Atrial Fibrillation During Pregnancy: Special Population Review

February 14, 2017

Is aspirin safe as antithrombotic therapy in pregnancy? Is electrocardioversion first-line treatment? Get the answers and other reminders, here.

[[{"type":"media","view_mode":"media_crop","fid":"56593","attributes":{"alt":"","class":"media-image media-image-right","id":"media_crop_9384442769025","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"7115","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 204px; width: 275px; float: right;","title":"","typeof":"foaf:Image"}}]]As a physiologic state pregnancy is associated with a variety of changes in hemodynamics, including expanded plasma volume, decreased systemic vascular resistance, increased cardiac output and augmented sinus heart rate. Palpitations and benign cardiac arrhythmias increase in incidence during pregnancy.

Although atrial fibrillation is a common arrhythmia, when it occurs during pregnancy, it can portend the presence of congenital heart disease, rheumatic valvular disease, alcohol abuse, hyperthyroidism, or electrolyte imbalance.  It can also represent terbutaline toxicity (which can be used as tocolytic therapy in prevention of preterm labor).  Women who develop AF should always receive an echocardiogram and laboratory workup. Once underlying conditions have been ruled out, the physician must determine whether the presence of AF has caused any change in placental perfusion (ie, whether the arrhythmia is hemodynamically significant), which may requires cardioversion.  In general, during pregnancy, rhythm control with electrical or pharmacologic cardioversion is preferred to rate control (to avoid side effects of antiarrhythmic medications). Electrical cardioversion can be safely done during all trimesters of pregnancy but fetal monitoring after the procedure is recommended in case of transient fetal arrhythmias.

Medication management for those who cannot be successfully cardioverted can be challenging as well. 

 â–º Beta blockers, especially during the first trimester, can result in fetal growth retardation. 

 â–º Metoprolol and atenolol interfere less with B2- mediated vasodilation or uterine relaxation and the incidence of fetal hypoglycemia is lower with those. 

 â–º Digoxin is safe during pregnancy and is not teratogenic even though it crosses the placenta. 

 â–º Verapamil and diltiazem should be second choice agents when beta blockers and digoxin fail as they can result in maternal or fetal bradycardia, heart block, decreased contractility and possible congenital malformations.

Anticoagulation should be pursued to avoid thromboembolic risk but can also pose maternal and fetal risks. The safety of aspirin therapy during the first trimester is uncertain but low-dose aspirin appears to be safe in the second and third trimesters.  Anticoagulation should be reserved for higher risk AF patients, such as those with rheumatic heart disease, prosthetic heart valves or prior CVA.

 

Source

Cacciotti L, Passaseo I.  Management of atrial fibrillation in pregnancy. JAFIB. 2010;3:48-52.