Comparison of Baseline Heart Rate Variability in Stable Ischemic Heart Disease Patients with and without Stroke in Long-Term Observation

Abstract

Decreased heart rate variability (HRV) has predictive value in postinfarction as well as in ischemic stroke patients. However, it is unknown if ischemic heart disease (IHD) patients who are at high risk of stroke have different HRV profile. The goal of this study was to compare baseline HRV (traditional and novel indices) in stable IHD patients with and without stroke in long-term observation. A total of 139 consecutive patients with stable IHD scheduled for coronary angiography were enrolled. Five-minute electrocardiogram readings were taken. Traditional and novel HRV measures were calculated. After 70.06 ± 4.297 months of follow-up, baseline HRV indices in patients who had had a stroke were compared with indices in patients without the aforementioned cerebrovascular event. During follow-up, 6 patients developed stroke. Compared to patients without such a cerebrovascular event, these patients with stroke had lower values for the following HRV indices: de Hann long-term irregularity (30,521 ± 32,767 versus 46,678 ± 25,328; P < .05), Yeh interval index (.0207 ± .0208 versus .0326 ± .0157; P < .05), Organ BAND (3.0563 ± 3.328 versus 4.515 ± 2.276; P < .05), Dalton standard deviation (SD) (17,887 ± 17,636 versus 29,859 ± 16,478; P < .05), Zugaib short-term variability (.004 ± .00416 versus .00622 ± .00418; P < .05), Zugaib long-term variability (.0161 ± .0151 versus .0247 ± .0115; P < .05), standard deviation of all NN intervals (8,954 ± 8,812 versus 16,724 ± 11,594; P < .05), total power (2,616 ± 4,855 versus 4,678 ± 4,653; P < .05), w2 (.71 ± .338 versus 1.719 ± 1.08; P < .05), w3 (1.399 ± .924 versus 2.552 ± 1.609; P < .05), and w4 (1.367 ± 1.705 versus 2.824 ± 2.027; P < .05). No significant differences in other analyzed indices were observed. Patients with IHD and stroke in long-term observation have different baseline profiles of HRV indices. Further investigations are needed to assess the usefulness of HRV analysis in stroke risk assessment.