What is the initial treatment for a patient presenting with ventricular tachycardia (Vtach) with a pulse?

Treatment for Ventricular Tachycardia with a Pulse

For hemodynamically stable VT with a pulse, initiate intravenous amiodarone at 150 mg over 10 minutes, followed by a continuous infusion of 1.0 mg/min for 6 hours, then 0.5 mg/min maintenance. 1, 2 For hemodynamically unstable VT with a pulse (systolic BP <90 mm Hg, altered mental status, chest pain, acute heart failure), perform immediate synchronized cardioversion starting at 100 J with appropriate sedation if the patient is conscious. 1, 3

Initial Assessment and Stabilization

Determine hemodynamic stability immediately by assessing for:

• Systolic blood pressure <90 mm Hg 1
• Acute altered mental status 1
• Ischemic chest discomfort 1
• Acute heart failure or pulmonary edema 1
• Signs of shock 1

While assessing, establish IV access, provide supplementary oxygen if needed, attach continuous cardiac monitoring, and obtain a 12-lead ECG without delaying treatment. 1

Treatment Algorithm Based on Hemodynamic Status

Hemodynamically Unstable VT (Blood Pressure <90 mm Hg or Signs of Shock)

Proceed immediately to synchronized cardioversion: 1, 3

• Provide sedation if the patient is conscious 3
• Start with 100 J synchronized shock 1, 3
• If unsuccessful, escalate to 200 J, then 360 J 3
• For polymorphic VT appearing rapid and chaotic, treat as ventricular fibrillation with unsynchronized 200 J shock 1

Hemodynamically Stable VT (Blood Pressure ≥90 mm Hg, No Acute Distress)

First-line pharmacologic therapy is intravenous amiodarone: 1, 2, 4

• Loading dose: 150 mg IV over 10 minutes 1, 2
• If VT recurs, repeat 150 mg bolus 1
• Maintenance infusion: 1.0 mg/min for 6 hours, then 0.5 mg/min 1, 2
• FDA-approved for frequently recurring VF and hemodynamically unstable VT refractory to other therapy 4

Alternative agents if amiodarone is unavailable or contraindicated:

Lidocaine (second-line): 1, 3

• Initial bolus: 1.0-1.5 mg/kg IV (typically 75-100 mg) 1, 3
• Supplemental boluses: 0.5-0.75 mg/kg every 5-10 minutes to maximum total loading dose of 3 mg/kg 1, 3
• Maintenance infusion: 2-4 mg/min (30-50 µg/kg/min) 1, 3
• Reduce infusion rates in elderly patients and those with CHF or hepatic dysfunction 1, 2

Procainamide (third-line): 1, 5

• Loading infusion: 20-30 mg/min up to 12-17 mg/kg 1
• Stop infusion if hypotension develops, QRS widens >50%, or arrhythmia suppressed 1
• Maintenance infusion: 1-4 mg/min 1
• Reduce infusion rates in renal dysfunction 1, 2
• Avoid in prolonged QT interval or CHF 1
• FDA-approved for documented life-threatening ventricular arrhythmias 5

Special Considerations for Polymorphic VT

For drug-refractory polymorphic VT, aggressively treat underlying ischemia: 1, 2

• Initiate IV beta-blockers (most effective therapy for polymorphic VT storm) 2
• Consider intra-aortic balloon pump 1, 2
• Pursue emergency coronary angiography and revascularization (PTCA/CABG) 1, 2

For torsades de pointes (polymorphic VT with prolonged QT):

• Administer magnesium sulfate 1-2 g IV bolus diluted in 10 mL D5W 1, 2
• Correct electrolyte abnormalities, particularly potassium and magnesium 1, 3

Critical Pitfalls to Avoid

Do not use calcium channel blockers (verapamil, diltiazem) for VT - they are contraindicated and may precipitate hemodynamic collapse or ventricular fibrillation. 3

Monitor for amiodarone-induced hypotension and bradycardia, particularly with IV bolus administration - the vasoactive solvents can cause significant hemodynamic effects. 1, 6 Consider administering a vasopressor before amiodarone if the patient is borderline hypotensive. 1

Do not treat isolated ventricular premature beats, couplets, or nonsustained VT - prophylactic antiarrhythmic therapy is not recommended and may be harmful. 1, 2

Avoid Class IC antiarrhythmics (flecainide, propafenone) in patients with prior MI or structural heart disease - they increase mortality risk. 2

Monitoring and Transition to Oral Therapy

Monitor heart rate, blood pressure, and continuous ECG during antiarrhythmic administration. 1 Most patients require IV therapy for 48-96 hours until ventricular arrhythmias stabilize. 4

When transitioning from IV to oral amiodarone: 1

• If IV therapy <1 week: start 800-1,600 mg/day oral 1
• If IV therapy 1-3 weeks: start 600-800 mg/day oral 1
• If IV therapy >3 weeks: start 400 mg/day oral 1

Antiarrhythmic infusions should be discontinued after 6-24 hours and the need for further therapy reassessed. 1 Address underlying causes including electrolyte disturbances, acid-base abnormalities, myocardial ischemia, and heart failure. 1, 2