Pseudo-pulseless electrical activity: A distinct hemodynamic state in cardiac arrest and its implications for resuscitation

Abstract

Pulseless electrical activity (PEA) is conventionally defined as organized electrical cardiac activity in the absence of a palpable pulse. It is managed as a single non-shockable arrest rhythm within advanced life support algorithms. Increasing use of point-of-care ultrasound and objective perfusion monitoring has revealed substantial physiological heterogeneity within this category. A clinically important subset demonstrates persistent cardiac mechanical activity despite absent palpable pulses, commonly referred to as PEA with cardiac mechanical activity (pseudo-PEA). In this review, pseudo-PEA is defined as the absence of a palpable pulse in the presence of cardiac mechanical activity visualized on point-of-care ultrasound. Across observational cohorts and systematic reviews, the presence of cardiac activity during PEA is consistently associated with higher rates of return of spontaneous circulation and short-term survival compared with cardiac standstill, suggesting that pseudo-PEA often represents a profound but potentially reversible low-flow state rather than complete electromechanical dissociation. Current resuscitation algorithms do not explicitly distinguish pseudo-PEA from true PEA, which may contribute to non-targeted therapy, delayed correction of reversible causes, and premature termination decisions. This narrative review synthesizes the physiological basis of pseudo-PEA, evaluates available diagnostic and prognostic evidence, and examines the operational risks of intra-arrest ultrasound, particularly interruption of chest compressions. We propose a physiology-guided resuscitation approach that integrates time-limited ultrasound with objective perfusion assessment. While this framework offers a more nuanced understanding of cardiac arrest physiology, the available evidence remains largely observational. Pseudo-PEA should therefore inform clinical reasoning rather than dictate management in isolation. Further prospective studies are required to determine whether physiology-guided strategies improve meaningful survival outcomes.

Keywords: Pulseless electrical activity with cardiac mechanical activity; Pulseless electrical activity; Cardiac arrest; Point-of-care ultrasound; End-tidal carbon dioxide; Coronary perfusion pressure; Physiology-guided cardiopulmonary resuscitation

Core Tip: Pulseless electrical activity (PEA) is traditionally treated as a uniform non-shockable cardiac arrest rhythm. Yet, bedside ultrasound and perfusion monitoring increasingly reveal a subgroup with residual cardiac mechanical activity called PEA with cardiac mechanical activity. This review reframes PEA with cardiac mechanical activity as a low-flow arrest state rather than true electromechanical dissociation, summarizes prognostic and physiological evidence supporting this distinction, and highlights the limitations of rhythm-based resuscitation algorithms. We propose a structured, physiology-guided resuscitation strategy that integrates time-limited ultrasound with perfusion targets to guide treatment escalation while preserving the quality of cardiopulmonary resuscitation.