The following are key points to remember from this state-of-the-art review of arrhythmias in pregnancy:

1. Pregnancy is associated with increased incidence of arrhythmias. Benign premature atrial and ventricular contractions are common. Proarrhythmic mechanisms may include increased plasma catecholamine concentrations, chronotropic effects of relaxin, mechanical effects of atrial stretch, increased ventricular end-diastolic volume due to volume expansion, and hormonal changes.
2. Normal heart rate progressively increases during pregnancy by 10-25% from pre-pregnancy values.
3. Supraventricular tachycardia can be treated acutely with vagal maneuvers and adenosine. Long-term suppression can be achieved with beta-blocker therapy (first-line), or digoxin or calcium channel blockers as second-line therapy.
4. Patients with evidence of pre-excitation should be treated with caution. Atrioventricular nodal blocking agents can increase conduction over the accessory pathway and may degenerate to ventricular arrhythmias.
5. In the absence of structural heart disease, beta-blockers and antiarrhythmic medications such as flecainide and sotalol can be used safely during pregnancy to treat tachyarrhythmias.
6. Cardiac arrest should be treated the same as for non-pregnant patients. Medication doses and defibrillation protocols are unchanged. Manual lateral displacement of the uterus can improve venous return and cardiac output. Preparation should be made for emergency cesarean delivery.
7. Beta-blockers can be used during pregnancy. There is a small risk of fetal growth restriction with long-term treatment, but no increased risk of congenital malformations. Neonatal hypoglycemia and bradycardia are rare possibilities. Beta-blockers are compatible with lactation.
8. Calcium channel blockers are considered second-line agents. Verapamil is preferred over diltiazem during pregnancy, and both are compatible with lactation.
9. Quinidine, procainamide, lidocaine, flecainide, propafenone, and sotalol cross the placenta but do not have known teratogenic effects and can be used during pregnancy. Quinidine therapy should be managed by an experienced electrophysiologist. Amiodarone should be avoided if possible.
10. Catheter ablation procedures are generally avoided during pregnancy. Arrhythmias that are drug-refractory or poorly tolerated have been treated with catheter ablations during pregnancy in experienced centers with techniques to reduce fluoroscopic exposure.

Clinical Topics: Arrhythmias and Clinical EP, Congenital Heart Disease and Pediatric Cardiology, Prevention, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Prevention, Novel Agents, Statins

Keywords: Adenosine, Adrenergic beta-Antagonists, Anti-Arrhythmia Agents, Arrhythmias, Cardiac, Bradycardia, Calcium Channel Blockers, Catheter Ablation, Digoxin, Electrophysiology, Fetal Growth Retardation, Heart Arrest, Heart Rate, Hypoglycemia, Infant, Newborn, Lactation, Placenta, Pregnancy, Primary Prevention, Quinidine, Relaxin, Tachycardia, Supraventricular, Women

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