VALIDATION OF A METHOD FOR CHOICE OF PACING MODE IN CAROTID-SINUS SYNDROME WITH OR WITHOUT SINUS BRADYCARDIA

A new method for selection of the pacing mode in 60 consecutive patients with severe cardioinhibitory or mixed carotid sinus syndrome was prospectively validated. DDD pacing was preferred for 26 patients with: (1) the cardioinhibitory form and who had symptomatic pacemaker effect; (2) mixed type I form, (cardioinhibitory and vasodepressor) with symptomatic pacemaker effect, ventriculoatrial conduction or orthostatic hypotension; (3) mixed type II; or (4) severe bradycardia. VVI pacing was selected in the remaining 34 patients without these symptoms. During a 32 +/- 10 month follow-up period syncope and severe dizziness presisted in five patients in the VVI group (15%) and in three patients in the DDD group (12%). Symptomatic relief occurred in 87% (52/60) of patients. Minor symptoms persisted in 47% of the VVI group and 42% of the DDD group. No patient developed cardiac insufficiency or intolerance to pacing. During a 2-month duration a single-blind, randomized, cross-over study compared VVI and DDD pacing, 69% of the patients programmed from DDD to VVI suffered more frequent, severe, and intolerable symptoms. (1) Thirty four of 60 patients (57% of the entire group) in whom VVI pacing was satisfactory were identified prior to pacemaker implant. In the remainder, VVI pacing was contraindicated as it produced frequent side effects. (2) The preimplant predictive value that VVI pacing would be successful was 85% for those eventually receiving VVI pacemakers and the preimplant predictive value that VVI pacing would fail was 69% for those who underwent DDD implant.