Abstract 14: Is Low Heart Rate Variability, a Marker of Autonomic Dysfunction, the Missing Link Between Migraine With Visual Aura and Cardioembolic Stroke?

Abstract

Introduction: Migraine with visual aura (MA) has been associated with the risk of cardioembolic stroke (CES). Low heart rate variability (HRV), a marker of cardiac autonomic dysfunction, has been shown to be associated with atrial fibrillation (AF) and risk of stroke. We investigated the association between low HRV and MA. We also examined whether the MA associated CES risk can be explained by a low HRV. Methods: Participants in the Atherosclerosis Risk in Communities cohort were interviewed for migraine history in 1993-1995; during a subsequent follow-up visit (1996-1998) HRV was measured using 6-minute EKG. HRV indices were calculated using the standard deviation of RR intervals (SDNN), the mean of all normal RR intervals (MeanNN), the root mean square of successive differences of RR intervals (RMSSD), low (LF) and high (HF) frequency power, and the LF/HF ratio. All HRV measures were categorized into quintiles. Logistic regression models were used to estimate ORs adjusted for sociodemographic and comorbid confounders. Mediation analysis was conducted to test if HRV was a mediator of MA associated CES risk, using Barron-Kenny’s causal step tests. Results: Of 11,939 participants assessed for headache 426 reported MA. A total of 164 incident CES occurred over a 20-year follow-up period. After covariate adjustment, there was a strong evidence of an association between low HRV and MA. The lowest HRV quintile was associated with higher odds of MA compared with the highest quintile for SDNN (OR, 1.5, 95% CI, 1.1–2.3), RMSSD (OR, 1.4; 95% CI, 1.1–2.1), LF (OR, 1.3; 95% CI, 1.0–1.8), HF (OR, 1.5; 95% CI, 1.1–2.1), and LF/HF ratio (OR, 1.5; 95% CI, 1.1–2.0). The data also suggests HRV may be a potential mediator between MA and CES. Conclusion: MA was associated with low HRV, suggestive of chronic autonomic dysfunction among this population. Alongside prior findings showing HRV-AF, HRV-Stroke and AF-Stroke link, the association may provide the missing link between MA and Stroke (Figure).