Pulseless Electric Activity or Electromechanical Dissociation
Larisa G. Tereshchenko · Circulation Arrhythmia and Electrophysiology · 2024
sudden cardiac arrest; pulseless electrical activity; resuscitation; electromechanical dissociation In this issue of the Journal, Holmström et al. 1 analyzed unique prospectively collected data.The authors obtained the data on 641 observed sudden cardiac arrest (SCA) cases that occurred in the presence of Emergency Medical Services (EMS) personnel and, thus, argued that an available electrocardiogram (ECG) reflected the true SCA initial rhythm.Holmström et al. 1 utilized the data of the prospective community-based studies of the SCA, the Oregon Sudden Unexpected Death Study (OregonSUDS), and the Ventura Prediction of Sudden Death in Multi-ethnic Communities (PRESTO) study.Adjudication of SCA cases was based on EMS reports, initial ECG strip recorded at the time of SCA, medical records, death certificates, and autopsy reports.The authors aimed to compare and contrast the clinical characteristics of individuals presented with the shockable versus non-shockable initial rhythms and, therefore, included "pulseless ventricular tachycardia (VT)" cases in the ventricular fibrillation (VF) group.Previously diagnosed coronary artery disease (CAD) was noted in 53.4%, and heart failure (HF) in 30.3% of the population.The authors found that anemia, older age, chronic kidney disease (CKD), obesity, and prearrest dyspnea were the most important predictors of pulseless electrical activity (PEA).In contrast, CAD, prearrest chest pain, and young age were the most important predictors of VF.The authors should be congratulated on their important endeavors.However, several aspects of comparison between "shockable VT/VF" and "non-shockable PEA" deserve additional comments.The development of SCA in the presence of EMS personnel is an infrequent clinical scenario.Theoretically, two different underlying stories can be unfolding.In one clinical scenario, an EMS team would attend to a patient who was initially presented with trivial clinical symptoms (e.g.chest pain, dyspnea) and, by a random chance, at the moment of ECG recording, a patient would develop SCA.In such a clinical scenario, an EMS team had a unique opportunity to capture a rare moment of SCA initiation and record the true initial SCA rhythm.The probability of such a clinical scenario is minuscule, but it is not zero.The second (more frequent) clinical scenario includes an EMS response to an SCA