Predictors of a sustained response to exercise training in patients with chronic heart failure: a telemonitoring study.

BACKGROUND Exercise training (ExT) improves exercise capacity in chronic heart failure, but the results of home-based training have been variable. We sought the predictors of favorable outcome using a telemonitoring approach. METHODS Exercise capacity and quality of life (QOL) were assessed in 30 patients (28 men, age 64 +/- 8 years) with symptomatic chronic heart failure and left ventricular ejection fraction < or = 35% (28% +/- 9%) undergoing 8 months of home ExT. Patients were provided with heart rate monitors and exercise diaries after undergoing 4 months of hospital-based ExT. Weekly telephone contact was established and heart rate data were downloaded bimonthly. Changes in peak oxygen consumption per unit time (V*O2) and QOL were compared between the 15 most and 15 least adherent patients defined by the number of hours per week at > 60% maximum heart rate, observed during heart-rate monitoring. RESULTS Peak V*O2 increased by 26% (P < .001) after 4 months of hospital ExT, but this increase had fallen to 8% (P = .07) at 12 months; only adherent patients (n = 15) showed persistent improvement of peak V*O2 at 12 months (P = .02). Improvement in peak V*O2 at 12 months was associated with baseline peak V*O2 (r = -0.61, P < .001) and hours logged on the heart rate monitor (r = 0.47, P = .01). Quality of life improvements were sustained at 12 months for the Minnesota Living with Heart Failure Questionnaire and Hare-Davis Depression Questionnaire. Nevertheless, QOL improvements achieved during the outpatient program were lost or attenuated at 12 months in nonadherent patients but were maintained in adherent patients. CONCLUSIONS Telemonitoring is feasible for following adherence to home ExT. Ongoing adherence is critical in obtaining sustained benefit from ExT in heart failure.