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Dual chamber pacing for patients with hypertrophic obstructive cardiomyopathy: a clinical perspective in 2000
J P Erwin1, R A Nishimura, M A Lloyd
1Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic Rochester, Rochester, MN 55905, USA.
Insights
Dual chamber pacing offers subjective symptom improvement for some hypertrophic obstructive cardiomyopathy patients. However, objective measures like maximal oxygen consumption did not significantly improve with this intervention.
Area of Science:
- Cardiology
- Medical Devices
Background:
- Hypertrophic obstructive cardiomyopathy (HOCM) can cause severe, exercise-limiting symptoms due to dynamic left ventricular outflow tract obstruction.
- Dual chamber pacing is a potential therapeutic option for symptomatic HOCM patients refractory to medical management.
Observation:
- This study evaluated the Mayo Clinic experience with dual chamber pacing in 38 HOCM patients with pacemakers implanted for intractable symptoms.
- Follow-up averaged 24 months, assessing subjective improvements and objective functional capacity.
Findings:
- Subjective symptom improvement was reported by 47% of patients following dual chamber pacing.
- No statistically significant difference was observed in maximal oxygen consumption compared to baseline (AAI pacing).
Implications:
- Dual chamber pacing may provide symptomatic relief for a subset of HOCM patients.
- The lack of objective functional improvement suggests careful patient selection and expectation management are crucial.
Abstract:
In some patients with hypertrophic cardiomyopathy, the dynamic left ventricular outflow tract obstructive gradient results in exercise-limiting symptoms of dyspnea, angina, and syncope. Dual chamber pacing has been proposed as a widely available alternative treatment for a subset of patients with symptomatic hypertrophic obstructive cardiomyopathy. Initial studies showed a reduction in gradient and an improvement in symptoms in almost 90% of patients with severe symptoms. We report the Mayo Clinic experience with dual chamber pacing in 38 patients with hypertrophic obstructive cardiomyopathy who had permanent pacemakers implanted for limiting symptoms intractable to medical therapy. After a mean +/- SD follow-up of 24 +/- 14 months, subjective improvement was reported in 47% of patients. However, there was no statistical difference between the maximal oxygen consumption at last follow-up and AAI pacing (atrial sensing and atrial pacing) (18.6 +/- 1.1 mL.kg-1.min-1) (i.e., when the pacemaker was implanted but not pacing continuously). This article discusses the clinical perspective on the utility of dual chamber pacing for patients with hypertrophic obstructive cardiomyopathy.