» Articles » PMID: 31278382

Heart Rate Variability, the Dynamic Nature of the Retinal Microvasculature and Cardiac Stress: Providing Insight into the Brain-retina-heart Link: the SABPA Study

Overview
Journal Eye (Lond)
Specialty Ophthalmology
Date 2019 Jul 7
PMID 31278382
Citations 1
Authors
Affiliations
Soon will be listed here.
Abstract

Background And Aims: Decreased heart-rate-variability (HRV) indicates increased sympathetic nervous system (SNS) activity and modulation with a shift in the sympatho-vagal balance towards SNS predominance. Increased SNS activity may precede volume-loading hypertension, contribute to increases in cardiac troponin T (cTnT), endothelial dysfunction and small vessel disease. Therefore, we investigated the retinal vasculature, HRV during flicker-light-induced-provocation (FLIP) and systemic cTnT, a marker of cardiac stress, to provide further evidence in support of the brain-retina-heart link.

Methods: Cross-sectional observations were obtained from a bi-ethnic cohort (N = 264), aged 23-68 years. Fasting serum samples for cTnT were obtained. Retinal vascular calibres were quantified from mydriatic eye fundus images and dynamic retinal vessel calibre responses were determined during FLIP. Time-and frequency domain parameters of HRV were calculated during FLIP for each participant.

Results: Africans had wider venules and attenuated time domain parameters during FLIP. In Africans, inverse associations emerged between arteriolar dilation and both cTnT and root-mean squared of the standard deviations of successive RR-intervals (rMSSD) (p = 0.030), and between arteriolar constriction and both low-frequency expressed in normalised units (LFnu) (p = 0.003) and high-frequency expressed in normalised units (p = 0.021). Wider venules inversely associated with standard deviation of the NN intervals (SDNN) as well as LFnu (p = 0.009) in Africans. An opposite profile was observed in Caucasians with both time-and frequency domain parameters of HRV in relation to retinal vessel structure and function.

Conclusion: FLIP elicited increased SNS activity and modulation in this bi-ethnic cohort. In Africans, decreased HRV during FLIP accompanied arteriolar and venular responses and elevated systemic levels of cTnT, implying that the SNS exerted a significant effect on the smooth muscle tone of the retinal vasculature. Disrupted retinal autoregulation may imply general autonomic nervous system dysfunction; exemplifying central control by the brain on all systemic regulatory functions, across different vascular beds.

Citing Articles

Acute mental stress-induced alpha or beta-adrenergic reactivity patterns linked to unique cardiometabolic risk profiles.

Wentzel A, Naude D, von Kanel R Sci Rep. 2025; 15(1):8668.

PMID: 40082568 PMC: 11906893. DOI: 10.1038/s41598-025-92961-2.


Delayed retinal vein recovery responses indicate both non-adaptation to stress as well as increased risk for stroke: the SABPA study.

Malan L, Hamer M, von Kanel R, Kotliar K, van Wyk R, Lambert G Cardiovasc J Afr. 2020; 32(1):5-16.

PMID: 33104153 PMC: 8756074. DOI: 10.5830/CVJA-2020-031.

References
1.
Grieshaber M, Mozaffarieh M, Flammer J . What is the link between vascular dysregulation and glaucoma?. Surv Ophthalmol. 2007; 52 Suppl 2:S144-54. DOI: 10.1016/j.survophthal.2007.08.010. View

2.
Lott M, Slocomb J, Shivkumar V, Smith B, Quillen D, Gabbay R . Impaired retinal vasodilator responses in prediabetes and type 2 diabetes. Acta Ophthalmol. 2013; 91(6):e462-9. PMC: 3749269. DOI: 10.1111/aos.12129. View

3.
Von Rosenberg W, Chanwimalueang T, Adjei T, Jaffer U, Goverdovsky V, Mandic D . Resolving Ambiguities in the LF/HF Ratio: LF-HF Scatter Plots for the Categorization of Mental and Physical Stress from HRV. Front Physiol. 2017; 8:360. PMC: 5469891. DOI: 10.3389/fphys.2017.00360. View

4.
Huemer K, Garhofer G, Zawinka C, Golestani E, Litschauer B, Schmetterer L . Effects of dopamine on human retinal vessel diameter and its modulation during flicker stimulation. Am J Physiol Heart Circ Physiol. 2002; 284(1):H358-63. DOI: 10.1152/ajpheart.00642.2002. View

5.
Pemp B, Palkovits S, Howorka K, Pumprla J, Sacu S, Garhofer G . Correlation of retinal neurodegeneration with measures of peripheral autonomic neuropathy in type 1 diabetes. Acta Ophthalmol. 2018; 96(7):e804-e810. PMC: 6282971. DOI: 10.1111/aos.13733. View