Pacing in hypertrophic obstructive cardiomyopathy. A randomized crossover study. PIC Study Group

Area of Science:

• Cardiology
• Medical Devices
• Clinical Trials

Background:

• Short atrioventricular delay dual chamber pacing shows potential for reducing outflow tract obstruction in hypertrophic obstructive cardiomyopathy.
• The precise mechanism behind this beneficial effect remains unclear.
• This pacing approach presents a promising new treatment avenue for hypertrophic obstructive cardiomyopathy.

Purpose of the Study:

• To evaluate the impact of pacemaker therapy on hypertrophic obstructive cardiomyopathy.
• To assess modifications in echocardiography, exercise tolerance, angina, dyspnea, and quality of life.

Main Methods:

• A randomized, multicenter, double-blind, cross-over study was conducted.
• 83 patients with drug-refractory symptoms underwent pacemaker activation vs. non-activation phases.
• Evaluated echocardiography, exercise capacity, and symptom scores over 12 weeks.

Main Results:

• Active pacing reduced the pressure gradient from 59 mmHg to 30 mmHg (P < 0.001).
• Exercise tolerance improved by 21% in patients with baseline limitations.
• Significant improvements were observed in dyspnea (NYHA class 2.4 to 1.4) and angina (1.0 to 0.4), alongside enhanced quality of life.

Conclusions:

• Pacemaker therapy offers significant clinical and hemodynamic benefits for patients with hypertrophic obstructive cardiomyopathy.
• Patients with a resting left ventricular outflow gradient over 30 mmHg and persistent symptoms benefit from this intervention.
• This therapy represents an effective treatment option for managing severe, drug-resistant hypertrophic obstructive cardiomyopathy.