Device‐Guided Slow Breathing Lowers Blood Pressure and Muscle Sympathetic Nerve Activity Acutely in Prehypertensive Patients with Post‐Traumatic Stress Disorder (PTSD)

Abstract

Patients with post‐traumatic stress disorder (PTSD) have elevated sympathetic nervous system (SNS) reactivity and impaired arterial and cardiovagal baroreflex sensitivity (BRS) that contribute to increased risk of developing hypertension and cardiovascular disease. Device‐ guided slow breathing (DGB) during which respiratory rate is guided to subphysiologic rates of ~5 breaths/min using a biofeedback device has been shown to lower blood pressure (BP) and sympathetic activity in hypertensive patients. We hypothesized that DGB acutely lowers BP, heart rate (HR), and improves arterial and cardiovagal BRS in Veterans with PTSD. In 10 prehypertensive Veterans with PTSD, we measured continuous beat‐to‐beat arterial BP, EKG, and muscle sympathetic nerve activity (MSNA) at rest, and during 15 minutes of DGB (RESPeRATE). BRS was assessed using the modified oxford technique by which BP was decreased and increased using intravenous boluses of nitroprusside and phenylephrine. Cardiovagal BRS and sympathetic BRS were quantified as the slope of the linear regression between systolic BP (SBP) and R‐R interval, and diastolic BP (DBP) and MSNA burst incidence (BI) and total activity (TA), respectively. BRS assessments were made once at baseline, and repeated once during the last 5 minutes of DGB. Study participants had prehypertension (mean BP 130±4/76±2 mmHg) and had confirmed PTSD. After 10 minutes of DGB, there was a significant reduction in SBP (by −9±2 mmHg, p=0.002) and mean arterial pressure (MAP, by −4±1 mmHg, p=0.009), and a trend towards reduced DBP (−2±1 mmHg, p=0.08). There was no significant change in HR (p=0.21) with DGB. There was also a significant reduction in MSNA burst frequency (29±3 vs. 21±2 bursts/min, p=0.009), and MSNA BI (46±4 vs. 35±4 bursts/100 heart beats, p=0.004) from baseline to end of DGB. There was no significant change in sympathetic BRS quantified using both MSNA BI (p=0.19) and total activity (p=0.22), or cardiovagal BRS (p=0.24), from baseline to during DGB. DGB acutely lowers BP and MSNA, but does not improve sympathetic or cardiovagal BRS in prehypertensive veterans with PTSD. Whether long‐term DGB chronically improves resting BP, SNS activity, and arterial BRS in PTSD should be tested in future studies.Support or Funding InformationSupported by VA Merit Grant 1I01CX001065; American Heart Association 15CSA24340001