LAUSR

To the Editor, We read with great interest the recent article by CJ et al. who described a method to perform robotic‐assisted transmitral septal myectomy and papillary muscle reorientation for hypertrophic obstructive cardiomyopathy (HOCM) combined with or without mitral valve repair. We appreciate the authors for their study describing their experience of the use of magnetic resonance imaging and multimodality echo for assessing the surgical planning of the myectomy and the technical aspects. Here we report our experience of a three‐dimensional (3D) printing technique‐assisted thoracoscopic transmitral myectomy of apical hypertrophic cardiomyopathy with concomitant mitral valve replacement and tricuspid valvuloplasty. A 68‐year‐old Asian man presented with a history of chest tightness that had progressively worsened with ordinary exertion during the previous 4 months, which had caused significant limitations on his activities of daily living (New York Heart Association Class III) came to our emergency department for treatment. The patient reported a medical history of atrial fibrillation. A remarkable systolic murmur in the mitral auscultation area was discovered during physical examination. Transthoracic echocardiography (TTE) revealed normal systolic function but significant concentrated left ventricular hyperpathy that was greater in the anterior apical region with severe mitral regurgitation, severe tricuspid regurgitation, and left atrial dilatation(diastolic diameter = 86mm). We simulated the patient's apical HOCM by computed tomography angiography (CTA) and 3D printing technique (Figure 1A‐1C). During the operation, we sutured the left atrial appendage for atrial fibrillation. Then the mitral valve was resected together with the subvalvular tissue (Figure 2A). A transmitral myectomy was performed to relieve the obstruction through thoracoscopic technique according to preoperative 3D reconstruction (Figure 2B,C). Besides, all papillary muscle markedly hypertrophied was shaved to reduce the risk of midventricular obstruction. Concomitant thoracoscopic mitral valve replacement and tricuspid valvoplasty were performed routinely. TTE re‐examination revealed an excellent outcome of the patient's heart function 3 months after discharge. HOCM may involve mainly the proximal septum and diffuse left ventricular hypertrophy, or other rare patterns, such as midventricular and apical hypertrophy. Due to extreme heterogeneity of septal morphology and left ventricular geometry can make apical myectomy extremely challenging, careful preoperative assessment by means of novel imaging tools (e.g., cardiac magnetic resonance) now allows tailoring of the apical excision on an individual basis. We used a 3D printing technique to simulate the pathological anatomy of this patient, which has proved helpful for providing a reliable assessment of the location, pattern, and distribution of left ventricular wall thickening in the apical region assisting preoperative planning and improving the surgical outcome. The transaortic approach may be challenging for