AUTHOR=Nederend Marieke , Jongbloed Monique R. M. , Kiès Philippine , Vliegen Hubert W. , Bouma Berto J. , Regeer Madelien V. , Koolbergen Dave R. , Hazekamp Mark G. , Schalij Martin J. , Egorova Anastasia D. 

TITLE=Atrioventricular Block Necessitating Chronic Ventricular Pacing After Tricuspid Valve Surgery in Patients With a Systemic Right Ventricle: Long-Term Follow-Up

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.870459

DOI=10.3389/fcvm.2022.870459

ISSN=2297-055X

ABSTRACT=Background 
Patients with transposition of the great arteries (TGA) after atrial switch or congenitally corrected TGA (ccTGA) are prone to systemic right ventricular (sRV) failure. Tricuspid valve (TV) regurgitation aggravates sRV dysfunction. Timely TV surgery stabilizes sRV function, yet development of atrioventricular (AV)-conduction disturbances in the course of sRV failure can contribute to sRV dysfunction through pacing-induced dyssynchrony. The aim of this study is to explore the incidence, timing and functional consequences of AV-block requiring ventricular pacing after TV surgery in sRV patients.
Methods
Consecutive adolescent and adult patients with an sRV who underwent TV surgery between 1989-2020 and follow-up at our center were included in this observational cohort study. 
Results
Data of 28 patients (53% female, 57% ccTGA, mean age at surgery 38±13 years) were analyzed. Mean follow-up was 9.7±6.8 years. Of the 22 patients at risk for high degree AV-block after surgery, 9 (41%) developed an indication for chronic ventricular pacing during follow-up, of whom 5 (56%) within 24 months postoperatively (3 prior to hospital discharge). 
QRS duration, a surrogate marker for dyssynchrony, was significantly higher in patients with chronic left ventricular pacing than in patients with native AV-conduction (217±24 vs 116±23 msec, p=0.000), as was the heart failure biomarker NT-pro-BNP (2746[1242–6879] vs 495[355–690] ng/L, p=0.004) and the percentage of patients with ≥1 echocardiographic class of deterioration of systolic sRV function (27 vs 83%, p=0.001). Of the patients receiving chronic subpulmonary ventricular pacing (n=12), 9 (75%) reached the composite endpoint of progressive heart failure (death, ventricular assist device implantation or upgrade to CRT). Only 4 (31%) patients with native AV-conduction (n=13) reached this composite endpoint (p=0.027). 
Conclusions
Patients with a failing sRV who undergo TV surgery are prone to develop AV-conduction abnormalities with 41% developing an indication for chronic ventricular pacing during 10 years of follow-up. Patients with chronic subpulmonary ventricular pacing have a significantly longer QRS complex duration, have higher levels of the heart failure biomarker NT-pro-BNP and are at a higher risk of deterioration of systolic sRV function and progressive heart failure.