Experimental and clinical electrocardiographic study of incomplete bundle branch block: Demetrio Sodi Pallares, M.D., Pablo Thomsen, M.D., Ennio Barbato, M.D., Jorge Soberón Acevedo, M.D., Bernardo L. Fishleder, M.D., and Antonio Estandía Cano, M.D., Mexico, D.F., Mexico