[Electrocardiographic features and vectorial analysis of cardiac potentials in electric shock-induced ventricular fibrillation (author's transl)].

Abstract

The authors examined the electrocardiographic features of ventricular fibrillation and other ventricular paroxysms induced by electric shock in the guinea pig. The analysis of the electrocardiographic patterns, as well as the vectorial study of the cardiac potentials during repeated episodes of ventricular "anarchy" induced in more than forty animals, showed the following data: 1. following electric shock, ventricular paroxysms appear, featuring paroxysmal tachycardia, typical or impure flutter, tachycardia--either "torsade de pointe" or "spindle" type, and typical ventricular fibrillation. Such different electrocardiographic patterns represent evolutive stages of electric activity disorganization, leading to a complete ventricular "anarchy". Such steps may reverse when reorganization of the electric activity and spontaneous defibrillation occur; 2. an attempt can be made at present to classify ventricualr paroxysms, thus eleminating semeiotic and semantic errors, still present in the literature, and providing a standardization of both nomenclature and electrocardiographic interpretation; 3. during fibrillation, the mean ventricular rate decays, featuring an exponential curve. This phenomenon accounts for a metabolic depletion of the myocardium: the higher the number of fibrillation episodes previously induced and subsided (either spontaneously or not) in the same animal, the faster the course of the phenomenon; 4. the vectorial analysis of the fibrillation potentials and, particularly, the graphic construction of "depolarization" and "repolarization" vectorcardiograms, in the differenttypes or variants of ventricular paroxysms, show that the basic mechanisms leading to ventricular electric activity disgregation are the multiple re-entry and the irregular spreading of the activation front; 5. on the basis of the acquired data, the authors believe that the "circus movement" theory (Wiggers) is still the most suitable for explaining the onset and the evolution of ventricualr fibrillation.