The poor have little access to health care
India will account for 60% of heart disease cases worldwide within two years, according to new research.
The study, published in the British journal Lancet, says that is nearly four times more than its share of the global population.
The study, by Canadian and Indian researchers, says one major problem is that Indians are unable to reach hospital quickly in an emergency.
Heart disease kills 7.1 million people globally each year.
It has been long known that South Asia has the highest level of acute coronary syndromes in the world, but this is the first comprehensive research which provides statistical data about heart disease.
"This registry is a major milestone, since it provides the first comprehensive view of the epidemic of acute coronary syndrome in India and helps to identify opportunities for improvement in care," news agency AFP quoted US cardiologist Kim Eagle as saying.
Smoking is a major risk factor for heart disease
"As the Indian economy grows, there is a possibility of further increases in cardiovascular disease before we see a decline similar to that being witnessed in developed countries," Mr Eagle, who was not involved with the research, warned.
The study has been carried out by a team of researchers, led by Dr Denis Xavier of St John's National Academy of Health Sciences in Bangalore and included others from Canada.
The team studied nearly 21,000 heart attack patients admitted to 89 hospitals in 50 cities across the country.
The risk factors in India were the same as elsewhere and included tobacco use, high levels of lipids in the blood due to diets rich in saturated fat, and hypertension, the study said.
But, it noted, there were causes specific to India - the most important being the time taken to get access to medical help.
On average, it took 300 minutes to reach a hospital in India, twice as long in rich nations. "Few patients used an ambulance to reach the hospital. Most used private or public transport" due to financial constraints, the report says.
Poverty also prevents most Indians from obtaining routine treatments including surgical procedures because most of them have to pay for it themselves.
The study also found that many of the Indian patients were younger by three to six years than those in richer nations.