ROMANIAN JOURNAL OF NEUROLOGY – VOLUME IX, NO. 3, 2010 151 CASE PRESENTATIONS 8 CEREBRAL ISCHEMIC STROKE IN A PATIENT WITH SICK SINUS SYNDROME Athena Mergeani, Dan Popescu, Florina Antochi Neurology Department, Emergency University Hospital, Bucharest, Romania ABSTRACT Sick sinus syndrome represent one of the cardiac arrhythmias which may cause ischemic stroke by hemody- namic or thrombo-embolic mechanism, often these two mechanisms coexist and potentiate each other. We present the case of the 65 years old male admitted to our clinic for an acute ischemic stoke in the right ca- rotid territory. The Doppler ultrasonography of the cervico-cerebral arteries performed the next day after the admission showed occlusion of the right internal carotid artery. The patient was transferred to the cardiology clinic where he underwent a DDDR pace-maker implantation. The ultrasonographic exam performed one week later showed repermeabilisation of the right internal carotid artery. Keywords: sick sinus syndrome, ischemic stoke, arrhythmias, internal carotid artery occlusion Author for correspondence: Florina Antochi, Emergency University Hospital, 169 Splaiul Independentei, Bucharest, Romania email: flrant@yahoo.com BACKGROUND Cardiac arrhythmias represent an important cause of ischemic stroke. The two mechanisms by which cardiac arrhythmias might cause transient or permanent focal cerebral ischemia are hemody- namic and thrombo-embolic. Embolism and hypo- perfusion oftentimes coexist and potentiate each other. The link between these two factors in the pathophysiology of brain infarction is the impaired clearance of emboli due to low flow states. Arrhyth- mias sufficiently severe to reduce cardiac output may reduce global cerebral perfusion, and the brunt may fall more severely in the areas with acquired arterial lesion producing focal cerebral ischemia. When most arrhythmias such as paroxysmal tachy- cardia and complete heart block become symptom- atic they produce global ischemia (i.e. syncope). Only arrhythmias which encourage atrial stasis, such as atrial fibrillation and sino-atrial disorders cause systemic and cerebral embolism. Chronic sino-atrial desease is variously defined, but shoud include at least sinus bradiarrhythmia, regular sinus bradycardia and sino-atrial block with or without sinus arrest. Many patients have also tachycardia, though this is sometimes considered a separate disorder (bradycardia-tachycardia syn- drome). Sick sinus syndrome is a high-risk source of ce- rebral embolism. The risk is probably greatest for those patients whose conditions evolve into a par- oxysmal or chronic atrial fibrillation pattern or those patients who have left atrial spontaneous echocardiographic contrast and decreased atrial ejection force. Patients with sick sinus syndrome may experience cerebral ischemia even after pace- maker insertion. VVI pacing is associated with a higher risk of embolic complications than atrial or dual-chamber stimulation. CASE STUDY We present the case of a 65 years old caucasian male who was admitted to our clinic for abrupt on- set of muscle weakness on his left side. The patient had medical history of arterial hypertension, parox- ysmal atrial fibrillation and flutter, and pulmonary oedema.