How to manage reflex tachycardia

Management of Reflex Tachycardia

Beta blockers, particularly metoprolol, are the first-line treatment for managing reflex tachycardia due to their ability to directly block the sympathetic response that causes the tachycardia. 1

Understanding Reflex Tachycardia

Reflex tachycardia is a compensatory increase in heart rate that occurs in response to a decrease in blood pressure. It commonly occurs as a side effect of vasodilating medications (particularly calcium channel blockers and direct vasodilators) and is mediated through baroreceptor reflexes.

First-Line Pharmacological Management

Beta Blockers

• Metoprolol is the preferred agent for ongoing management of reflex tachycardia 2, 1
  • Starting dose: 25-50 mg orally twice daily
  • Can be titrated up to 200 mg daily based on heart rate response
  • Mechanism: Blocks beta-1 adrenergic receptors, preventing catecholamine-induced increases in heart rate
  • Advantages: Cardioselective, well-tolerated, effective at preventing reflex tachycardia 1, 3

Alternative Agents

• Non-dihydropyridine calcium channel blockers (if beta blockers are contraindicated) 2
  • Diltiazem: 120-360 mg daily in divided doses
  • Verapamil: 120-360 mg daily in divided doses
  • Caution: Do not combine with beta blockers due to risk of profound bradycardia 2

Acute Management of Reflex Tachycardia

For acute episodes of reflex tachycardia, particularly in supraventricular tachycardia (SVT):

1. Vagal maneuvers (first-line for hemodynamically stable patients) 2

   • Valsalva maneuver
   • Carotid sinus massage (after confirming absence of carotid bruits)

2. Adenosine (if vagal maneuvers fail) 2

   • 6 mg rapid IV push, followed by 12 mg if needed
   • Advantages: Rapid onset, short half-life
   • Contraindicated in severe asthma

3. IV beta blockers or calcium channel blockers (if adenosine fails) 2

   • Metoprolol: 5 mg IV over 2-5 minutes, may repeat up to 3 doses
   • Diltiazem: 0.25 mg/kg IV over 2 minutes

4. Synchronized cardioversion for hemodynamically unstable patients 2

Special Considerations

Medication-Induced Reflex Tachycardia

• For dihydropyridine calcium channel blocker-induced reflex tachycardia:
  • Add a beta blocker rather than increasing the calcium channel blocker dose 4
  • Consider switching to a non-dihydropyridine calcium channel blocker

Contraindications to Beta Blockers

• Severe bronchospastic disease
• Decompensated heart failure
• High-grade AV block
• Severe sinus node dysfunction

Monitoring and Follow-up

• Monitor heart rate and blood pressure regularly
• Assess for symptoms of bradycardia or hypotension
• Titrate medication dose based on heart rate response and symptom control

Pitfalls to Avoid

• Do not abruptly discontinue beta blockers in patients with coronary artery disease as this may precipitate angina or myocardial infarction 1
• Avoid combining beta blockers with non-dihydropyridine calcium channel blockers due to risk of profound bradycardia 2
• Do not use beta blockers in uncompensated heart failure as they may precipitate cardiogenic shock 1
• Be cautious with beta blockers in patients with asthma; if necessary, use cardioselective agents like metoprolol at the lowest effective dose 1

For patients with inappropriate sinus tachycardia unresponsive to beta blockers, ivabradine may be considered as it has been shown to be effective and better tolerated than metoprolol in some patients 3.