Objective:To evaluate the early effects of combined transaortic and transapical approach to septal myectomy in patients with complex hypertrophic obstructive cardiomyopathy(HOCM).Methods:We consecutively enrolled 20 complex HOCM patients who received transaortic and transapical myectomy in fuwai hospital from January 2019 to October 2019. Echocardiography was performed to compare left atrial size, left ventricular end diastolic diameter, peak left ventricular outflow gradient, ventricular septal thickness, mitral systolic anterior motion and mitral regurgitation grade before and after operation. Furthermore, pre-operative and post-operative electrocardiogram were also analyzed to determine the incidence of bundle branch block. Functional status was evaluated by New York Heart Association functional class.Results:Of the 20 complex hypertrophic cardiomyopathy patients, 7(35%) HOCM patients with long-segment septal hypertrophy more than 7cm, 4(20%) patients had both mid-ventricular obstruction and left ventricular outflow obstruction. Apical hypertrophic cardiomyopathy with LOVT obstruction was observed in 5 patients(25%) and aneurysm was found in 4(20%) HOCM patients. Postoperative thickness of ventricular septum was significantly decreased compared with that of preoperation[(21.1±3.6)mm vs.(13.4±3.1)mm]. Peak LOVT gradient or mid-ventricular gradient also significantly reduced after operation[(77.0±21.0) mmHg vs.(9.2±3.4) mmHg] or [(71.0±23.0) mmHg vs. 0 mmHg, 1 mmHg=0.133 kPa]; After surgery, mitral systolic anterior motion disappeared, mitral regurgitation degree reduced from (1.9±1.5) to (0.2±0.4); NYHA class improved from(2.1±0.2) to(1.3±0.5). New incidence of left bundle branch block occurred in 9 patients, and 1 patient developed complete bundle branch block and implanted permanent pacemaker. The 30-day survival was 100%.Conclusion:Combined transaortic and transapical septal myectomy is an effective and reasonably safe procedure for patients with complex hypertrophic obstructive cardiomyopathy.