Rate-responsive pacing in patients with heart failure: long-term results of a randomized study.

AIMS

Chronotropic incompetence (CI) in patients with congestive heart failure (CHF) develops frequently under beta-blocker and amiodarone therapy. It can be corrected by pacing. We performed a randomized study to test whether pacing is beneficial in CHF patients with CI.

METHODS AND RESULTS

Congestive heart failure patients under combined beta-blocker and amiodarone therapy (n = 77) were randomly assigned to inhibited pacing (INH; basal rate 40 bpm/hysteresis 30 bpm; n = 38) or to DDDR pacing with optimized atrioventricular delay (OPT; stimulation rate 65-120 bpm, n = 39). Groups showed similar baseline values in NYHA class, heart rate, and ejection fraction (EF) and were followed up to 10 years. The resting and mean 24 h heart rate after 1 year decreased by -2.6/-5 bpm in INH, but increased by +3.6/+6.0 bpm in the OPT group (P < 0.001). The QRS interval after 1 year increased by 12 +/- 23 ms in the INH group, but +32 +/- 36 ms in the OPT group (P < 0.01). Patients with INH developed a greater left ventricular EF (LVEF) when compared with OPT patients (+10.6 +/- 8 vs. +2 +/- 10%, respectively; P = 0.04). Changes in LVEF were negatively correlated with heart rate, but not with QRS width changes. Prognosis and the event rate were better in the INH group.

CONCLUSION

In the long-term follow-up, single-site ventricular pacing in patients with CHF and low LVEF is associated with significant clinical events and a poor prognosis.