pvc
p waves represent depolarization and activation of the atria which are followed normally after120 to 200 milliseconds by the QRS complex which represents activation of the ventricles. The PVC (inside red circle) is wider and weirder and disrupts the regular interval between beats (green lines).

I recorded the above AliveCor tracing in my office on a patient who suffers palpitations due to PVCs (we’ll call her Janet).

The wider, earlier beat (circled in red) in the sequence is the PVC. The prematurity of the PVC means that the heart has not had the appropriate time to fill up properly. As a result, the PVC beat pumps very little blood and may not even be felt in the peripheral pulse. Patients with a lot of PVCs, say ocurring every other beat in what is termed a bigeminal pattern, often record an abnormally slow heart rate because only one-half of the heart’s contractions are being counted.

While recording this, every time Janet felt one of her typical “flip-flops,” we could see that she had a corresponding PVC and the cause of her symptoms was made clear.

There is a pause after the PVC because the normal pacemaker of the heart up in the right  atrium (the sinus node) is reset by electrical impulses triggered by the PVC.. The beat after the PVC is more forceful due to a more prolonged time for the ventricles to fill and  Consequently, most  patients feel this pause after the PVC rather than the PVC itself,

PVCs are common and most often benign. I have patients who have

ECG from 70 year very vigrous man who had 20 thousand PVCs in 24 hours. Every third beat is a PVC (green arrow)
ECG from 70 year old very vigorous man who had 20 thousand PVCs in 24 hours. Every third beat is a PVC (green arrow PVC, blue arrow normal QRS.)This patient feels nothing with his frequent PVCs. He has had them probably lifelong and definitely for the last 10 years without any adverse consequences.

thousands of them in a 24-hour period and feel nothing. On the other hand, some of my patients suffer disabling palpitations from very infrequent PVCs. From an electrical or physiologic standpoint, there seems to be neither rhyme nor reason to why some patients are exquisitely sensitive to premature beats.

How Do I Know If My PVCs Are Benign?

My patient, Janet, is a great example of how PVCs can present and how inappropriate or inaccurate heart tests done to evaluate PVCs can lead to anxiety and unnecessary and dangerous subsequent testing.

A year ago,  Janet began experiencing a sensation of fluttering in her chest that appeared to be random. Her general practitioner noted an irregular pulse and obtained an ECG, which showed PVCS. He ordered two cardiac tests for evaluation of the palpitations: a Holter monitor and a stress echo.

A Holter monitor consists of a device the size of a cell phone connected to two sensors or electrodes that are stuck to the skin of the chest area. The electrical activity of the heart is recorded for 24 or 48 hours, and a technician then scans the entire recording looking for arrhythmias while trying to correlate any symptoms the patient recorded with arrhythmias. The Holter allows us to quantitate the PVCs and calculate the total number of PVCs occurring either singly or strung together as couplets (two  in a row), or triplets (three in a row.)

Janet’s Holter monitor showed that over 24 hours her heart beat  around 100,000 times with around 2500 PVCs during the recording.  Unfortunately, the report did not mention symptoms, so it was not possible to tell from the Holter if the PVCs were the cause of her palpitations.

A stress echocardiogram combines ultrasound imaging of the heart before and after exercise with a standard treadmill ECG. It is a very reasonable test to order in a patient with palpitations and PVCs, as it allows us to assess for any significant problems with the heart muscle, valves or blood supply and to see if any more dangerous rhythms like ventricular tachycardia occur with exercise. If it is normal, we can state with high certainty that the PVCs are benign.

Benign, in this context, means the patient is not at increased risk of stroke, heart attack, or death due to the PVCs.

In the right hands, a stress echocardiogram is superior to a stress nuclear test for these kinds of assessments for three reasons:

-Reduced rate of false positives (test is called abnormal, but the coronary arteries have no significant blockages)

-No radiation involved (which adds to costs and cancer risk)

-The echocardiogram allows assessment of the entire anatomy of the heart, thus detecting any thickening (hypertrophy), enlargement  or weakness of the heart muscle, that would mean the PVCs are potentially dangerous.

