Antitachycardia Pacing for SVT
Antitachycardia pacing (ATP) is a Class IIa recommendation for acute termination of SVT in adult congenital heart disease (ACHD) patients who are hemodynamically stable and anticoagulated, with success rates of 54-82%, but it is NOT a standard first-line therapy for typical SVT in the general adult population. 1
Role in Adult Congenital Heart Disease (ACHD)
Atrial pacing can be effective for acute treatment in ACHD patients with SVT (particularly atrial tachycardia or atrial flutter) who are hemodynamically stable and anticoagulated per AF guidelines. 1
- Small observational studies demonstrate ATP successfully terminates 54-82% of acute episodes of atrial tachycardia or atrial flutter in ACHD patients 1
- ATP is particularly valuable when concerns exist about antiarrhythmic medication use or when significant sinus node dysfunction is present 1
- Procainamide can be used as adjunctive therapy to improve the efficacy of pacing conversion of atrial flutter 1
Ongoing Management in ACHD
Atrial pacing may be reasonable (Class IIb) to decrease recurrences of atrial tachycardia or atrial flutter in ACHD patients with sinus node dysfunction. 1
Historical Use in General SVT Population
While older research from the 1980s-1990s demonstrated that implantable antitachycardia pacemakers could effectively manage drug-resistant reentrant SVT 2, 3, 4, this approach has been largely superseded by catheter ablation, which offers superior outcomes with single-procedure success rates of 94.3-98.5% for AVNRT and AVRT. 5
- Long-term ATP therapy reduced hospital admissions from 1 per patient-month to 1 per 137 patient-months in historical cohorts 2
- However, 42% of patients still required concomitant antiarrhythmic drugs 2
- ATP became ineffective in 10% of patients during long-term follow-up 4
Critical Safety Concerns
Atrial fibrillation is induced in 8-12% of ATP attempts, with sustained AF occurring in 75% of these cases. 6
- Atrial pacing carries a 12% risk of inducing AF compared to 2% with ventricular pacing 6
- Multiple premature beats increase AF risk more than single premature beats 6
- In 6% of patients, SVT could only be terminated by inducing another arrhythmia 6
Absolute Contraindications
ATP is contraindicated (Class III) in patients with:
- Tachycardias that are accelerated or converted to fibrillation by pacing 1
- Accessory pathways with capacity for rapid anterograde conduction, regardless of whether they participate in the tachycardia mechanism 1
Current Clinical Context
For the general adult population with typical SVT (AVNRT, AVRT), catheter ablation is the first-line definitive therapy, not antitachycardia pacing. 5
- Catheter ablation success rates exceed 90-95% for common SVT types 5
- ATP is now primarily reserved for the specialized ACHD population where catheter ablation faces technical challenges (limited venous access, hypertrophied atrial tissue, multiple reentrant circuits) 1
- In ACHD patients, catheter ablation success rates are lower (70-85%) with recurrence rates of 20-60% within 2 years, making ATP a more viable alternative 1
Common pitfall: Do not consider ATP as equivalent to modern catheter ablation for typical SVT in structurally normal hearts—the evidence base for ATP predates the widespread adoption and refinement of ablation techniques that now offer superior long-term outcomes with minimal morbidity.