Operative Technique of Myectomy for Midventricular Obstructive Hypertrophic Cardiomyopathy

Patient selection for hypertrophic cardiomyopathy (HCM) surgery is based on clinical presentation risk factors and imaging studies. The main modalities of imaging are echocardiography and cardiac MRI. It is often productive for the surgeon to spend time in the imaging department interacting directly with the imaging specialists in order to plan the extent of myectomy during surgery. 

A special note should be made of the extent of the septal thickening in two planes: both circumferentially and longitudinally from the base to apex. Any additional locations of septal thickening at midventricular and apical level should also be noted. Further attention should be directed to the right ventricular side of the septum causing right ventricular outflow obstruction, which is vital and often ignored. These observations can be immensely useful for planning the location and extent of incision, along with the depth and extent of muscle resection. 

Additionally, mitral and aortic valve abnormalities, such as a bicuspid aortic valve and the presence of anomalous muscle bundles, should be noted. The knowledge gained from personal discussion with the echocardiographer and radiologist will equip the surgeon with the tools for adequate surgical preplanning.

References

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2. Bigelow WG, Trimble AS, Auger P, et al: The ventriculomyotomy operation for muscular subaortic stenosis: A reappraisal. J Thorac Cardiovasc Surg 52:514–524, 1966

3. McIntosh CL, Maron BJ: Current operative treatment of obstructive hypertrophic cardiomyopathy. Circulation 78:487–495, 1988

4. Mohr R, Schaff HV, Danielson GK, et al: The outcome of surgical treatment of hypertrophic obstructive cardiomyopathy: Experience over 15 years. J Thorac Cardiovasc Surg 97:666–674, 1989