Current operative treatment of obstructive hypertrophic cardiomyopathy.

O perative intervention has been an important part of the therapeutic strategy for patients with hypertrophic cardiomyopathy (HCM) for the past 30 years. 1-6Cleland,' in 1958, was the first to successfully perform a transaortic myectomy in a patient with the obstructive form of this disease by resecting a small amount of muscle from the thickened upper portion of the ventricular sep- tum.Shortly thereafter, Morrow2 modified and refined the ventricular septal myotomy-myectomy operation,3* which he eventually performed on 350 patients.About the same time, Bigelow et a14 suc- cessfully pioneered the myotomy operation (ventriculomyotomy) that was similar to the myotomy- myectomy except that no muscle was actually removed from the ventricular septum.]345678910111213141516 Operative intervention has improved symptoms in many patients with HCM, in whom medical therapy has failed, by virtue of relieving the subaortic pressure gradient and reducing left ventricular pressures.'718The experiences gained from the clinical appraisal of these patients during a long period of time, as well as from technical advances in echocardiographic techniques, have con- siderably enhanced our understanding of the role of operation in HCM and have altered our concepts regarding the intraoperative management of such patients.Because of this evolution in our knowledge, it would appear important at this time to appraise the current status of operation in the treatment strategy of patients with obstructive HCM.Concept of Dynamic Subaortic Obstruction Left ventricular outflow tract gradients and sub- aortic obstruction in HCM are dynamic in nature, that is, they can be reduced or augmented by *Also known as left ventricular myotomy-myectomy, ventric- ulomyectomy, or Morrow procedure.