Cardiovascular Rhythm Management

Introduction to Cardioversion and Antiarrhythmic Therapy

• The American Heart Association recommends cardioversion as a highly effective treatment for terminating paroxysmal supraventricular tachycardia (PSVT), but notes the risk of immediate recurrence due to premature atrial or ventricular complexes that can occur after the procedure 1
• The American College of Cardiology and the American Heart Association emphasize the importance of assessing hemodynamic stability in patients with tachycardia, looking for signs of instability such as altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or shock 2, 1

Antiarrhythmic Medications

• In patients with pre-excitation or accessory pathways, the American College of Cardiology suggests ibutilide or procainamida IV may be beneficial for patients with pre-excited atrial fibrillation who are hemodynamically stable 1
• The American Heart Association advises against using digoxin in patients with pre-excitation due to the risk of ventricular fibrillation, with a strength of evidence supported by multiple studies 1, 3
• The American College of Cardiology recommends using beta blockers and calcium channel blockers with extreme caution due to the risk of potentiation of hypotensive and bradycardic effects 4
• The choice between calcium channel blockers and beta blockers should be based on the patient's comorbidities and specific contraindications, with calcium channel blockers recommended as the first option (Class IIa, Level B-R) for hemodynamically stable patients without heart failure 1

Treatment of PSVT

• Vagal maneuvers, including the Valsalva maneuver, carotid sinus massage, and modified Valsalva, have a success rate of ~27.7% when techniques are combined, and are recommended as a Class I, Level B-R treatment for supraventricular tachycardia 5, 1
• Adenosine is recommended if vagal maneuvers fail, with a first dose of 6 mg rapid IV push followed by saline flush, and a second dose of 12 mg if required, as recommended by the American College of Cardiology and the American Heart Association 5, 2, 6, 7, 1
• Adenosine IV has a success rate of ~95% of patients and is recommended as a Class I, Level B-R treatment for supraventricular tachycardia 1
• The following treatment recommendations are based on the American College of Cardiology guidelines:

Special Considerations

• Wolff-Parkinson-White syndrome requires special consideration, with avoidance of AV nodal blocking agents such as calcium channel blockers, beta blockers, and digoxin, as recommended by the American College of Cardiology 5
• Pregnant patients should follow the same management algorithm, with vagal maneuvers as the first-line treatment, adenosine as a safe second-line option, and synchronized cardioversion with careful electrode pad placement to direct energy away from the uterus 1
• Infants and children <1 year should avoid verapamil due to the risk of cardiovascular collapse, and digoxin should be avoided if pre-excitation is suspected, while beta-blockers are generally safe but require monitoring for bradycardia and hypotension 7, 1

Long-term Management

• For patients with spontaneously reverted supraventricular tachycardia (SVT), referral to a heart rhythm specialist for consideration of catheter ablation is recommended as the first-line long-term management strategy due to its high success rate and superior efficacy compared to pharmacological therapy 1
• Catheter ablation has a low complication rate and is cost-effective compared to long-term medical therapy, as recommended by the American College of Cardiology 1
• Regular assessment of rhythm status with ECG and Holter monitoring is necessary for all patients with supraventricular bigeminy, as recommended by the American College of Cardiology and the American Heart Association 8, 9
• Evaluation for the presence of accessory pathways, especially Wolff-Parkinson-White syndrome, is crucial in patients with supraventricular bigeminy, as recommended by the American College of Cardiology and the American Heart Association 8, 10