Heart-Rate Variability Correlates to Choroidal Thickness in Central Serous Chorioretinopathy

Abstract

Purpose

Patients with central serous chorioretinopathy (CSC) have previously been shown to have a lower heart rate variability (HRV), implying a lower vagal tone. Vagal tone alters mineralocorticoids, which in turn affect the thickness of the choroid. Since increased choroidal thickness is characteristic of CSC, we wanted to investigate its correlation with HRV.

Patients and Methods

In this case–control study, 21 acute CSC patients and 31 healthy controls were included. Diagnosis was confirmed by optical coherence tomography (OCT) and retinal examination. HRV was evaluated following accepted standards. Outcome measures were chosen beforehand as follows: Standard deviation of N–N intervals (SDNN), root mean square of successive differences (RMSDD), low frequency/high frequency ratio (LF/HF ratio), and standard deviation ratio from commonly used Poincare plot (SD2/SD1 ratio). Choroidal thickness was measured using OCT directly under the foveola.

Results

Patients and healthy controls did not differ in health and medical characteristics in addition to CSC disease. Choroidal thickness was greatest in patients with CSC (mean±SD: 342±80 μm) compared to controls (235±60 μm, p<0.0001). A correlation was observed between LF/HF ratio and choroidal thickness in patients with CSC (Pearson correlation 0.63, p=0.02), where the CSC group had a lower LF/HF ratio (Median 2.39 ms², IQR: 1.2–4.34 ms²) compared to controls (Median 1.2 ms², IQR: 0.9–2.4 ms², p=0.06) and SD2/SD1 ratio (CSC 0.59±0.2 vs controls 0.74±0.3, p=0.06).

Conclusion

We found a correlation between the thickness of the choroid and the HRV-measured LF/HF ratio in patients with CSC and showed a borderline significant reduction in HRV measurements in patients with CSC. The data imply that vagal alterations exist in patients with CSC. Due to the low n, this should be considered as a pilot study. Further studies are warranted to elucidate mechanisms and validate findings.

Keywords:

• vagus
• vagal tone
• heart rate variability

Data Sharing Statement

Data are available upon request.

Ethics Approval and Informed Consent

The project was approved by the Regional Committee of Ethics in Research of the Region of Zealand (jr. no. SJ-510) and the Danish Data Protection Agency (jr. no. REG-17-2016). Participants gave their oral and written informed consent prior to enrollment.

Author Contributions

All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

CRM has previously received a travel grant from Bayer. CBM reports grants from Region of Zealand Research fund, Fight for Sight Denmark and Synoptikforeningen, during the conduct of the study; grants from Bayer, outside the submitted work. The authors report no other conflicts of interest in this work.

Additional information

Funding

This project was funded by the Region Zealand Research Fund, Fight for Sight Denmark, and Synoptikfonden. The sponsors had no influence on the design or execution of the project or the decision to publish it.