Stroke in paced patients with sick sinus syndrome: relevance of atrial mechanical function, pacing mode and clinical characteristics.

Patients with sick sinus syndrome have a high prevalence of cerebral ischemia and emboli of the viscera and extremities. The present study was designed to establish the prevalence of stroke in patients with sick sinus syndrome, with specific attention to pacing mode, atrial function (evaluated using Doppler echocardiography) and the clinical condition of the patients. The prospective study analyzed 80 consecutive patients with sick sinus syndrome who received either atrial, dual chamber or ventricular pacemakers. Patients underwent a cranial CT scan at the time of enrollment and again at the end of the study 24 months later. End points of the study were cerebral ischemia or emboli of the viscera or extremities. Clinical and echocardiographic features were assessed at the beginning of the study. A multivariate regression analysis was applied to all variables that had at least a marginal univariate predictive value. Cerebral ischemia occurred in 13 patients and emboli of the viscera or extremities were observed in 2 patients. Univariate predictors for embolism consisted of a prior history of cerebrovascular disease (p < 0.001), low atrial ejection force (p < 0.01) and a dilated left atrium with spontaneous echo contrast (p < 0.05). Independent risk factors for stroke included a history of previous cerebral ischemia, age > 65 years, left atrial echo contrast on an echocardiogram and a depressed atrial ejection force. These findings identified patients at high risk for the development of peripheral embolism among the group of patients paced for sick sinus syndrome.