Wide QRS tachycardia during treatment with class ic antiarrhythmic agents in a patient with atrial fibrillation: report of 2 cases / 대한내과학회지

Wide QRS tachycardia may represent a rare proarrhythmic effect of some antiarrhythmic agents. Class Ic antiarrhythmic agents produce rate- dependent ventricular conduction slowing due to use-dependent sodium channel blockade, causing QRS prolongation in cases with an increased heart rate. The authors describe two cases of atrial flutter with 1:1 atrioventricular conduction exhibiting a wide QRS tachycardia while on therapy using flecainide and propafenone, and the difficulty in interpreting the ECG.

Wide QRS tachycardia during treatment with class ic antiarrhythmic agents in a patient with atrial fibrillation: report of 2 cases / 대한내과학회지

Wide QRS tachycardia may represent a rare proarrhythmic effect of some antiarrhythmic agents. Class Ic antiarrhythmic agents produce rate- dependent ventricular conduction slowing due to use-dependent sodium channel blockade, causing QRS prolongation in cases with an increased heart rate. The authors describe two cases of atrial flutter with 1:1 atrioventricular conduction exhibiting a wide QRS tachycardia while on therapy using flecainide and propafenone, and the difficulty in interpreting the ECG.