Right Atrial Endocardial Mapping: Implications of Abnormally Prolonged and Fractionated Electrograms

pp 425-431

Abstract

There are several limitations in the clinical electrophysiologic studies of patients with atrial vulnerability, such as those with sick sinus syndrome and paroxysmal atrial fibrillation. During programmed atrial stimulation it turns out relatively easy to induce atrial fibrillation in those patients, perturbing the electrophysiologic study and further detailed analysis of the electrical properties of the atrial muscle. Therefore, all the data obtained by endocardial mapping of the right atrium during sinus rhythm acquire an important relevance in the understanding of the electrophysiologic sustrate of the atrium. The recent investigations based on the recording of local abnormal atrial electrograms during sinus rhythm and their characteristic distribution in the right atrium of patients with paroxysmal atrial fibrillation have provided us new information on the electrophysiologic properties of the diseased atrium. We have previously demonstrated that abnormal atrial electrograms  reflect an electrophysiologic abnormality of the atrium and that they are characteristic of paroxysmal atrial fibrillation, idiopathic or associated to sick sinus syndrome. The endocardial catheter mapping of the right atrium in patients with paroxysmal atrial fibrillation has shed more light on the understanding of the electrophysiologic sustrate of atrial fibrillation. The detection of ab-normal atrial electrograms identifies a group of patients with augmented atrial vulnerability anda high predisposition to develop spontaneous and induced episodes of atrial fibrillation.