Cardiovascular autonomic function in poststroke patients.

BACKGROUND: Autonomic dysregulation is frequent in acute ischemic stroke. Several studies concluded that imbalance between sympathetic and parasympathetic cardiovascular function predisposes to malignant cardiac arrhythmia. However, there are few data on cardiovascular autonomic function in post-acute stroke patients.
OBJECTIVE: To study cardiovascular autonomic function 18 to 43 months after lacunar stroke. PATIENTS AND METHODS: We continuously monitored R-R intervals (RR(int)), mean blood pressure (BP(mean)), and respiration in 15 patients (8 women, aged 43 to 73 years) after right-sided stroke, in 13 patients (7 women, aged 50 to 75 years) after left-sided stroke, and in 21 age- and sex-matched controls at rest. We used autoregressive spectral analysis to assess sympathetic and parasympathetic modulation as powers of RR(int) and BP(mean) oscillations in the low-frequency (LF: 0.04 to 0.15 Hz) and high-frequency bands (HF: 0.15 to 0.5 Hz).
RESULTS: Mean values of RR(int), BP(mean), and respiratory frequency did not differ between patients after right- or left-sided stroke and controls (p > 0.05). Patients after right-sided stroke showed a trend toward elevated LF power of RR(int) as compared with patients after left-sided stroke and controls (p < 0.10). HF powers of RR(int) were reduced in patients after right- and left-sided stroke as compared with controls (p < 0.05). LF/HF ratio of RR(int) was elevated in patients after right-sided stroke as compared with patients after left-sided stroke and controls (p < 0.05).
CONCLUSION: Irrespective of the side of the ischemia, post-acute stroke patients showed a parasympathetic cardiac deficit. Additionally, sympathetic cardiovascular modulation was increased in patients after right-sided stroke. Post-acute stroke patients might be at an increased risk for cardiac arrhythmia after unopposed sympathetic stimulation.