Phase quadrature shift between left and right ventricles during a ventricular tachycardia attack.

Equilibrium gated nuclear angiography was performed on a patient during an attack of ventricular tachycardia and then after conversion to sinus rhythm. Global and regional wall motion was assessed by means of isocontours, Fourier phase analysis and factor analysis. Ventricular phase histograms showed a 100 degrees difference between ventricles: left ventricular filling time occurred during right ventricular contraction. The earliest phase was located in the septum and the sequence of activation showed a large delay of left ventricular activation. After conversion to sinus rhythm, a right bundle branch block was observed, being almost the inverse of the latter situation.