The Relationship Between Rhythm Variability and the Structural and Functional State of the Heart in Patients with Cerebral Atherosclerosis

Abstract

The objective: to identify the presence of relationships between indicators of HRV and the structural and functional state of the heart in patients with cerebral atherosclerosis (CA) stage 1–3, depending on the hemispheric localization of the ischemic focus.Materials and methods. In a comprehensive study, 229 patients with CA 1–3 rd degree took part. The patients were divided into 4 groups: І - those who had ischemic stroke (IS) in the right hemisphere (RH); II – transferred IS in the left hemisphere (LH); ІІІ – with CA of 1st – 2nd degree (without IS – comparison group); IV – a general group of patients who have undergone ischemic atherothrombotic stroke. The age of patients of the examined groups ranged from 55 to 75 years. All patients underwent transthoracic echocardiography and an ECG with an assessment of heart rate variability (HRV). Statistical analysis was performed using non-parametric methods (Mann – Whitney test, Spearman’s rank correlation coefficient). Results are presented as medians and 25%, 75% quartiles. To identify the relationship between the indicators of the structural and functional state of the heart and HRV, a correlation analysis was carried out with the calculation of the Spearman’s rank correlation coefficient.Results. In the general group of patients undergoing IS, one inverse correlation was established between the indices of the left ventricular myocardial mass index (MMI) and LF/HF% (r=–0,298), and in the group of patients without IS with CA 1–2 stages were established to relate the index of the relative wall thickness of the LV with the HRV and LF/HF indices (r=–0,196 and r=0,183 respectively) and 2 links of the LV diastolic myocardial function index with HRV and the triangular index (r=0,202 and r=0,217 respectively). When comparing groups of patients with different localization of IS, it was found that for patients with IS in the L, there is a characteristic of 3 MMLV connections with PNN50% and LF/HF% (0,322, –0,304 and –0,373 respectively), whereas for patients with the localization of IS in RH links no links were established.Conclusions. In patients with cerebral atherosclerosis without ischemic stroke, a decrease in HRV with activation of the sympathetic nervous system is associated with concentric LV remodeling and more severe left ventricular diastolic dysfunction. The presence of an ischemic focus in the left hemisphere of the brain, in contrast to the right hemisphere, determines more pronounced changes in HRV in patients as the degree of LV hypertrophy increases, which determines the high risk of repeated vascular events.