proarrhythmic effect
Pronunciation: pro-ah-RITH-mik ih-FEKT
The paradoxical worsening of existing arrhythmias or induction of new arrhythmias by antiarrhythmic drugs. A significant concern in arrhythmia management.
Full Definition
Proarrhythmic effect refers to the paradoxical ability of antiarrhythmic medications to worsen existing arrhythmias or cause new, potentially more dangerous arrhythmias. This effect can manifest as increased frequency of the target arrhythmia, conversion to a more malignant rhythm, or development of entirely new arrhythmias such as torsades de pointes. Proarrhythmia is a class effect of antiarrhythmic drugs and occurs through various mechanisms including prolongation of refractoriness, slowing of conduction, and alteration of automaticity. The risk is higher in patients with structural heart disease, electrolyte abnormalities, or concurrent medications that affect cardiac electrophysiology. Recognition of proarrhythmic effects led to the principle that antiarrhythmic therapy should be used judiciously and with careful monitoring.
Usage
Usage note: Use 'proarrhythmic' as an adjective; 'proarrhythmia' as a noun form is also acceptable.
In Context
- "The patient developed a proarrhythmic effect with increased ventricular ectopy after starting flecainide." — Cardiology consultation note
- "Careful monitoring is essential to detect any proarrhythmic effect when initiating class IC antiarrhythmic therapy." — Clinical practice guideline