[Hypoperfusion of the brain in cardiac rhythm disorders].

In 134 patients (age 41-74 years) with symptoms of a transient ischaemic attack the authors made an ultrasonic dopplerometric examination of the main arteries of the head and a rheoencephalographic examination using the method of polygraphic recording with an ECG tracing II. st. 1. as well as in extreme position of the head and neck. In the investigated group in seven subjects a severe disorder of the cardiac rhythm was recorded with more than one third of ectopic ventricular contractions. The authors elaborated criteria for the objective expression of the impact of haemodynamic changes on the cerebral circulation. When doing so, they took into account the number of inadequate ventricular contractions with a pulse deficit in the periphery, the frequency of inadequate contractions and their haemodynamic effect the consequence of which was reduction of the pulse volume and slowing down of the blood flow. According to these criteria dysrhythmia was the cause of cerebral ischaemia in 4.5% of all subjects included in the authors' group. In the group of patients with a severe disorder of the cardiac rhythm dysrhythmia was the cause of a transient ischaemic attack in 86% of the patients. Trespassing of the ischaemic threshold is promoted also by a poorer blood supply in extreme positions of the head and neck which may occur in everyday life or during sleep.