Vectocardiographic analysis of right ventricular electrical conduction delay

Introduction: The electrocardiographic interpretation of end conduction delay (ECD) in the right ventricular branch of the heart has already generated some hypotheses that this right branch is not single, as anatomically demonstrated, and can be divided into distinct terminal branches when we analyze tracings through the vectorcardiogram. Methods: There were 227 electrocardiograms selected, with typical characteristics defined as ECD of patients from the electrocardiography service of the Centro Universitário Saúde ABC, of both sexes, in the age range of 18 to 87 years, with varied ethnicities, weight and height, with cardiovascular risk factors or without them. We performed vectorcardiograms in these patients to observe the behavior of the final portion of electrical conduction. Results: Analyzing the vectorcardiographic tracings of patients who presented ECD in electrocardiogram, we confirmed in the recording by the frontal plane, the presence of ECD but recorded in three distinct regions; 103 patients in the right upper quadrant between -120° and -150°, 45 patients in the right lower quadrant between +170° and -170°, and medial, and 79 patients in the right lower quadrant between +110° and + 140°. Conclusion: Electrical depolarization of the heart in the right ventricle in electrocardiographic tracings apparently records typical alterations that we can diagnose as depolarization of a single bundle; but when we performed vectorcardiograms, we recorded three distinct zones of right ventricular depolarization with delay; i.e., three distinct sectors of right ventricle free wall delay, such as type I (upper), type II (lower) and type III (medial).