Medication-induced QT Prolongation
Drug-related lengthening of the QT interval on ECG, particularly concerning in elderly patients due to polypharmacy and altered drug metabolism.
Full Definition
Medication-induced QT prolongation refers to drug-related lengthening of the QT interval on electrocardiogram, representing delayed ventricular repolarization that can predispose to potentially fatal arrhythmias such as torsades de pointes. In geriatric cardiology, this condition is of particular concern due to age-related changes in drug metabolism, increased prevalence of polypharmacy, and baseline prolongation of conduction intervals in elderly patients. Common offending medications include antiarrhythmics, antibiotics (especially fluoroquinolones and macrolides), antipsychotics, and some antidepressants. Elderly patients are at increased risk due to slower drug clearance, drug-drug interactions, electrolyte abnormalities, and structural heart disease. Management involves medication review, electrolyte correction, ECG monitoring, and consideration of alternative therapeutic agents when prolongation exceeds 500 milliseconds or increases by more than 60 milliseconds from baseline.
Usage
Usage note: Always specify corrected QT interval (QTc) measurements and reference normal values for age and gender.
In Context
- "The patient developed medication-induced QT prolongation after starting azithromycin, requiring ECG monitoring." — Medication safety alert
- "Medication-induced QT prolongation was identified during routine ECG review, prompting medication reconciliation." — Cardiology consultation