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[Obstructive myocardiopathic hypertrophy and sequential atrioventricular stimulation. Immediate results and long term
J C Tascón1, A Albarrán, F Hernández
1Servicio de Cardiología. Hospital Universitario 12 de Octubre. Madrid.
Insights
Sequential AV pacing effectively reduces obstruction and improves heart function in severe hypertrophic obstructive cardiomyopathy patients. This pacing therapy offers a viable, less invasive alternative to surgery, especially for older individuals.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
Background:
- Hypertrophic obstructive cardiomyopathy (HOCM) presents challenges in primary treatment selection.
- The efficacy of sequential pacing in HOCM remains a subject of ongoing debate.
- Evaluating pacing's impact on cardiac function and clinical outcomes in medically refractory HOCM is crucial.
Purpose of the Study:
- To assess the effects of sequential pacing on left ventricular systolic and diastolic function in HOCM patients.
- To investigate the repercussions of pacing on the pathophysiology of HOCM.
- To determine changes in clinical evolution and functional class in HOCM patients unresponsive to medical therapy.
Main Methods:
- Thirty-four patients with severe HOCM (Functional Class III-IV) were evaluated.
- The study involved Holter monitoring, serial echo-Doppler assessments, and cardiac catheterization.
- Thirty patients received permanent dual-chamber pacemakers, with function assessed hemodynamically and via imaging.
Main Results:
- Sequential pacing significantly reduced subaortic gradient, left ventricular pressures, and mitral regurgitation.
- Diastolic function showed marked improvement, evidenced by increased early filling and E/A relation.
- All patients experienced improved functional class, enabling reduced pharmacological therapy.
Conclusions:
- Sequential AV pacing is effective in reducing hemodynamic obstruction and improving diastolic function in selected severe HOCM patients.
- Pacing leads to significant symptomatic improvement and allows for decreased medical treatment.
- This modality presents a viable alternative to surgery, particularly for elderly HOCM patients, with potentially lower risks.
Background:
Sequential pacing as a primary treatment for patients with severe hypertrophic obstructive cardiomyopathy is still under controversy. In this study we sought to evaluate the effects of pacing on left ventricular systolic and diastolic function, its repercussion on pathophysiology and the possible changes in clinical evolution and functional class in patients who didn't respond to medical therapy.
Patients And Methods:
Thirty-four patients with severe hypertrophic obstructive cardiomyopathy in functional class III-IV underwent evaluation. The mean age was 64 +/- 11 years. Sixty-two per cent were over 65. The study protocol included Holter monitoring, baseline echo-Doppler, during pacing, at 6 months and at the end of follow-up, and a complete catheterization and coronary angiography. Mean follow-up time was 36 +/- 20 month (range 6-74). In four patients sequential pacing was ineffective and the protocol had to be discontinued. Thirty patients received a permanent dual-chamber pacemaker and systolic and diastolic function were evaluated by hemodynamic, angiographic and eco-Doppler studies.
Results:
Long-term stimulation reduced the subaortic gradient from 95 +/- 38 to 39 +/- 28 mmHg (p < 0.001), left ventricular systolic pressure from 207 +/- 38 to 164 +/- 30 mmHg (p < 0.001) and left ventricular end-diastolic pressure from 23 +/- 7 to 14 +/- 5 mmHg (p < 0.001), pulmonary capillary wedge pressure from 19 +/- 7 to 14 +/- 5 mmHg (p < 0.001), ejection fraction from 79 +/- 6 to 71 +/- 6% (p < 0.001) and mitral insufficiency. Diastolic function improved with an increase in early filling from 39 +/- 11 to 52 +/- 10% (p < 0.001) and E/A relation from 0.93 +/- 0.4 to 1.6 +/- 0.8 (p < 0.001), and a reduction in late filling from the left ventricle from 36 +/- 10% to 24 +/- 10% (p < 0.001). The speed of the E wave increased from 0.83 +/- 0.3 to 0.92 +/- 0.3 (p < 0.001) and we observed a reduction of the A wave from 93 +/- 0.3 to 0.66 +/- 0.2 (p < 0.001), pressure-half time from 95 +/- 34 to 66 +/- 19 ms (p < 0.001) and we observed deceleration time from 320 +/- 90 to 221 +/- 57 (p < 0.01). All patients have improved their functional class, allowing a reduction in pharmacological therapy. Two exitus of cardiological origin occurred.
Conclusions:
Sequential AV pacing in selected patients with severe hypertrophic obstructive cardiomyopathy can reduce subaortic gradient, pulmonary capillary wedge, left ventricular filling pressures and the severity of mitral regurgitation, and improve the markedly altered diastolic function. The significant symptomatic improvement allows a reduction in medical treatment. Thus, it represents a viable alternative to open-heart surgery, particularly in elderly patients, with lower morbidity and mortality rates.