Atrioventricular Block in Pregnancy: 15.8 Seconds of Asystole

Abstract

Atrioventricular (AV) block in pregnancy is infrequently encountered and there is little management guidance available. We present a case of a 24-year-old G3P1011 at 24 weeks' gestation who presented to the obstetrics and gynecology clinic complaining of palpitations, fatigue, and dyspnea on exertion. Cardiology workup including an electrocardiogram (ECG) and Holter monitor detected second-degree type II (Mobitz) AV block with the longest asystole event lasting 15.8 seconds. A St. Jude's dual-chamber pacemaker (Abbott Laboratories, Abbott Park, IL) was implanted immediately. Standard radiation precautions were taken with additional shielding for the fetus. The patient experienced significant improvement in her symptoms. The patient went into labor at 37 3/7 weeks. Due to non-reassuring fetal heart tones, a cesarean section was performed, and a healthy baby girl was born. The management of heart block in pregnancy can be divided into involving those who are symptomatic and those who are asymptomatic. Symptoms of heart block can include palpitations, fatigue, dyspnea, and/or syncope; the presence of these symptoms warrants the placement of a pacemaker, preferably during pre-pregnancy or during the first two trimesters, as high-grade heart block is associated with significant mortality. Those who are in their last trimester or postpartum should consider the use of a temporary pacemaker as heart block could be due to pregnancy-related cardiovascular changes. For women with heart block, labor and delivery could result in worsening of bradycardia due to uterine contractions displacing blood into the central circulation. Most women with heart block do well in labor and delivery and having a pacemaker is not necessarily an indication for a cesarean section.

Pregnancy maternal fetal outcomes among pregnancies complicated with atrioventricular block

“…Atrioventricular block (AVB) is caused by the dysfunction of the cardiac electroconductive pathways and characterized by a prolongation of the PR interval on the electrocardiogram (ECG) [ 10 ]. According to the pattern and feature of the disruption of electrical activity, the blocks are classified in three categories: first degree, second degree (Mobitz type 1 or 2), and third-degree [ 10 , 11 ]. The pathogenesis underlying the block could be an anatomical defect or functional impairment in the heart’s conduction system [ 11 ].…”

“…According to the pattern and feature of the disruption of electrical activity, the blocks are classified in three categories: first degree, second degree (Mobitz type 1 or 2), and third-degree [ 10 , 11 ]. The pathogenesis underlying the block could be an anatomical defect or functional impairment in the heart’s conduction system [ 11 ].…”

“…Previous study reported that a patient with type II of II° AVB identified at 24 gestational weeks. She had symptoms of palpitations and fatigue and experienced episodes of asystole, and the longest episode lasted for 15.8 s [ 12 ]. In our study, other mild arrhythmias were also frequently present in the patient with II° AVB type I AV block.…”

A case report of high-degree AV block in pregnancy

“…In such cases, a temporary pacemaker may be placed in the patient. [ 5 ] A routine test such as a 12-lead ECG is often adequate to diagnose a CHB. To diagnose the underlying cause of the electrical abnormality in our patient, we proceeded with a cardiac MRI during the puerperal period.…”

Pregnancy and complete atrioventricular block: a case report

“…Bradycardia in pregnancy due to complete atrioventricular block (CAVB) is a rare but serious occurrence 1 , 2 . The incidence of CAVB is estimated to be 1 in 15 000 to 20 000 live births 3 , and it can be congenital or acquired.…”