Improved Hypertrophic Obstructive Cardiomyopathy by Left Ventricular Apex Epicardial Pacing

Abstract

We report a case of severe hypertrophic obstructive cardiomyopahy (HOCM) that was markedly improved by left ventricular (LV) apex epicardial pacing. A 55-year-old woman with HOCM had suffered from dyspnea. Cardiac catheter examination showed a resting pressure gradient across the LV outflow tract of 198 mmHg despite combined medication. During the examination, right dual-chamber pacing could not sufficiently reduce the pressure gradient. Therefore, we treated the patient with LV apex epicardial pacing. The procedure decreased the pressure gradient to 10 mmHg. Clinical symptoms were markedly improved. LV apex epicardial pacing may be an alternative therapy for patients with HOCM who are refractory to other medical treatment. IntroductionPatients with hypertrophic obstructive cardiomyopathy (HOCM) may present with progressive incapacitating symptoms, including dyspnea, angina, and syncope. These patients have a characteristic left ventricular outflow tract (LVOT) obstruction that divides the LV into a high-pressure apical region and a lower pressure subaortic region. Medical treatment (1, 2) or dual-chamber pacing (3, 4) can reduce LVOT obstruction and diminish symptoms. Patients who do not respond positively to these therapies require percutaneous transluminal septal myocardial ablation (PTSMA) (5, 6) or surgical resection of the affected portion of the interventricular septum (7,8). However, PTSMA is an irreversible therapy and reportedly causes complete atrioventricular (AV) block in about 50% of patients, some of them requiring a permanent pacemaker (9). Surgical resection requires extracorporeal circulation and is associated with a moderate surgical risk of 5% or greater (7). Recently, the effectiveness of LV epicardial pacing was proposed (10). Matsumoto demonstrated that LV postero-lateral epicardial pacing through the coronary sinus branch effectively reduced the pressure gradient more than right AV sequential pacing in a patient with HOCM (10). The author suggested that alterations of LV wall motion in association with an elimination of systolic anterior movement (SAM) and mitral regurgitation, caused by an inversion of the LV activation sequence, might result in the improvement of hemodynamics and the amelioration of obstruction (10). We report a case of severe HOCM that did not react to right dual-chamber sequential pacing with medication, but exhibited marked improvement by LV apex pacing with an epicardial lead. Case ReportA 55-year-old woman with HOCM had suffered from dyspnea and palpitation on effort for 2 years (NYHA class III). Because her symptoms were not improved by medical treatment, she was admitted to our hospital. On admission, her blood pressure was 96/54 mmHg and heart rate was 42 beats/min. A grade 4/6 ejection murmur at the left sternal border and 2/6 holosystolic murmur at the apex were audible. A 12-lead electrocardiogram revealed LV hypertrophy with a strain pattern. Echocardiographic findings showed asymmetric septal hypertrophy, narrowing of the midzone in LV (mid-LV), SA...

Effect of Biventricular Pacing on Left Ventricular Outflow Tract Pressure Gradient in a Patient with Hypertrophic Cardiomyopathy and Normal Interventricular Conduction

“…Rinaldi et al 9 examined the effect of biventricular pacing in a patient with HOCM and intraventricular conduction delay and observed a dramatic improvement in symptomatic status, exercise time, and hemodynamics assessed by echocardiography. Recently, Yufu et al 4 reported that left ventricular apical epicardial pacing markedly reduced LVOT gradient in a HOCM patient. However, they did not implant a right ventricular pacemaker lead and did not investigate the effect of biventricular pacing on pressure gradient 4 …”

“…Recently, Yufu et al 4 reported that left ventricular apical epicardial pacing markedly reduced LVOT gradient in a HOCM patient. However, they did not implant a right ventricular pacemaker lead and did not investigate the effect of biventricular pacing on pressure gradient 4 …”

“…Some studies reported that dual‐chamber (DDD) pacing with short atrioventricular (AV) delay can result in clinical and hemodynamic improvement 2,3 . Recently, LV epicardial pacing was proposed as an alternative treatment for patients with HOCM 4 . We report the effect of biventricular pacing on LVOT pressure gradient in a patient with HOCM.…”

Biventricular / Left Ventricular Pacing in Hypertrophic Obstructive Cardiomyopathy: An Overview

“…Subsequent single and multicentre randomized trials demonstrated average LVOT gradient reductions of only 50 percent and no improvement in exercise capacity [24-26], suggesting a placebo effect for the symptomatic improvement [24,27]. One possible explanation for this limited response could be that the change in motion of the interventricular septum induced by RVA pacing is too small to significantly reduce the LVOT gradient, because many HOCM patients have a very rapid AV conduction [28] and/or the RVA sites are at a distance away from the LV apex [29]. Moreover, recent long-term follow-up data suggests that DDD pacing in HOCM patients might have a deleterious effect on survival and heart failure by comparison with conservative management [30].…”

“…Later on, LV/biV pacing showed a significant LVOT gradient reduction superior to RVA pacing in HOCM patients without intraventricular conduction delay [29,33-35]. Recently, published data from three small studies suggest that LV/biV pacing might be efficient for LVOT gradient reduction and symptom improvement in a large proportion of HOCM patients not suitable for myectomy or ASA (Table 1) [36,39].…”