Impaired Autonomic Modulation and Abnormal Circadian Variation in Male Twins with Posttraumatic Stress Disorder Open Access

Weng, Lei (2014)

Permanent URL: https://etd.library.emory.edu/concern/etds/vx021f791?locale=en
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Abstract

Background : Posttraumatic stress disorder (PTSD) is associated with increased risk of developing cardiovascular disease . A core symptom of PTSD is sleep disturbance, which may lead to impaired autonomic modulation at night and downstream cardiometabolic abnormalities. We aimed to investigate nighttime and day-night differences in heart rate variability (HRV), a measure of autonomic function, in a group of veteran twins with PTSD versus without PTSD.

Methods: HRV was measured by power spectral analysis on 24-hour ambulatory electrocardiogram in 134 middle-aged veteran male twins. PTSD status was assessed with the Structured Clinical Interview for Psychiatry Disorders. We used mixed-effects regression models to analyze the association of current PTSD (symptoms within 30 days) and nighttime HRV, while adjusting for potential confounding due to cardiovascular, familial, and genetic factors through twin models that compare PTSD discordant twin brothers.

Results: Current PTSD (n=16) was associated with lower low-frequency (LF) HRV during nighttime both in individual twins and within 15 pairs discordant for current PTSD. We observed a 0.77 ln ms2 lower LF HRV (p <.001) during nighttime in twins with current PTSD versus controls. The association persisted after adjustment for confounding factors. Patients with current PTSD also showed significantly lower high-frequency (HF) HRV and very-low-frequency (VLF) HRV during nighttime in unadjusted models, although after multivariate adjustment the associations lost significance. Twins with current PTSD exhibited a decrease in LF and HF HRV at night compared to the day (adjusted p = 0.09, p <.01), whereas for controls without current PTSD, the trends were in the opposite direction, and both HF and LF HRV increased at night.

Conclusion: Veterans with PTSD exhibited reduced LF HRV at night, which may indicate diminished parasympathetic regulation secondary to disturbed sleep. These findings suggest a possible role of sleep perturbation and autonomic dysregulation as a mechanism of increased cardiovascular risk in PTSD.

Table of Contents

Table of Contents

Introduction..................................................................................................1

Method.........................................................................................................4

Subjects.........................................................................................................4

Measurement of HRV........................................................................................4

Assessment of PTSD, Depression........................................................................5

Other Measurements.........................................................................................6

Statistical Analysis............................................................................................7

Multivariate Modeling.........................................................................................8

Within-Pair Analysis...........................................................................................9

Genetic Influences.............................................................................................9

Results...........................................................................................................11

Baseline Characteristics......................................................................................11

Association of PTSD with HRV..............................................................................11

HRV Differences Between AM Awake Hours and Nighttime........................................12

Analysis of PTSD Symptoms as a Continuous Measure..............................................13

Discussion.......................................................................................................14

Future Directions................................................................................................16

Reference........................................................................................................17

Tables.............................................................................................................23

Figures............................................................................................................28

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