What is a good medicine to treat paroxysmal Supraventricular Tachycardia (SVT) in a patient with end-stage disease and hypotension?

Treatment of Paroxysmal SVT in a Patient with End-Stage Disease and Hypotension

Synchronized cardioversion is the recommended treatment for paroxysmal SVT in a patient with end-stage disease and hypotension, as pharmacological agents may worsen hemodynamic instability. 1

Initial Management Algorithm

1. Hemodynamically unstable patients (with hypotension):

   • Proceed directly to synchronized cardioversion
   • The American Heart Association recommends synchronized cardioversion for any persistent SVT resulting in hypotension, altered mental status, signs of shock, chest pain, or acute heart failure symptoms 1

2. If cardioversion equipment is not immediately available:

   • Consider vagal maneuvers as a temporizing measure
   • These include the Valsalva maneuver (patient exhaling forcibly against a closed glottis) 1
   • Note: Carotid sinus massage should be avoided due to risk of stroke, especially in end-stage disease patients 1

Pharmacological Considerations

Most pharmacological agents commonly used for SVT are problematic in hypotensive patients:

• Calcium channel blockers (verapamil, diltiazem):

  • Contraindicated in hypotensive patients due to their negative inotropic effects and potential to worsen hypotension 1
  • Diltiazem and verapamil should only be used in hemodynamically stable patients 1

• Beta blockers:

  • Can worsen hypotension and heart failure 1
  • Should be avoided in patients with compromised hemodynamics

• Adenosine:

  • While adenosine is typically first-line for stable SVT, it must be used with caution in this scenario
  • The ACC/AHA/HRS guidelines caution that adenosine should be used carefully when the patient is hemodynamically compromised 1
  • If used, adenosine should be administered in a monitored environment with emergency equipment readily available 1
  • Initial dose is 6 mg rapid IV bolus, followed by saline flush; can increase to 12 mg if needed 1, 2

Special Considerations for End-Stage Disease

• Patients with end-stage disease may have impaired venous return, which could necessitate higher doses of adenosine if this agent is used 3
• The setting should include continuous ECG monitoring and frequent blood pressure measurements 4
• A defibrillator and emergency equipment should be readily available 4

Key Pitfalls to Avoid

1. Do not delay cardioversion in a hemodynamically unstable patient while attempting pharmacological therapy
2. Do not administer verapamil or diltiazem to hypotensive patients, as these can precipitate cardiovascular collapse
3. Do not use verapamil in patients with SVT associated with Wolff-Parkinson-White syndrome, as it may precipitate ventricular tachycardia or fibrillation 1
4. Do not attempt carotid sinus massage in elderly patients or those with carotid bruits due to risk of stroke 1

In summary, synchronized cardioversion is the safest and most effective approach for treating paroxysmal SVT in a patient with end-stage disease and hypotension, as it avoids the hemodynamic compromise associated with pharmacological agents.