Alternative Methods
Dual chamber pacing (DDD) may be able to relieve symptoms in those patients who are deemed high risk for ASA. Krejci et al. compared the long-term effects of DDD pacing and ASA in symptomatic patients. Patients treated with DDD pacing had reduced NYHA class symptoms, and LVOT gradient, however no significant difference in change in LVOT gradient and left ventricular ejection fraction (LVEF) was found between both groups. The ASA group showed greater improvement in NYHA class, greater reduction in interventricular septum (IVS) thickness and LV diastolic diameter. Both groups were followed up over a period of 7-8 years and revealed that ASA can provide a consistent reduction in LVOT gradient over this period. Surgical myectomy or ASA can effectively reduce the physical obstruction in HOCM by reducing basal septal hypertrophy and relieve SAM, and are the ideal methods for symptomatic patients, DDD appears to produce promising results in the long term reduction of LVOT gradients and may be useful in high risk patients, this however will require further study. [19]
Surgical myectomy (SM) has been deemed to be gold standard in the invasive treatment of HOCM, and a preferable option to younger and low risk patients (table 3). Surgical myectomy is also a convenient option to those who need concomitant cardiac surgery such as coronary artery bypass grafting or surgical valve replacement. Good results have been shown in high volume centres. Rastegar et al. performed surgical myectomy on patients with NYHA class III-IV symptoms; they found significant reduction in resting LVOT gradients. Of the 31 patients who had severe MR, 87% had no or mild MR post procedure. 30-day deaths were 0.8% and no patient required repeat intervention, and 3% had ASA prior to SM and required reintervention due to heart failure symptoms. 43 out of 482 patients needed PPM, 4 developed ischaemic stroke in the peri operative period and 21% developed atrial fibrillation. At follow up 64% had NYHA class I and 29% with class II symptoms. [20] Xin et al. evaluated the follow up results of those who underwent ASA and SM. No significant differences were noted in IVS thickness reduction, LV end diastolic diameter, or degree of SAM at follow up between the two groups. There was however greater reduction in the resting LVOT gradient in the SM group, with 81% of patients having completely eliminated their pressure gradients. Both groups showed improvement with NYHA class, but there was no significant difference. PPM implantation was 24% and 7.7% in the ASA and SM groups respectively and hospital stay was much shorter in the ASA group. [21] Yao et al. also produced promising results with SM, showing no deaths within 30 days, post-operative hospital stay was around 10 +/- 5, and NYHA reduced greatly from 2.5- and 5-years post-surgery. Severe and moderate MR had completely disappeared and the most common post-operative arrhythmia was left bundle branch block (LBBB) 24.5%. [22]
Firoozi et al. performed a non-randomised cohort study comparing ASA and SM. They found that both procedures had significant reduction in LVOT gradients; with 91% of SM patients having a gradient below 20 mmHg post procedure, compared to the 74% in the ASA group. 15% of the ASA group required PPM compares to the 4% in the SM group. The improvement in functional class was similar in both groups. Peak VO2 was greater in the myectomy group. Peak LVOT gradient at 12 months were similar in both groups. [23]