What is the ideal treatment for a 69-year-old male patient with Supraventricular Tachycardia (SVT), Hypertension (HTN), and a history of Right Bundle Branch Block (RBBB), currently on Losartan (Losartan) 20mg, with recent cardiac monitoring showing frequent runs of SVT and moderate left atrial dilation?

Treatment for SVT in a 69-Year-Old Male with Hypertension and RBBB

For this 69-year-old male with frequent runs of SVT, hypertension, and RBBB, the ideal treatment is to initiate an oral beta blocker for ongoing management while considering referral for an electrophysiology study with the option of catheter ablation for definitive treatment.

Assessment of Current Situation

• Patient has:
  • Frequent SVT (362 runs, longest 16.6 seconds at 118 bpm)
  • Hypertension (currently on Losartan 20mg)
  • Right Bundle Branch Block (RBBB)
  • Moderate left atrial dilation
  • Normal LV function (LVEF 57-60%)
  • Normal myocardial perfusion
  • Currently asymptomatic

Treatment Algorithm

Step 1: Pharmacological Management

1. Initiate beta blocker therapy

   • First-line therapy for SVT management in patients without ventricular pre-excitation 1
   • Options include:
     • Metoprolol succinate 25-50mg daily (can titrate up to 200mg daily)
     • Atenolol 25-50mg daily (can titrate up to 100mg daily)
   • Benefits:
     • Reduces frequency and duration of SVT episodes
     • May help with hypertension control
     • Safe in patients with structural heart disease

2. Optimize antihypertensive therapy

   • Current Losartan dose (20mg) is subtherapeutic
   • Increase Losartan to 100mg daily 2
   • Benefits:
     • Better BP control
     • Potential regression of left ventricular hypertrophy 3, 4
     • May reduce risk of conduction system disease progression 5

Step 2: Non-Pharmacological Management

1. Patient education on vagal maneuvers

   • Teach proper Valsalva technique (forceful exhalation against closed airway for 10-30 seconds while supine) 1
   • Application of cold, wet towel to face (diving reflex) 1
   • These techniques can terminate acute SVT episodes

2. Referral for EP study with option for catheter ablation

   • Class I recommendation for diagnosis and treatment of SVT 1
   • Provides potential for definitive cure without need for chronic medication
   • High success rates with low complication rates
   • Particularly important given:
     • Frequent runs of SVT
     • Moderate left atrial dilation (risk factor for progression)
     • RBBB (may complicate future management)

Alternative Pharmacological Options (If Beta Blockers Contraindicated)

1. Non-dihydropyridine calcium channel blockers

   • Diltiazem or verapamil (Class I recommendation) 1
   • Effective for SVT control but monitor for hypotension

2. Class IC antiarrhythmics (if no structural heart disease)

   • Flecainide 50mg twice daily, can increase to 100mg twice daily 1, 6
   • Maximum recommended dose: 300mg/day 6
   • Contraindicated in structural heart disease

Important Considerations and Pitfalls

1. Monitoring for conduction abnormalities

   • Patient already has RBBB
   • Beta blockers and calcium channel blockers can worsen conduction disorders
   • Monitor PR and QRS intervals during follow-up

2. Left atrial dilation

   • Moderate left atrial dilation increases risk for developing atrial fibrillation
   • More aggressive treatment may be warranted to prevent progression

3. Asymptomatic nature of arrhythmia

   • Despite being asymptomatic, frequent SVT runs can lead to:
     • Tachycardia-induced cardiomyopathy
     • Progression to symptomatic arrhythmias
     • Development of atrial fibrillation

4. Avoid digoxin

   • While mentioned as an option in guidelines, it should be considered only if other agents fail
   • Higher risk of toxicity in elderly patients

Follow-up Recommendations

• ECG at 1 month to assess PR and QRS intervals
• Holter monitoring at 3 months to assess SVT burden
• Reassessment of symptoms and consideration for EP study/ablation if:
  • SVT episodes increase in frequency or duration
  • Patient develops symptoms
  • Evidence of tachycardia-induced cardiomyopathy develops

The combination of beta blocker therapy with optimized losartan dosing provides the best pharmacological approach while EP study with potential ablation offers definitive treatment for this patient's SVT.