Right ventricular pacing at conventional sites (outflow tract, middle RV, apex) with increasing voltages did not change QRS morphology or duration to capture the His-Purkinje system.
RCT (n=12)
Random order
Does pacing from conventional right ventricular sites (apical and nonapical) capture the His-Purkinje system and narrow QRS duration in patients with normal baseline QRS?
Conventional right ventricular pacing from the apex, mid-RV, or outflow tract cannot capture the His-Purkinje system or narrow the QRS duration, indicating no electrical synchrony advantage among these sites.
INTRODUCTION: Direct His bundle capture may negate ventricular electrical dyssynchrony induced by right ventricular (RV) apical pacing. We sought to evaluate if direct His bundle pacing is possible with conventional pacemaker lead implantation at various sites in the RV. METHODS: Consecutive patients underwent RV pacing using standard implantable active fixation pacing leads in a random order in the RV outflow tract, middle RV, and RV apex at stimulation threshold and at increasing voltages of 2.5, 5, 7.5, and 10 volts (V). At each location, QRS width and morphology on 12-lead electrocardiograph (ECG) were compared in sinus and paced rhythm at the different voltages. RESULTS: Twelve patients underwent a total of 2,160 paced QRS measurements. Progressive increases in stimulation voltage did not change QRS morphology or duration regardless of site of pacing (RV outflow tract, middle RV, and RV apex) in any of the 12 ECG leads. In addition, apart from the stimulation threshold between the RV outflow tract and RV apex, there was no statistically significant difference in QRS duration between the three pacing sites. CONCLUSION: In patients with a baseline normal QRS duration, none of the three conventional RV pacing sites were able to produce QRS narrowing and capture the His-Purkinje system. Furthermore, based on paced QRS duration as an indirect surrogate of electrical LV dyssynchrony, there was no clear advantage of one pacing site over another.
Pang et al. (Thu,) conducted a rct in Patients undergoing right ventricular pacing (n=12). Right ventricular pacing at various sites (outflow tract, middle RV, apex) vs. Different pacing sites and sinus rhythm was evaluated on QRS width and morphology on 12-lead ECG. Right ventricular pacing at conventional sites (outflow tract, middle RV, apex) with increasing voltages did not change QRS morphology or duration to capture the His-Purkinje system.