What is the treatment for tachycardia (elevated heart rate)?

Treatment for Elevated Heart Rate (Tachycardia)

The treatment of elevated heart rate depends critically on whether the patient is hemodynamically stable or unstable—unstable patients require immediate synchronized cardioversion, while stable patients should receive vagal maneuvers followed by adenosine for supraventricular tachycardia (SVT), or rate control agents for other tachyarrhythmias. 1

Initial Assessment and Stabilization

First, determine if the tachycardia is causing hemodynamic instability:

• Signs of instability include: acute altered mental status, ischemic chest discomfort, acute heart failure, hypotension, or other signs of shock 1
• Provide supplementary oxygen if the patient shows signs of increased work of breathing or inadequate oxygenation 1
• Attach a cardiac monitor, evaluate blood pressure, and establish IV access 1
• Obtain a 12-lead ECG to define the rhythm, but do not delay cardioversion if the patient is unstable 1

Critical caveat: With ventricular rates <150 bpm in the absence of ventricular dysfunction, the tachycardia is more likely secondary to an underlying condition rather than the cause of instability 1

Treatment Algorithm Based on Stability and Rhythm Type

For Hemodynamically UNSTABLE Patients

Proceed immediately to synchronized cardioversion 1

• Establish IV access and administer sedation if the patient is conscious, but do not delay cardioversion if the patient is extremely unstable 1
• Initial energy doses:
  • Atrial fibrillation: 120-200 J biphasic 1
  • Atrial flutter/SVT: 50-100 J 1
  • Monomorphic ventricular tachycardia: 100 J 1
• Increase energy in stepwise fashion if initial shock fails 1

For Hemodynamically STABLE Patients

Sinus Tachycardia

Do NOT treat the heart rate directly—identify and treat the underlying cause 1

• Sinus tachycardia (>100 bpm) usually results from physiologic stimuli: fever, anemia, hypotension/shock 1
• Critical warning: When cardiac function is poor, cardiac output may be dependent on the rapid heart rate; "normalizing" the heart rate can be detrimental 1
• No specific drug treatment is required 1

Supraventricular Tachycardia (SVT)

Step 1: Attempt vagal maneuvers first 2, 1

• Valsalva maneuver or carotid sinus massage has approximately 28% success rate 2
• This is the recommended first-line intervention 2

Step 2: If vagal maneuvers fail, administer adenosine 2, 1

• Dose: 6 mg rapid IV bolus followed by saline flush 2
• If unsuccessful, give 12 mg rapid IV bolus 2
• Success rate: Approximately 95% for AVNRT (AV nodal reentrant tachycardia) 2
• Adenosine has a very short half-life with minimal sustained hemodynamic effects 2
• Can be given while preparing for synchronized cardioversion in unstable patients (Class IIb) 1

Step 3: Alternative pharmacologic agents if adenosine fails or is contraindicated 1

• IV beta blockers (esmolol, metoprolol), diltiazem, or verapamil are useful for acute treatment 1, 2
• These agents are moderately effective, terminating or slowing the rate in 30-50% of patients 1
• Monitor closely for hypotension or bradycardia 1

Critical warning: Avoid verapamil or diltiazem in patients with suspected ventricular tachycardia or pre-excited atrial fibrillation (Wolff-Parkinson-White syndrome), as they may cause hemodynamic collapse 2

Atrial Fibrillation/Flutter with Rapid Ventricular Response

For rate control in stable patients:

• IV or oral beta blockers, diltiazem, or verapamil are the drugs of choice 1
• Diltiazem mechanism: Slows AV nodal conduction and prolongs AV nodal refractoriness, selectively reducing heart rate during tachycardias with little effect on normal AV conduction 3
• Diltiazem hemodynamics: Decreases blood pressure and systemic vascular resistance, but maximal effects occur within 2-5 minutes 3
• Mean plasma diltiazem concentration of 80 ng/mL produces 20% heart rate reduction; 130 ng/mL produces 30% reduction 3

For rhythm control (cardioversion to sinus rhythm):

• Oral dofetilide or IV ibutilide are useful for acute pharmacological cardioversion 1
• IV amiodarone can be used but is less effective than ibutilide 1
• Synchronized cardioversion is indicated if pharmacologic therapy fails 1

Important consideration: Acute antithrombotic therapy is recommended in patients with atrial flutter, aligning with recommendations for atrial fibrillation 1

Focal Atrial Tachycardia

• IV beta blockers, diltiazem, or verapamil are useful for acute treatment in hemodynamically stable patients 1
• These agents terminate or slow the ventricular rate in approximately 30-50% of patients 1
• Synchronized cardioversion is recommended for hemodynamically unstable patients 1

Common Pitfalls to Avoid

1. Treating compensatory sinus tachycardia: In patients with poor cardiac function, the elevated heart rate may be maintaining cardiac output—lowering it can worsen hemodynamics 1

2. Using AV nodal blockers in pre-excitation syndromes: Verapamil, diltiazem, or beta blockers in Wolff-Parkinson-White syndrome with atrial fibrillation can cause hemodynamic collapse 2

3. Delaying cardioversion in unstable patients: Do not delay cardioversion to obtain a 12-lead ECG or establish IV access if the patient is extremely unstable 1

4. Ignoring underlying causes: Always evaluate for and treat reversible causes: hypoxemia, hypovolemia, electrolyte abnormalities, myocardial ischemia, drug effects 1

5. Inadequate monitoring: Monitor vital signs closely when using any rate-controlling medications, as hypotension can develop 1, 2, 3

Special Considerations

Tachycardia-induced cardiomyopathy: Persistent or highly frequent tachyarrhythmias with uncontrolled heart rate can cause reversible ventricular dysfunction and heart failure 4. While cardiac function typically recovers after rate control (mean 53.5 days), recurrent heart failure and sudden death can occur, requiring long-term follow-up 4

Narrow-complex tachycardia treatment hierarchy: Vagal maneuvers → adenosine → verapamil/diltiazem → consider nadolol, sotalol, propafenone, or amiodarone as second-line options 1