Assessment of VVI diagnostic pacing mode in patients with cardioinhibitory carotid sinus syndrome.

In this study, we used Holter pacemakers in a group of 13 patients affected by severe carotid sinus syndrome in order to evaluate its evolution. All the patients had one to three syncopal episodes and frequent other symptoms such as fainting, dizziness, lightheadedness and pre-syncope interferring with their daily activity so that pacemaker therapy was considered necessary. Patient selection criteria were: presence of the isolated cardioinhibitory type, absence of associated sinus dysfunction and absence of symptomatic VVI pacemaker effect. All the patients received a Micropacer 1 device; among special functions, bradycardia events counter was activated and programmed so that each sequence of three consecutive beats at a cycle length 1.5 sec (i.e., 4.5 sec total interval) could be recognized and stored in its memory. The follow-up lasted 13 +/- 7 months. Brady events occurred in eight out of 13 patients (62%), during this period. Syncope and major symptoms disappeared in all the patients; mild dizziness recurred rarely in two patients and were not linked to brady-events recording. In conclusion, disappearance of severe symptoms observed after pacemaker implant in cardioinhibitory carotid sinus syndrome seems to depend from pacing therapy, in most cases, yet from the benign natural course of the disease in some other cases.