Relationship between Ischemic Stroke and Pulse Rate Variability as a Surrogate of Heart Rate Variability

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System
• Neurology

Background:

• Autonomic reflexes are crucial for maintaining cardiovascular homeostasis during postural changes like standing.
• Impaired autonomic function, leading to dizziness and falls, is common in stroke survivors.
• Heart rate variability (HRV) is a gold standard for assessing autonomic function, but pulse rate variability (PRV) is often used for ambulatory monitoring.

Purpose of the Study:

• To compare the efficacy of PRV against HRV in monitoring autonomic reflex function in ischemic stroke survivors.
• To evaluate the agreement between PRV and HRV during a sit-to-stand test in stroke survivors and healthy controls.

Main Methods:

• Continuous electrocardiography and blood pressure monitoring were performed on ischemic stroke survivors and age-matched controls during a 10-minute sit-to-stand test.
• Beat-by-beat heart period (RR and PP intervals), blood pressure (SBP, DBP), and pulse arrival time (PAT) were derived.
• Time and frequency domain HRV (from RR intervals) and PRV (from PP intervals) metrics were calculated.

Main Results:

• Stroke survivors exhibited lower pulse arrival time (PAT) during standing, indicating increased arterial stiffness compared to controls.
• The agreement between HRV and PRV was significantly reduced in stroke survivors compared to controls while standing.
• These findings highlight potential discrepancies when using PRV as a surrogate for HRV in this patient group.

Conclusions:

• PRV may not be a suitable surrogate for HRV in assessing autonomic cardiovascular control in stroke survivors during postural challenges.
• Caution is advised when interpreting PRV data in stroke survivors, particularly in ambulatory or portable monitoring scenarios.
• Further research is needed to validate alternative methods for autonomic function assessment in stroke populations.