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Personalized distal ventricular pacing therapy reduced obstruction and improved exercise performance in patients with HCM with refractory, symptomatic LVMCO.

Distal ventricular pacing therapy tailored to individual patient characteristics significantly reduced obstruction and improved exercise performance in patients with hypertrophic cardiomyopathy with refractory, symptomatic left ventricular mid-cavity obstruction (LVMCO), according to a study published in Circulation: Arrhythmia and Electrophysiology.

“Our group has pioneered the use of invasive hemodynamic assessments made during a multisite pacing study to determine optimal pacing configurations,” wrote corresponding author Saidi A. Mohiddin, MD, of St. Bartholomew’s Hospital in London, England, and study coauthors. “Initial data obtained in severely symptomatic patients with LVMCO with conventional indications for device therapy demonstrated that this personalized prescription of pacing approach reduced LVMCO gradients and was associated with symptomatic improvement in an unrandomized cohort of 16 patients.”

Encouraged by the observational data, researchers conducted a single-center, randomized, blinded trial of personalized prescription of pacing in 16 patients with LVMCO with severe drug-refractory symptoms. Patients received 6 months of active personalized prescription of pacing therapy guided by invasive hemodynamics or backup pacing in a crossover design.

In personalized prescription of pacing, patient-specific pacing-site and atrioventricular delays were chosen based on LVMCO gradient reduction and acceptable pacing parameters.

According to the study, with best-site pacing, the mean baseline LVMCO gradient dropped 60%, from 80 ±29 mm Hg to 31 ±21 mm Hg. During implant, one cardiac vein perforation occurred, causing the withdrawal of a single patient.

Fifteen patients entered crossover, during which two withdrawals occurred due to adverse events unrelated to the study. Among the 13 patients who completed crossover and were asked in which phase, if any, they felt better, 69% chose the active pacing phase while still masked to treatment allocation. Thirty-one percent reported no symptom differences between the phases, researchers reported.

Personalized prescription of pacing was associated with a 43 ±47 m mean increase in distance on the 6-minute walk test compared with backup pacing. Other secondary outcome measures, including the Short Form-26 general health score and Kansas City Cardiomyopathy Questionnaire scores, also showed benefits with personalized prescription of pacing.

“This study provides the basis for a multicenter trial of personalized prescription of pacing for LVMCO and for the use of site-specific pacing in managing other forms of hypertrophic cardiomyopathy,” the researchers wrote.