When the Thyroid Stops the Heart: Landmark Review Maps Cardiac Arrest in Thyroid Storm

In the emergency rooms and intensive care units of the world, few endocrine emergencies burn as hot or as fast as thyroid storm. The thyroid gland, a small butterfly-shaped organ at the base of the neck, suddenly floods the bloodstream with hormone, driving the heart into overdrive, the body into fever, and the nervous system into chaos. Mortality remains high even with modern treatment, and the single most dramatic complication — the heart stopping altogether — has long been documented only in scattered case reports. Now a comprehensive scoping review published in BMC Endocrine Disorders has assembled the largest picture to date of what happens when thyroid storm and cardiac arrest collide in the same patient, and the findings carry a provocative signal that clinicians cannot ignore.

The scoping review, led by researchers from Philadelphia College of Osteopathic Medicine and the University of Pennsylvania Health System, took an unusually rigorous approach to a messy body of literature. The team searched PubMed, Scopus and Embase without any lower limit on publication date, capturing every English-language case report, case series and conference abstract that described thyroid storm together with a documented cardiac arrest. Because the same patient can appear in multiple publications — a follow-up letter, a conference presentation, a subsequent case series — the investigators linked publications and patients separately, a methodological detail that matters enormously when the unit of analysis is the individual clinical story. After screening, seventy-six publications describing seventy-eight patients formed the final evidence base. Data extraction was performed with the assistance of artificial intelligence tools but verified by two authors working independently in duplicate, a hybrid workflow that reflects how modern evidence synthesis is evolving under the pressure of ever-growing medical literature.

The review was registered prospectively on the Open Science Framework, and the authors followed the PRISMA-ScR reporting checklist for scoping reviews, both steps that strengthen confidence in the completeness and transparency of the search. The work received no external funding, and the authors declared no competing interests, circumstances that reduce the risk of commercial influence on how the findings were framed and interpreted.

What emerges from the assembled cases is a portrait of extraordinary clinical complexity. Thyroid storm itself is defined by decompensation across multiple organ systems: fever, tachycardia, agitation or delirium, gastrointestinal symptoms, and heart failure. When cardiac arrest is layered on top of this physiology, the resuscitation becomes a battle on two fronts. The review documented ventricular dysfunction in forty-nine of the seventy-eight patients, a strikingly high proportion that underscores how profoundly the thyrotoxic state can impair the heart muscle itself. Thyrotoxic cardiomyopathy — the weakening of cardiac contractility driven by excess thyroid hormone — has long been recognized in the literature, but its frequency among patients who arrest suggests it may be a central mechanism linking the endocrine crisis to cardiovascular collapse. The authors note, however, that the timing of cardiac function assessments varied considerably across reports, making it difficult to distinguish pre-existing dysfunction from storm-induced deterioration or from the aftermath of resuscitation itself.

The arrest rhythms captured in the published cases span the full spectrum of cardiac arrest presentations, including ventricular fibrillation, ventricular tachycardia, and pulseless electrical activity, the latter being particularly concerning because it often reflects a metabolic or structural cause that defibrillation cannot correct. This diversity of rhythms is consistent with the heterogeneous mechanisms by which thyroid storm can stop the heart: sustained tachyarrhythmia degenerating into ventricular fibrillation, profound cardiogenic shock progressing to asystole or pulseless electrical activity, or electrolyte and hemodynamic derangements destabilizing the myocardium in less predictable ways.

The most discussed finding of the review concerns beta-blockers. These drugs are a cornerstone of standard thyroid storm management, recommended by the American Thyroid Association to control the adrenergic surge that drives much of the syndrome’s danger. Yet in this collection of arrest cases, beta-blocker receipt at some point in the reported course was documented in fifty-five patients, and in twenty-eight of them the source publications described a temporal relationship between administration and the arrest — including instances of recurrent arrests temporally linked to repeated administration. The authors are careful and explicit about what this number does and does not mean. The denominator consists entirely of published cardiac-arrest cases; there is no comparison group of thyroid storm patients who received beta-blockers and did not arrest. The finding therefore cannot estimate treatment-related risk, cannot establish causality, and cannot speak to comparative safety across treatment strategies. It is a signal of where attention should be directed, not a verdict on a therapy that remains standard of care for most presentations of the disease.