Unfortunately, my patient’s stress echo (done at another medical center) was botched and read as showing evidence for a blockage when there was none.  An invasive and potentially life-threatening procedure, a cardiac catheterization was recommended.  Similar to the situation I’ve pointed out with the performance and interpretation of echocardiograms (see here),  there is no guarantee that your stress echo will be performed or interpreted by someone who actually knows what they are doing.  So, although the stress echo in published studies or in the hands of someone who is truly expert in interpretation, has a low yield of false positives, in clinical practice the situation is not always the same.

Given that Janet was very active without any symptoms, she balked at getting the catheterization and came to me for a second opinion. I felt the stress echo was a false positive and did not feel the catheterization was warranted. We discussed alternatives, and because Janet needed more reassurance of the normality of her heart (partially because her father had died suddenly in his sixties) and thus the benignity of her palpitations/PVCs, she underwent a coronary CT angiogram instead. This noninvasive exam (which involves IV contrast administration, and is different from a coronary calcium scan), showed that her coronary arteries were totally normal.

lad-ccta
Images from Janet’s coronary CT angiogram showing the left anterior descending (LAD) coronary artery coming off the aorta. The LAD (and her other coronaries) were totally free of any plaque build-up.)

Benign PVCs-Treatment Options

Once we have demonstrated that the heart is structurally normal, reassurance is often the only treatment that is needed.  Now that the patient understands exactly what is going on with the heart and that it is common and not dangerous, they are less likely to become anxious when the PVCs come on.

PVCS can create a vicious cycle because the anxiety they provoke can cause  an increase in neurohormonal factors (catecholamines/adrenalin) that may increase heart rate , make the heart beat stronger and increase the  frequency of the PVCs.

Some patients, find their PVCs are triggered by caffeine (tea, soda, coffee, chocolate) or stress, and reducing or eliminating those triggers helps greatly. Others, like Janet, have already eliminated caffeine, and are not under significant stress.

Since I’m already over a thousand words in this post, I’ll discuss treatment options for these patients with benign PVCs who continue to have troubling symptoms after reassurance and caffeine reduction in a subsequent post.

Prematurely Yours,

-ACP

 

Shoddy Cardiovascular Screenings Are More Likely to Cause Harm Than Good

I was recently made aware, by one of my patients, of a brochure from one of the large hospital chains in the St. Louis area  that advertised “healthy heart screenings.” The website for this enterprise says the following:

Healthy Heart Screenings

In partnership with Health Fair, SSM Health Care will utilize a mobile clinic that will travel around the St. Louis area approximately 16 times per month. Screenings range from basic biometrics to cardiovascular.

Basic test package ($179) includes:
Echocardiogram Ultrasound
Stroke / Carotid Artery Ultrasound
Abdominal Aortic Aneurysm Ultrasound
Electrocardiogram (EKG)
Peripheral Arterial Disease (PAD) Test
Hardening of the Arteries Test (ASI)

Steven Nissen has discussed the dangers of these types of screenings in an article for Cardiosource.org (the online voice of the American College of Cardiology)  entitled “Screenings and Executive Physicals: Hazardous to Your Health.”

Being proactive about cardiovascular health is generally considered to be a good thing, however, these types of screenings have the potential for doing more harm than good.

First off, individuals should recognize that this service is being offered by hospital systems solely for the purpose of getting more patients into their system for further testing and procedures.

Secondly, the service is being performed by a “mobile clinic.” These types of mobile clinics typically exist to make as much money as they can. Quality control is not one of their goals. They seek high volume , rapid throughput and minimal expenses. The mobile clinic is most likely utilizing the cheapest equipment, technicians  and interpreters of these studies that they can get.

Cheap equipment and inexperienced or poorly trained technicians are more likely to yield studies which are difficult to interpret or introduce errors and artifacts. Artifacts in an imaging study are images which appear to be abnormalities but are not. The more artifacts in a study, the more inappropriate subsequent testing will most likely be performed.

One of the tests offered in this package is an ultrasound of the heart or echocardiogram. The echocardiogram is a brilliant technological development that allows us to image the structure and function of the heart. Abnormalities ranging from weakness in the pump function of the heart to leakage from the valves can very accurately be diagnosed with echocardiography when it is done right.  I have devoted a large part of my career to studying, writing about and insuring quality control in echocardiography and I have seen first hand many misdiagnoses made in the hands of the inexperienced, shoddy, greedy or unscrupulous.

Let’s consider the many ways a poorly done or interpreted echocardiogram can lead to more harm than good.

