Longitudinal psychophysiological studies of heart rate: mediating effects and implications for treatment.

Fear conditioning models of posttraumatic stress disorder (PTSD) propose that noradrenergic activation at the time of trauma leads to over-consolidation of trauma memories and contributes to PTSD. This model suggests that resting heart rate (HR) in the acute phase after trauma may reflect the strength of the noradrenergic response and may represent an initial marker of those who are at risk of PTSD development. Ten prospective studies are reported that assessed the relationship of resting HR within 1 week of trauma and subsequent PTSD. Whereas 8 of the 10 studies found that elevated HR in the acute phase was associated with increased risk of subsequent PTSD, there was much variability in the HR levels and subsequent PTSD. The current data suggest multiple pathways to PTSD development that may not necessarily involve elevated HR. The data indicate that HR in the acute phase cannot be accurately used to identify people who are at risk for PTSD. The association between HR and PTSD does suggest that HR is a useful means to test fear conditioning models of trauma response.