While most research has focused on treatment that improves survival, doctors have recently begun to pay attention to people's sense of well-being, too.
"There is no standard exercise regimen for patients with heart failure," said Dr Gloria Yeh of Harvard Medical School in Boston, who worked on the study.
"Current options include things like treadmill or bicycling, and other conventional exercises," she said. "Tai chi may be another good option as it incorporates low-moderate intensity aerobic exercise, strength training, deep breathing, in addition to aspects of relaxation and stress management."
Her study, published in the Archives of Internal Medicine, is the largest so far to look at the effect of regular tai chi on heart failure patients.
The researchers followed 100 patients who had been randomised to either a 3-month tai chi exercise program or educational sessions with a nurse.
After the program, the two groups fared similarly on a walk test and an oxygen-uptake test. But those who had done tai chi said they felt better physically and emotionally.
For instance, the tai chi group improved by 19 points on a quality of life scale designed for people with heart failure, whereas those in the education-only group remained at their initial level.
The tai chi group also reported being in a better mood, and they became more confident about engaging in other exercises.
Dr Yeh says tai chi "is relatively low-cost, as it requires no equipment or special facility. The cost of classes can vary but is similar to other exercise classes offered in the community."
Dr John R. Teerlink, who wrote an editorial on the findings, said the results seemed encouraging. On the other hand, he said, a 100-patient "trial with tai chi is interesting, but not definitive by any means."
Even so, said Dr Teerlink, a cardiologist at the University of California, San Francisco, "We tell our heart patients to do what they like doing and try to stay involved with their community, and tai chi is an excellent way to do that."
(Reuters Health, Frederik Joelving, April 2011)