Abstract 13: Heart Rate Changes in Nonshockable Rhythms Prior to In-Hospital Cardiac Arrest in Patients with Structural Heart Diseases
Background: Survival after in hospital cardiac arrest (IHCA) remains low. Over past decades, only the initial rhythms of IHCA in relation to survival have been reported. Accordingly, the objective of this study was to compare the heart rate changes immediately prior to IHCA.
Methods: In a prospective pilot study, sinus rhythm electrocardiograms (ECG) prior to IHCA with initial rhythms of pulseless electrical activity (PEA) and asystole were obtained by the continuous telemetry monitoring system. Full disclosure ECG papers (25 mm/s paper speed) of 5-6 ECG leads were obtained for two minutes at time of arrest and for any significant rhythm changes prior to the time of documented IHCA. Then two minutes of full disclosure ECG papers in hourly increments for eight hours prior to documented time of IHCA were obtained. Intervals between R waves measured and the lowest HR was obtained for each minute. Linear regression and Wilcoxon signed rank test were used to compare the difference in heart rate (HR) between the hour of cardiac arrest and 8 hours prior to cardiac arrest. Over the 8 months of the study, out of 45 patients with structural heart diseases, 18 patients from intensive care and step down units were included. There were 33% female, 69±14 years old with ejection fractions of 55%±15.
Results: There were 13 patients who had PEA and five patients who had asystole as their first initial rhythms prior to IHCA. In PEA group, HR decreased within 1-24 minutes (5.4±6.2 minutes) prior to documented time of IHCA. In asystole group, the HR decreased within 1-12 minutes (6.2±4.7 minutes) in four patients and one patient's HR decreased 78 minutes prior to documented time of IHCA. There was a significant difference in the rate of change in HR during the hour of cardiac arrest as compared to the eight hours prior to IHCA in PEA and asystole groups (p=0.008; p=0.043 respectively).
Conclusion: These results indicate variable, albeit significant decreases in HR over time, and its detection prior to IHCA might have an immediate prognostic impact on the timely treatment of some patients with PEA and asystole.
- © 2011 by American Heart Association, Inc.