Electrovectorcardiographic study of negative T waves on precordial leads in arrhythmogenic right ventricular dysplasia: Relationship with right ventricular volumes

Abstract

In 24 cases of arrhythmogenic right ventricular (RV) dysplasia, the electrovectorcardiographic (ECG-VCG) behavior of T horizontal (wave and loop) was analyzed and the data compared with RV angiographic volumes. Arrhythmogenic RV dysplasia was diagnosed on the basis of echocardiographic and angiographic data in all subjects. At ECG, T wave was negative in V 1 in nine subjects (37%), in V 1-V 2 in six (25%), in V 1-V 3 in two (8%), in V 1-V 4 in one (4%), in V 1-V 5 in two (8%), and in V 1-V 6 in four (16%). Nine subjects (37%) presented a bifid T wave in V 2-V 4. At VCG, T horizontal loop showed three morphologic characteristics: (1) counterclockewise rotation with a mean axis range of +15° to −10° (average, +5°); (2) a figure-eight pattern with a mean axis range of +10° to −40° (average, −17°); and (3) clockwise rotation with a mean axis range of −40° to −110° (average, −70°). T wave changes seem to be primary and independent from QRS changes. RV and diastolic volumes ranged from 100 to 320 m 1/m 2 (average, 169 ± 69). The extension of T wave negativity on precordial leads has a direct relationship with RV enlargement (r = 0.89, p < 0.01). T changes are probably caused by dislocation of the left ventricle backwards secondary to RV dilatation, asynchronous RV repolarization, or intraparietal RV conduction defects.