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Every day scientists are discovering more about the effects of the novel coronavirus, the virus that causes COVID-19. We are quite aware that the novel coronavirus has a devastating effect on the lungs and airways. What we are now beginning to discover, however, are the many effects this disease has on other organ systems. One of those organ systems is the cardiovascular system, specifically the heart.
Does Coronavirus Attack the Heart?
Increasingly, doctors have been seeing patients with telltale signs of myocardial infarction (heart attack), but when explored further there is no evidence that these patients had an actual heart attack. One of the telltale signs patients are presenting with is an increase in a marker of heart muscle injury found in the blood called troponin. Another of these signs consists of certain specific changes on an ECG (a readout of the heart’s electrical activity). Again, no evidence of an actual heart attack is found in these patients.
What is found, however, is that these patients all seem to have one thing in common: They all have tested positive for COVID-19. Surprisingly, one study showed that up to 20% of coronavirus patients had some signs of heart muscle injury.
Though the mechanism by which the heart is injured by COVID-19 is not well understood, there are several hypotheses. First, we know that SARS-CoV-2 (the novel coronavirus) attaches to angiotensin-converting enzyme 2 (ACE2) receptors on the cells of the lungs. That is how the virus is allowed entry and causes so much havoc there. One hypothesis is that SARS-CoV-2 attaches to the same type of ACE2 receptors that are also found in the heart.
Another hypothesis is that heart muscle injury is secondary to lung injury. Because the lungs can’t extract enough oxygen from the air, the heart then suffers and is injured due to lack of oxygen.
A third hypothesis is that the immune system of the person infected with the novel coronavirus goes into overdrive and attacks its own organs, including the heart. This is a hyperinflammatory reaction known as a cytokine storm.
Finally, infection with COVID-19 is seen to lead to increased coagulability of the blood. That is to say, a person infected with the virus may be more likely to develop blood clots that could travel to the heart and other organs, cutting off vital oxygen supply to those organs.
Hypotheses for mechanism of heart muscle injury in COVID-19 patients:
- Direct attack by the virus on ACE2 receptors in the heart
- Decreased oxygen supply to the heart due to lung injury
- Immune system in overdrive causing hyperinflammatory reaction (cytokine storm)
- Increased coagulability of the blood leading to increased blood clots
What Does This Mean in Pregnancy?
Whatever the mechanism of injury, the heart of a pregnant woman is already under a significant amount of strain. A pregnant woman is already at a higher risk of developing many heart-related conditions. Among these are: aortic dissection, blood clotting disorders, arrythmias, and valve dysfunction.
While pregnant, a woman’s body goes through significant changes, including changes that directly affect the heart. We see an increase in the amount of blood that must be pumped throughout the body, which makes the heart beat harder and faster. There is also a marked increase in the elasticity of the blood vessels making it even more difficult for the heart to pump that extra blood where it needs to go. A direct attack from the novel coronavirus could make the heart of a pregnant woman extremely inefficient.
To add to that, the extra work that the heart must do requires extra oxygen. If the lungs are injured due to infection with SARS-CoV-2, then it is more difficult for the lungs to extract enough oxygen from the air to power the heart. This decreased oxygen supply could lead to increased risk of heart muscle injury for pregnant women.
Similarly, since pregnant women are already at an increased risk for developing blood clots, adding the increased risk of blood hypercoagulability from infection with SARS-CoV-2 would only seem to heighten the risk of developing a thrombus or embolism.
With all of that being said, it is important to keep in mind that more studies must be done to properly assess the risk of injury to the cardiovascular system in pregnant women infected with SARS-CoV-2. The best way to protect yourself from increased risk of heart muscle injury due to infection with the novel coronavirus is to avoid getting the virus in the first place. Practicing social distancing and frequent hand washing are two ways to prevent getting COVID-19.