Effect of right ventricular pacing site on QRS width

Area of Science:

• Cardiology
• Electrophysiology
• Medical Device Technology

Background:

• Right ventricular pacing is crucial for managing bradycardia and certain tachycardias.
• The pacing site within the right ventricle can influence ventricular depolarization and QRS duration.
• Understanding optimal pacing locations is essential for improving pacing efficiency and reducing potential complications.

Purpose of the Study:

• To evaluate the impact of different right ventricular pacing sites on QRS duration.
• To identify specific pacing locations that result in the shortest paced QRS duration.
• To compare QRS duration across five distinct right ventricular pacing sites.

Main Methods:

• Fifty patients (16 with bradycardia, 34 with tachycardia) were enrolled.
• The right ventricle was divided into five pacing regions: high/low right ventricular outflow tract, mid-septum, low septum, and apex.
• Right ventricular pacing was performed sequentially at each of the five sites using an electrode catheter.

Main Results:

• Paced QRS duration varied significantly across pacing sites, ranging from 143 ± 17 ms (low right ventricular outflow tract) to 167 ± 18 ms (apex).
• The shortest QRS duration was observed during mid-septal and low right ventricular outflow tract pacing compared to apical pacing in most patients.
• In 32% of patients, QRS duration was similar between septal and apical pacing sites.

Conclusions:

• Pacing from the right ventricular septum, especially the low outflow tract, can lead to shorter QRS durations.
• Site selection for right ventricular pacing can influence QRS duration, with septal pacing showing a trend towards narrower complexes.
• Individual patient variability exists, and QRS duration may be similar across different pacing sites in a subset of patients.