Survival from in-hospital cardiac arrests (IHCA) due to pulseless electrical activity (PEA) or asystole remains extremely poor. Our understanding of the pathophysiology of PEA is limited, and management of IHCA largely follows a “one size fits all” approach due to the lack of reliable methods to determine underlying cause in real-time.
Changes on continuous electrocardiogram (ECG) preceding IHCA reflect the underlying cause and pathophysiology of IHCA.
We evaluated adult patients with IHCA from PEA/asystole at a tertiary care hospital between 3/2010 – 8/2014 with at least 3 hours of continuous ECG data preceding IHCA. We determined the likely cause of IHCA by reviewing of clinical, lab, imaging, and autopsy data. We analyzed up to 24 hours of continuous ECG data evaluating for changes in rhythm, PR interval, QRS and ST/T wave morphology leading up to IHCA.
Eighty-nine patients were studied (mean age 62 ± 18 years, 54% male). Return of spontaneous circulation was obtained in 65 (73%) and 24 (27%) survived to discharge. We found 5 distinct patterns of ECG changes leading up to and including the arrest rhythm (Table). Causes of cardiac arrest were significantly different between the group (Fischer’s exact p<0.001). Notably, a severe right ventricular strain ECG pattern was found preceding PEA caused by pulmonary embolism, asphyxia from large mucus plugs or massive aspiration, acute respiratory distress syndrome, and cardiogenic shock with biventricular failure.
Distinct patterns of changes in rhythm and ECG morphology which reflect different underlying causes and pathophysiology of IHCA were identified. Recognition of these patterns may provide an opportunity for better understanding of PEA mechanisms and outcomes, and allow for real-time prediction of IHCA cause to help direct management.