Cardiac resynchronization therapy in adult patients with repaired tetralogy of fallot and left ventricular systolic dysfunction.

BACKGROUND: Although left ventricular (LV) systolic dysfunction is known to occur in adults with repaired Tetralogy of Fallot (TOF), the effects of cardiac resynchronization therapy (CRT) are not well characterized.
METHODS: We retrospectively divided all patients with repaired TOF and impaired LV ejection fraction (LVEF ≤ 40%) undergoing CRT at our institution (n = 10) into two groups: de novo CRT (group A, n = 6) or upgrade from existing device (group B, n = 4). Echocardiograms were reviewed at baseline, medium-term (>6 months post-CRT), and long-term follow-up. CRT response was defined as reduction in LV end-systolic volume (LVESV) ≥15% at medium term.
RESULTS: Age at surgical repair was 13.1 ± 16.0 years, age at CRT was 44.4 ± 12.5 years, and baseline LVEF was 24.0 ± 10.5%. Group A demonstrated a preponderance of right ventricular (RV) conduction delay, whereas all patients in group B demonstrated RV pacing at baseline. At medium-term follow-up, patients in group A showed significant improvements in LVEF, LV end-diastolic volume (LVEDV), and LVESV. Group B also demonstrated a significant improvement in LVEF with favorable trends in LV volumes. Of nine patients with complete data at medium term, eight showed evidence of CRT response. Average long-term follow-up was 53.4 ± 29.3 months. At long-term follow-up, LVEF, LVEDV, and LVESV remained numerically better than baseline, although the results were no longer significant.
CONCLUSIONS: Adult patients with repaired TOF and LV systolic dysfunction demonstrate significant medium-term response to CRT, even among those with RV conduction delay. The long-term impact of CRT in this population requires further characterization. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.