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Subacute and chronic effects of DDD pacing on left ventricular diastolic function in patients with non-obstructive
K Watanabe1, M Sekiya, S Ikeda
1Department of Cardiology, Saiseikai Saijo Hospital, Ehime, Japan.
Insights
Dual-chamber (DDD) pacing significantly improved symptoms and exercise capacity in patients with non-obstructive hypertrophic cardiomyopathy (HNCM) refractory to medication. This intervention enhanced left ventricular diastolic function, suggesting its potential therapeutic value.
Area of Science:
- Cardiology
- Medical Devices
- Heart Failure
Background:
- Non-obstructive hypertrophic cardiomyopathy (HNCM) presents challenges in symptom management and exercise intolerance.
- Pharmacotherapy often proves insufficient for patients with HNCM.
- Dual-chamber (DDD) pacing is a potential therapeutic option for improving cardiac function.
Purpose of the Study:
- To evaluate the efficacy of DDD pacing in ameliorating symptoms and enhancing exercise tolerance in patients with HNCM.
- To assess the impact of DDD pacing on left ventricular diastolic function in HNCM patients.
Main Methods:
- Seven patients with HNCM, unresponsive to pharmacotherapy, underwent permanent DDD pacemaker implantation.
- New York Heart Association (NYHA) functional class and treadmill exercise tests were conducted before and after pacing.
- Echocardiography was performed to assess left ventricular diastolic function, including flow velocity patterns and filling rates.
Main Results:
- DDD pacing led to significant improvements in the ratio of early to late diastolic flow velocity, deceleration time, peak filling rate, NYHA functional class, and exercise tolerance.
- Left ventricular dimensions, fractional shortening, ejection fraction, acceleration time, and isovolumic relaxation time showed no significant changes.
- Two patients were excluded due to adverse reactions during temporary pacing.
Conclusions:
- DDD pacing effectively improves symptoms and functional status in HNCM patients, correlating with enhanced left ventricular diastolic function.
- This pacing strategy may be beneficial for both obstructive and non-obstructive hypertrophic cardiomyopathy cases refractory to medical treatment, with careful patient selection.
Abstract:
The present study examined the ability of dual-chamber (DDD) pacing to improve symptoms and exercise tolerance in patients with non-obstructive hypertrophic cardiomyopathy (HNCM). Seven patients with HNCM who had failed to benefit from pharmacotherapy participated in the study. The New York Heart Association (NHYA) functional class status and exercise tolerance, which was determined by the treadmill exercise test, were recorded and an echocardiographic observation was performed before, and 1 week, 3 months and 1 year after the implantation of a permanent DDD pacemaker. The atrioventricular delay (AVd) was determined by measuring the point of peak rapid filling velocity and maximum cardiac output (CO). Two patients were not implanted with a permanent pacemaker because their CO and blood pressure decreased or because palpitation occurred during temporary pacing. The ratio between early and late peaks of flow velocity (1.56, 1.21,0.95, and 0.86 before implantation and 1 week, 3 months and 1 year after implantation, respectively); deceleration time (ms: 263.2, 217.6, 204.6, 187.0); peak filling rate (ml/s: 146.2, 204.0, 233.2, 243.6); NYHA functional class status (2.0, 1.8, 1.6, 1.4); and exercise tolerance (s: 203, 264, 403, 480) were significantly improved after implantation. However, left ventricular dimension, percent fractional shortening, ejection fraction, acceleration time and the isovolumic relaxation time were not changed significantly. In conclusion, DDD pacing improved symptoms and the NYHA functional class status, which is associated with improvement of left ventricular diastolic function. It is proposed that DDD pacing would be useful in patients not only with obstructive but also non-obstructive hypertrophic cardiomyopathy refractory to medical treatment, depending on the careful selection of subjects.