Management of Supraventricular Tachycardias

Patient Selection and Treatment

The American Heart Association recommends flecainide as the preferred treatment over amiodarone for supraventricular tachycardias (SVT) in patients without structural heart disease, while amiodarone should be reserved as a second-line agent for patients who cannot take other antiarrhythmics or who have structural heart disease 1
The European Society of Cardiology suggests that recent-onset atrial fibrillation (<48 hours) without structural heart disease can be treated with flecainide 2
Patients with significant ventricular dysfunction (ejection fraction <35%) or structural heart disease should be treated with caution, and amiodarone may be considered as a second-line agent 1, 3
Flecainide can be used for ongoing management of SVT in adult congenital heart disease patients, as recommended by the American Heart Association 1
Flecainide is contraindicated in patients with cardiogenic shock, sinus or AV conduction disease (without pacemaker), Brugada syndrome, and atrial flutter (unless concomitant AV nodal therapy is used), as stated by the American College of Cardiology and Circulation 4, 1

The initial dose of flecainide for PSVT and PAF is 50 mg every 12 hours, with slow upward titration, and the maximum maintenance dose should be 150 mg every 12 hours, as recommended by the American Heart Association and American College of Cardiology 4, 5, 6, 1
For patients with severe renal impairment (creatinine clearance ≤35 mL/min), the dose should be reduced to 100 mg once daily or 50 mg twice daily, with frequent plasma level monitoring required, as recommended by the American Heart Association, American College of Cardiology, and National Kidney Foundation 4, 5, 6, 1

Baseline ECG is recommended before initiation of flecainide therapy, and follow-up ECG is recommended after 3-5 days of therapy, at each dose change, and at regular intervals thereafter, as recommended by the American College of Cardiology and European Heart Journal guidelines 2, 1
Trough plasma levels should be maintained between 0.2-1.0 mcg/mL, and levels above 0.7-1.0 mcg/mL require close monitoring, as recommended by the European Heart Journal guidelines 7
Flecainide has a risk of proarrhythmic effects in 7-8% of patients, higher in those with serious ventricular tachycardia and reduced myocardial function, as stated by the American Heart Association 1
Non-cardiac effects of flecainide include dizziness, visual disturbances, and headaches, as reported by the National Institutes of Health 1

In patients with PSVT, flecainide is effective in approximately 80-90% of patients, and the addition of a beta-blocker increases efficacy to >90% for symptomatic tachycardia, as recommended by the American College of Cardiology 8
In patients with PAF, flecainide is effective in approximately 70-75% of patients 8
Flecainide can be effective for ongoing management in pregnant patients with highly symptomatic SVT, but should be avoided in the first trimester when risk of congenital malformations is greatest, as recommended by the American College of Cardiology 1
In pediatric patients, all use of flecainide should be directly supervised by a pediatric cardiologist, with initial doses and monitoring requirements varying by age, as recommended by the American Academy of Pediatrics 1

Supportive care, including continuous cardiac monitoring, maintaining adequate oxygenation, and correcting electrolyte abnormalities, is essential in managing flecainide toxicity, as recommended by the American College of Cardiology and European Heart Journal guidelines 4, 2, 1
Sodium bicarbonate therapy is the first-line treatment for flecainide toxicity, with an initial bolus of 1-2 mEq/kg IV (or 50-100 mL of 8.4% solution) followed by continuous infusion, as recommended by the American College of Cardiology and European Heart Journal guidelines 4, 2
Calcium gluconate (1-2 g IV) may be used to help stabilize myocardial cell membranes in patients with flecainide toxicity, as recommended by the American College of Cardiology and European Heart Journal guidelines 2, 1

When switching from another antiarrhythmic to flecainide, at least 2-4 plasma half-lives should elapse for the drug being discontinued, as recommended by the American College of Cardiology 1
For acute treatment of pre-excited tachycardias, flecainide is preferred over adenosine, which may produce AF with rapid ventricular rate, as recommended by the American Heart Association 8