With supervision, patients prone to heartbeat irregularities who have an implanted cardioverter defibrillator (ICD) can exercise safely, and derive benefits, according to European investigators.

ICDs are pacemaker-like devices that monitor heart rhythm and, if necessary, deliver a shock to correct irregularities.

“The referral of ICD patients to exercise training programs is negatively influenced by the fear of inappropriate shock delivery during exercise,” Dr. Luc Vanhees from the University of Leuven, Belgium, told Reuters Health.

His group’s findings show that this is not common, and that “exercise training leads to favorable physical adaptations.”

Vanhees and his colleagues compared the effects of a 3-month exercise training program in 92 ICD patients and 473 “control” patients without ICDs, and report the results in the European Heart Journal.

Training intensity was similar in ICD and control patients, and both groups showed significant improvements in oxygen uptake and heart rate - although the effects were smaller in the ICD patients.

“Clinically, we were also impressed by the clear psychological impact of the program,” Vanhees said. “Whether this was a result of exercise training or a result from the social impact of the program is yet not clear.”

In six cases, the ICD delivered an appropriate shock to counteract an abnormally fast heartbeat between training sessions, and there were “no inappropriate treatments delivered outside the training sessions,” the researchers report.

“Patient’s exercise training program should be supervised by skilled therapists (physiotherapists, exercise therapists), under supervision or in the near presence of a cardiologist,” Vanhees advised. “The intensity of exercise should be controlled by heart rate monitoring devices.”

SOURCE: European Heart Journal, July 2004.