Introduction: Wide paced QRS duration reflects large ventricular conduction delay. The aim of this study was to detect relationship between paced QRS duration and underlying conduction disturbances.
Methods: Study subjects were 125 patients with a DDD pacemaker (mean 76±9 year-old, 65 males, RV apical pacing in 61 and non-apical pacing in 63) and preserved LV function. Underlying conduction disturbances were sinus node dysfunction (SND) in 25, AH/BH block in 60 and HV block in 34 patients. Paced QRS duration was compared among those groups.
Results: Paced QRS duration was significantly wider in patients with HV block (178 ± 12 msec) than in patients with SND and AH/BH block (159 ± 17 and 155 ± 14 msec, p<0.01). This tendency was similar if compared among the patients with non-apical pacing. Positive correlation between the intrinsic and paced QRS duration was also found (r=0.48, p<0.01).
Conclusions: Patients with HV block showed wider paced QRS duration regardless of the RV pacing site. Conduction disturbance may exist more widely in the ventricle in patients with HV block, therefore, they are potentially candidate for CRT.