Mike Godfrey was 19 when he found out he had HIV.

He was 29 when he began antiretroviral therapy.

He was 43 when he had a heart attack.

“I felt fluttery,” he said. “Weird and fluttery. It went away. I ignored it. A week later, it came back, and this time I felt something in my arm too. I was too stupid to call an ambulance. I got in a cab and went to the hospital.”

Mr. Godfrey’s experience exemplifies something a few AIDS specialists have long suspected, and cardiologists have now found evidence to support: People infected with H.I.V. have more heart attacks and have them earlier in life. Even patients whose infection is well suppressed by AIDS drugs are at higher risk.

Experts in the field said doctors need to be better informed about this little-known threat to their H.I.V.-positive patients. The threat also reinforces a message that public health experts keep emphasizing: H.I.V. is no longer an automatic death sentence, but it is still a dangerous disease.

“I think most cardiologists and most H.I.V. specialists are not really aware of this,” said Dr. Priscilla Y. Hsue, a cardiologist at San Francisco General Hospital who treats many AIDS patients. “Most of the people I see are referred to me after they’ve had a heart attack, a bypass, a stent. To me, that’s too late. We should be screening people for coronary disease, aggressively treating blood pressure, aggressively treating cholesterol.”

People with H.I.V. have more than four times the risk of sudden heart attack as their uninfected peers, Dr. Hsue and her colleagues reported last month in The Journal of the American College of Cardiology.

The most likely explanation is that both the virus and the drugs that fight it cause chronic inflammation, said Dr. Paul M. Ridker, a Harvard Medical School professor who led pioneering studies that established the connection between inflammation and heart disease. (He was not involved in the study published last month.) Also, he said, the drugs cause the liver to make more cholesterol, another heart attack risk factor.

While the link between H.I.V. and heart disease is not generally known in the medical profession, some doctors who specialize in the treatment of AIDS patients have long suspected such a connection.

“I’ve had a number of patients - men in their late 40s and early 50s - who were just found dead at home,” said Dr. Steven G. Deeks, an AIDS expert at the University of California, San Francisco, who was not involved in the study. “I’ve always thought that was happening more than it should.”

Both the virus that causes AIDS and other infections that can accompany it can inflame tissues, he said. Inflammation can produce blood clots, which can cause heart attacks. And in the intestines, the virus can cause “leaky gut syndrome,” by which other inflammatory microbes enter the bloodstream.

Dr. Zian H. Tseng, a heart rhythm specialist and a co-author with Dr. Hsue of the new study, said he stumbled on the H.I.V.-cardiac connection while he was doing a survey of every sudden heart attack death in San Francisco and noticed that many victims were taking antiretroviral drugs.

“Initially, I thought it was just because of the high prevalence of H.I.V.-positive people in San Francisco, but it was clearly more than that,” he said.

The researchers scoured the medical records of 2,860 patients who were seen between 2000 and 2009 in Ward 86, San Francisco General’s famous AIDS clinic. For those who had died, they checked death certificates and paramedic reports and interviewed doctors and family members, trying to see how many had had heart attacks.

They acknowledged some limitations: Smoking and recreational drug use are more common among people with H.I.V., and few of the dead were autopsied. But all deaths that looked like overdoses, suicides or assaults, as well as slow AIDS deaths, were excluded.