It is not uncommon for arrhythmias to occur during pregnancy. How to manage it safely and reasonably? To save the mother without damaging the fetus. Pregnancy is not a contraindication to the implantation of an ICD (implantable cardioverter-defibrillator), and electrical cardioversion can and should be used for any sustained tachycardia that causes hemodynamic instability and threatens the safety of the fetus. Radiofrequency ablation can also be used for supraventricular tachycardia when necessary, but with lead-suit protection and avoidance of X-rays with ultrasound when possible.
Strategies for the management of some arrhythmias in pregnancy
Atrioventricular nodal regurgitation and atrioventricular regurgitant tachycardia
Vagus nerve stimulation can be started with manual stimulation and, if ineffective, with rapid sedation of adenosine (9-18 mg, pellet-based sedation).
In addition to adenosine, selective beta-blockers or digoxin are the first-line agents, followed by sotalol, flecainide, and propafenone. DC resuscitation of 10-50 J can be considered for those who fail to respond to pharmacological therapy, and 50-100 J for those who develop hemodynamic disturbances.
Atrial flutter and atrial fibrillation
1. Anticoagulation therapy.
Anticoagulation therapy and/or transesophageal ultrasound should be given before resetting atrial flutter or atrial fibrillation to exclude left atrial thrombus.
Atrial fibrillation of less than 48 h and without risk of thromboembolism can be treated with intravenous heparin or therapeutic doses of low molecular heparin before resetting.
Atrial flutter or atrial fibrillation lasting longer than 48 h or of unknown duration must be given anticoagulation 3 weeks prior to elective resuscitation. Continuation of anticoagulation after resuscitation depends primarily on the patient’s risk of thromboembolism.
The choice of anticoagulant needs to be combined with the period of pregnancy: vitamin K antagonists are recommended from the 4th month until 1 month before the expected delivery date. A weight-adjusted therapeutic dose of low molecular heparin is given during the first and last trimester of pregnancy.
2. Ventricular rate control.
Beta-blockers are preferred, and verapamil is only used as a secondary drug of choice. Prophylactic antiarrhythmic drugs can be considered for those whose symptoms are still severe after heart rate control, and flecainide and propafenone should be used in combination with AV node blockers. Dronedarone is not currently recommended for use in pregnancy.
3. Rhythm control.
Intravenous ibrit or flecainide are usually effective, but experience with their use in pregnancy is limited. Amiodarone has many adverse effects and should be considered only when other drugs or electrical resuscitation are ineffective.
Ventricular tachycardia
Symptomatic before pregnancy, preferably treated with catheter ablation before pregnancy.
Pregnant ventricular tachycardia episodes that are hemodynamically stable can be treated with medication first, with procainamide recommended.
Ventricular tachycardia with tip-twist due to QT prolongation can be treated with magnesium sulfate (1-2 g in 1-2 min).
Verapamil can be used for idiopathic right ventricular/left ventricular outflow tract VT.
Immediate electrical cardioversion is required for severe symptoms or hemodynamic disturbances. 50-100 J of direct current cardioversion is given once, or 100-360 J if ineffective; even in hemodynamically stable ventricular tachycardia, prompt pharmacological or electrical cardioversion is desirable. Amiodarone should be considered only when other treatments are ineffective.
Slow arrhythmias
The prognosis is usually good in pregnant women without underlying heart disease, but those with structural heart disease may develop new symptoms or worsen existing symptoms. In the presence of symptomatic bradycardia, the pregnant woman should be placed in the left lateral position. Temporary pacing support may be given in cases of persistent symptoms.
Finally, the authors note that most arrhythmias in pregnancy are benign and a few may worsen. Accurate interpretation of the electrocardiogram is the basis for a rational evaluation and treatment. Anti-arrhythmic treatment is broadly similar to that for non-pregnant patients, but the adverse effects on the fetus need to be considered. In the event of a maternal life-threatening arrhythmia, even drugs that are not recommended for use in pregnancy may be considered.