What is the management plan for a patient presenting to the Emergency Department (ED) with ventricular tachycardia (VT) during pregnancy?

Management of Ventricular Tachycardia in Pregnancy

If the patient is hemodynamically unstable, perform immediate electrical cardioversion or defibrillation—this is the definitive first-line intervention for VT in pregnancy regardless of gestational age. 1

Immediate Stabilization and Assessment

Hemodynamic Status Determines Initial Management

• Unstable VT (hypotension, altered mental status, severe dyspnea, chest pain): Proceed directly to synchronized electrical cardioversion at 50-100 J 1, 2, 3

  • Apply electrode pads with energy trajectory directed away from the uterus 1
  • Cardioversion is safe at all stages of pregnancy and takes priority over pharmacologic therapy 1
  • Perform fetal monitoring during and immediately after cardioversion if time permits 1

• Stable VT (preserved blood pressure, alert, no severe symptoms): Consider pharmacologic conversion while preparing for cardioversion 1

  • IV sotalol or procainamide should be considered for acute conversion of hemodynamically stable monomorphic sustained VT 1
  • IV amiodarone should be considered only when VT is refractory to electrical cardioversion or not responding to other drugs, despite being FDA Category D 1
  • Note: Amiodarone carries significant fetal risks (thyroid dysfunction, growth restriction) and should be used at the lowest effective dose only when all other options have failed 4, 5

Critical Diagnostic Workup

Obtain 12-lead ECG immediately to characterize VT morphology and identify the origin 6, 7:

• Left bundle branch block pattern suggests right ventricular outflow tract (RVOT) VT 7
• Right bundle branch block pattern suggests left ventricular origin 1

Perform urgent transthoracic echocardiography to assess 1, 7:

• Left ventricular ejection fraction (LVEF)
• Structural heart disease
• Regional wall motion abnormalities
• Signs of peripartum cardiomyopathy (LVEF <45%, may occur in last 6 weeks of pregnancy or early postpartum) 1, 4

Rule out peripartum cardiomyopathy in any pregnant woman presenting with new-onset VT during the last 6 weeks of pregnancy or postpartum period 1, 4

Ongoing Management After Acute Stabilization

For Idiopathic VT (No Structural Heart Disease)

RVOT VT (most common idiopathic VT in pregnancy):

• First-line prophylaxis: Oral metoprolol or propranolol 1, 8
  • Metoprolol is preferred over other beta-blockers due to lower incidence of fetal growth retardation 8
  • Never use atenolol—it causes significantly increased fetal growth restriction 8, 4
• Alternative: Oral verapamil 40 mg daily if beta-blockers are ineffective or contraindicated 1, 7
• Second-line: Oral sotalol may be considered (FDA Category B—remote chance of fetal harm) 1, 5

Left fascicular VT:

• Usually does not respond to beta-blockers 1
• First-line: Verapamil (mechanism involves calcium entry in depolarized Purkinje fibers) 1

For VT with Structural Heart Disease or Peripartum Cardiomyopathy

Initiate heart failure management 1:

• Beta-blocker therapy (metoprolol preferred) is recommended for all patients if tolerated 1, 8
• Contraindicated drugs: ACE inhibitors, ARBs, and renin inhibitors throughout pregnancy 1, 4
• Avoid mineralocorticoid receptor antagonists 1

Consider ICD implantation for 1:

• Sustained VT with low ejection fraction
• Aborted sudden cardiac death
• Recurrent syncopal VT
• Subcutaneous ICD may be considered during pregnancy to avoid fluoroscopy, though experience is limited 1

Refractory or Recurrent VT

Catheter ablation may be considered for drug-refractory and poorly tolerated tachycardias 1:

• Preferably performed with zero-fluoroscopy technique using echocardiography guidance 9, 3
• Can be performed at any stage of pregnancy if clinically necessary 9
• Should ideally be performed before pregnancy if known history of VT 1

Monitoring and Follow-Up

Continuous cardiac monitoring throughout hospitalization 6, 7

Fetal monitoring with regular assessment of fetal heart rate and growth 8, 6:

• Closer monitoring of fetal growth is recommended for all pregnant women on beta-blockers due to association with intrauterine growth retardation 8
• Monitor for fetal bradycardia, hypoglycemia, and signs of distress 5

Serial echocardiography if peripartum cardiomyopathy is diagnosed or suspected 1, 10

Continuous monitoring during labor and delivery due to increased arrhythmia risk during this period 5

Delivery Planning

Multidisciplinary pregnancy heart team should coordinate care involving cardiology, obstetrics, anesthesia, and neonatology 7, 10

Timing of delivery:

• If VT is refractory to medical management and causing maternal hemodynamic compromise, early delivery (if fetus is viable) may be the best therapeutic option 9, 10
• Continue cardiac monitoring throughout labor and delivery 5

Postpartum management:

• Continue beta-blocker therapy throughout the postpartum period, especially in patients with congenital long QT syndrome or catecholaminergic polymorphic VT (highest risk period is 40 weeks after delivery) 1
• Cardiac monitoring for 48 hours postpartum 7
• Do not breastfeed while on sotalol due to high levels in breast milk (milk:plasma ratio 5.4:1) and risk of neonatal bradycardia and beta-blockade symptoms 5

Common Pitfalls to Avoid

• Never delay cardioversion in unstable patients to attempt pharmacologic conversion 1
• Never use atenolol as it significantly increases fetal growth restriction compared to other beta-blockers 8, 4
• Avoid amiodarone unless absolutely necessary due to fetal thyroid toxicity and growth restriction (FDA Category D) 1, 4
• Do not assume benign etiology—always rule out structural heart disease and peripartum cardiomyopathy with echocardiography 1, 10
• Do not discontinue beta-blockers postpartum in high-risk patients (LQTS, CPVT) as this is a critical period for arrhythmia recurrence 1