November 20, 2023Open Access
View Full PaperImpedance cardiogram based exploration of cardiac mechanisms in post‐traumatic stress disorder during trauma recall
Key Result
PTSD symptom activation during trauma recall was associated with real-time reductions in several cardiac contractility measures despite sympathetic nervous system activation.
Study Design
Type
Observational (n=137)
Structured PICO
Does trauma recall alter cardiac contractility and autonomic measures in male veterans with PTSD compared to those without PTSD?
P
Population
137 male veterans (17 with PTSD, 120 without PTSD) evaluated for cardiac contractility and autonomic measures during a laboratory-based traumatic reminder stressor.
E
Exposure
Laboratory-based traumatic reminder stressor (trauma recall)
C
Comparator
Non-PTSD veterans undergoing the same stressor
O
Outcome
Real-time effects on cardiac contractility and autonomic measures (derived from synchronized electrocardiogram and impedance cardiogram)surrogate
Trauma recall in veterans with PTSD is associated with deteriorated cardiac contractility despite sympathetic activation, suggesting a potential pathophysiological mechanism for their increased heart failure risk.
Abstract
Post-traumatic stress disorder (PTSD) is an independent risk factor for developing heart failure; however, the underlying cardiac mechanisms are still elusive. This study aims to evaluate the real-time effects of experimentally induced PTSD symptom activation on various cardiac contractility and autonomic measures. We recorded synchronized electrocardiogram and impedance cardiogram from 137 male veterans (17 PTSD, 120 non-PTSD; 48 twin pairs, 41 unpaired singles) during a laboratory-based traumatic reminder stressor. To identify the parameters describing the cardiac mechanisms by which trauma reminders can create stress on the heart, we utilized a feature selection mechanism along with a random forest classifier distinguishing PTSD and non-PTSD. We extracted 99 parameters, including 76 biosignal-based and 23 sociodemographic, medical history, and psychiatric diagnosis features. A subject/twin-wise stratified nested cross-validation procedure was used for parameter tuning and model assessment to identify the important parameters. The identified parameters included biomarkers such as pre-ejection period, acceleration index, velocity index, Heather index, and several physiology-agnostic features. These identified parameters during trauma recall suggested a combination of increased sympathetic nervous system (SNS) activity and deteriorated cardiac contractility that may increase the heart failure risk for PTSD. This indicates that the PTSD symptom activation associates with real-time reductions in several cardiac contractility measures despite SNS activation. This finding may be useful in future cardiac prevention efforts.