Related Experiment Videos
[Pacemaker therapy of hypertrophic obstructive cardiomyopathy. PIC (Pacing in Cardiomyopathy) Study Group]
E Meisel1, T Rauwolf, M Burghardt
1Klinik für Kardiologie, Herz- und Kreislaufzentrum an der Technischen Universität Dresden. cardiology@meisel.de
Insights
Dual-chamber pacemaker (DDD) therapy significantly reduces pressure gradients and improves symptoms in patients with hypertrophic obstructive cardiomyopathy. This pacing approach offers a viable treatment option, particularly for older individuals.
Area of Science:
- Cardiology
- Medical Devices
Background:
- Pharmacological treatments for hypertrophic obstructive cardiomyopathy (HOCM) are often insufficient.
- Surgical myectomy and septal ablation are alternatives, but comparative data with pacing is limited.
- Short atrioventricular delay dual-chamber pacing has shown promise in reducing HOCM-related outflow tract obstruction.
Purpose of the Study:
- To prospectively evaluate the efficacy of dual-chamber pacemaker (DDD) therapy with optimized short atrioventricular delay in patients with drug-refractory hypertrophic obstructive cardiomyopathy.
- To compare DDD pacing against an inactivated pacemaker mode (AAI) in a randomized crossover design.
Main Methods:
- A multicenter, prospective, double-blind, randomized crossover study involving 83 patients with symptomatic HOCM and pressure gradients >30 mm Hg.
- Patients received a DDD pacemaker and were randomized to activated (DDD) or inactivated (AAI) modes for 12 weeks, followed by crossover.
- Hemodynamic parameters (echo-Doppler), exercise capacity (spiroergometry), and symptom scores (NYHA, angina, dyspnea, quality of life) were assessed.
Main Results:
- DDD pacing significantly reduced the median pressure gradient from 59 to 30 mm Hg (p < 0.001) after 12 weeks.
- Patient endurance improved by 21% in the DDD mode.
- Significant improvements were observed in NYHA functional class, dyspnea, and angina symptoms.
- Age was a significant factor, with marked improvements noted in patients aged 60-70 years.
Conclusions:
- DDD pacemaker therapy with optimized short AV delay is effective in reducing pressure gradients and improving symptoms in patients with hypertrophic obstructive cardiomyopathy.
- This pacing strategy is particularly beneficial for older patients.
- Further randomized studies are needed to compare pacing with myectomy and septal ablation for younger patients or those with higher gradients.
Abstract:
Clinical management of patients with symptoms caused by pharmacological refractory hypertrophic obstructive cardiomyopathy must consider surgical myectomy, percutaneous transluminal septal myocardial ablation and implantation of a DDD pacemaker. Until now, no prospective, double blind, randomized studies have yet been carried out to determine the merits of each of these treatment alternatives. However, uncontrolled studies have shown that short atrioventricular delay dual-chamber pacing reduces outflow tract obstruction. Aim of the study was to investigate the results of the pacemaker therapy in a prospective, double blind randomized crossover procedure. All patients with hypertrophic obstructive cardiomyopathy included in this multicenter study were either refractory or intolerant to drugs and typically had pressure gradients higher than 30 mm Hg. In 83 patients, mean age 53 (18 to 82) years who responded favorably to a temporary pacing test, a DDD pacemaker was implanted. After echo- and echo-Doppler-based measurements of hemodynamic parameters the patients were randomized into 2 groups, those with an implanted pacemaker in the inactivated mode (AAI) and those with a pacemaker in the activated mode (DDD with optimized short AV delay). A crossover of these groups was performed after 12 and 24 weeks, respectively. Both objective parameters of echo including Doppler, and spiroergometry, and subjective parameters of angina, dyspnea, and quality of life were recorded. Additionally, subgroups based on age decades were analyzed. After 12 weeks in the DDD mode, regardless of the randomization sequence, a decrease of the pressure gradient from 59 +/- 36 mm Hg (median) to 30 +/- 25 mm Hg was proven significant (p < 0.001). The endurance of the patients who, during screening, achieved less than 10 minutes of exercise by the Bruce protocol improved by 21% under DDD mode. The main symptoms, as measured by the NYHA classification, improved statistically significant from a mean of 2.4 to 1.7 for functional class, from a mean of 2.4 to 1.4 for dyspnea and from a mean of 1.0 to 0.4 for angina. Subgroup analysis showed improvements depended significantly upon age, with a marked improvement between the ages of 60 and 70, which was statistically significant as compared to other decades. Subjective improvements in the quality-of-life of patients was measured using a specially developed questionnaire. These findings justify, by all means, the intention to implant a DDD pacemaker in older patients. In younger and/or such patients with elevated pressure gradients, the results of ongoing randomized studies comparing myectomy, PTSMA and pacing have to be considered.