COVER STORY: HEART ATTACKS
The X Syndrome
New research shows that a mysterious set of genetic factors put Indians at high risk. Can anything be done?
To the outside world, Amar Banerjee, 42, was at the prime of his career and seemingly in good health. Banerjee, a Bhopal-based sales executive, was careful with the way he treated his body-he was a regular at the gym, rarely smoked, went easy on the sweet stuff and avoided late nights. A heart attack was the farthest thing from his mind though a few years earlier, his ageing mother had suffered one.
Then one evening, while returning home, Banerjee felt a sharp pain sear through his left chest and felt his arm turn limp. It was so intense that he almost lost balance and dashed his scooter against the sidewalk. He felt nauseated and knew there was something terribly wrong with him. He was rushed to a local hospital where doctors diagnosed his condition as a myocardial infarct caused by excessive clogging of the arteries in his heart.
Banerjee was stunned. Given the fact that he led a relatively healthy lifestyle, being diagnosed with a serious heart problem was incomprehensible. But the doctors were not surprised. For them, Banerjee was one more victim of Syndrome X-a condition that predisposes Indians to a whole repertoire of biochemical bullets blasting the heart. Syndrome X is now increasingly seen by experts as the prime culprit for the alarming rise in heart diseases in the country. Ironically the understanding of its potential for mischief came from several recent studies of Indians living in the US. The most important is a recently concluded 10-year study of 4,500 patients by the Coronary Artery Disease Institute (CADI) in Lisle, Illinois, that found the Indian community had much higher levels of a deadly genetic factor called lipoprotein A, or LP(a), than other ethnic groups. It is 10 times deadlier in causing clogged arteries that lead to heart attacks than bad cholesterol such as Low Density Lipoproteins (LDL).
Spearheaded by LP(a) the extraordinary factors called Cardiac Syndrome X by specialists leave Indians four times more prone to heart disease than Chinese, Japanese, Caucasians and Hispanics. "We're in the midst of a heart disease epidemic," says Professor S.C. Manchanda, head of cardiology at the All India Institute of Medical Sciences (AIIMS), Delhi. "In India, approximately four people die of heart attacks every minute because Indians are genetically predisposed to the disease."
But how exactly and why? Like FBI agents probing abnormal phenomena in the popular TV serial, the medical fraternity is racing to discover the cause and effects of Syndrome X. At the heart of the matter is the heart itself. The fist-sized organ is among the most hard working in the body. As precise as a clock, it pulsates almost every second, pumping 10-15 tonnes of blood a day-enough to flood a basketball court-to keep the body alive. For doing this, the heart muscles require enormous amounts of energy. Oxygen-drawn from the respiratory system and absorbed by blood that reaches the heart through the blood vessels-is its main fuel. Much like water seeping through a blocked pipe, the blood flow slows down when the arteries are clogged. When large clots reduce blood flow to a trickle, the oxygen-starved heart muscles start dying. The result is a heart attack. Similar blockage in brain arteries causes a stroke. Other organs have more vessels, so the blood/oxygen flow is not throttled.
Every day, the heart and its circulatory system are engaged in a battle of biblical proportions to keep the main highways of blood transportation free from blockage. The cloggers-in-chief are cholesterol-soft, waxy substances produced by the liver. Their daily job is to maintain cell walls, hormones and other tissues. As they piggy-back on proteins in the blood, they are named according to the type of carrier they associate with and can be classified as the good, the bad and the ugly.
First, the bad: excess LDL cholesterol fall along the arterial wayside and create havoc. Accumulated LDL cholesterol then clings to the walls of blood vessels and (HDL)-rush in, modifies its form, damaging and scrapping off the cells lining the vessel. All this activity attracts immune cells which then get trapped. LDL cholesterol, immune cells, vessel-lining cells and other substances jammed together, form a thick, hard, deposit called plaque, which gets thicker with time to clog the arteries. Cheering LDL on in its malevolent ways is a fat called triglyceride (TG), an ugly customer obtained from foods like butter, and present in blood to provide instant energy or stored as body fat for future use. As the arteries watch helplesslessly, the good cholesterol-High Density Lipoprotein (HDL)-rush in, preventing clogging by mopping up the littered cholesterol and shuttling them back to the liver. So plenty of HDL cholesterol and less of LDL cholesterol and TG would be the condition of choice to prevent a heart attack.
Among Indians, it's as if all the worst conditions for heart disease were hand-picked and clubbed together to complicate matters as Syndrome X. It bombards Indians with high levels of LDL, low levels of HDL, high TGs and insensitivity to insulin (a cause of diabetes), to compound their susceptibility to hypertension and "central" obesity.
International studies detected this Indian peculiarity. In 1958, research conducted in Singapore first established that Indians have thicker blood and more of LP(a) than the Chinese. The significance was not well understood, till 1990, when Dr Enas K. Enas, CADI's director studying over 4,500 patients, found that the US-based Indian community displayed similar tendencies that doctors began to pay heed. A subsequent 10-year study conducted by Enas confirmed that one out of four Indian-Americans had high levels of LP(a) as compared to the Japanese, Chinese, Caucasians and Hispanics.