Tag Archives: cycling

I’m Having Chest Pain: Is It a Heart Attack?

IMG_4219I can tell you exactly when the pain started. I was riding  my bike in Forest Park, the great urban park of St. Louis. Ordinarily, I cycle from my house to the park, cutting across the  ivy-covered semi-Ivy league campus of nearby Washington University and circling its beautiful acres on a recently refinished bike path.

As I started the slow incline that parallels Skinker Avenue just West of Forest Park, a cyclist flashed past me. I could swear he said “Oh dear, oh dear. I shall be late.”

Instead of continuing straight along the bike path, the late cyclist suddenly veered to the left, following a heretofore untraveled spur that led up into the dark, impenetrable forests of the park.

At this point, the sensible, sixty-something portion of my psyche should have taken over and had me continue on the relatively straight, flat and well-traveled road that I had grown accustomed to. Alas, it was the teenage boy who took control and insisted on us taking the road less traveled.

The spur of the bike path had not been regularly maintained and there were numerous rough spots: ridges and chasms emerged with disconcerting frequency as I progressed.

The lure of exploration pulled me on. I kept my speed up as I descended a hill with the path turning sharply to the right. Suddenly an even sharper right turn emerged with a particularly uneven section of path. I lost control of the bike and landed heavily on my left side.

I felt a sudden sharp pain just to the left of my breastbone about midway in my chest.

As a cardiologist I spend a lot of time talking to people about chest pain and thinking about what is causing it.

The heart is in the chest and it is natural to believe that pain that comes from this area could be a manifestation of the dreaded heart attack. Since heart attacks are the #1 killer of both men and women  and they can very quickly lead to life-threatening arrhythmias it is wise to take seriously  any pain in the chest.

Three Types of Chest Pain

I was trained to sort what patient’s described to me about their chest pain  into three bins: Typical anginal pain, atypical anginal pain and non cardiac pain.

Angina is doctor-speak for chest pain that is due to the heart muscle not getting enough blood (usually due to a blocked coronary artery)

Cardiologists consider any discomfort from the lower ribs up to the bottom of the neck as chest pain although patients often don’t perceive it as a pain.

Heart attack pain often feels like a pressure, a heaviness or a burning and in addition to somewhere in the anterior chest region it can manifest in the neck or jaw or one or both of the upper arms.

My chest pain was  worse  when I took a deep breath (pleuritic) and this almost always indicates a lung cause or inflammation in the muscle/bones/joints that are related to breathing. Furthermore, pushing on the ribs  made it worse making it virtually certain that it was musculoskeletal.

A brief (well done) history and physical exam therefore would assign my chest pain to the “non cardiac” bin.

Typical anginal pain is brought on by exertion, lasts 3-15 minutes and is relieved by nitroglycerin or rest.

pretest likelikhood cadThe probability of a patient with non cardiac chest pain having significantly blocked coronary arteries is generally lower than that of a patient with typical anginal pain. However, as this chart demonstrates, patients (generally those with significant risk factors) can have severely blocked coronary arteries and have non cardiac chest pain.

For example, I have risk factors of age (>55 years), being male, hyperlipidemia and hypertension. A cardiac catheterization done on me at the time of my non cardiac chest pain might well show significantly blocked coronary arteries. Of course, these blocked arteries would have absolutely nothing to do with my pain.

This fundamental paradox is the source of a lot of the overtesting and over treatment that occurs in cardiology. Most of the time, chest pain that prompts a patient to come to the ER or doctor’s office does not fall easily into the non cardiac category or the typical anginal category: these are the atypical anginal patients.

Additional testing is required , progressing from EKGS and cardiac enzymes to stress testing to cardiac catheterization. If there are elevation of the cardiac enzymes or abnormalities of the EKG that indicate a recent or active heart attack then a cardiac catheterization is warranted because it is very highly likely that a tightly blocked coronary artery is the cause and opening that artery will be beneficial.

However, most patients have normal cardiac enzymes and unremarkable EKGS and can end up getting catheterizations (due to either  inaccurate stress tests or cardiologist’s recommendation) that they don’t need.

Once a catheterization is done, patients may then get a stenting procedure on a blocked coronary artery that wasn’t causing any problems. Not uncommonly, multiple blocked coronary arteries are found and the patient is rushed off to have a bypass operation. If the blocked arteries weren’t the cause of the patient’s chest pain (i.e. the pain was non cardiac) these procedures are likely doing more harm than good.

When To Go To ER With Chest Pain

I’ve spent thirty years fielding after hours telephone calls from patients who are having  chest pain.

It is not easy to make a reliable determination of who is likely having a heart attack or other potentially dangerous cardiac problem and who is not just based on the history.

If a patient called me describing what I described above I would likely advise him to go to the ER for evaluation (although I would be pretty sure it wasn’t a heart attack: sometimes rib fractures are associated with collapsed lungs or hemorrhage into the pleural space and sometimes trauma to the chest can cause heart damage). It’s always better to err on the side of caution when were’ dealing with potentially life-threatening problems.

After office hours, the only way to get an electrocardiogram and cardiac enzymes to be sure that the chest pain is or is not a heart attack is to go to an ER. Generally, if the patient has escalated the level of concern to calling the on call cardiologist, the symptoms are worrisome.

The bottom line for me is that you only get one chance to die (You only die once (YODO)

If you’re having a heart attack at any second your heart can go into ventricular tachycardia or ventricular fibrillation and you will die within minutes.

