In 2004, the Mayo Clinic reported: "Cardiac rehabilitation raises your chances of surviving at least three years after a heart attack by more than 50 percent." The Mayo study found that about half of the 1,821 eligible patients in one Minnesota county participated in a rehab program.

And nearly half (48 percent) of the deaths within three years of hospital discharge were attributable to not participating in cardiac rehabilitation. "On average, for patients who participated in cardiac rehab, it was almost as if the heart attack never had happened. They had the same three-year survival as what would be expected from area residents of the same age and sex who had not suffered heart attacks," said Veronique Roger, M.D., the Mayo Clinic cardiologist who led the study. "Increased participation in cardiac rehabilitation could lead to improved survival among a large proportion of heart attack patients." Another finding was that women were less likely to participate in cardiac rehab.

In 2007, research from Brandeis University revealed fewer than one-in-five (18.7 percent) patients get cardiac rehab services after a heart attack or coronary bypass surgery. But, bypass patients are much more likely (31.0 percent) than heart attack patients (13.9 percent) to receive rehabilitation.

The study evaluated Medicare claims data from 267,427 men and women age 65 and older who survived at least 30 days after being released from a hospital following a heart attack or coronary bypass surgery in 1997. Despite Medicare coverage of cardiac rehabilitation services, women participated less than men, older patients less than younger ones, and non-whites much less than whites. There were big geographic differences in use, ranging from 53.5 percent of patients in Nebraska to 6.6 percent in Idaho.

In 2005, the American Heart Association said that physicians should aggressively encourage patients to enter cardiac rehab programs. "Cardiac rehabilitation programs remain underused in this country, with only 10 to 20 percent of the 2 million eligible patients a year who experienced heart attack or underwent cardiac revascularization procedures participating," said Arthur Leon, M.D., chairman of the writing group and Henry L. Taylor professor in exercise science and health enhancement at the University of Minnesota in Minneapolis.

"In addition to a low physician referral rate, factors contributing to the under use of the services include poor patient motivation and inadequate third-party reimbursement. We need to motivate physicians to be more progressive in educating and referring patients to cardiac rehabilitation programs and motivate insurance companies to cover them." It was noted that research had found average cardiac death was 26 percent lower in rehabilitation patients who were exercise-trained compared with those who received "usual care." There were also 21 percent fewer nonfatal heart attacks, 13 percent fewer bypass surgeries and 19 percent fewer angioplasties in the exercise-trained people.

Leon said the specific benefits of the exercise training component are improved functional capacity for the patient, improved blood vessel function, improvement in cardiovascular risk factors, improved coronary blood flow, improved electrical stability of the heart muscle (thus reducing the risk of a fatal heart rhythm disturbance), reduced risk of blood clots and reduced cardiac work and oxygen requirements.