Preclinical experiments detected cardiac electrical effects that were not fully reflected by conventional QT measurements.
Researchers studied perfused guinea-pig hearts and human induced-pluripotent-stem-cell-derived cardiomyocytes. Higher experimental exposures altered conduction and prolonged late repolarization measures, including action-potential duration at 90% repolarization. QT and corrected QT did not significantly change in the isolated-heart experiments. The human-derived cell preparation also showed selective late-repolarization effects.
These were isolated organs and cells, not clinical anesthesia patients. The authors did not directly measure corresponding plasma concentrations, limiting translation of experimental dosing to human exposure. Ionic mechanisms were inferred rather than completely established, and an electrical change is not a measured rate of clinical arrhythmia.
For cardiac toxicology, specify the preparation, exposure metric and endpoint. Normal QT in this model does not mean every electrical parameter was unchanged, while altered action potentials do not prove human torsades or sudden death. Patient-specific rhythm records and competing cardiac factors remain necessary for causal interpretation.
Source reviewed: Clinically Relevant Doses of Remimazolam Modulate Cardiac Electrophysiology Late Repolarization Prol (PMC13074361). Forensic applications above are interpretive analysis of the supplied paper.
Related reading: Congenital-Heart Catheterization Study Added Remimazolam During Sevoflurane Anesthesia.