Sepsis-Induced Cardiomyopathy and Cardiac Arrhythmias: Pathophysiology and Implications for Novel Therapeutic Approaches

In the context of multi-organ involvement in sepsis, cardiac toxicity is manifested as sepsis-induced cardiomyopathy (SICM). To date, no unified SICM definition exists, though a left ventricular ejection fraction ≤ 50% and/or an absolute drop ≥ 10% from baseline are the most widely accepted components. Several molecular pathways have been associated with SICM, including (i) pro-inflammatory mediator-induced cardiac depression; (ii) sarcolemmal membrane dysfunction; (iii) autonomic nervous system (ANS) imbalance; (iv) blunted cardiovascular response to catecholamines; (v) dysfunctional intracellular calcium handling; (vi) mitochondrial dysfunction; (vii) metabolic reprogramming; and (viii) disturbed endothelial and microcirculatory function. Atrial and ventricular arrhythmias-particularly atrial fibrillation-commonly complicate disease management and are associated with adverse outcomes. Key mechanisms outlining sepsis-induced arrhythmogenesis are (i) inflammation; (ii) electrolyte imbalances; (iii) myocardial ischemia; (iv) QT prolongation/dispersion; (v) adrenergic overactivation; (vi) calcium mishandling; and (vii) fever-induced arrhythmogenesis in Brugada. Established therapeutic approaches include prompt treatment with antibiotics, hemodynamic optimization, and/or selective use of beta-blockers. Furthermore, several molecules are currently being investigated targeting numerous pathways activated in sepsis. Vitamin C, ginsenoside Rc, Schistosoma Japonicum cystatin, and gasmerdin-D inhibitor Y2 exert anti-inflammatory actions, while melatonin and α-ketoglutarate regulate mitochondrial homeostasis. Triiodothyronine targets microcirculatory optimization and regulates protective pathways against stress-related cell death. Engineered exosomes may facilitate targeted drug delivery, inflammatory response modulation, and activation of pathways related to cell survival, while sodium octanoate exhibits anti-inflammatory actions coupled with improved energy metabolism. Finally, gene-regulating therapies aiming at inflammatory response optimization have also been proposed and are currently under development. Future research should aim to standardize the SICM definition, translate emerging therapeutics into clinical practice, identify novel molecular targets, and implement personalized treatment strategies for SICM.