Reverse ventricular remodeling and improved functional capacity after ventricular resynchronization in advanced heart failure.

Background: Ventricular resynchronization is a non-pharmacological treatment for advanced heart failure refractory to drug therapy and with intraventricular conduction delay. We describe the time course of echocardiographic and functional recovery after resynchronization in 31 patients (mean age 67 +/- 8 years).

Methods: We evaluated NYHA class, echocardiogram, respiratory function, and cardiopulmonary test before pacemaker implantation (baseline), after 1-3 months (short-term evaluation), and 10-15 months afterwards (long-term evaluation, n = 21 patients). Mortality at 1 year was considered.

Results: Both at short and long-term, patients improved NYHA class, ventricular function, and ventricular volumes. Already at short-term, we observed an increase in oxygen consumption at peak exercise (12.6 +/- 0.6 vs 10.5 +/- 0.5 ml/kg/min), oxygen consumption at anaerobic threshold (9.8 +/- 0.6 vs 8.3 +/- 0.6 ml/kg/min) and oxygen pulse (8.3 +/- 0.5 vs 7.5 +/- 0.5 ml/beat). Ventilatory efficacy (VE/VCO2 slope) and alveolo-capillary diffusion (estimated by the measurement of lung diffusion capacity for carbon monoxide - DLCO) improved only at long-term (VE/VCO2: 40.7 +/- 1.6 vs 45.3 +/- 1.8; DLCO: 70.3 +/- 2.7 vs 59.4 +/- 5.9% of predicted, p = 0.05). The 1-year mortality was 9.7%.

Conclusions: Ventricular resynchronization is linked to a fast and prolonged recovery of NYHA class, echocardiographic variables and stress tolerance. The improvement of indexes known to carry a prognostic value confirms that ventricular resynchronization can positively interfere with the evolution of the disease.