Heart rate and QRS duration as biomarkers predict the immediate outcome from pulseless electrical activity

Introduction Pulseless electrical activity (PEA) is commonly observed in in-hospital cardiac arrest (IHCA). Universally available ECG characteristics such as QRS duration (QRSd) and heart rate (HR) may develop differently in patients who obtain ROSC or not. The aim of this study was to assess prospectively how QRSd and HR as biomarkers predict the immediate outcome of patients with PEA. Method We investigated 327 episodes of IHCA in 298 patients at two US and one Norwegian hospital. We assessed the ECG in 559 segments of PEA nested within episodes, measuring QRSd and HR during pauses of compressions, and noted the clinical state that immediately followed PEA. We investigated the development of HR, QRSd, and transitions to ROSC or no-ROSC (VF/VT, asystole or death) in a joint longitudinal and competing risks statistical model. Results Higher HR, and a rising HR, reflect a higher transition intensity (“hazard”) to ROSC (p < 0.001), but HR was not associated with the transition intensity to no-ROSC. A lower QRSd and a shrinking QRSd reflect an increased transition intensity to ROSC (p = 0.023) and a reduced transition intensity to no-ROSC (p = 0.002). Conclusion HR and QRSd convey information of the immediate outcome during resuscitation from PEA. These universally available and promising biomarkers may guide the emergency team in tailoring individual treatment.publishedVersio

Development of Electrocardiographic Characteristics During Resuscitation from Pulseless Electrical Activity

Background Pulseless electrical activity (PEA) refers to patients in cardiac arrest in whom the electrocardiogram (ECG) shows organized electrical activity. In cardiac arrest in hospital, PEA is the presenting rhythm in around 40% of cases. In the out-of-hospital setting, PEA is the presenting rhythm in about 20% of cardiac arrests. The ECG is a recording of the electrical activity of the heart, and is widely used in diagnosis of heart disease and monitoring of heart function. The presence of ECG complexes represents a possible source of information during PEA. The development of ECG characteristics during the provision of advanced life support (ALS) for cardiac arrest with PEA has not been investigated previously. Aims of the Thesis 1. To describe the development of ECG characteristics during ALS in patients with and without return of spontaneous circulation (ROSC). 2. To explore the effect of intravenous adrenaline on the development of the ECG characteristics during ALS. 3. To investigate the development of ECG characteristics based on the cause of cardiac arrest. Methods We measured QRS complex width (the duration of ventricular depolarization) and QRS complex rate (heart rate) at all pauses in compression during the provision of ALS. Studies I and III included patients with cardiac arrest at St. Olav University Hospital, Trondheim, Norway. Study II included patients with cardiac arrest out-of-hospital in the city of Oslo, Norway, that were originally part of a randomized controlled trial of intravenous access during ALS. We examined whether QRS complex width and heart rate during ALS were related to whether ROSC was obtained or not (all three studies), whether adrenaline was administered (study II), and whether there was a cardiac or other, non-cardiac etiology of arrest (study III). Statistical methods included correlation analysis, multivariate analysis of variance, analysis of covariance, and various mixed model methods. Results In studies I and II, we found that the pattern of change in QRS width and heart rate differed between patients who obtained and did not obtain ROSC. More specifically, QRS width decreased and heart rate increased in patients who obtained ROSC. This difference was consistent in the in- and out-of-hospital populations. In study II, we found that heart rate increased in patients who received adrenaline during ALS, more in patients who obtained ROSC, but also in patients who did not obtain ROSC. Study III showed that the development in QRS width differed between patients with a cardiac etiology of arrest compared to patients with other etiologies; QRS was wider in the cardiac etiology patients, but narrowed in those that did obtain ROSC. In the other etiology groups, QRS width was narrower throughout ALS. Conclusion QRS narrowed and heart rate rose during the provision of ALS for cardiac arrest with PEA in patients who did obtain ROSC, but not in those who died. The same pattern of change in QRS width and heart rate was seen in the in-hospital and out-of-hospital populations studied. Heart rate increased in patients who did get adrenaline during ALS out-of-hospital, even if they did not obtain ROSC. QRS width was wider in patients with cardiac etiology of in-hospital cardiac arrest, but narrowed in those who obtained ROSC. Patients with other, non-cardiac, etiologies had narrower QRS widths that did not change during ALS

The effect of intravenous adrenaline on electrocardiographic changes during resuscitation in patients with initial pulseless electrical activity in out of hospital cardiac arrest

Introduction Presence of electrocardiographic rhythm in the absence of palpable pulses defines pulseless electrical activity (PEA) and the electrocardiogram (ECG) may provide a source of information during resuscitation. The aim of this study was 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 potential effects of adrenaline on these characteristics. Methods Patients with OHCA and initial PEA, part of randomized controlled trial of ALS with or without intravenous access and medications, were included. A total of 4840 combined observations of QRS complex rate (heart rate) and width were made by examining defibrillator recordings from 170 episodes of cardiac arrest. Results We found Increased heart rate (47 beats per minute) and reduced QRS complex width (62 ms) during ALS in patients who obtained return of spontaneous circulation (ROSC); while patients who received adrenaline but died increased their heart rate (22 beats per minute) without any concomitant decrease in QRS complex width. Conclusion ECG changes during ALS in cardiac arrest were associated with prognosis, and the administration of adrenaline impacted on these changes