Cardiovascular Disease in Pregnancy
Case 2: Arrhythmia in Pregnancy
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In acute severe regurgitation refractory to therapy, surgery may be unavoidable.
If the fetus is mature enough, delivery should occur prior to surgery. In patients with any valvular regurgitation, vaginal delivery is preferable, and symptomatic patients should receive regional anesthesia with epidural or spinal to minimize the cardio- vascular consequences of catecholamine surges. In some cases, an assisted second stage of labor may be appropriate [1].
Congenital bicuspid aortic valves are often associated with an underlying aor- topathy, and it is important to screen for concomitant aortic dilation and aneurysm.
Likewise, there is an important link between bicuspid aortic valves and coarctation of the aorta, and individuals with bicuspid aortic valves should be screened for this condition as well. Approximately 50 % of patients with bicuspid aortic valve and aortic valve pathology (aortic stenosis or aortic regurgitation) have dilation of the ascending aorta [7]. Also, dilation is often maximal at the distal end of the ascend- ing aorta, which cannot be adequately visualized with transthoracic echocardiogra- phy, and Magnetic Resonance Imaging (MRI) or Compted Tomography (CT) of the chest should be performed prior to conception. Pre-pregnancy surgery should be considered when the thoracic aortic diameter reaches 50 mm [8]. Immer et al. [9]
found that increased aortic root dilation during pregnancy in patients with bicuspid aortic valve carries a significant risk of type A aortic dissection.
Our patient underwent a transthoracic echocardiogram, with visualization of the aortic root, which was mildly dilated. The entire ascending aorta, aortic arch, and descending aorta were not fully visualized. Dedicated MRI of the aorta without contrast administration (an optimal choice to decrease radiation exposure) showed stable dilation of the aortic root and no evidence of coarctation, thoracic aneurysm, or dissection. She underwent a normal pregnancy, with regularly scheduled follow- up with her cardiologist. In the setting of congenital bicuspid aortic valve disease, screening of first-degree relatives, including children, siblings, and parents, is rec- ommended [8].
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to sinus rhythm at 83 bpm. Her shortness of breath and chest discomfort resolve.
She is admitted for further monitoring on telemetry, but she remains in sinus rhythm for 24 hours (h) and is discharged home without medication changes. Twelve days later, she re- presents with recurrent symptoms and is found to have a supraventricu- lar tachycardia at 157 bpm. She is given adenosine 6 mg IV once, with resolution of the tachycardia and reestablishment of sinus rhythm. During the preceding 10 days, she noted intermittent palpitations for 1–2 min before resolving either on their own or with vagal maneuvers. She is admitted for monitoring and started on digoxin 0.125 mg daily. She undergoes induction of labor on hospital day three, with place- ment of an epidural, and delivery of a healthy baby boy at 37 0/7 weeks gestation.
On hospital day six, she undergoes an electrophysiology study and atrioventricular nodal reentrant tachycardia (AVNRT) ablation. She is discharged on hospital day seven in stable condition.
Premature extra beats and atrial tachyarrhythmias are more frequent and may even manifest for the first time, during pregnancy. The sensation of palpitations is common in pregnancy, with sinus tachycardia, premature atrial contractions, and premature ventricular complexes representing the most common findings [10, 11].
Premature beats manifest most frequently during the second trimester. They are not associated with adverse maternal or fetal outcomes and require treatment only if symptoms are intolerable to the mother. The occurrence of atrial fibrillation or atrial flutter is relatively rare during pregnancy and is usually associated with hyperthy- roidism or structural cardiac disease [1], such as underlying valvular disease, con- gestive heart failure, or congenital heart disease.
AVNRT is the most common supraventricular arrhythmia in pregnant and non- pregnant women. In patients with a preexisting history of supraventricular tachycardia, the incidence of recurrence during pregnancy is as high as 20–44 % in case studies [12, 13]. Previously highly symptomatic tachyarrhythmias should be
Fig. 1 ECG of supraventricular tachycardia
J.B. Whelan and L.S. Feinberg
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treated with catheter ablation prior to pregnancy, when possible. During pregnancy, as in our patient, most supraventricular arrhythmias represent a WHO class II risk category, with a small increase in maternal mortality and a moderate increase in morbidity.
Typically, supraventricular tachyarrhythmias are not well tolerated in pregnancy, if rapid and sustained. Thus, the general preference is to restore sinus rhythm.
AVNRT or atrioventricular reentrant tachycardia (AVRT) involving an accessory pathway can often be terminated by successful vagal maneuvers, such as having the patient perform the Valsalva maneuver and cough vigorously or by applying carotid sinus pressure. If vagal maneuvers fail, adenosine is the first drug of choice and can be administered safely and intravenously in pregnancy for diagnostic and therapeu- tic purposes [13, 14]. Adenosine interrupts conduction down the accessory atrioven- tricular nodal pathway by prolonging the refractory period of the atrioventricular (AV) node and revealing the underlying atrial arrhythmia. Intravenous metoprolol can be used if adenosine fails and serves to slow the ventricular rate to control symptoms but will not typically convert the rhythm to sinus. Direct current synchronized car- dioversion is also safe in all stages of pregnancy [13] and is used typically in situa- tions of hemodynamic instability or arrhythmias refractory to medical therapy.
Digoxin is considered safe in pregnancy and can be used to control the ventricular rate but is not an effective medication to use in the acute setting [13]. Other agents, such as specific medications acting on the AV node (beta- blockers, non-dihydropyr- idine calcium channel blockers; most class C agents) (Table 5), may also be safe and tolerated during pregnancy to treat the symptoms of the arrhythmia. Antiarrhythmic drug therapies can be toxic to the developing fetus and should be discontinued prior to conception [13]. Major controlled studies of antiarrhythmic drugs during preg- nancy are lacking. Typically, antiarrhythmic therapy is reserved for hemodynamic compromise or refractory or recurrent arrhythmia. Specific antiarrhythmic medica- tions are considered safer to use in pregnancy, such as sotalol (class B), flecainide
Table 5 Federal drug administration pregnancy categories Risk class Risk of medication in pregnancy
A Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters)
B Animal reproduction studies have failed to demonstrate a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women
C Animal reproduction studies have shown an adverse effect on the fetus, and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks
D There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks
X Studies in animals or humans have demonstrated fetal abnormalities, and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits
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(class C), and ibutilide (class C) [13]. They have not demonstrated any adverse fetal effects, but experience with these medications in pregnancy is limited. Amiodarone is usually recommended against in pregnancy. It is a pregnancy class D medication and its use in pregnancy should be restricted to arrhythmias that are resistant to other drugs or are life threatening [15]. Bypass tract or atrioventricular nodal ablation is possible during pregnancy if necessary and is best performed during the second tri- mester when the fetus has undergone initial development and the mother and fetus can still be adequately shielded from radiation exposure.