Spanish registry of cardiac resynchronization therapy in adults with congenital heart disease (RETRACCA): clinical outcomes at one year follow-up

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Spanish Society of Cardiology Background There are limited data about the impact of cardiac resynchronization therapy (CRT) in adults with congenital heart disease (CHD) with conflicting results in patients (P) with systemic right ventricle (SRV). Objectives We analyzed the one-year outcomes of adults with CHD implanted with CRT and the impact of CRT in P with SRV as compared with systemic left ventricle (SLV). Methods Data were analyzed from the Spanish Registry of CRT in adults with CHD (RETRACCA). This is an observational, ambispective (66 % retrospective), multicenter Registry, including 74 adults with CHD implanted with a CRT device from 6 Spanish centers from 2007 to 2021. Ventricular function was assessed by echocardiography and graded on a four-point ordinal scale. Response to CRT was defined as an improvement in NYHA functional class and/or systemic ventricular ejection fraction by at least one category. In addition to changes in functional class and ventricular function, other outcomes analyzed included mortality, heart transplantation and CRT-related complications. Results 68 P completed one year of follow-up. Table 1 shows the baseline characteristics of the P prior to CRT. The two main indications for CRT were depressed systolic function of the systemic ventricle with more than 40 % ventricular pacing (69 %) and severely depressed systolic function of systemic ventricle, NYHA FC II-IV and QRS > 150 (18 %). Sixty percent of P received a CRT-ICD, whereas 40 % received a CRT-pacemaker. The approach for CRT system implantation was transvenous in 70 % of the patients, mixed in 21 % and fully epicardial in 9 %. Overall, 43 out of 68 patients (75 %) responded to CRT either by improvement of NYHA FC (56 %) and/or systemic ventricular function (41 %). Compared with baseline, CRT was associated with significant improvement in NYHA FC (p