Heart rate variability (HRV), as assessed during a deep breathing test, may lead to improved diagnosis of posttraumatic stress disorder (PTSD), according to a study published in Frontiers in Psychiatry.
It is estimated that between 8% and 15% of clinically recognized pregnancies and up to 30% of all pregnancies result in miscarriage — a loss that can be devastating for everyone. There are limited data on the strength of the association between perinatal loss and subsequent common mental health disorders, such as anxiety, depression, and PTSD. The prevalence of PTSD among this group is still unknown, and one of the factors that contribute to the absence of data is that diagnostic evaluation is subjective.
To address this issue, researchers from Anhembi Morumbi University (UAM) in São José dos Campos, Brazil, along with teams in the United States and United Arab Emirates (UAE), investigated biomarkers for the severity of PTSD. The hope is that the research will enable psychiatrists to assess women who experience pregnancy loss more objectively. Study author Ovidiu Constantin Baltatu, MD, PhD, a professor at Brazil's UAM and the UAE's Khalifa University, spoke to Medscape about the study.
Under the guidance of Baltatu, psychologist Cláudia de Faria Cardoso carried out the research as part of her studies in biomedical engineering at UAM. Fifty-three women were recruited; the average age of the cohort was 33 years. All participants had a history of at least one perinatal loss. Pregnancy loss intervals ranged from less than 40 days to more than 6 months.
Participants completed a clinical interview and a questionnaire; PTSD symptoms were assessed on the basis of criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. The instrument used for the assessment was the Brazilian version of the Posttraumatic Stress Disorder Checklist (PCL-5). In addition, to evaluate general autonomic dysfunction, patients completed the Composite Autonomic Symptom Score 31 (COMPASS-31) questionnaire.
HRV was assessed during a deep breathing test using an HRV scanner system with wireless electrocardiography that enabled real-time data analysis and visualization. The investigators examined the following HRV measures: standard deviation (SD) of normal R-R wave intervals (SDNN), square root of the mean of the sum of the squares of differences between adjacent normal R wave intervals, and the number of all R-R intervals in which the change in consecutive normal sinus intervals exceeds 50 ms divided by the total number of R-R intervals measured.
Of the 53 participants, 25 had been diagnosed with pregnancy loss–induced PTSD. The results indicated a significant association between PCL-5 scores and HRV indices. The SDNN index effectively distinguished between patients with PTSD and those without.
To Baltatu, HRV indices reflect dysfunction of the autonomic nervous system (ANS), one of the major neural pathways activated by stress.
Although the deep breathing test has been around for a long time, it's not widely used in current clinical practice, he said. According to him, maximum and minimum heart rates during breathing at six cycles per minute can typically be used to calculate the inspiratory-to-expiratory ratio, thus providing an indication of ANS function. "Our group introduced the study of HRV during deep breathing test, which is a step forward," he said.
The methodology used by the team was well received by the participants. "With the deep breathing test, the women were able to look at a screen and see real-time graphics displaying the stress that they were experiencing after having suffered trauma. This visualization of objective measures was perceived as an improved care," said Baltatu.
In general, HRV provides a more objective means of diagnosing PTSD. "Normally, PTSD is assessed through a questionnaire and an interview with psychologists," said Baltatu. The subjectivity of the assessment is one of the main factors associated with the underdiagnosis of this condition, he explained.
It is important to remember that other factors, such as a lack of awareness about the problem, also hinder the diagnosis of PTSD in this population, Baltatu added. Women who have had a miscarriage often don't think that their symptoms may result from PTSD. This fact highlights why it is so important that hospitals have a clinical psychologist on staff. In addition, Baltatu pointed out that a woman who experiences a pregnancy loss usually has negative memories of the hospital and is therefore reluctant to reach out for professional help. "In our study, all psychological care and assessments took place outside of a hospital setting, which the participants seemed to appreciate," he emphasized.
Baltatu and his team are conducting follow-up research. The preliminary results indicate that the biomarkers identified in the study are promising in the assessment of patients' clinical progress. This finding may reflect the fact that the HRV indices have proven useful not only in diagnosing but also in monitoring women in treatment, because they are able to identify which patients are responding better to treatment.
Front Psychiatry. 2019 Jan 17;9:735. Full text