Introduction of transcatheter edge-to-edge repair in patients with congenital heart disease at a children's hospital.

BACKGROUND: Atrioventricular valve regurgitation (AVVR) is a devastating complication in children and young adults with congenital heart disease (CHD), particularly in patients with single ventricle physiology. Transcatheter edge-to-edge repair (TEER) is a rapidly expanding, minimally invasive option for the treatment of AVVR in adults that avoids the morbidity and mortality associated with open heart surgery. However, application of TEER in in CHD and in children is quite novel. We describe the development of a peri-procedural protocol including image-derived pre-intervention simulation, with successful application to four patients. AIMS: To describe the initial experience using the MitraClip system for TEER of dysfunctional systemic atrioventricular valves in patients with congential heart disease within a pediatric hospital. METHODS: A standardized screening and planning process was developed using cardiac magnetic resonance imaging, three dimensional echocardiography and both virtual and physical simulation. Procedures were performed using the MitraClip G4 system and patients were clinically followed post-intervention. RESULTS: A series of four CHD patients with at least severe AVVR were screened for suitability for TEER with the MitraClip system: three patients had single ventricle physiology and Fontan palliation, and one had repair of a common atrioventricular canal defect. Each patient had at least severe systemic AVVR and was considered at prohibitively high risk for surgical repair. Each patient underwent a standardized preprocedural screening protocol and image-derived modeling followed by the TEER procedure with successful clip placement at the intended location in all cases. CONCLUSIONS: The early results of our protocolized efforts to introduce TEER repair of severe AV valve regurgitation with MitraClip into the CHD population within our institution are encouraging. Further investigations of the use of TEER in this challenging population are warranted.

Long term follow-up after ventricular tachycardia ablation in patients with congenital heart disease.

BACKGROUND: Ventricular tachycardia (VT) is frequently encountered in patients with repaired and unrepaired congenital heart disease (CHD), causing significant morbidity and sudden cardiac death. Data regarding underlying VT mechanisms and optimal ablation strategies in these patients remain limited. OBJECTIVE: To describe the electrophysiologic mechanisms, ablation strategies, and long-term outcomes in patients with CHD undergoing VT ablation. METHODS: Forty-eight patients (mean age 41.3 ± 13.3 years, 77.1% male) with CHD underwent a total of 57 VT ablation procedures at two centers from 2000 to 2017. Electrophysiologic and follow-up data were analyzed. RESULTS: Of the 77 different VTs induced at initial or repeat ablation, the underlying mechanism in 62 (81.0%) was due to scar-related re-entry; the remaining included four His-Purkinje system-related macrore-entry VTs and focal VTs mainly originating from the outflow tract region (8 of 11, 72.7%). VT-free survival after a single procedure was 72.9% (35 of 48) at a median follow-up of 53 months. VT-free survival after multiple procedures was 85.4% (41 of 48) at a median follow-up of 52 months. There were no major complications. Three patients died during the follow-up period from nonarrhythmic causes, including heart failure and cardiac surgery complication. CONCLUSION: While scar-related re-entry is the most common VT mechanism in patients with CHD, importantly, nonscar-related VT may also be present. In experienced tertiary care centers, ablation of both scar-related and nonscar-related VT in patients with CHD is safe, feasible, and effective over long-term follow-up.

Improvement in ventricular function with rhythm control of atrial arrhythmias may delay the need for atrioventricular valve surgery in adults with congenital heart disease.

OBJECTIVE: Atrial arrhythmias and atrioventricular valve regurgitation (AVVR) are common causes of morbidity among adults with congenital heart disease (ACHD). The impact of rhythm control on AVVR in this population is unknown. We sought to determine whether a rhythm control strategy is associated with greater freedom from AV valve surgery than a rate control strategy. DESIGN: Patients evaluated by both ACHD and electrophysiology specialists at a single academic center were screened for atrial arrhythmias and at least moderate-severe AVVR. Clinical and electrographic data were abstracted. All echocardiograms were interpreted by a single echocardiographer blinded to treatment strategy. Patients were followed until AV valve surgery, heart transplantation, death, or last clinical follow-up. RESULTS: Rhythm control was attempted in 9 of 24 identified patients. Among these nine patients, arrhythmias were eliminated in three and reduced from persistent to paroxysmal in another three. In the rhythm control group, mean left ventricular ejection fraction improved from 54.4 ± 12.4% to 60.0 ± 11.5% (P = .02) and mean right ventricular systolic function increased nearly one grade (P = .02). AVVR did not decrease significantly. No significant change in left or right ventricular systolic function, or AVVR was observed among the 15 patients treated with rate control. Four-year survival free of AV valve operation and heart transplant was 88% in the rhythm control group and 31% in the rate control group (P = .04). CONCLUSIONS: In ACHD patients with atrial arrhythmias and at least moderate-severe AVVR, a rhythm control strategy was associated with improved biventricular systolic function. This improvement in ventricular function and symptoms may allow valve surgery to be deferred.