Overcalling valve problems

In addition to imaging the structure or anatomy of the heart, during an echocardiogram a technique called Doppler allows us to measure the direction, velocity and location of blood flow within the heart. Doppler, developed in the 1980s, allows us, among other things, to see if the heart valves are doing their job of allowing blood to move forward while preventing back flow. In many normal individuals, a small or trivial  amount of back flow (called regurgitation or insufficiency) can be noted. The honest, experienced cardiologist will recognize this as normal. However, if the study is performed ineptly and misread, a normal individual could be mislabeled as having a significant heart valve problem leading to unnecessary stress and anxiety and the potential for additional inappropriate and potentially dangerous testing.

This might seem like just a theoretical concern, but in the 2000s as part of a settlement with the drug company Wyeth, the maker of Fen-Phen, hundreds of thousands of patients who had taken Fen-Phen for weight loss were screened by echocardiography to look for valve problems.  Thousands of individuals with normal hearts were diagnosed with significant valvular problems after undergoing echocardiography examinations set up by the lawyers engaged in the suit. These exams were often done in hotel suites and some cardiologists made millions reading thousands of these in a short period of time. Forbes has a good summary of the scandal entitled the $22 Billion Gold Rush  here. To quote:

“Material misrepresentations” amounting to “pervasive fraud” drove 70% of the serious claims that were found payable by the Wyeth trust fund, says Joseph Kisslo, a court-appointed cardiologist who reviewed a sample of 1,000 echocardiograms in late 2004. “Thousands of people have been defrauded into believing that they have valvular heart disease when in fact they do not,” Kisslo said in a report he wrote for the trust.

I saw a number of patients who had been identified by these shoddy echocardiograms as having significant valve problems and were convinced they had serious heart problems. After I obtained and reviewed the echocardiograms I was able to reassure the patients that their hearts were normal.

Misdiagnosing the function of the heart

The echocardiogram is our premier tool for looking at how the main pumping chamber or left ventricle (LV) is working. A left ventricle that is not functioning properly leads to heart failure. The LV fills with oxygen-rich blood from the lungs when it is relaxed (diastole) and then contracts (systole) and pumps the blood out into the aorta and to the rest of the body. Precise and well-made recordings and measurements of the blood flow during diastole allow the knowledgeable cardiologist to interpret how well the heart is functioning during diastole. Similarly, recordings of the LV allow interpretation of function during systole.

Misinterpretation of both the systolic and diastolic function of the heart are common in echocardiograms that are done by inexperienced sonographers and/or cardiologists.

Misinterpretation of artifacts

Due to various technical factors (outlined in detail here), a normal heart imaged by echocardiography may appear to have an abnormality. These artifacts are more likely due to poor quality equipment and inexperienced or incompetent sonographers. The more experienced the cardiologist reading the study, the less likely that these will be interpreted as pathology.

I have encountered numerous examples of what are normal variations of the heart anatomy or artifacts read on echocardiograms as possible tumors or clots or masses within the heart. Patients invariably end up getting unnecessary testing or surgery when such misdiagnoses are made; they also experience unnecessary stress and worry.

Making Sure You Get a Good Echocardiogram

If you are undergoing an echocardiogram, whether it be for screening which I (and the American Heart Association and the American College of Cardiology) do not recommend or for an appropriate indication (see here for appropriate indications), then it is in your best interest for you to make sure that the test is done and interpreted optimally.

Ideally, your test is being done by a sonographer who has undergone a recognized training program and is credentialed as a Registered Diagnostic Cardiac Sonographer (RDCS by the American Registry of Diagnostic Sonographers) or a Registered Cardiac Sonographer (RCS by the Cardiovascular Credentialing International).

Your echocardiogram should be done in a facility which has been certified by the Intersociety Accreditation Committee for Echocardiography (ICAEL). This will insure that the equipment, personnel , reports and interpretations are meeting minimal standards and that there is in place an ongoing program of quality assessment.

Your echocardiogram should be interpreted by a cardiologist who has undergone appropriate training in echocardiography and is staying up to date with the latest technology and information in the area. ICAEL certification of the lab will verify this to some extent. Even better, is a cardiologist who is Board Certified in Echocardiography.

In summary, don’t pay for an echocardiogram done by a mobile lab as part of a cardiovascular screening program no matter where it is performed or who is promoting it.  Although you may think you are being proactive about your health, chances are you will be more harmed than helped by the outcome.

