Congenital complete atrioventricular block (CCAVB) is a rare disease that occurs in approximately 1 of every 20 000 pregnancies [1] and is believed to be caused by transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies [2]. An early diagnosis is crucial as without pacemaker implantation this condition is associated with a high neonatal mortality rate. The risk factors for unfavorable diagnosis are a slow ventricular rate (below 50–60/min), cardiogenic shock, and fetal edema [3–5].
The presented case concerns a premature female infant, in whom pacemaker implantation was performed within 2 hours after birth. The CCAVB was diagnosed at the beginning of the 3rd trimester based on fetal echocardiography.
After CCAVB diagnosis, watchful waiting strategy was implemented. At the 29th week of gestation, the fetus presented with a heart rate below 60/min. Pharmacological therapy with salbutamol, digoxin, and steroid therapy was started. The fetus’s condition worsened, and it started to accumulate fluid in the body cavities. Control echocardiography showed a significantly enlarged left ventricle with impaired contractility with low ejection fraction (EF) of 17% (Figure 1A) and significant bradycardia of 40–50/min. The pregnant female was transported to our Center and a cesarean section (CC) was performed. The infant was delivered at the 31st week of gestational age. The birth weight was 1970 g. Due to cardiopulmonary compromise, the newborn required respiratory therapy. Electrocardiography (ECG) showed a complete atrioventricular block with an atrial rate of 167/min and ventricular rate of 42/min (Figure 1B). Single bolus of atropine followed by adrenaline, milrinone, and dopamine infusions were administered without any improvement. Isoprenaline was not given due to immediate surgical qualification for pacemaker implantation. Transthoracic echocardiography (TTE) showed a markedly enlarged left ventricle with decreased myocardial contractility (LVEF, 21%), bradycardia 28–40/min, and decreased cardiac output. Implantation of a single chamber pacing system Microny II SR+2525T by Jude Medical with a bipolar epicardial electrode (Figure 1C, D) was performed. On the 12th day following pacemaker implantation, the left ventricular EF was 40% as measured by the biplane Simpson method.
This case is not the first described in the literature; however, what stands out is the fact that the patient’s mother was intentionally transferred to our Center before delivery for the procedure of pacemaker implantation immediately after the CC, which reduced the total length of intervention and risk of interhospital transport. We believe that in children in the gestational age group (31–34 hbd) with previously mentioned risk factors, the decision to deliver the baby and perform immediate implantation of the pacemaker should not be delayed [4].
In 1-month follow-up, the general condition of our patient was good, with proper body weight gain. TTE showed decreased EF (44%) measured by the Simpson method (Figure 1E) requiring spironolactone and digoxin. However, in 2-year follow-up, the contractility decreased significantly down to 20% due to progressive dilated cardiomyopathy, requiring cardiac resynchronization therapy (CRT) and pharmacotherapy including angiotensin-converting enzyme 1 (ACE1), carvedilol, digoxin, and diuretics. Despite effective electrostimulation and CRT, the prognosis is poor due to dilated cardiomyopathy, and the patient is a candidate for a heart transplant.
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