Used in artrial fibrillation or supraventricular tachycardias with an accessory pathway

h. Flecainide is a potent blocker of sodium channels and therefore slows conduction. The effect of flecainide can be seen on the ECG as lengthening of the PR interval and widening of the QRS complex.

Flecainide is known to be negatively inotropic and may result in bradycardia and hypotension. Other side-effects documented include blurring of vision and oral paraesthesiae.