ELECTROPHYSIOLOGICAL STUDIES IN THE EVALU ATION OF ATRIAL-FIBRILLATION

Electrophysiological studies of the atrium provide a means of evaluati ng the parameter involved in the process of fibrillation. The study of atrial vulnerability, initially limited to the test of provocation of the arrhythmia. has widened to include analysis of the substrate. Sho rtened refractory periods and regional conduction defects play a role in the creation of reentry pathways. Variations in the heart rate infl uence these Parameters and explain the fundamental role of the autonom ic nervous system OD the uniformity of the activation front. The risk of atrial fibrillation is related essentially to thrombo-embolism : at rial vulnerability was investigated in 70 patients with unexplained ce rebrovascular accidents. Globally, one out of two patients had patholo gical substrates. This study of atrial vulnerability showed that it wa s possible to identify a group of patients at risk of atrial fibrillat ion. even before the arrhythmia was recorded. This prognostic approach Could also he applied to the investigation of preexcitation and synco pe. and to the evaluation of the effects of pharmacological interventi on.