Retrograde Conduction to the Atria in Ventricular Tachycardia By ALBERT

CONTRARY to the prevalent view that retrograde conduction to the atria in ventricular tachycardia is rare,' the author has recorded tracings consistent with such conduction relatively frequently with simultaneous standard and esophageal leads. The standard electrocardiographic tracings often fail to demonstrate atrial activity accurately, because the atrial deflections are small and lost in the deflections of the ectopic ventricular activity. This is apparent from a comparison of lead II with the simultaneously recorded esophageal lead in most of the illustrations of this paper, and probably explains why so few cases of ventriculo-atrial (V-A) conduction in ventricular tachycardia have heretofore been recognized. Sir Thomas Lewis described the first clinical case of ventricular tachycardia in 19092 and observed that in dogs retrograde conduction to the atria was common.3 A review of the clinical literature by Foster and Thayer in 19504 yielded only three cases of 1:1 V-A conduction and six cases of V-A conduction with variable block. These authors concluded from the illustrations of 81 published cases of ventricular tachycardia that in 40 it was impossible to recognize the atrial activity. The interpretation of V-A conduction was made in standard electrocardiographic leads1' 5-26 and recently in esophageal lea.ds.25, 27-32