Cardiac resynchronisation therapy significantly increased exercise cardiac output by 19.3% (P=0.0048) and peak cardiac power output by 37.2% (P=0.0008) in patients with severe heart failure.
Cohort (n=17)
Does CRT pacemaker implantation improve exercise capacity and functional reserve in patients with severe heart failure and widened QRS?
CRT significantly improves cardiac flow, pressure, and power-generating capacity during exercise in patients with severe heart failure, correlating with improved exercise capacity and symptoms.
Effect estimate: +19.3%
p-value: p=0.0048
BACKGROUND: While information on how cardiac resynchronisation therapy (CRT) affects cardiac performance at rest is readily available, the mechanisms whereby CRT alters cardiac function during maximal exercise are unclear. AIMS: We examined the medium-term effects of CRT on cardiac and physical functional reserve of patients with severe heart failure (CHF) and prolonged QRS duration. METHODS: Seventeen consecutive patients with severe CHF (NYHA III-IV) and widened QRS underwent maximal cardiopulmonary exercise testing with non-invasive central haemodynamic measurements before and 6-8 weeks after CRT pacemaker implantation. RESULTS: After CRT there were significant increases in exercise cardiac output by 19.3% (P=0.0048) from 9.5+/-3.4 l min(-1), peak mean arterial blood pressure by 14.1% (P=0.0001) from 91.3+/-13.6 mm Hg, and peak cardiac power output by 37.2% (P=0.0008) from 1.92+/-0.74 W. There were no significant changes in these variables at rest. Exercise duration (+42.3%, P=0.0002), NYHA functional class (P=0.0001) and SF-36 symptom score (P=0.0006) were also significantly improved. Powerful surrogate indicators of prognosis were also significantly improved with CRT: peak O(2) consumption (+20.9%, P=0.0007), VE/VCO(2) slope (-20.0%, P=0.005) and circulatory power (+42.0%, P=0.0012). CONCLUSION: In this cohort of patients, post-implant CRT significantly improved the flow-, pressure- and power-generating capacity of the failing hearts. This may be causally related to the improvements observed in exercise capacity, functional class and symptom scores.
Schlosshan et al. (Wed,) conducted a cohort in severe heart failure (CHF) and prolonged QRS duration (n=17). Cardiac resynchronisation therapy (CRT) vs. Baseline (before CRT) was evaluated on exercise cardiac output (+19.3%, p=0.0048). Cardiac resynchronisation therapy significantly increased exercise cardiac output by 19.3% (P=0.0048) and peak cardiac power output by 37.2% (P=0.0008) in patients with severe heart failure.