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

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 V1 in nine subjects (37%), in V1-V2 in six (25%), in V1-V3 in two (8%), in V1-V4 in one (4%), in V1-V5 in two (8%), and in V1-V6 in four (16%). Nine subjects (37%) presented a bifid T wave in V2-V4. At VCG, T horizontal loop showed three morphologic characteristics: (1) counterclockwise rotation with a mean axis range of +15 degrees to -10 degrees (average, +5 degrees); (2) a figure-eight pattern with a mean axis range of +10 degrees to -40 degrees (average, -17 degrees); and (3) clockwise rotation with a mean axis range of -40 degrees to -110 degrees (average, -70 degrees). T wave changes seem to be primary and independent from QRS changes. RV and diastolic volumes ranged from 100 to 320 m1/m2 (average, 169 +/- 69). The extension of T wave negativity on precordial leads has a direct relationship with RV enlargement (r = 0.89, p less than 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.