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Can the COVID-19 vaccine affect your heart?

Although the COVID-19 vaccine appears to have helped in preventing deaths due to COVID across the world, there has been a lot of heated debate about the possible side-effects of the vaccine on the Cardiovascular system in recent months. The COVID-19 vaccines are among the most effective in medical history, however, like with any other vaccine, there is potential for side effects or inconvenience that some people experience after getting their shots.

There have been some studies linking the mRNA COVID-19 vaccine and the risk of developing myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the outer lining of the heart) in adolescents and young adults. However, most of these studies show that the incidence of myocarditis or pericarditis resulting from the vaccine is less than 1 in 20,000, which makes it very small, though not quite negligible [1]. There have also been concerns around developing Thrombosis, an abnormal clot formation that causes stroke, heart attack and other major issues [2]. The side effects of COVID-19 vaccine after the second shot may be more intense than the ones experienced after the first shot.

In some very rare instances, patients have experienced an abnormal immune response to the COVID-19 vaccine [2]. In these cases, the platelet count of the body goes down and a clot forms. This has only been seen in very rare cases (less than 1 in 50,000) and primarily in individuals receiving the AstraZeneca vaccine for COVID-19. As of mid-October 2021, officials had confirmed 945 reports nationwide of myocarditis or pericarditis out of nearly 400 million doses given of the two vaccines. Cases were more common in adolescent males and young adults [3]. 

The good news is that the risk of these complications is very low and most of these cases have been mild and self-resolving. Most side effects happen within the first three days after vaccination and typically last only 1 to 2 days. However, if you experience the rare side effects of the vaccine like chest pain or discomfort, shortness of breath, heart inflammation, nausea or vomiting in the days following your COVID-19 vaccination, it would be advisable to seek medical attention at the earliest. 

Amongst users of the Frontier X device, we have come across a few anecdotal cases where the COVID-19 vaccine seems to have had an effect on the heart health of an individual. A 61-yr Physician using the device reported that he observed more frequent ECG abnormalities (pre-mature atrial contractions, pre-mature ventricular contractions and a short episode of supra-ventricular tachycardia) in his data recorded in the week immediately following the vaccine shot. This was reflected in the Pie-chart showing him the percentage of normal sinus rhythm (blue) and Other rhythm (yellow), immediately after taking the COVID-19 vaccine: 

ECG Abnormalities

It was also reflected in the atypical ECG morphology recorded during his walks and jogs:

ECG Heart Rate

Two other users also reported a temporary increase in atypical ECG rhythm patterns, which reverted to the normal patterns in about 7-8 days. Since one of the users had configured the device to give him alerts when his Heart Rate crossed 130 beats/min, this change in ECG rhythm also gave rise to vibration alerts during his interval workout (shown as vertical red lines):

ECG Rhythm

Determining whether the COVID-19 vaccine affects your heart or not can be more complicated than you think, because it is practically challenging to monitor your heart health continuously. While there are many wearables measuring Heart Rate, there are very few which can measure your ECG continuously during exercise, and alert you if some key parameter is going beyond the expected range.  

The Frontier X is a leading smart wearable device currently available in the market, which allows you to not only record high quality continuous ECG during all activities, but also gives you real-time vibration alerts when parameters are going beyond their expected thresholds. The device also provides an analysis of your ECG rhythm, and measures Cardiac Strain - an indicator for whether your heart is getting enough Oxygen. The mobile application that accompanies the Frontier X further allows you to share your ECG with any third party with the click of a button.

Since each heart is unique, it is going to be very difficult to draw a conclusion about whether the COVID-19 vaccine can affect your heart, though the numerous studies on this topic indicate that the odds of adverse effects are statistically low. So while the Frontier X may not be able to settle this contentious debate, it can certainly help in tracking the changes to your unique heart as a result of the vaccine, or any other changes to your lifestyle.  

If you have any questions about the effects of the COVID-19 vaccine on heart health, or about ECG changes in general, please reach out to We wish you a very safe and merry Christmas!

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