Changes in paced signals may predict in‐hospital cardiac arrest

1 Background

An increasing number of patients with chronic illnesses have implanted cardiac rhythm devices such as pacemakers and implantable cardioverter‐defibrillators (ICDs). This study was conducted to identify potentially useful predictors of in‐hospital cardiac arrest (I‐HCA) within paced electrocardiogram (ECG) signals from cardiovascular patients with implanted medical devices.

2 Methods

In this retrospective study of 17 subjects, full‐disclosure ECG traces prior to the time of documented I‐HCA were analyzed to determine R‐R intervals and QRS durations (QRSd).

3 Results

Ventricular paced QRSd prolongation was observed prior to I‐HCA in 10/16 (63%) subjects. QRSd was significantly greater immediately preceding cardiac arrest than during each of the 8 hours prior to cardiac arrest (P < 0.05). Heart rate changes (measured using standard deviation) within 15 minutes of cardiac arrest were significantly greater in subjects with pulseless electrical activity (PEA)/asystolic arrest compared to those with cardiac arrests due to ventricular tachycardia/ventricular fibrillation (VT/VF) (10.13 vs 3.31; P  =  0.024). Significant differences over the 8 hours preceding cardiac arrest in heart rate (74 vs 86 beats/min; P  =  0.002) and QRS duration (172 ms vs 137 ms; P < 0.001) were observed between subjects with initial rhythms of VT/VF and those with initial rhythms of PEA/asystole.

4 Conclusions

Patterns of diagnostic ECG features can be extracted from the telemetry data of patients with implanted medical devices prior to adverse events including I‐HCA. The detection of these significant changes might have an immediate prognostic impact on the timely treatment of some patients at risk of adverse events.