That said, the signal has a plausible physiological basis that clinicians have long debated. In a heart already stressed by severe thyrotoxicosis — often with underlying ventricular dysfunction, high-output demands, and possible structural disease — the negative inotropic effects of beta-blockade can, in susceptible individuals, tip the balance toward circulatory collapse. This concern is not new; case reports of cardiovascular collapse after beta-blocker administration in thyrotoxic patients have appeared sporadically for decades, and some experts have suggested particular caution in patients with coexisting heart failure or cardiomyopathy. The review’s contribution is to aggregate these scattered anecdotes systematically and to demonstrate how frequently the temporal association appears in the published record, giving the question enough weight to justify prospective study.

Beyond beta-blockers, the review catalogued the aggressive supportive therapies deployed in these patients. Extracorporeal membrane oxygenation, plasma exchange, and continuous renal replacement therapy were reported in twenty-nine patients. Each of these interventions represents an escalation of care aimed at buying time while definitive therapy — thionamides to halt new hormone synthesis, iodine to block hormone release, glucocorticoids to address the hormonal crisis and possible adrenal insufficiency, and cholestyramine to interrupt enterohepatic recirculation — takes effect. Plasma exchange in particular has emerged in recent years as a rapid method of removing circulating thyroid hormone, and its appearance in nearly a third of these arrest cases suggests that clinicians confronting the most severe presentations are increasingly reaching for extracorporeal and apheresis-based rescue therapies. ECMO, which can support both cardiac and respiratory function during refractory arrest or profound shock, offers a bridge until the thyroid storm itself can be controlled.

The outcomes data reveal both encouragement and persistent uncertainty. Discharge alive was explicitly reported in thirty-nine patients, death in fifteen, and transfer to another facility while alive without explicit discharge wording in two. For twenty-two patients — more than a quarter of the cohort — the final outcome could not be established from the published record. That proportion of unresolvable cases is itself a finding: it quantifies how incomplete the case-report literature is when it comes to the questions that matter most to patients and families. Survival in nearly half of documented cases, many of them involving prolonged resuscitation and advanced support, is arguably better than the historical reputation of thyroid storm would predict, but selection bias in what gets published makes any survival estimate unreliable.

This selection bias deserves emphasis. Case reports are not a random sample of disease. They are written when something unusual, instructive, or dramatic occurs, and they are published when editors find them noteworthy. A patient who receives a beta-blocker and does fine generates no report; a patient who arrests shortly after receiving one does. This asymmetry mechanically inflates any apparent association between an intervention and a bad outcome in the case-report literature, and it is precisely why the review’s authors repeatedly caution against causal interpretation. The same bias applies to the ventricular dysfunction figures, the rhythm distributions, and the outcome tallies. What the review offers is a map of the terrain — the range of presentations, the chronology of treatments, the mechanisms that source authors themselves proposed — rather than a measurement of risk.

The chronology of treatment relative to arrest was one of the most valuable dimensions the review was able to reconstruct, and also one of the most frustrating. The authors found that reporting of treatment timing was inconsistent and often absent, limiting the ability to determine whether arrests occurred before, during, or after specific interventions, or how much time elapsed between them. Where timing was described, the granularity varied from precise minutes to vague references to hospital day. This documentation gap is not merely an academic annoyance; it is the difference between being able to test or dismiss a safety hypothesis and being left with an unresolvable ambiguity. The review’s identification of incomplete reporting of treatment timing and cardiac function as a central limitation is, in effect, a set of instructions for how future case reports should be written.

The path toward better answers runs through prospective, standardized data collection, as the authors conclude. Registries of thyroid storm cases with protocolized capture of medication timing, serial cardiac function assessments, arrest rhythms, and outcomes would transform this evidence base from anecdote to analysis. In the meantime, the review gives clinicians a structured reference for a scenario most will encounter rarely, if ever, and gives researchers a clearly demarcated set of open questions. For a condition as lethal and as fast-moving as thyroid storm complicated by cardiac arrest, the careful mapping of seventy-eight published journeys is a meaningful beginning, even as it makes plain how much remains unknown about the safest sequence of therapies when the thyroid storm and the failing heart must be treated at the same time.

Subject of Research: Cardiac arrest as a complication of thyroid storm, mapped through a scoping review of published case reports

Article Title: Thyroid storm and cardiac arrest: a scoping review of case presentations

Article References: Young, A., Fink, J., Monteleone-Haught, D., Falcon, M., & Banka, S. (2026). Thyroid storm and cardiac arrest: a scoping review of case presentations. BMC Endocrine Disorders. https://doi.org/10.1186/s12902-026-02676-2

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02676-2

Keywords: thyroid storm, cardiac arrest, beta-blockers, thyrotoxicosis, cardiomyopathy, ECMO, ventricular dysfunction, scoping review, endocrine emergency, resuscitation, heart failure, hyperthyroidism