Is cardiac arrest still a binary clinical diagnosis? Toward electro-mechanical–hemodynamic phenotyping in the era of point-of-care ultrasound

Q: What is the clinical evidence from this study?

Study design: Review. Population: Cardiac arrest. Intervention: Point-of-care ultrasound (PoCUS) electro-mechanical-hemodynamic phenotyping vs. Conventional rhythm- and pulse-based cardiac arrest classification.

Gabriele Via; Francesco Corradi; Guido Tavazzi; Adrian View-Kim Wong

doi:10.5826/tuj.2026.19728

November 10, 2026The Ultrasound JournalOpen Access

Is cardiac arrest still a binary clinical diagnosis? Toward electro-mechanical–hemodynamic phenotyping in the era of point-of-care ultrasound

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Key result

PoCUS enables electro-mechanical-hemodynamic phenotyping of cardiac arrest beyond traditional Advanced Life Support categories.

Why the study?

Point-of-care ultrasound directly reveals cardiac mechanical activity and circulatory flow, challenging the traditional rhythm-pulse classification of cardiac arrest by exposing physiologically distinct states concealed within current categories.

Key Points

To establish an integrated electro-mechanical-hemodynamic framework that uses point-of-care ultrasound to categorize cardiac arrest presentations into distinct pathophysiological phenotypes.
Conceptual physiology-based framework development synthesizing point-of-care ultrasound (PoCUS), Doppler imaging, and invasive arterial pressure monitoring into cardiac arrest classification.
The framework classifies arrest into three principal phenotypes: shockable cardiac arrest (ventricular fibrillation/pulseless ventricular tachycardia), zero-flow arrest (asystole and non-contractile or agonal pulseless electrical activity), and severe low-flow arrest (pseudo-pulseless electrical activity with organized contraction).
Shockable and zero-flow states require mechanical circulation substitution via compressions and defibrillation or vasopressors, whereas severe low-flow states refocus therapy on optimizing and supporting residual native circulation.
PoCUS integrates mechanical context with diagnostic pathology, helping detect occult ventricular fibrillation, dynamic signs of tamponade or acute cor pulmonale, and phenotype transitions during resuscitation.

Structured PICO

P

Population

Patients presenting with cardiac arrest (CA), with a specific focus on non-shockable presentations and pulseless electrical activity (PEA).

I

Intervention

Point-of-care ultrasound (PoCUS), supplemented by Doppler ultrasound (carotid or femoral) and invasive arterial-pressure monitoring, for electro-mechanical-hemodynamic phenotyping during cardiopulmonary resuscitation.

C

Comparator

Conventional Advanced Life Support (ALS) operational assessment based on electrocardiographic (ECG) rhythm analysis and manual central pulse palpation.

This conceptual review proposes an integrated electro-mechanical-hemodynamic framework using point-of-care ultrasound to classify cardiac arrest into shockable, zero-flow (asystole, standstill-PEA, agonal-PEA), and severe low-flow (contraction-PEA) phenotypes to refine diagnosis, prognosis, and resuscitation research.

Limitations

Conceptual framework without primary original clinical trial data
Very-low-certainty existing evidence for the direct effects of PoCUS on patient-centered survival outcomes
No validated Doppler or invasive blood pressure thresholds currently define circulation sufficient for vital-organ perfusion or when chest compressions confer net benefit in C-PEA
Risk of ultrasound misinterpretation and cardiopulmonary resuscitation interruptions among insufficiently experienced operators
Formal evidence base for intra-arrest diagnostic accuracy remains constrained by methodological challenges inherent to cardiac-arrest research
Quantitative Doppler parameters require external validation before adoption as a hemodynamic threshold
Evidence specifically validating quantitative transesophageal echocardiography-derived flow measurements for grading spontaneous circulation during cardiac arrest remains limited

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Implication

May support ultrasound phenotyping in arrest; challenges rhythm-based ALS classification but leaves open outcome validation.

Abstract

BACKGROUND: Cardiac arrest (CA) remains operationally recognized through clinical signs of absent effective circulation and classified primarily by electrical rhythm. Point-of-care ultrasound (PoCUS) challenges this rhythm-pulse paradigm by directly revealing cardiac mechanical activity and, with Doppler, circulatory flow, exposing physiologically distinct states concealed within current CA categories. METHODS: This physiology-based conceptual manuscript proposes an integrated electro-mechanical-hemodynamic framework for CA and translates it into PoCUS-consistent phenotyping, portraying CA presentations (CA phenotypes) as pathophysiological states that may transition from one to another along a spontaneous or treatment-modified continuum. CLINICAL IMPLICATIONS: The framework distinguishes three principal phenotypes: shockable CA (ventricular fibrillation/pulseless ventricular tachycardia); zero-flow CA, encompassing Asystole and PEA without organized ventricular contraction (S-PEA) or with agonal mechanical activity (A-PEA); and severe low-flow CA (C-PEA), in which organized ventricular contraction persists despite absent palpable pulse, and may generate residual circulation. PoCUS can define mechanical states, identify reversible causes, contextualize diagnostic findings, reveal occult shockable activity, and track phenotype transitions. Doppler and invasive arterial-pressure monitoring further characterize spontaneous flow and pressure and may support phenotype-informed treatment. CONCLUSIONS: Electro-mechanical-hemodynamic phenotyping extends established ALS classification by providing a standardized physiological language for distinct CA states, enabling more homogeneous research populations, phenotype-specific resuscitation research, and rigorous evaluation of PoCUS-informed management. Taken together, these physiological distinctions provide a rationale for reconsidering how cardiac arrest is characterized and how PoCUS-derived information could inform future research, evidence reviews, and resuscitation recommendations.

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Cite This Study

Via et al. (2026) conducted a review in Cardiac arrest. Point-of-care ultrasound (PoCUS) electro-mechanical-hemodynamic phenotyping vs. Conventional rhythm- and pulse-based cardiac arrest classification was evaluated. Point-of-care ultrasound enables electro-mechanical-hemodynamic phenotyping of cardiac arrest into shockable, zero-flow (Asystole, S-PEA, A-PEA), and severe low-flow (C-PEA) states.

synapsesocial.com/papers/6af46d8f7bb3da179b850111 https://doi.org/10.5826/tuj.2026.19728

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Is cardiac arrest still a binary clinical diagnosis? Toward electro-mechanical–hemodynamic phenotyping in the era of point-of-care ultrasound

Key Points

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Is cardiac arrest still a binary clinical diagnosis? Toward electro-mechanical–hemodynamic phenotyping in the era of point-of-care ultrasound

Key Points

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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