PROVIDENCE, RI — Could heart rate variability be an indicator of when a form of transcranial magnetic stimulation would be effective in treating post-traumatic stress disorder?
A new study suggested that might be the case. The report in the journal Neuromodulation points out that PTSD is associated with autonomic dysfunction, as indicated by deficits in the sympathetic and parasympathetic nervous systems. Elevated heart rate and reduced heart rate variability (HRV) are indicators of that dysfunction.1
Researchers from the Warren Alpert Medical School at Brown University and the VA Providence Healthcare System advised that intermittent theta-burst stimulation (iTBS has shown effectiveness in PTSD, adding, “Nevertheless, it remains unclear whether HRV may be an iTBS biomarker for PTSD and whether iTBS impacts autonomic activity.”
To find out, the study team recruited 50 veterans with PTSD to participate in a randomized controlled trial, receiving 10 daily sessions of sham-controlled iTBS (right dorsolateral prefrontal cortex, 1,800 pulses/day, 80% active motor threshold, 9.5 min).
Focusing on the 47 with a usable dataset, researchers assessed HRV as predictors of clinical response immediately after stimulation. Specifically, they evaluated iTBS effects on autonomic response (mean RR interval, root-mean-square of successive differences [RMSSD], total power [TP] and low-frequency/high-frequency [LF/HF] ratio), using an ultra-short approach.
Results indicated that TP and RMSSD were significant predictors of acute clinical response to iTBS. “Individuals with higher TP had better response to iTBS with improved symptoms on the Clinician-Administered PTSD Scale (rs = -0.58, p = 0.004), and higher functionality on the Social and Occupational Function Scale (rs = 0.43, p = 0.04),” the authors wrote. “Similarly, higher RMSSD was associated with superior outcomes (rs = -0.44, p = 0.04). No other significant changes in HRV metrics were observed (p ≥ 0.05).”
Study authors said their findings indicate that autonomic activity is a potential low-cost and technically simple predictive biomarker of iTBS response in PTSD, adding that less autonomic dysfunction was associated with superior clinical improvements with iTBS.
“Future studies might consider HRV acquisition during iTBS, as well as prospective testing of these findings in patients with elevated hyperarousal,” the researchers recommended.
- Cosmo C, Seligowski AV, Aiken EM, Van’t Wout-Frank M, Philip NS. Heart Rate Variability Features as Predictors of Intermittent Theta-Burst Stimulation Response in Posttraumatic Stress Disorder. Neuromodulation. 2022 Jun;25(4):588-595. doi: 10.1111/ner.13529. Epub 2022 Feb 3. PMID: 35670065.