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[Do giant negative T waves represent apical hypertrophic cardiomyopathy? Left ventriculographic and cardiac biopsy
Abstract:
Whether giant negative T waves (GNT) of 1 mV or greater represent the electrocardiographic characteristics of idiopathic cardiomyopathy, particularly apical hypertrophic cardiomyopathy, is controversial. To clarify this point, a comparative study was conducted for 57 persons with GNT (GNT+ group) and 57 persons of hypertrophic cardiomyopathy with either asymmetric septal hypertrophy or diffuse hypertrophy of the ventricular wall in the absence of GNT (GNT- group). Patients with cerebral vascular accidents, myocardial infarctions, valvular heart disease, myopericarditis, and implanted pacemakers were excluded from the study because these patients' ECGs may show GNT. Left ventriculograms were investigated at end-diastole in the right anterior oblique projection. The GNT+ group showed a spade-like configuration indicating a marked reduction in the lumen of the apical cavity in 25 cases (43.9%); a kidney or banana-like configuration indicating the inferior wall bulging into the left ventricular cavity in its mid-zone in eight cases (14.0%), and an oval configuration which indicated no deformity of the left ventricular cavity in 24 (42.1%). The spade-like configuration was also seen in four cases (7.0%) of the GNT- group. A study of ventricular wall thicknesses based on left ventriculography showed that 25.5% of cases with GNT did not have concomitant apical hypertrophy. Generally, the GNT+ group cases had a significantly thicker anterior left ventricular wall and apical hypertrophy compared to the GNT- group. The hypertrophic states of the apical wall and anterior wall of the left ventricle correlated well. The GNT+ group included a significantly larger percentage of patients who were middle aged and older than did the GNT- group, and the frequency of accompanying hypertension was significantly higher in the former. The confirmed or suspected familial occurrence of cardiomyopathy (CM) was observed in 32 cases (56.1%) of the GNT- group, and in 18 cases (31.6%) of the GNT+ group, i.e., the incidence was significantly lower in the GNT+ group. In an endomyocardial biopsy study, 40 cases (70.1%) of HCM without GNT had bizarre myocardial hypertrophy with disorganization (BMHD). The incidence of BMHD in the GNT+ group was 21/57 (36.8%)-significantly lower than in the GNT- group. In the GNT- group, there was no significant difference in the incidence of BMHD between relatively young and old patients or between patients with and without accompanying hypertension; whereas, in the GNT+ group, it was significantly lower among those with accompanying hypertension and in older patients than in those without accompanying hypertension and in younger patients.(ABSTRACT TRUNCATED AT 400 WORDS)