title: Electrophysiologic findings in carotid sinus massage.
abstract: Thirty patients with carotid sinus syndrome were electrophysiologically studied. In 14 patients carotid sinus massage was performed during atrial and ventricular stimulation, and the conduction times were measured. The AH-time was prolonged by more than 120 ms in 6 patients (20%); the HV-time was prolonged in 6 patients by more than 55 ms (20%); 5 patients had bundle branch block (16.7%); The sinus node recovery time was prolonged in 7 out of 27 patients (26%). Ten patients (33%) did not have additional electrophysiologic abnormalities. There was a predominance of carotid sinus syndrome on the right side. During carotid sinus massage there was a significant increase of the AH-time, but there were no significant changes of the HV-time or the width of the QRS-complexes. Twenty-one patients developed an atrial asystole and 9 patients an atrial bradycardia and an additional AV-block. There was a longer AH-time and a longer prolongation of the AH-time in the patients who developed an AV-block. Twelve out of 14 patients (85.7%) developed an AV-block during carotid sinus massage and atrial pacing. During ventricular pacing 5 of 14 patients (35.7%) revealed a complete retrograde block before carotid sinus massage and 5 of the remaining 9 patients developed a total retrograde block during carotid sinus massage. Consequently, in 71.4% of the patients with carotid sinus syndrome complete retrograde conduction block and atrial asystole can be expected during attacks of ventricular asystole and simultaneous ventricular pacing. In conclusion, there is a high incidence of additional disturbances of the sinus node function and AV-conduction in patients with carotid sinus syndrome. AAI pacemakers are contraindicated due to the common development of additional AV-block during carotid sinus massage. Physiologic pacing might contribute to better hemodynamics, particularly in patients with the mixed type of carotid sinus syndrome.
mesh_terms: D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D002346:Carotid Sinus / Q000503:physiopathology*; D004558:Electric Stimulation; D004562:Electrocardiography; D005260:Female; D006323:Heart Arrest / Q000503:physiopathology*; D006327:Heart Block / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013577:Syndrome