 

Should You Get a Routine Annual Electrocardiogram (ECG)?

Recently, the skeptical cardiologist  was asked by his  old friend and life coach (OFALCSC) whether he was correct to refuse the annual electrocardiogram (ECG) which his primary care doctor had recommended during an annual physical.

ECG showing atrial fibrillation
ECG showing atrial fibrillation

Most of my patients feel that the ECG has the ability to tell me  quite a bit about their heart. The technique utilizes electrodes on the arms, legs and chest region which  record with precision, the depolarization and repolarization of the upper chambers (atria) and lower chamber (ventricles) of the heart.

The ECG is THE tool for assessing the rhythm of the heart.  If performed and interpreted properly (not always a given) it tells us very precisely whether we are in normal (sinus) rhythm, wherein the atria contract synchronously before the ventricles contract, or in an abnormal rhythm. It is also very good at telling us whether you are having a heart attack.

If you are, however, like the OFALSC, and feel fine (meaning without symptoms or asymptomatic), exercise regularly, have never had heart problems,  and have a pulse between 60 and 90, the value of the routine annual ECG is very questionable. In fact, the United States Preventive Services Task Force (USPFTF)

“recommends against screening with resting or exercise electrocardiography (ECG) for the prediction of coronary heart disease (CHD) events in asymptomatic adults at low risk for CHD events”

(for asymptomatic adults at intermediate or high risk for CHD they deem the evidence insufficient). The USPSTF feels that that the evidence only supports an annual BP screen along with measurement of weight and a PAP smear.

To many, this seems counter-intuitive: how can a totally benign test that has the potential to detect early heart disease or abnormal rhythms not be beneficial?

There is a growing movement calling for restraint and careful analysis of the value of all testing that is done in medicine. Screening tests, in particular are coming under scrutiny.
Even the annual mammogram, considered by most to be an essential tool in the fight against breast cancer, is now being questioned.

My former cardiology partner, Dr. John Mandrola, who writes the excellent blog at www.drjohnm.org, has started an excellent discussion of a recent paper that shows no reduction of mortality with the annual mammogram. He looks at the topic in the context of patient/doctor perception that “doing something” is always better than doing nothing, and the problem of “over-testing.”

In my field of cardiology there is much testing done. It ranges from the (seemingly) benign and (relatively) inexpensive electrocardiogram to the invasive and potentially deadly cardiac catheterization. For the most part, if patients don’t have to pay too much, they won’t question the indication for the tests we cardiologists order. After all, they want to do as much as possible to prevent themselves  from dropping dead from a heart attack and they reason that the more testing that is done, the better, in that regard.

The Problem of False Positives and False Negatives

But all testing has the potential for negative consequences because of the problem of false positives and negatives. To give just one example: ECGs in people with totally normal hearts are regularly interpreted as showing a prior heart attack. This is a false positive. The test is positive (abnormal) but the person does not have the disease. At this point, more testing is likely to be ordered; specifically, a stress test. Stress tests in low risk, asymptomatic individuals often result in false positive results. After a false positive stress test, it is highly likely that a catheterization will be ordered. This test carries potential risks of kidney failure, heart attack, stroke and death. It is bad enough that the cascade of testing initiated by an abnormal, false positive,  screening test results in unnecessary radiation, expense and bother but  in some cases it end up killing patients rather than saving lives.

On the other end of the spectrum is the false negative ECG. Most of my patients believe that if their ECG is normal then their heart is OK. Unfortunately the ECG is very insensitive to cardiac problems that are not related to the rhythm of the heart or an acute heart attack.

Patients who have 90% blockage of all 3 of their major coronary arteries and are at high risk for heart attack often have a totally normal ECG. This is a false negative. The patient has the disease (coronary artery disease), but the test is normal. In this situation the patient may be falsely reassured that everything is fine with their heart. The next day when they start experiencing chest pain from an acute heart attack, they may dismiss it as heart burn instead of going to the ER.

More and more, screening tests like the ECG and the mammogram  are rightfully being questioned by patients and payers. For a more extensive discussion about which tests in medicine are appropriate check out the American Board of Internal Medicine’s www.choosingwisely.org.

Keep in mind: not uncommonly,  doing more testing can result in worse outcomes than doing less.