Covid-19’s ‘heart of darkness’

Nine months into the worst pandemic in a century, most of the world is still susceptible and continues to fear Covid-19’s initial onslaught. But some who have supposedly ‘recovered ’may suffer long-term or permanent respiratory and cardiovascular consequences.

While the initial focus has been on SARS-CoV-2’s effects on the lungs, soon we will likely have to contend with Covid-19’s effects on the heart and this coronavirus may put the COR in CORonary. We have just started talking about Long Covid (long-term Covid-19 effects) but we might be talking about it for decades. Before we try to explore the effects of Covid-19 on the heart, let us acknowledge that we are operating in a bit of a knowledge vacuum, the heart of darkness if you will. With that caveat, let’s try to get to the heart of it.

Does severe Covid-19 cause heart disease or does heart disease result in severe Covid-19? Is SARS-CoV-2 a heartbreaking virus or one that hits the heartbroken? All of the above. Covid-19 has been implicated in acute coronary syndrome (heart attacks and similar emergencies), myocarditis (heart muscle inflammation), cardiomyopathy (heart muscle disease), arrhythmia (heart rhythm and rate disorders) and heart failure. Those with pre-existing heart disease (heart attacks, coronary artery disease or heart failure) are more likely to develop severe Covid-19 and die.

We also know that risk factors for heart disease like diabetes, hypertension, obesity, kidney disease and smoking are also risk factors for severe Covid-19. Confounding! Hospitalised Covid-19 patients do develop heart problems and some patients who seem to have heart emergencies like heart attacks actually turn out to have Covid-19.

Worrying findings

Doctors know Covid-19 hits damaged hearts worse and suspect that Covid-19 may be unmasking previously undetected heart disease but new evidence suggests that SARS-CoV-2 may be a heart virus. You may wonder how does a virus that supposedly hits the lungs also affect the heart? There are many interesting theories.

The ACE-2 receptor that SARS-CoV-2 uses to infect human cells is one of the most important receptors in the cardiac system, and the virus may cause heart damage because of its interaction with ACE-2. The virus may deprive the heart of oxygen (hypoxia) or blood (ischemia). Severe infection and an out-of-control immune response to the virus (cytokine storm) might stress the heart beyond its limits. The virus may be directly damaging the heart but it is unclear if the virus causes more heart damage than other infections. Severe bacterial pneumonia and influenza can also cause heart damage. It is possible that we’re seeing more heart problems because there are so many Covid-19 cases. Again, it may be a combination of all of the above.

Some studies suggest that even healthy hearts may be susceptible to the virus and heart damage can persist even after recovery from Covid-19. A study in Germany reported cardiac inflammation in 60 per cent of patients 70 days after Covid-19 diagnosis. Most of these patients weren’t even hospitalised. Some had very mild Covid-19 and no pre-existing illness.

There has been some concern over the study design and statistical analysis but, nonetheless, these figures are worrying.

A study in the laboratory (not on actual patients) suggested the virus might directly affect the heart muscle. Several US college athletes who had mild or asymptomatic infection were detected to have evidence of cardiac damage. It is unclear if this is a case of over-diagnosis and if other infections may have similar effects, but this is also troubling.

It is difficult to comment on the long-term effects of Covid-19 because we’re just getting to know SARS-CoV-2. But in the short term, two things are clear. This is not the flu and even those who survive may face long-term consequences. Many have found the political apathy to the pandemic heartbreaking but taking Covid-19 lightly might just break your heart!

The writer is a doctor who specialises in Internal Medicine, Co-author of “The Coronavirus: What You Need To Know About The Global Pandemic,” and Co-founder, DIY.health, an AI-powered health tech start-up. Views are personal