[Clinical cardiac electrophysiological studies in carotid sinus syndrome].

The aim of the present study was to evaluate the impact of electrophysiological study in the diagnosis and treatment of carotid sinus syndrome. The indications for the study include (1) attempting to exclude other cardiogenic causes of syncope; block, tachyarrhythmia, (2) diagnosing a vasodepressor response in the presence of cardioinhibitory type of carotid sinus syndrome, (3) determination of the optimal pacing mode in patients who need pacemaker implantation for treatment. 51 patients, 40 male (78%) and 11 female (22%) with an average age of 62 years suffering from carotid sinus hyperaesthesia--3000 ms ventricular asystole on carotid sinus massage--were investigated with electrophysiological study. The A-H interval in 8 patients (16%), the H-V interval in 5 pts (10%) were prolonged in the His bundle electrocardiogram. In 39 patients (76%) sinoatrial block, in 12 patients (24%) A-H block was found during carotid sinus massage. Early A-H Wenckebach block occurred in 8 patients (16%). Retrograde (V-A) conduction was present in 36 patients (70%) at a frequency of 65-85 bpm, and 22 pts (43%) at a frequency of 120-180 bpm. Sinus node disease was found in 10 patients (20%) according to the sinus node recovery time and sinoatrial conduction time. In 8 patients (16%) supraventricular and in 4 patients (8%) ventricular tachyarrhythmia was induced during study. The atrial stimulation could not prevent the occurrence of A-V block during carotid sinus massage in any of the 51 patients. In 2 patients (4%) the vasodepressor reaction with ventricular stimulation was determined.(ABSTRACT TRUNCATED AT 250 WORDS)