title: [Right blocks in interauricular communication].
abstract: The purpose of this study is to establish some electro-vectorcardiographic criteria useful in the differential diagnosis of right fascicular and truncular blocks in 72 cases of atrial septal defect proven by hemodynamic and surgical data. In all cases, the conduction disorder was analyzed by conventional electrocardiograms; in many cases, additional right unipolar thoracic and intracavitary leads were utilized; and in 22 cases high fidelity records were obtained with a Simultrace Recorder V6R. Right block was studied in vectorcardiographic curves recorded in three planes following the method of Grishman's cube. This block was considered as proximal or truncular in 46 cases: of minor degree in 8 and of intermediate degree in 38. In these cases the difference in time of onset of the intrinsicoid deflection between the free right ventricular wall and the low anterior right septal mass was up to 30 msec. Distal or fascicular block was diagnosed in 26 cases: RASB in 10 and RPSB in 16. The difference in time of onset of the intrinsicoid deflection between the free right ventricular wall and the right anterior-inferior septal mass exceeded 30 msec. The highest values were observed in aVR and V1, in the cases with RASB; in aVF, V3R and V1, in the cases with RPSB. The SF loop was diphasic in the presence of proximal block, appearing above the 0 point in the cases with RASB and below this point in the cases with RPSB. SH loop was anterior when truncular block existed, lateral when there was RASB and plus or less diphasic in the cases with RPSB. Sometimes, Q-Tc interval was prolonged in V2 and V3, grossly related to telediastolic pressure in the right ventricle. The facts reported here permit the formulation of the following conclusions: 1. The morphologic aspects of the electrocardiographic and vectorcardiographic curves are very useful for recognizing RASB. In order to establish the differential diagnosis between RBBB of intermediate degree and RPSB, it is necessary to perform a thoracic electric mapping. 2. The clockwise rotation of the entire SH loop, observed in 27 of 38 cases of intermediate degree RBBB, is probably due to the more important manifestation of right parietal electromotive forces because of the ventricular enlargement. 3. The prolonged Q-Tc interval in some right unipolar leads reflects the diastolic overloading of the homolateral ventricle (increased telediastolic pressure).
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000209:etiology*; D006344:Heart Septal Defects, Atrial / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014672:Vectorcardiography
vernacular_title: Bloqueos derechos en la communicación interauricular.