Introduction:
Presence of electrocardiographic rhythm, documented by the electrocardiogram (ECG), in the absence of palpable pulses defines pulseless electrical activity (PEA). Our aims were to examine the development of ECG characteristics during advanced life support (ALS) from Out-of-Hospital-Cardiac-Arrest (OHCA) with initial PEA, and to explore the effects of epinephrine on these characteristics.
Methods:
Patients with OHCA and initial PEA in a randomized controlled trial of ALS with or without intravenous access and medications were included. QRS widths and heart-rates were measured in recorded ECG signals during pauses in compressions. Statistical analysis was carried out by multivariate regression (MANOVA).
Results:
Defibrillator recordings from 170 episodes of cardiac arrest were analyzed, 4840 combined measurements of QRS complex width and heart rate were made. By the multivariate regression model both whether epinephrine was administered and whether return of spontaneous circulation (ROSC) was obtained were significantly associated with changes in QRS width and heart rate. For both control and epinephrine groups, ROSC was preceded by decreasing QRS width and increasing rate, but in the epinephrine group an increase in rate without a decrease in QRS width was associated with poor outcome (fig).
Conclusion:
The QRS complex characteristics are affected by epinephrine administration during ALS, but still yields valuable prognostic information.
Heart rate complexity: an early prognostic marker of patient outcome after cardiac arrest
