[Anesthetic management of a patient with mid-ventricular obstructive hypertrophic cardiomyopathy treated with dual-chamber pacing].

: A 64-year-old man complicated with mid-ventricular obstructive hypertrophic cardiomyopathy (MVO) was scheduled for resection of rectum cancer under general anesthesia with epidural block. Because of unexpected circulatory collapse at the induction of anesthesia, the operation was canceled. Therefore three weeks later, we inserted a temporary dual-chamber (DDD) pacing device before induction of general anesthesia, and we could maintain stable hemodynamics during general anesthesia. In the patients with MVO, blood outflow from the left ventricle to the aorta is decreased by the abnormal blood flow produced by hypertrophy of the mid left ventricle when inotropic stimulation is applied. Even in an asymptomatic patient with MVO, the hemodynamic catastrophe could occur during the operative period. In patients with hypertrophic obstructive cardiomyopathy (HOCM), DDD pacing appears to be effective to reduce the pressure gradient between the left ventricle and the aorta. Similarly, in our case, DDD pacing was effective to maintain the hemodynamic state during general anesthesia in a patient with MVO.