RESUMO
The relationship of subarachnoid hemorrhage and cardiac arrhythmias was studied utilizing a Sprague-Dawley rat model. A total of 30 male animals were divided into five groups and given subarachnoid injections of either blood, blood fractions, or control substances. Blood pressure, intracranial pressure, serum electrolytes, arterial blood gases, hypothalamic multiple unit activity and an electrocardiogram were concurrently monitored. Cardiac arrhythmias were graded on a 0 to 4 + objective scale. Control parameter values were similar for all animals. Arrhythmias, hypotension, and decreased hypothalamic multiple unit activity were seen with infusion of whole blood and packed red blood cells. Packed red blood cells were statistically demonstrated to have the most potent arrhythmogenic effect. Cardiac histopathology revealed myocardial contraction band lesions most predominant in the packed red blood cell group. In addition, significant QT interval prolongation was observed after subarachnoid injection of either whole blood or packed red blood cells. These findings indicate that packed red blood cells, or a component thereof, may play an important role in the etiology of immediate (i.e. acute) post subarachnoid hemorrhage induced cardiac arrhythmias.