Thus, I have to have a very low threshold for advising trips to the ER. If I’m wrong, the patient  could die.

I didn’t go to the ER because I was 100% certain that my chest  pain was non cardiac. I’m also a doctor and therefore a very bad patient. I survived, however, and over several weeks the pain gradually subsided.

As a result of this fall (and several other bike falls I’ve had in the last few years) I’ve re-evaluated my cycling. I’m going to stay on very well-maintained paths and slow way down when the going gets rough.

Hopefully, this will allow me to continue the cycling which I’m convinced is helping to prevent me from visiting the ER with a true heart attack!

Skeptically Yours

-ACP

Urban Cycling Part I: Does Biking To Work Make You More or Less Likely to Die?

5Boro Bike Riders crossing the summit of the Queensboro aka 59th Street aka "Feelin Groovy" Bridge
5Boro Bike Riders crossing the summit of the Queensboro aka 59th Street aka “Feelin Groovy” Bridge. For some reason the significant other of the skeptical cardiologist (SOSC) has decided to stop here to look at her cell phone, thereby creating a traffic hazard.

The skeptical cardiologist recently participated in the 5 Boro New York City Bike Tour. It was quite cool.

This annual event allows 32,000 bike riders to stream from Manhattan to the Bronx to Queens, Brooklyn and Staten Island along 40 miles of traffic-free (except for thousands of cyclists) roads

Unlike my previous rides in Brooklyn and Manhattan (under the guidance of legendary Park Slope flaneur, NYC biking advocate, and old high school chum David Alquist) I was not in constant peril from automobile encounters because we cyclists had the mean streets of New York all to ourselves.

Take a look at this video to understand “why cyclists come from around the world for an experience of the Big Apple unlike any other”.

Urban Cycling as Transportation

The NYC event, and the fact that this is “bike to work week,” lead me to ponder aspects of urban bike riding, specifically, cycling as transportation.  Since cycling is physical exercise and there is scientific evidence (observational studies only) linking regular physical activity to a significant cardiovascular risk reduction, we might expect that it would help us live longer. 

A reasonable physical activity goal , endorsed by most authorities,  is to engage in moderate-intensity aerobic physical activity for a minimum of 30 min on 5 days each week or vigorous-intensity aerobic activity for a minimum of 20 min on 3 days each week. This level of exercise helps with weight control, fitness and is associated with lower mortality from cardiovascular disease .

METS:calories
METs and calories consumed per hour for various physical activities

The metabolic equivalent of task (MET) is a measure of the energy cost of physical activity. The chart to the left gives METs for various activities.  Individuals should be aiming for 500–1,000 MET min/week. Leisure cycling or cycling to work (15 km/hr) has a MET value of 4 and is characterized as a moderate activity  A person shifting from car to bicycle for a daily short distance of 7.5 km would meet the minimum recommendation (7.5 km at 15 km/hr = 30 min) for physical activity in 5 days (4 MET × 30 min × 5 days = 600 MET min/week).

 

Thus, cycling to work for many individuals would provide the daiy physical activity that is recommended for cardiovascular benefits. However, cycling in general, and urban cycling in particular, carries a significant risk of trauma and death from accidents and possibly greater exposure to urban pollutants.

bikversuscardeaths
from CBS (Statistics Netherlands) Traffic and Transport, 2008

This table shows the estimated numbers of traffic deaths per age category per billion passenger kilometers traveled by bicycle and by car (driver and passenger) in the Netherlands for 2008. These data suggest that there are about 5.5 times more traffic deaths per kilometer traveled by bicycle than by car for all ages. Interestingly, there is no increase in risk for individuals aged 15-30 years. On the other hand , those of us in the “baby-boomer” generation (?slowed reflexes, poor eyesight, impaired hearing) and older are at an 8 to 17 fold increase risk.

In the Netherlands, where a very large percentage of the population regularly rides bikes, there has been considerable scientific study of the overall health consequences of biking and we have reasonably good data on the question of relative safety of biking versus driving a car for short distances. You can watch the happy people of Groningen (“the world’s cycling city”, where 57% of the journeys in the city are made by bicycle) riding their bikes below.

Health Impact of Transition from Car to Bike for Short Trips

One study quantified the impact on all-cause mortality if 500,000  people made a  transition from car to bicycle for short trips on a daily basis in the Netherlands and concluded

For individuals who shift from car to bicycle, we estimated that beneficial effects of increased physical activity are substantially larger (3–14 months gained) than the potential mortality effect of increased inhaled air pollution doses (0.8–40 days lost) and the increase in traffic accidents (5–9 days lost). Societal benefits are even larger because of a modest reduction in air pollution and greenhouse gas emissions and traffic accidents.

Apart from the highest average distance cycled per person, the Netherlands is also one of the safest countries in terms of fatal traffic accidents so it’s reasonable to ask whether these data apply to other countries. This study concluded

 When  traffic accident calculations for the United Kingdom were utilized, where the risk of dying per 100 million km for a cyclist is about 2.5 times higher, the overall benefits of cycling were still 7 times larger than the risks.

If you decide to bike to work this week, braving the elements , the possible automobile collisions and the automobile exhaust you can rest comfortably with the thought that not only are you  prolonging your own life but by reducing greenhouse gas emissions and air pollution you are contributing to the health of everyone around you.