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

Abstract

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. 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. 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). 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.