Want to survive a heart attack, heart failure or pneumonia? Go to a busy hospital.

Researchers reported on Wednesday that patients suffering from the three common health problems were less likely to die when treated in hospitals that frequently handle those illnesses.

Pneumonia patients treated at larger-volume hospitals were 5 percent less likely to die in the first month than patients treated at hospitals that handled few cases. The death rate for heart failure was 9 percent lower for busy hospitals and 11 percent lower for heart attacks.

Dr. Joseph Ross of the Mount Sinai School of Medicine in New York and colleagues studied Medicare claim data from 2004 through 2006 for their study, published in the New England Journal of Medicine.

They found that once a hospital annually treated 610 patients for a heart attack, 500 for heart failure or 210 for pneumonia, patients had the lowest risk of dying, at least during the first 30 days.

Teaching hospitals generally needed fewer patients to attain a lower risk of death, they discovered.

There are small-volume hospitals that are doing well, and large volume hospitals that aren't, Ross said in a telephone interview.

But in general, hospitals that treat the fewest patients were the riskiest.

Clearly our small-volume hospitals need to be lifted up a bit, Ross said. One solution may be to help them do things the way larger-volume facilities do, so their success rates will improve.

Previous studies have shown that patients who receive surgery or other procedures do better if they are treated by doctors with the most experience.

The study is the first to look at common medical conditions in the same way and see if there is a threshold for achieving low death rates.

The researchers calculated, for example, that a hospital that only treated 17 heart attacks a year could see its 30-day death rate drop by 20 percent if the facility cared for an additional 100 heart attack patients a year. If it had 70 cases a year to begin with, adding 100 more would result in a 10 percent reduction.

Adding 100 cases to a hospital that already treats 236 heart attacks would cut the death rate by just 4 percent. The threshold of improvement was reached once the annual volume hit 610.

Ross said a good gauge for quality of care that individual patients can use could be found at hospitalcompare.hhs.gov, which directly looks hospital performance.

(Editing by Maggie Fox and Peter Cooney)