Cardiac tissue – epinephrine-induced arrhythmia sensitization

Cardiac tissue – epinephrine-induced arrhythmia sensitization is a physiological and toxicological phenomenon rather than a specific molecular target like a receptor or enzyme. It describes a state in which the myocardium becomes abnormally sensitive to the arrhythmogenic effects of epinephrine (adrenaline), significantly lowering the threshold for life-threatening ventricular arrhythmias (PubMed, PMID: 6342524). This sensitization is classically associated with exposure to halogenated hydrocarbons, such as the anesthetic halothane or industrial solvents like trichloroethylene (StatPearls, "Halothane Toxicity"). The underlying mechanism involves the complex interaction of these sensitizing agents with alpha-1 and beta-1 adrenergic receptors and cardiac ion channels, which destabilizes the heart's electrical conduction system (NIH, PubChem). In clinical practice, this phenomenon is a major safety concern because a sudden release of endogenous catecholamines—triggered by stress or pain—can induce fatal ventricular fibrillation in a sensitized heart. Consequently, the administration of exogenous epinephrine is often contraindicated in the presence of known sensitizing agents to prevent sudden cardiac arrest.

Other names

Myocardial sensitizationCatecholamine-induced arrhythmia sensitizationCardiac sensitizationEpinephrine-induced cardiac sensitizationHalogenated hydrocarbon-induced arrhythmia

The mechanism involves the sensitization of cardiac adrenergic receptors and the modulation of ion channel kinetics, which reduces the electrical stability of the myocardium and facilitates the development of re-entrant arrhythmias in the presence of catecholamines.