[1st degree and 2nd degree blocks (Wenckebach type) during right ventricular stimulation in the course of...

Right axial deviation and delay between stimulation and ventricular response was observed during pacing of the apex of the right ventricle in Prinzmetal angina. The degree of deformation of the ventricular complex and the length of this delay appear to be related to the severity of the anginan, the length of the preceding diastolic period and the amplitude of stimulation. This observation demonstrates the presence of conduction defects at the heart of ischaemic myocardium and may explain the failure of prophylactic pacing in Prinzmetal angina complicated by paroxysmal atrioventricular block.