Sick sinus syndrome following aneurysmal subarachnoid hemorrhage -A case report

A 62 years old female patient with a history of hypertenion was referred to our hospital 24 hours after the sudden onset of headache followed by a loss of consciousness. The patient was drowsy with severe nuchal rigidity. A CT scan revealed a diffuse subarachnoid hemorrhage with intraventricular reflux and cerebral angiograms showed an anterior communicating aneurysm. The laboratory findings of the blood were normal. The electrocardiogram showed T-U waves. About 40 hours after the onset of subarachnoid hemorrhage, severe sinus bradycardia under 40 bpm with sinus arrhythmia and sinus arrest were noted on the monitoring ECG. Since the repeated intravenous infusion of atropine did not succeeded in controlling sinus bradycardia, temporary cardiac pacing was introduced. The following day, the patient was underwent a successful aneurysmal clipping with her heart rate being controlled by cardiac pacing. Since the holter ECG at 4 days after the operation showed a sinus bradycardia of 50-60 bpm but no severe bradycardia and sinus arrest, it was decided to discontinue the cardiac pacing. Repeated holter ECG and myocardial electrophysiological studies performed postoperatively were normal, therefore, a severe sinus bradycardia which occurred during the acute stage of subarachnoid hemorrhage was considered to be a central neurogenic arrhythmia. We therefore conclude that careful ECG monitoring is required in the acute stage of aneurysmal subarachnoid hemorrhage and temporary cardiac pacing is essential in managing sick sinus syndrome.