Very late-onset complete atrioventricular block following deployment of Amplatzer membranous ventricular septal defect occluder.

RATIONALE

Although implantation of Amplatzer membranous ventricular septal defect occluder (AVSDO) is an alternation to surgical treatment, the interventional therapy is disapproved by FDA due to high incidence of complete atrioventricular block (cAVB) post closure during early and middle term follow-up. However, long-term outcomes of the accumulating numbers of patients who had received AVSDO in the past decades, still remain an issue of concern and late occurrence of potentially catastrophic heart block long after hospital discharge is especially worrying, but rarely documented. We firstly reported a pediatric case with very late-onset cAVB occurring over ten years following transcatheter closure of PmVSD using AVSDO.

PATIENT CONCERNS

A 5-year old female received transcatheter closure of PmVSD sized 10-mm on left ventricular angiography with a 14-mm AVSDO owning to a history of recurrent lower respiratory tract infections. Post-procedure echocardiography documented no arrhythmias, residual shunt and aortic regurgitation. All electrocardiogram (ECG) recordings were completely normal and transthoracic echocardiography (TTE) examination showed the device was in the proper position and there was neither residual shunt nor valves regurgitation. Ten years after operation, the patient was re-admitted into our hospital due to recurrent syncope.

DIAGNOSES

A 12-lead ECG showed cAVB with a minimal heart rate of 42 bpm. Device flattening was revealed on 2-dimensional TTE and the occluder appeared to return to its original size and shape. Computed tomography and magnetic resonance imaging of brain did not reveal any intracranial hemorrhages, ischemic changes, or space-occupying lesions. Electroencephalogram detected no epileptiform discharge. Other possible etiologies resulting in cAVB such as myocarditis, hypothyroidism and connective tissue diseases were excluded. Therefore, it was ultimately considered the cAVB was mostly likely to be associated with device closure of PmVSD using AVSDO.

INTERVENTIONS

The child was empirically treated with prednisone (1-2 mg/Kg daily).

OUTCOMES

Unfortunately, no improvement was observed. A permanent pacemaker was implanted. The following course was uneventful.

LESSONS

For patients following transcatheter closure of PmVSD using AVSDO, the risk period for developing heart block after device closure appears to be much longer than we speculated. Long-term, perhaps and life-long followed up needs to be considered for this group of patients.