Unusual ventricular activation produced by temporary transvenous cardiac pacing: electrovectorcardiographic findings.

Complete heart block (CHB) results from dysfunction of the cardiac conduction system, which results in complete electrical dissociation. The ventricular escape rhythm can have its origin anywhere from the atrioventricular node to the bundle branch-Purkinje system. CHB typically results in bradycardia, hypotension, fatigue, hemodynamic instability, syncope, or even Stokes-Adams syndrome. Escape rhythm originating above the bifurcation of the His bundle (HB) produces narrow QRSs with relatively rapid heart rate (HR) (except in cases of His system disease). We present a middle-aged man with an HR of 34 bpm, progressive fatigue, in whom a temporary pacemaker was implanted in the subtricuspid region. The post-intervention electrocardiogram had unusual features.