Complications after stroke or myocardial infarction predicted by decreased Vagal activity

The heart rate varies due to the interplay between sympathetic and vagal nervous activity. Whereas vagal factors lead to deceleration of the heart rate is sympathetic activity leading to heart rate acceleration. With recent developments of signal-processing these factors can be distinguished via automated techniques. Several studies have confirmed that under critical care conditions the cardial capacity to decelerate is prognostically relevant.

In an impressively large population of 5730 patients representing the complete spectrum of medical emergencies at the University of Tübingen, Christian Eick and coauthors have shown that the cardiovagal deceleration capacity is a strong and independent predictor of complication and short-term mortality. This information is available already shortly after admission and was retrieved within 10 to 30 minutes from the start of ECG recordings in the emergency room. Established risk stratification as with the Modified Early Warning Score (MEWS) can be supported and even significantly improved with this cardiovagal information.
Eick C, Rizas KD, Meyer-Zürn CS, Kroga-Bada P, Hamm W, Kreth F et al. Autonomic Nervous System Activity as Risk Predictor in the Emergency Department. Crit Care Med 2015; 43:1079–1086.

The fact that the deceleration capacity can be obtained automatically within minutes at first contact would offers even a great chance for early risk stratification in the emergency ambulance and may effectively support the triage of emergencies. The next logical step is a prospective study in order to show whether the clinical decision making based on the deceleration capacity will lead to a better outcome. The authors emphasize that the technology is inexpensive, readily available, and can be implemented in existing monitoring devices.