Impaired retention of technetium-99m tetrofosmin in hypertrophic cardiomyopathy

The purpose of this study was to determine whether; myocardial imaging usin g technetium-99m tetrofosmin can noninvasively identify myocardial damage i n hypertrophic cardiomyopathy (HC). The study consisted of 10 patients with apical HC, 10 with asymmetric septal HC (ASH) group, 5 with dilated cardio myopathy (DC)-like group, and 20 healthy subjects. With use of a bull's-eye map of single-photon emission computed tomographic imaging, the total defe ct score of tetrofosmin and the washout rate were assessed in 5 segments (s eptum, and anterior, lateral, and inferior walls, and apex) of the left ven tricle. A localized increase in defect score and washout rate was observed in the hypertrophied region in the group with apical HC. An increased washo ut rate was observed in the ASH group regardless of hypertrophy, suggesting that tetrofosmin retention by the mitochondria was impaired in the entire left ventricular wall. The washout rate was further increased at all segmen ts in the DC-like group versus the ASH group, Tetrofosmin retention by mito chondria was impaired in the entire left ventricular wall in the ASH group and was increased further in the DC-like group. The dysfunction of myocardi al cells was limited to the hypertrophied region in the apical HC group. (C ) 2001 by Excerpta Medica, Inc.