Lactate levels hamper electrical cardioversion in critically ill patients with atrial fibrillation, highlights research

A new study published in the journal of Nature Scientific Reports revealed that lactate levels interfere with the electrical or mechanical cardioversion in critically sick atrial fibrillation (AF) patients. Atrial fibrillation is the most prevalent kind of dysrhythmia, which affects 20% of patients in intensive care units (ICUs). It has been shown that some factors, such as the severity of the disease and systemic inflammatory response syndrome, predispose people to developing AF.

It has been demonstrated that AF in critically ill patients increases the risk of stroke and systemic embolism, as well as in-hospital and long-term mortality and intensive care unit duration of stay. Since the entire spectrum of illness severity is addressed and early treatment may affect results, emergency departments (ED) are essential to the acute management of AF. When it comes to personalized therapy choices and identifying patients who are at risk for additional clinical deterioration, AF patients in an emergency department environment need specific care.

Despite no universal indicator of critical disease, lactate has been thoroughly investigated in this context as a proxy for anaerobic metabolism and oxygen mismatch. Among ED patients expressing sepsis symptoms, intermediate and elevated lactate levels were linked to a higher fatality rate. Thus, this study examined the relationship between AF cardioversion effectiveness at various lactate levels and severe illness in ED patients.

This retrospective single-center research that examined 3535 incidents of AF from 2012 to 2022 was conducted. Cardioversion (CV) to sinus rhythm (SR) based on blood lactate levels (mmol/L) was the primary result. The quintiles of lactate levels were lac <1.1, 1.1–1.3, 1.4–1.7, 1.8–2.3, and >2.3 mmol/L. As lactate levels increased, overall CV success decreased. Also, 1021 instances (SR 95%) underwent electrical CV (eCV), 706 cases (SR 72%) underwent medical CV (mCV), 523 cases (SR 88%) underwent facilitated CV, and 591 cases (46 percent of all patients without therapy) underwent spontaneous conversion.

ECV worked regardless of lactate levels. And, conversion success for mCV declined as lactate levels rose. As lactate levels rose, the risk of cardioversion success dropped overall, particularly medical cardioversion success rates declined. Overall, rising lactate levels in ED patients lowered the likelihood of cardioversion success overall and medical cardioversion success rates. However, lactate levels did not correlate with the efficacy of electrical cardioversion.

Reference:

Gupta, S., Schnaubelt, S., Oppenauer, J., Lutnik, M., Cacioppo, F., Spiel, A., Domanovits, H., Sulzgruber, P., & Niederdöckl, J. (2025). Analyzing the association of critical illness and cardioversion success in patients with atrial fibrillation at the emergency department. In Scientific Reports (Vol. 15, Issue 1). Springer Science and Business Media LLC. https://doi.org/10.1038/s41598-025-85224-7