Stroke is frequently followed by electrocardiographic (ECG) changes. The aim of the present study was to evaluate the global incidence of these changes after ischemic or hemorrhagic strokes, but it focused on cardiac arrhythmias. In ischemic strokes, these were correlated with the side of the lesion(s). The study was retrospective, and 450 patients (out of 971 examined) were entered in the study based on the following inclusion criteria: (1) "completed" stroke (352 ischemic and 98 hemorrhagic), (2) ECG on admission, and (3) at least 1 previous ECG. We also examined 71 patients with carotid or vertebro-basilar transient ischemic attacks (TIA). As controls, 71 patients suffering from nonvascular neurologic diseases were examined. The results were as follows: In stroke patients, new-onset ECG abnormalities were present in 75% of cases, and cardiac arrhythmias accounted for 28.7%. Cardiac arrhythmias were observed in 21.9% of ischemic strokes (26.8% of patients with right hemispheric lesion and 14.3% of those with left hemispheric lesion) and in 20.4% of hemorrhagic strokes, with the highest incidence in subarachnoid hemorrhage (37.5%). The mechanisms of genesis of cardiac arrhythmias occurring after stroke are still not well understood. Some evidence supports the hypothesis of a "cardiac cortical rhythm control site," probably lying within the middle cerebral artery territory. Vascular damage to this area could be followed by cardiac arrhythmias related to a disinhibition of the right insular cortex with resulting increased sympathetic tone. Our data seem to indicate that ischemic involvement of the right hemisphere induces a higher risk for cardiac arrhythmia occurrence than that of the left hemisphere.