Key result
Right ventricular apex pacing yielded significantly higher mean R-wave amplitudes than outflow tract pacing (23 ± 13 mV vs 14 ± 8 mV; P<0.001), with similar ease of implantation.
Why the study?
Does pacing at the right ventricular outflow tract with active fixation leads compared to the right ventricular apex with passive leads affect electrical characteristics and complications in heart failure patients with LBBB?
RCT (n=36)
Single-blind
Crossover
Does pacing at the right ventricular outflow tract with active fixation leads compared to the right ventricular apex with passive leads affect electrical characteristics and complications in heart failure patients with LBBB?
Absolute Event Rate: 14% vs 23%
p-value: p=<0.001
In patients undergoing bifocal right ventricular pacing, R-wave amplitudes are higher at the RV apex compared to the outflow tract, though implant success rates are similar.
Right ventricular apex placement may enhance sensing reliability in bifocal pacing; extends RCT data on position-specific electrical performance in heart failure.
Bifocal RIGHT ventricular stimulation (BRIGHT) is an ongoing, randomized, single-blind, crossover study of atrial synchronized bi-right ventricular (RV) pacing in patients in New York Heart Association heart failure functional class III, a left ventricular ejection fraction <35%, left bundle branch block and QRS complexes >/=120 ms. This analysis compared the electrical and handling characteristics, and the complications of pacing at the RV apex (Ap) with passive, versus RV outflow tract (OT) with active fixation leads. A mean of 1.6 +/- 0.9 and 2.2 +/- 2.0 attempts were needed to position the Ap and OT leads, respectively (ns). R-wave amplitudes at Ap versus OT were 23 +/- 13 mV versus 14 +/- 8 mV (n = 36, P < 0.001). R-wave amplitudes at the Ap remained stable between implant and M7. R-wave amplitudes at the OT could not be measured after implantation. In two patients, atrioventricular block occurred during active fixation at the OT. Conduction recovered spontaneously within 4 months. Ventricular fibrillation was induced in one patient during manipulation of an Ap lead in the RV. Marked differences were found between leads positioned in the OT versus Ap, partly related to the difference in lead design. Mean R-wave amplitude was higher at the Ap that at the OT. Ease and success rate of lead implant was similar in both positions.
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C.J. et al. (2005) conducted an RCT in Heart failure (n=36). Right ventricular outflow tract (OT) pacing with active fixation leads vs. Right ventricular apex (Ap) pacing with passive fixation leads was evaluated on R-wave amplitude (mV) (p=<0.001). Right ventricular apex pacing yielded significantly higher mean R-wave amplitudes than outflow tract pacing (23 ± 13 mV vs 14 ± 8 mV; P<0.001), with similar ease of implantation.
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