What is the best medication to treat tachycardia?

Best Medication to Treat Tachycardia

The best medication depends critically on the type of tachycardia and hemodynamic stability: for narrow-complex supraventricular tachycardia (SVT), adenosine is first-line after vagal maneuvers; for atrial fibrillation with rapid ventricular response, beta-blockers or diltiazem are preferred; and for wide-complex ventricular tachycardia, amiodarone combined with beta-blockers is recommended. 1, 2

Hemodynamic Stability Assessment First

Before selecting any medication, determine if the patient is hemodynamically unstable (hypotension with systolic BP ≤90 mmHg, altered mental status, chest pain, acute heart failure). If unstable, synchronized cardioversion is the treatment of choice regardless of tachycardia type, not medication. 1

Narrow-Complex Tachycardia (QRS <120ms)

Supraventricular Tachycardia (SVT)

• First attempt vagal maneuvers (Valsalva maneuver or carotid massage if no bruit), which succeed in approximately 28% of cases 3
• Adenosine is the first-line pharmacological agent with 6 mg rapid IV bolus followed by saline flush, then 12 mg if no response after 1-2 minutes 1, 3, 4
• Adenosine terminates approximately 95% of AVNRT cases and has minimal sustained hemodynamic effects due to its very short half-life 1, 3
• Must be given in a monitored environment as it causes transient complete heart block; avoid in asthmatics due to bronchospasm risk 4

Atrial Fibrillation/Flutter with Rapid Ventricular Response

• Beta-blockers and diltiazem are the drugs of choice for acute rate control 1
• Beta-blockers were the most effective drug class in the AFFIRM study, achieving rate control endpoints in 70% of patients versus 54% with calcium channel blockers 1
• Intravenous metoprolol is highly effective: mean dose 9.5 mg reduces ventricular rate from 134 to 106 bpm within 10 minutes in 81% of patients 5
• Diltiazem or verapamil are alternatives, particularly preferred in patients with bronchospasm or COPD where beta-blockers are relatively contraindicated 1
• Digoxin may be used in heart failure patients but is no longer first-line due to delayed onset (60 minutes) and reduced efficacy in high sympathetic states 1

Multifocal Atrial Tachycardia (MAT)

• Metoprolol is highly effective: oral doses of 25-50 mg restore sinus rhythm in all patients within 1-3 hours, with mean heart rate reduction of 54 bpm 6, 7
• Can be safely administered to patients with respiratory failure without serious adverse effects 7

Wide-Complex Tachycardia (QRS ≥120ms)

Monomorphic Ventricular Tachycardia (VT)

• Amiodarone combined with beta-blockers is first-line for hemodynamically stable VT: 150 mg IV over 10 minutes, then 1.0 mg/min for 6 hours, then 0.5 mg/min maintenance 2
• Procainamide is recommended for stable monomorphic VT without severe heart failure or acute MI: loading 20-30 mg/min up to 12-17 mg/kg, then 1-4 mg/min infusion 1, 2
• Lidocaine is an alternative, particularly when VT is ischemia-related: 1.0-1.5 mg/kg bolus, supplemental boluses of 0.5-0.75 mg/kg every 5-10 minutes to maximum 3 mg/kg, then 2-4 mg/min infusion 2, 4

Polymorphic VT

• Intravenous beta-blockers are the single most effective therapy for polymorphic VT storm 2
• For torsades de pointes with suspected hypomagnesemia: magnesium 8 mmol IV bolus 2

Undifferentiated Wide-Complex Tachycardia

• IV adenosine may be considered as it is relatively safe, may convert the rhythm, and helps diagnose the underlying mechanism 1

Junctional Tachycardia

• Intravenous beta-blockers are reasonable first-line (specifically propranolol), terminating or reducing tachycardia in approximately 30-50% of patients 1
• Intravenous diltiazem, procainamide, or verapamil are reasonable alternatives when beta-blockers are ineffective 1

Critical Pitfalls to Avoid

• Never use verapamil or diltiazem in suspected VT or pre-excited atrial fibrillation (Wolff-Parkinson-White with AF), as they may cause hemodynamic collapse 3, 4
• Avoid digoxin for chemical cardioversion of atrial fibrillation—it has no role and may perpetuate AF 1
• Reduce lidocaine infusion rates in elderly patients and those with heart failure or hepatic dysfunction to avoid toxicity 2
• Reduce procainamide infusion rates in renal dysfunction 2
• Hypotension occurs in 20-50% of patients receiving beta-blockers for tachycardia; esmolol causes more hypotension (53%) than propranolol (17%) but is rapidly reversible 8

Special Considerations

For patients requiring short-term control where a rapidly titratable agent is needed, esmolol (ultra-short-acting beta-blocker) is FDA-approved for rapid ventricular rate control in atrial fibrillation/flutter, with maintenance doses of 50-300 mcg/kg/min effective in 60-70% of patients 8