The objective of the investigation was an attempt to analyze some aspects of the heart-brain relationship. The group was formed by 626 patients with the diagnosis of focal cerebral ischaemia (CI) and 191 patients with the diagnosis of subarachnoidal haemorrhage (SAH). It was revealed that the CI group comprised 77.3% patients with a pathological finding on the heart. Analysis revealed moreover that in the group of patients with "congestive heart failure" there was a significantly higher percentage of patients with a severe neurological deficit as compared to the group with a "normal" ECG (p < 0.001). Atrial fibrillation causes a fivefold increase of the risk of cerebral infarction. The incidence of ECG abnormalities of various types was significantly higher in the group of patients with CI during long-term ECG monitoring, as compared to the results of conventional ECG examination (p < 0.001). The value of long-term ECG monitoring was confirmed also in an investigation of these changes in a group of patients with arterial hypertension, quari potential candidates of cerebral infarction. The relationship between cardiac and cerebral function was tested also in an investigation focused on the incidence of ectopic activity and changes of the QT interval. It was revealed that while the percentage rate of ectopic activity assessed by conventional ECG examination was in the group of "improved" patients 18.0%, long-term monitoring revealed a rate as high as 48.0%, the difference being statistically significant. Similar significant differences were observed also on analysis of the QT interval: in the group of patients with neurological "improvement" the QT interval was significantly shorter, as compared with the group with neurological "deterioration". It was assumed that the prolonged QT interval could be the cause of sudden death. A cardio-cerebral relationship was found also on analysis of changes of the cerebral circulation (CBF) in different forms of cardiac insufficiency. It was revealed that isolated ventricular extrasystoles reduced the CBF by 8.0%, isolated atrial extrasystoles by 12% and in atrio-ventricular tachyarrhythmia the CBF is reduced by as much as 25.0%. The cerebro-cardiac relationship was tested in a group of patients with SAH. ECG abnormalities of a varying type were found in 30.7% of the patients with SAH. They are described in as many as 100% of patients and were detected also other in cerebral disorders, such as contusion of the brain, intraoerebral haemorrhage and cerebral tumours.

Keywords: Arrhythmias, Cardiac /complications/; Cerebrovascular Disorders /etiology/; Electrocardiography; Heart Failure /complications/; Humans; Ischemic Attack, Transient /etiology/; Middle Aged; Subarachnoid Hemorrhage /etiology/