THE RELATIONSHIP OF THE SUBARACHNOID INJECTION OF BLOOD AND BLOOD FRACTIONS WITH CARDIAC RATE CHANGE AND ARRHYTHMIAS

The relationship of subarachnoid hemorrhage and cardiac arrhythmias wa s studied utilizing a Sprague-Dawley rat model. A total of 30 male ani mals were divided into five groups and given subarachnoid injections o f either blood, blood fractions, or control substances. Blood pressure , intracranial pressure, serum electrolytes, arterial blood gases, hyp othalamic multiple unit activity and an electrocardiogram were concurr ently monitored. Cardiac arrhythmias were graded on a 0 to 4 + objecti ve scale. Control parameter values were similar for all animals. Arrhy thmias, hypotension, and decreased hypothalamic multiple unit activity were seen with infusion of whole blood and packed red blood cells. Pa cked red blood cells were statistically demonstrated to have the most potent arrhythmogenic effect. Cardiac histopathology revealed myocardi al contraction band lesions most predominant in the packed red blood c ell group. In addition, significant QT interval prolongation was obser ved after subarachnoid injection of either whole blood or packed red b lood cells. These findings indicate that packed red blood cells, or a component thereof, may play an important role in the etiology of immed iate (i.e. acute) post subarachnoid hemorrhage induced cardiac arrhyth mias.