MY APPROACH to the Pregnant Patient With a Supraventricular Tachycardia
Arrhythmias can cause cardiovascular complications in pregnancy. Palpitations are a common symptom in pregnancy, and electrocardiography (ECG) or ambulatory ECG monitoring can be conducted to determine correlation of the symptoms with arrhythmias. The differential diagnosis for supraventricular tachycardia (SVT) in pregnant patients is similar to that for non-pregnant patients, and includes atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), atrial fibrillation (AF) or flutter, and atrial tachycardia (AT). Increase in circulating plasma volume and hyperdynamic circulation in pregnancy can predispose to SVT. SVT can occur in pregnant patients with structurally normal hearts or with structural heart diseases such as valvular heart disease, hypertrophic cardiomyopathy, or congenital heart disease.
Workup of SVT in pregnancy should include a comprehensive history and physical examination. Attention must be paid to duration and frequency of episodes; concomitant cardiac symptoms such as chest pain, dyspnea, orthopnea, and syncope; past medical history of cardiac and non-cardiac disorders; and social history such as alcohol, drug, and caffeine intake. Physical examination will aid in detection of heart failure or structural heart disease. The ECG in tachycardia and sinus rhythm aids in the diagnosis of the specific etiology of the SVT. Attention must be paid to the presence of manifest pre-excitation and chamber enlargement on ECG. Echocardiography is an essential and safe tool to identify patients with structural heart disease in pregnancy. Laboratory studies should include evaluation for anemia, electrolyte disorders, and thyroid function testing.
Hemodynamically unstable patients with SVT should undergo DC cardioversion. The risk of fetal arrhythmia from cardioversion is minimal but present, and fetal monitoring should be performed. For stable patients with AVNRT or AVRT, vagal maneuvers such as Valsalva maneuver or carotid sinus massage are first-line therapy. Intravenous adenosine is unlikely to be harmful to the fetus due to its short half-life, and is an appropriate second choice. AV nodal blocking agents can be used as a third-line option. Among AV nodal blocking agents, digoxin is considered safe in pregnancy, followed by calcium channel blockers such as verapamil. Beta blockers other than atenolol can be used in the second or third trimester after appropriate counseling regarding intra-uterine growth restriction. The use of atenolol should be avoided in pregnancy. AV nodal blocking agents can also be used to prevent recurrent AVNRT and AVRT.
Rate control of AF can be achieved by AV nodal blocking agents. Antiarrhythmic agents, including flecainide and sotalol, can be used in pregnancy as part of rhythm control strategy. Patients with valvular atrial fibrillation or non-valvular AF with high CHADS2VASc scores are at risk for stroke, and anticoagulation, usually with heparin, must be continued in pregnancy and discontinued at the time of delivery.
There are reports of catheter ablation in pregnancy using non-fluoroscopic methods such as intra-cardiac echocardiography and electroanatomic mapping. Catheter ablation can be considered in advanced centers for patients with frequent and symptomatic recurrences.
Management of supraventricular tachycardia in pregnancy can be a challenging process due to drug-related toxicities to the mother and the fetus, and difficulty with ablation procedures due to risks of fluoroscopy. Arrhythmias can certainly be exacerbated by pregnancy. Addressing arrhythmias with potentially curative procedures such as ablation should be considered in women of childbearing age who are planning a pregnancy to prevent the quandary of arrhythmia management in the pregnant patient.
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