RIght VErsus Left Apical transvenous pacing for bradycardia: Results of the RIVELA randomized study.

AIMS: To compare cardiac function when pacing from the right or left ventricular apex in patients with preserved left ventricular systolic function, at 1-year follow-up.

METHODS: Prospective, multicentre centre randomizing conventional right ventricular apical (RVA) versus left ventricular apical (LVA) pacing using a coronary sinus lead in patients requiring ventricular pacing for bradycardia. Follow-up was performed using 3D-echocardiography at 6 and 12 months.

RESULTS: A total of 36 patients (age 75.4 ± 8.7 years, 21 males) were enrolled (17 patients in the RVA group and 19 patients in the LVA group). A right ventricular lead was implanted in 8 patients in the LVA group, mainly because of high capture thresholds. There were no differences in the primary endpoint of LVEF at 1 year (60.4 ± 7.1% vs 62.1 ± 7.2% for the RVA and LVA groups respectively, P = 0.26) nor in any of the secondary endpoints (left ventricular dimensions, left ventricular diastolic function, right ventricular systolic function and tricuspid/mitral insufficiency). LVEF did not change significantly over follow-up in either group. Capture thresholds were significantly higher in the LVA group, and two patients had unexpected loss of capture of the coronary sinus lead during follow-up.

CONCLUSIONS: Left univentricular pacing seems to be comparable to conventional RVA pacing in terms of ventricular function at up to 1 year follow-up, and is an option to consider in selected patients (e.g. those with a tricuspid valve prosthesis).