What is the role of Ivabradine (Ivabradine) in treating Supraventricular Tachycardia (SVT)?

Role of Ivabradine in Treating Supraventricular Tachycardia (SVT)

Ivabradine has limited indications for SVT, primarily showing benefit in inappropriate sinus tachycardia (IST), but has minimal evidence supporting its use in other forms of SVT.

Inappropriate Sinus Tachycardia (IST)

• Ivabradine is reasonable for ongoing management in patients with symptomatic IST (Class IIa, Level B-R recommendation) 1
• In a small randomized crossover trial, ivabradine (2.5-7.5 mg twice daily) significantly reduced daytime heart rate from 98.4±11.2 bpm to 84.7±9.0 bpm compared with placebo (p<0.001) 1
• Ivabradine improves exercise tolerance and symptoms in patients with IST, with many patients reporting complete symptom resolution 1
• In observational studies, ivabradine was more effective than metoprolol in reducing heart rate and improving symptoms in IST patients 1
• Long-term follow-up shows that ivabradine treatment leads to both heart rate normalization and quality-of-life improvement in IST patients 2

Combination Therapy for IST

• The combination of beta blockers and ivabradine may be considered for ongoing management in patients with particularly refractory IST symptoms (Class IIb, Level C-LD recommendation) 1
• In a small observational study, adding ivabradine (7.5 mg twice daily) to metoprolol succinate (95 mg daily) reduced heart rate more effectively than metoprolol alone 1
• On combination therapy, symptoms related to IST were resolved in all patients, with the combined therapy being well tolerated 1
• The 2019 ESC guidelines also recognize the combination of ivabradine and beta-blockers for symptomatic patients with IST 1

Safety Considerations

• Ivabradine is generally well-tolerated with an excellent safety profile demonstrated in large RCTs in heart failure patients 1
• The most common side effect is phosphenes (enhanced brightness in a portion of the visual field), reported in approximately 3% of patients 1
• When using combination therapy with beta-blockers, patients should be monitored closely for excess bradycardia 1
• No episodes of severe bradycardia or syncope were reported in long-term studies of ivabradine for IST 2

Other SVT Subtypes

• There is limited evidence for ivabradine in other forms of SVT beyond IST 3
• Case reports suggest potential benefit in:
  • Atrial tachycardia as a bridge to ablation 4
  • Non-paroxysmal junctional tachycardia with interference atrioventricular dissociation 5
  • Refractory SVT in pediatric patients 3

Treatment Algorithm for SVT

1. First-line approach for SVT:

   • Standard treatments (vagal maneuvers, adenosine, beta-blockers, calcium channel blockers) remain first-line for most SVT types 1
   • Catheter ablation has high success rates for common SVTs: 96-97% for AVNRT and 93% for AVRT 1

2. For Inappropriate Sinus Tachycardia:

   • Start with evaluation and treatment of reversible causes 1
   • If symptomatic, consider ivabradine 2.5-7.5 mg twice daily 1
   • Beta-blockers may be considered but have modest effectiveness 1
   • For refractory symptoms, consider combination of ivabradine and beta-blockers 1

3. For other SVT types:

   • Ivabradine should only be considered in refractory cases where standard treatments have failed 3
   • Consider ivabradine as a bridge to definitive treatment (e.g., ablation) 4

Clinical Implications

• Ivabradine works by selectively inhibiting the "funny" current (If) in the sinoatrial node, reducing heart rate without other hemodynamic effects 1
• This mechanism makes it particularly effective for IST but limits its utility in other SVT mechanisms 1
• The 2019 ESC guidelines note that ivabradine for IST is not an approved indication by the European Medicines Agency 1
• Catheter ablation remains the definitive treatment for most SVTs, with success rates of 80-100% for focal atrial tachycardia 1