proarytmia

Proarrhythmia refers to the development of new or worsened arrhythmias in a patient who is already being treated for a pre-existing arrhythmia, often with antiarrhythmic drugs. This phenomenon can occur due to the direct proarrhythmic effects of the medication itself, or it can be a consequence of the altered electrophysiological state of the heart caused by the drug. It is a significant concern in the management of cardiac rhythm disorders, as it can lead to potentially life-threatening arrhythmias.

The mechanisms underlying proarrhythmia are complex and vary depending on the specific antiarrhythmic drug and the patient's underlying cardiac condition. Some drugs can prolong the action potential duration and refractory period, which can paradoxically promote reentrant arrhythmias. Others can block ion channels in a way that leads to delayed repolarization and an increased risk of torsades de pointes, a polymorphic ventricular tachycardia. Factors such as electrolyte imbalances, underlying structural heart disease, and drug interactions can also increase the susceptibility to proarrhythmic events.

Recognizing and managing proarrhythmia requires careful clinical evaluation, including electrocardiogram monitoring, to distinguish new arrhythmias from the original condition or other causes. Treatment involves discontinuation of the offending drug, correction of any contributing factors, and potentially the initiation of alternative antiarrhythmic therapy or device-based interventions.