ATRIOVENTRICULAR NODAL PARASYSTOLE ASSOCIATED WITH COMPLETE A-V HEART BLOCK

A rare case of atrioventricular nodal parasystole in the presence of complete A-V block is reported. The parasystolic beats interfered, at times, with the synchronization of the sinus rhythm and the idioventricular beats. Carotid sinus stimulation did not change the parasystolic rate during and after the procedure. Coronary artery disease, responsible for A-V block, may have caused the destruction of vagal nerve fibers innervating the parasystolic focus. The concept that the shortest manifest P-P′ interval in A-V nodal parasystole represents the refractory period of A-V nodal tissues and not the refractory period of atrial muscle would adequately explain the long interval between sinus beat and parasystole in our case and others. © 1969.