ORLANDO – Pacing at the bundle of His was associated with significantly reduced morbidity and mortality, compared with right ventricular pacing, over time in a large observational registry of patients needing a permanent pacemaker for bradycardia, Mohamed Abdelrahman, MD, reported at the annual meeting of the American College of Cardiology.
The superiority of His-bundle pacing (HBP) was concentrated in patients who required ventricular pacing more than 20% of the time. This finding is consistent with previous reports that even a modest utilization of ventricular pacing is sufficient to boost the risk of left ventricular dysfunction secondary to electrical and mechanical dyssynchrony, added Dr. Abdelrahman of the Geisinger Heart Institute in Danville, Pa.
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Dr. Mohamed Abdelrahman
The primary study endpoint was a composite of all-cause mortality, heart-failure hospitalization, and biventricular pacing upgrade. During a mean 2 years of follow-up, this endpoint was reached in 25% of the HBP group, compared with 32% of the RVP group, for a significant 29% relative risk reduction. In patients with a ventricular pacing burden greater than 20%, the primary endpoint occurred in 25% of the HBP group and 36% of patients with RVP, for a 35% relative risk reduction. However, in patients who required ventricular pacing less than 20% of the time, there was no significant difference in the primary outcome between the two groups.
Heart failure hospitalization occurred in 12.4% of the HBP group and 17.6% of the RVP patients, for a 37% relative risk reduction. In patients with ventricular pacing more than 20% of the time, the rates were 12.4% and 20.1%, for a 46% relative risk reduction in favor of HBP.
Among patients with a ventricular pacing burden of more than 20%, all-cause mortality occurred in 18% of the HBP group, compared with 23.7% of RVP-treated patients.
One patient in the HBP group required an upgrade to biventricular pacing, as did six patients in the RVP group. Lead revision was necessary in 14 patients in the HBP group, versus 2 in the RVP group. Pericardial effusion within the first month of pacemaker implantation occurred in three patients in the RVP group and did not occur in the HBP group.