Cardiac Testing Post COVID-19: Of Echos and MRIs

CVCT CardioBrief published online earlier this week a letter from a group of “clinicians, researchers and imaging specialists” who are concerned about the “presentation, interpretation and media coverage of the role of cardiac magnetic resonance imaging in the management of asymptomatic patients recovered from COVID-19.”

It’s short and sweet but makes many excellent points.

Let’s look at their major points (bulleted and red) one by one

• Studies¹²³ investigating the prevalence of myocarditis in patients with recent COVID-19 have found features of subclinical myocarditis on cardiac magnetic resonance (CMR) imaging in patients without symptoms.

Reference 1 is the German cardiac MRI study that first got me “worried” about cardiac consequences of COVID-19. It has gotten a lot of flack (spearheaded by posts on Twitter including those of Dr. Venk Murthy, the first author on this letter), has been revised and errors corrected. It still has me worried which brings us to point two of the letter:

• Some commentators have raised concern that COVID-19 may lead to frequent, serious long-term cardiac sequelae even among people who have had mild infection and are currently asymptomatic.

This is definitely true, lots of prominent doctors have suggested this. Here’s what I (a not so prominent doctor) wrote:

Note that left ventricular ejection fraction (LVEF), the most common measure of the systolic or pumping function of the heart although lower in the COVID-19 patients was not depressed below normal values. This means these cardiac abnormalities would not be detected on more commonly available cardiac diagnostic methods like echocardiography.

Also note that risk-factor matched controls have a fair number of CMR abnormalities and that we don’t know what cardiac MRI would show in a comparison group of patients recovering from the flu.

Despite these limitations, “given reports of ongoing cardiac symptoms in many post-COVID-19” I agreed with an accompanying JAMA editorial,” entitled “Coronavirus Disease 2019 (COVID-19) and the Heart—Is Heart Failure the Next Chapter?” and written by two prominent heart failure researchers/clinicians and JAMA editors, Clyde Yancy and Gregg Fonarow, which concluded:

“We wish not to generate additional anxiety but rather to incite other investigators to carefully examine existing and prospectively collect new data in other populations to confirm or refute these findings. We hope these findings represent that of a select cohort of patients. Yet, if this high rate of risk is confirmed, the pathologic basis for progressive left ventricular dysfunction is validated, and especially if longitudinal assessment reveals new-onset heart failure in the recovery phase of COVID-19, then the crisis of COVID-19 will not abate but will instead shift to a new de novo incidence of heart failure and other chronic cardiovascular complication”

Both I and the prominent authors of the editorial I quote state a long list of caveats and other things that would need to be proven before knowing that COVID-19 creates long-term cardiac consequences. However, most non-scientist readers of media reports tend to filter out all the boring caveats (which we must face and incorporate continuously in clinical medicine) and focus on worst-case (or best case) scenarios.

• We wish to emphasize that the prevalence, clinical significance and long-term implications of CMR surrogates of myocardial injury on morbidity and mortality are unknown.

Absolutely true.

• Further, it is unclear if the elevated T1 and T2 flagged in these studies are clinically significant, particularly in isolation, if treatment is needed, and, if so, what the management should be.  These important questions should inspire future prospective studies.

Totally agree. I’m no expert on CMR but having utilized it in my cardiomyopathy patients, researched the literature and discussed with experts in the field I know that LGE (late gadolinium enhancement) is the most validated tool and has well established diagnostic and  prognostic data. It was the LGE data in the German CMR study I was most concerned about. As this table demonstrates (left column asymptomatic COVID-19, right column matched controls) the COVID-19 group had a five-fold higher prevalence of non ischemic LGE (and pericardial effusion.)

The letter concludes with a request that professional societies discourage CMR screenings;

Nonetheless, these reports have attracted significant media coverage, at times amplified by speculation on possible clinical implications, thus generating substantial anxiety amongst members of the general public. As a result, we are aware that some individuals are seeking CMR testing despite the absence of cardiac symptoms. We believe that, given the preliminary nature and limitations of the current evidence, testing asymptomatic members of the general public after COVID-19 is not indicated outside of carefully planned and approved research studies with appropriate control groups.

In light of your societies’ standing in the community and advocacy against low-yield testing and low-value medical care through your sponsorship of the Choosing Wisely, Image Wisely, and other similar campaigns, we request that you offer clear guidance discouraging CMR screening for COVID-19 related heart abnormalities in asymptomatic members of the general public.

It’s really hard to justify CMR testing on asymptomatic patients post COVID-19, hopefully physicians and patients will avoid ordering them in this situation.

Evaluation of Heart Failure Post COVID-19

But what about patients with signs or symptoms of heart failure that develop after COVID-19? Typically, heart failure symptoms consist of breathlessness, fatigue or leg swelling, symptoms which are also common following respiratory illnesses thus likely to be common after COVID-19 illness whether or not there is any cardiac pathology.

For now, my approach to such patients will be exactly like my approach to any other non-COVID-19 patient in whom symptoms could be due to heart failure. Following a detailed history and physical exam we will check and ECG and an echocardiogram. The echocardiogram is a wonderful tool for evaluating patients who may have congestive heart failure as it is totally noninvasive, ubiquitous (in the US), inexpensive (or should be) and painless.

A well-performed and well-interpreted echocardiogram gives information on the structure and pump function of the left ventricle (EF), pressures in the heart and pulmonary arteries, right ventricular function, valvular function and is the gold standard for determining presence or absence of pericardial effusion.

I’ll also check some basic lab tests on such patients including tests of kidney and liver function, blood counts, thyroid function, CRP and a BNP or pro BNP level.

I would not order CMR on these post COVID-19 heart failure patients unless abnormalities on one or more of the tests in conjunction with the history and physical convinced me the patient had evidence of myocarditis or cardiomyopathy.

We have lots to learn about COVID-19 and the heart. CMR evaluation of post-COVID-19 in the context of well thought-out research protocols can contribute to our understanding but CMR evaluation of asymptomatic COVID-19 patients would create unnecessary confusion, fear, and anxiety which would outweigh any clinical benefits.

Ultrasonically Yours,

-ACP