Pediatric Cardiac Surgery Fellow Montreal, Quebec, Canada
Case background: A term newborn girl, with no family history of cardiomyopathies and previously found to have third-trimester fetal tachycardia, was noticed to be tachycardic at birth. Electrocardiography (ECG) showed a heart rate (HR) of 210 with normal QTc. A transthoracic echocardiogram (TTE) revealed a dilated left ventricle (LV) with slightly reduced function, leading to a suspicion of idiopathic ventricular tachycardia. She spontaneously converted and was subsequently discharged home. Two months later, she presented to the emergency room with vomiting, hypotonia, and cyanosis. ECG showed ventricular tachycardia with HR of 170, which persisted despite beta-blocker treatment. This led to the administration of adenosine, after which she became pulseless. Cardiopulmonary resuscitation was performed for 90 minutes, culminating in her cannulation for neck venoarterial ECMO (VA-ECMO). She then underwent a Rashkind septostomy for left ventricular decompression. Echocardiography showed severe biventricular dysfunction consistent with tachycardia-induced cardiomyopathy (TIC), and temporary atrial and ventricular pacing wires were inserted to manage and overdrive her arrhythmia. Despite extensive medical antiarrhythmic management and electrical cardioversion, her tachyarrhythmia recurred while on ECMO.
Management Challenges: TIC is a reversible disease caused by persistent tachyarrhythmias leading to LV dilatation and severely impaired cardiac function. In infants who cannot verbalize symptoms, signs of cardiac failure may only appear days after tachycardia onset. It is managed with anti-arrhythmic medication, cardioversion or catheter ablation. However, around 16% of children will require mechanical circulatory support via ECMO or BH-VAD, occasionally leading to heart transplantation. Although previous studies have reported myocardial recovery on ECMO support only, we decided to rapidly transition our patient towards Berlin Heart ventricular assist device (BH-VAD) support given that she had no significant recovery of the left ventricle and persistent arrhythmic episodes after 8 days on ECMO. Initially, tachyarrhythmias remained challenging to control despite pacemaker support and antiarrhythmic medical treatment. Her rhythm alternated between sinus and junctional patterns before eventually stabilizing several weeks later, coinciding with progressive left ventricular recovery. Given her sustained clinical and echocardiographic improvement, as well as myocardial perfusion imaging showing complete myocardial viability, the decision was made to defer heart transplantation and to proceed instead with a gradual weaning of BH-VAD support. Typically, BH-VAD is rarely used as a bridge to recovery. Yet, its management has improved throughout the years, resulting in a growing number of patients undergoing device explantation with good clinical outcomes. Given that the literature describing BH-VAD explantation criteria is very scarce, our strategy was to first control the arrhythmia before initiating weaning trials with the ACTION protocol over a four-week period. Following a 60-minute interval without VAD support, cardiac catheterization revealed normal cardiac output and wedge pressures (maximum 8 mmHg, corrected SvO₂ of 60%). Consequently, the BH-VAD was successfully explanted. The left ventricular apex and aortic cannula were removed, and the defect was repaired with a bovine pericardial patch. Cardiopulmonary bypass and cross-clamp times were 172 and 80 minutes, respectively. Postoperatively, her heart rate remained stable, and transthoracic echocardiography demonstrated preserved left ventricular dimensions and function (LVEF 66%) and normal systolic function. Inotropic support was gradually withdrawn. She was discharged home at the age of 7.5 months on flecainide, ivabradine, and propranolol after an ICU stay of 157 days. However, she was readmitted a few days later due to complete atrioventricular (AV) block with an ectopic ventricular rhythm (HR 40–45 bpm), which resolved after intravenous isoproterenol. The etiology remained uncertain. Her permanent pacemaker subsequently failed to capture, requiring surgical lead revision. In conclusion, BH-VAD is a reasonable option for mechanical circulatory support in pediatric patients with treatment-resistant TIC and may be successfully explanted with full cardiac function recovery and arrythmia control. Our report is, to our knowledge, the first to describe the use of BH-VAD as a bridge to recovery in an infant with TIC.
