What is the treatment for tachycardia in pregnancy?

Treatment of Tachycardia in Pregnancy

The first-line treatment for tachycardia in pregnancy should follow a stepwise approach beginning with vagal maneuvers, followed by adenosine for supraventricular tachycardia (SVT), with synchronized cardioversion reserved for hemodynamically unstable patients. 1

Initial Assessment and Management

Supraventricular Tachycardia (SVT)

1. Vagal Maneuvers

   • First-line intervention for SVT 1
   • Techniques:
     • Valsalva maneuver: Patient bears down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg)
     • Carotid sinus massage: Apply steady pressure over carotid sinus for 5-10 seconds (after confirming absence of bruits)
     • Cold stimulus: Applying ice-cold wet towel to face 1
   • Should be performed with patient in supine position

2. Pharmacological Management (if vagal maneuvers fail)

   • Adenosine (Class I recommendation)

     • First-line drug for SVT in pregnancy 1
     • Initial dose: 6 mg IV rapid bolus
     • If ineffective: Up to 2 subsequent doses of 12 mg
     • Safe during pregnancy due to short half-life (unlikely to reach fetal circulation) 1
     • Transient maternal side effects include chest discomfort and flushing

   • Beta-blockers (Class IIa recommendation)

     • Reasonable when adenosine is ineffective or contraindicated 1
     • Options: IV metoprolol or propranolol
     • Administer as slow infusion to avoid hypotension 1
     • Caution: May cause intrauterine growth restriction if used in first trimester 2

   • Calcium Channel Blockers (Class IIb recommendation)

     • IV verapamil may be considered when adenosine and beta-blockers fail 1
     • Higher risk of maternal hypotension compared to adenosine 1

3. Electrical Cardioversion

   • Indicated for hemodynamically unstable SVT when pharmacological therapy fails 1
   • Safe at all stages of pregnancy 1
   • Apply electrode pads to direct energy away from uterus 1
   • Fetal monitoring recommended during and after procedure 1
   • Energy dosing same as for non-pregnant patients 1

Atrial Flutter and Atrial Fibrillation

• Rare during pregnancy unless structural heart disease or hyperthyroidism present 1
• For hemodynamically unstable patients: Immediate electrical cardioversion 1
• For stable patients: IV ibutilide or flecainide may be considered 1
• Anticoagulation required before elective cardioversion for AF/flutter ≥48 hours 1

Ventricular Arrhythmias

• Electrical cardioversion for hemodynamically unstable ventricular tachyarrhythmias 3, 4
• For stable ventricular tachycardia: IV procainamide or lidocaine 3, 4
• Consider implantable cardioverter-defibrillator for life-threatening ventricular arrhythmias 3

Special Considerations

Medication Safety

• Avoid medications in first trimester when possible 1, 2
• Use lowest effective dose with regular monitoring 1
• Beta-blockers generally well-tolerated but may cause intrauterine growth restriction 2
• Amiodarone should be avoided due to potential fetal toxicity 2, 5

Timing of Treatment

• For minimally symptomatic arrhythmias: Conservative approach with observation and rest 2
• For debilitating symptoms or hemodynamic compromise: Prompt intervention required 2

Pitfalls to Avoid

1. Delaying cardioversion in hemodynamically unstable patients
2. Using amiodarone as first-line therapy (risk of fetal toxicity)
3. Applying pressure to eyeballs (dangerous and abandoned practice) 1
4. Abrupt discontinuation of beta-blockers (risk of rebound tachycardia) 6
5. Overlooking underlying causes (hyperthyroidism, structural heart disease) 1

Long-term Management

• Prophylactic antiarrhythmic therapy only if symptoms are intolerable or cause hemodynamic compromise 1
• Options include digoxin or selective beta-blockers (metoprolol) as first-line agents 1
• Catheter ablation should be considered only in special cases if necessary during pregnancy 1

By following this stepwise approach, most tachyarrhythmias in pregnancy can be effectively managed while minimizing risks to both mother and fetus.