The trend of sudden cardiac arrest and heart attacks continued in 2023 as people with no prior warning symptoms collapsed doing seemingly harmless activities - working out, running marathons, or doing dandia raas. Shocking deaths of school children, adolescents and younger adults left people in disbelief. One of the factors that experts say could be at play behind these sudden deaths is the inflammation of heart muscles post Covid. (Also read | Year Ender 2023: Screen addiction to mindless snacking; harmful habits in kids that left parents worried)

Stress has also emerged as a major risk factor for sudden cardiac deaths that can affect any age group, apart from usual suspects like diabetes, hypertension, smoking, poor lifestyle choices, lack of exercise, and bad dietary habits. Cardiologists feel the most important cause behind sudden cardiac death remains coronary artery disease, a condition where coronary arteries get blocked. A change in lifestyle and adoption of healthy habits can help keep your heart healthy.

What is a sudden cardiac death?

"In 2023, so many sudden deaths, particularly among younger people, made a lot of news. This trend has been very concerning to the public as well as to the doctors. Most of these deaths, unfortunately, have occurred without any prior warning. And many of these people who died were not known to have any heart disease. Sudden cardiac death is defined as a death where a patient dies within one hour of the onset of symptoms. Most of these sudden deaths are not because of heart attacks," says Dr T.S. Kler, Chairman – BLK-Max Heart & Vascular Institute, BLK Max Super Specialty Hospital, New Delhi.

Heart attack

A heart attack is a condition that occurs when one of the arteries, the vessel that supplies the blood to the heart muscle, suddenly gets blocked.

Dr T.S. Kler says that heart attack causes only 15% of sudden cardiac deaths, and the others occur due to underlying previous conditions.

"Though a major heart attack can also cause sudden cardiac death, if we have to see, roughly 15% of the sudden cardiac deaths are because of an acute heart attack, which is usually a massive one. And it occurs because of a very large artery getting blocked. Certainly, 85% of sudden deaths are not because of an acute heart attack but may have been because of previous conditions," says Dr Kler.

Dr Kler says a person is more prone to sudden cardiac death in case of already damaged heart muscles.

"The most important condition that we're certain will increase the risk of sudden heart attack when there is already some damage to the heart muscle. We estimate the pumping capacity of the heart using echocardiogram defined as called ejection fractions. Normally, the ejection fraction is more than 55%. If the ejection fraction drops below 35% and the patient has already had a history of heart attacks in the past, these patients are highly prone to sudden cardiac death," says the expert.

Cardiomyopathy

Dr Kler says cardiomyopathy, which is primarily disease of the heart muscles in the heart arteries, could be the culprit behind rise in sudden cardiac deaths and the involvement of Covid-19 cannot be ruled out due to post-Covid inflammation of heart muscle.

"In 2023, what has happened is that these deaths have occurred more frequently than before. We don’t know for sure, whether these deaths had any definite relationship to Covid or not. But most of us believe that people who have moderate to severe Covid can have heart involvement, and they could have what is called inflammation of the heart muscle, which is termed as myocarditis. So, it is very likely that a few of these deaths precipitated due to post-Covid inflammation in the heart muscle. Unfortunately, in our country, we don't do autopsies on these patients. I would highly recommend that for all these patients who die, particularly those below 40 years of age, we have an autopsy for them," says Dr Kler.

Hereditary disease

"Some of the deaths in younger people also occur because of some hereditary diseases of the heart, like hypertrophic cardiomyopathy, where the heart muscle gets thick, and these patients are also prone to sudden cardiac death. There are a few other conditions where the heart on echocardiography is normal, but they could have Qt prolongation, as Brugada syndrome. These are some of the conditions that the general public doesn't know about. They can only be detected with a proper cardiac checkup," says Dr Kler.

Coronary artery disease

Considering the total number of sudden cardiac deaths, the most important cause remains coronary artery disease, where people develop blockage in the coronary arteries as per Dr Kler. He says the best strategy to prevent these sudden deaths is to follow a healthy lifestyle, stop smoking, keep cholesterol under check, control diabetes, and hypertension.

"Anybody who's more than 35 years of age should have an annual cardiac checkup. This is the only way that we can prevent these catastrophes of sudden cardiac death," advises the expert.

Stress, a major cause for sudden cardiac deaths

Stress and air pollution are emerging to be major risk factors for sudden cardiac deaths.

"We heard a lot of news, post-Covid and post-vaccination, about young patients having cardiac events that ultimately resulted in a negative outcome, or maybe cardiac arrest and death. So, the reason behind it is that, if you go into the causes of heart attacks, as you rightly said, stress has become a major risk factor. Stress at the workplace, stress at home, or social stress of any kind have become the major reasons. Besides, one of the novel or new risk factors is pollution, especially PM 2.5 and PM 10 particulate matter. So, these two have become major risk factors besides diabetes, hypertension, smoking, a bad lifestyle, not a certain lifestyle, a lack of exercise, and bad dietary habits. These are the major causes of dyslipidaemia. So, these are the major risk factors," says Dr. Bhupendra Singh, Consultant Cardiology, Manipal Hospital, Ghaziabad.

Why people are having cardiac arrest while exercising

"There are many syndromes that can lead to sudden cardiac arrest or sudden collapse while exercising, and one of the most common causes of these patients developing cardiac arrest is hypertrophic cardiomyopathy. And second are some sort of arrhythmias, especially ventricular tachycardia and ventricular fibrillation. They can develop because of certain congenital diseases or congenital heart conditions, which lead to these problems, and these are some of the most common causes of cardiac arrest during exercise. So, we need to actually look into the medical profile and medical picture," adds Dr Singh.