Not just Sunjay Kapur, a bee sting and a wasp bite triggered heart attack in 2 patients: Can a shock allergic reaction damage your heart?

What is Kounis syndrome?

A rare condition where heart attacks and sudden cardiac arrests occur due to allergic or hypersensitivity reactions to medication, food, insect stings, or even exposure to an unfamiliar environment. The allergic reaction initially manifests as shortness of breath.

The allergic reaction causes the body to release a compound called histamine to counter and neutralise the pathogen in the body. This widens blood vessels, leading to a rapid and sharp drop in blood pressure. If blood pressure drops too low, the heart may struggle to pump enough oxygenated blood to vital organs and itself, leading to oxygen deprivation and damage to the heart muscle. This amounts to stress for those with already weakened cardiovascular systems. It can, therefore, trigger abnormal heart rhythms or arrhythmia, especially in those with underlying heart conditions. This malfunctioning of the heart’s electrical system can lead to sudden stoppage of the heart, what we know as sudden cardiac arrest.

Anaphylaxis can let fluid and proteins leak from the bloodstream into surrounding tissues. This decreases blood volume and blood pressure further.

In some cases, anaphylaxis can narrow the coronary arteries, further reducing blood flow to the heart muscle. But the most common reaction is plaque rupture in people with pre-existing coronary artery disease, leading to a heart attack.

How allergic reactions trigger heart blockages

The heart, which has to pump blood under stress, may suffer plaque rupture. The 31-year-old patient had just 40 per cent plaque but it got dislodged, triggering blood clots to cover the tear on the wall, leading to blockages. So we had to open up his artery by putting in a stent or a small bridge to keep it widened. The second patient did not need a stent because he had plaque erosion, where the plaque only loses its outer lining but still exposes the underlying core, triggering a blood clot that blocks the artery.

How to prevent heart attacks during allergic reactions?

First and foremost, the patient should be revived with steroids or a strong dose of adrenaline, given by an injection or drip in their vein. The patient should be given oxygen and get an electrocardiogram (ECG) done.

(Dr Shetty is lead cardiologist, Sparsh Hospitals, Bengaluru)