Cardiac arrest: Why does it happen suddenly and who is at risk? An explainer

Mint

2 days ago

Cardiac arrests have increasingly become a stark reminder of how you are going about your life one moment, and the next, without warning, it can all come to a halt. Every time a sudden death makes the headlines – especially involving young individuals – the conversation circles back to how unpredictable and fragile life can be.
A few days ago, actor Shefali Zariwala, best known for her 'Kaanta Laga' song in the early 2000s, died of cardiac arrest following a sudden drop in blood pressure, according to preliminary reports.
It was the latest in a string of such incidents. Before Shefali Zariwala, actor Sidharth Shukla, singer KK, comedian Raju Srivastava and others also passed away due to cardiac arrest.
Such incidents have triggered public concern and curiosity about how cardiac arrest strikes.
Are there any underlying conditions or symptoms one should watch for? What is cardiac arrest, and how is it different from a heart attack? Why do cardiac arrests happen suddenly?
Cardiac arrest occurs when the heart suddenly stops all activity, cutting off the flow of blood to the brain and other organs, which leads to a loss of consciousness. If not treated immediately, it can quickly result in death.
While heart attack and cardiac arrest are often used interchangeably, the two terms are not the same.
A heart attack occurs when blood flow in an artery supplying the heart is blocked. Cardiac arrest does not happen due to blockages, but a heart attack can disrupt the heart's activity, potentially leading to sudden cardiac arrest.
According to Johns Hopkins University, 'If cardiac arrest occurs suddenly with no other existing heart conditions, it's more likely to be caused by a heart attack.'
While there are many causes of cardiac arrest, such as lack of oxygen, high levels of potassium or magnesium, blood loss, and conditions affecting the heart's four valves, the primary causes are:
Arrhythmia: Arrhythmia refers to an abnormal heartbeat, when the heart beats too fast, too slow, or irregularly. It happens when the electrical signals that coordinate your heartbeats don't function properly.
Johns Hopkins says 'Ventricular fibrillation' – rapid heartbeat in the two lower chambers of the heart, causing the heart to tremble – is the most common cause of cardiac arrest.
The World Health Organisation (WHO) says, 'Ventricular fibrillation is generally considered to be the most frequent arrhythmia responsible for sudden cardiac death.'
Enlarged heart: When the heart muscle dilates or thickens.
Coronary artery disease: Johns Hopkins says that Coronary artery disease happens when 'the coronary arteries are narrowed and thickened by blockages of plaque, which restricts the flow of blood to the heart.'
Some heart problems are hereditary, and some are lifestyle choices. Other than that, alcohol abuse, heart disease, high cholesterol, obesity, and smoking are some factors that can increase the chances of a cardiac arrest.
Dr Sudhir, a pathologist at AIIMS-Delhi, said, 'While older individuals often suffer cardiac arrests due to arterial blockages, in younger people, sudden deaths may also be linked to genetic heart conditions, binge drinking, drug use...'
(With inputs from Johns Hopkins and WHO)