Electrical manifestations of dead myocardium associated to proximal blocks of intermediate degree

The electrical manifestation of dead myocardium associated to incomplete bundle branch block, i.e., with a limited "jumping wave" phenomenon, are exposed. Our description is based on previous experimental studies and validated by electro-anatomical comparisons. In previous experimental reports, the electrical manifestations of dead myocardium in the presence of varying degrees of associated block have also been described. The main electrocardiographic changes are related to the location and extent of damaged region and to degree of bundle branch block. If a left bundle branch block coexists with dead myocardium, small Q waves are registered in left unipolar leads exploring the damaged area. In these leads, the signs of subepicardial or transmural injury are increased. When a right proximal block coexists, the main changes concern the morphologies registered in the unipolar right epicardial and precordial leads. The electrical changes are due to the spatial orientation of the electromotive forces of ventricular depolarization and repolarization. The electrocardiographic changes described here can be satisfactorily understood in the light of the present knowledge on the ventricular electrical phenomenon.