[Changes in cerebral circulation during various types of cardiac arrhythmias]

The cerebral volume blood flow was measured in acute canine experiments in three major arteries of the brain using an electromagnetic flowmeter. Paroxysms of ventricular tachycardia caused by electric stimulation of the heart resulted in varying degrees of reduction of the cerebral blood flow and arterial pressure that was most significant with cardiac contractions rate exceeding 240/min. Bradycardia with the contractions rate below 60/min also caused a reduction of the cerebral blood flow and arterial pressure. A parabolic correlation was revealed between the changes in the heart contractions rate and the amount of decrease of the cerebral blood flow and arterial pressure. Grouped ventricular extrasystoles resulted in a brief sharp fall of the cerebral blood flow...