Researchers conducted a randomized clinical trial involving 173 adults across 14 hospitals in Brazil. These patients had symptomatic heart failure with reduced ejection fraction and a specific heart rhythm block known as left bundle-branch block. The study compared conduction system pacing, which preferentially targets the left bundle-branch area, against standard biventricular pacing.
The primary results showed that conduction system pacing failed to meet noninferiority standards and was actually inferior to biventricular pacing. Specifically, the risk of death, heart failure hospitalizations, or urgent visits was higher with conduction system pacing. Additionally, changes in left ventricular ejection fraction were 3.8% lower on average with the new pacing method.
While total direct medical costs were lower with conduction system pacing, the clinical outcomes were worse. The study authors note that these findings do not support using conduction system pacing as the routine first-line resynchronization strategy for this specific population. Readers should understand that this trial was limited to a small number of patients and a single country, which may affect how widely these results apply.