Ventricular torsion and cardiac suction effect: The electrophysiological analysis of the cardiac band muscle

Abstract

Introduction and objectives: The Torrent Guasp concept postulates that the ventricles are formed by a continuous muscle band that begins at the level of the pulmonary valve and extends to the aortic root, limiting in this way the two ventricular chambers. This specific anatomical arrangement would support the interpretation of two fundamental aspects of left ventricular dynamics: 1) the torsion mechanism and 2) the physiology of rapid diastolic filling by the suction effect. Methods: Five patients with no structural cardiac abnormalities and normal QRS complexes underwent three-dimensional endoepicardial electroanatomic mapping during ablation of lone atrial fibrillation or concealed epicardial accessory pathways. The propagation times of the electrical activation by the muscular band was measured in milliseconds (ms). Results: 1) The apical loop is activated by a simultaneous depolarization of the distal descending and proximal ascending band segments. 2) At the point of crossing of both bands a radial activation spreads from the descending to the ascending band. From this point, begins a simultaneous and opposing activation of the proximal and distal ascending band. 3) The activation of the distal ascending band segment is the latest. Conclusions: The novel activation sequence of the Torrent Guasp band found in this study would explain the previous process triggering the ventricular torsion and suction mechanism. Moreover, this work demonstrates that activation of the ascending band segment completes the QRS. This finding explains the persistent contraction of this muscle segment during early diastole, rejecting the traditional concept of passive relaxation.