Background: Cold exposure decreases ischemic threshold in patients with coronary artery disease and preserved left ventricle (LV) function. The impact of cold exposure and the effect of acute angiotensin-converting enzyme (ACE) inhibitor therapy on maximal exercise capacity have not been studied in patients with symptomatic congestive heart failure.
Methods and results: Eleven patients with New York Heart Association class II and III congestive heart failure, aged 61 6 years (mean SD), with LV ejection fraction 25 6%, completed four symptoms-limited maximal exercise tests at 20 C and -8 C in a cold chamber. The exercise tests were performed while the patients were treated with lisinopril for three days, or a placebo. Cold exposure significantly decreased exercise duration in patients treated with a placebo (506 156 s [20 C] versus 419 182 s [-8 C], P<0.01). Rate-pressure products measured at 4 min during the test and at peak performance were significantly increased at -8 C. Patients treated with lisinopril exhibited a significant attenuation of the decrease in exercise time in the cold (-17% for placebo versus -6.6% for lisinopril, P<0.05).
Conclusions: Cold temperature increases cardiac demand in response to exercise and significantly reduces maximal exercise capacity in patients with symptomatic heart failure. Acute treatment with lisinopril attenuates the impact of cold on exercise capacity.