PERMANENT PACING FOR CARDIOINHIBITORY MALIGNANT VASOVAGAL SYNDROME

Objective-To evaluate the effect of permanent pacing in cardioinhibito ry malignant vasovagal syndrome. Patients and methods-37 patients with permanent pacemakers for cardioinhibitory malignant vasovagal syndrom e. All presented with syncope (median six episodes, median frequency t wo episodes a year) and after conventional investigation and invasive electrophysiological assessment they remained undiagnosed, and without a generally accepted indication for pacemaker implantation. In all va sovagal syncope with cardioinhibition (heart rate at syncope <60 beats /min) developed during tilt tests performed according to the Westminst er protocol (head up tilt at 600 with a footplate support for 45 minut es or until syncope intervenes). Dual chamber pacemakers were implante d in 35 (95%) and VVI pacemakers in the remaining two (5%). Results-Ov er a mean (SD) follow up since implantation of 50.2 (23.9) months symp tomatic improvement occurred in 89%: 62% remained free of syncope and 27% were completely symptom free. The collective syncopal burden of th ese 37 patients was reduced from 136 to 11 episodes each year. During follow up three patients died from unrelated causes. Patients who beco me asystolic during the tilt test (sinus pause of at least four second s) experienced no greater benefit from pacing than those with less ext reme cardioinhibition. Patients who remained free of syncope since imp lantation were younger than those who continued to experience syncope. Patients who remained completely symptom free after implantation were younger, more likely to be male, and had had fewer syncopal episodes before implantation than those who continued to experience syncope or presyncope. No other demographic, clinical, investigative, or pacing v ariable suggested a more favourable outcome after implant. Conclusions -This retrospective and uncontrolled experience suggests a possible ro le for permanent pacing in selected patients with cardioinhibitory mal ignant vasovagal syndrome. Improved acquisition of tilt test data may enable better selection of patients who are suitable for permanent pac ing. A randomised prospective study to compare permanent pacing with n o treatment or with medical treatment in cardioinhibitory malignant va sovagal syndrome is indicated.