Background: The risk of adverse events in patients with left ventricular non-compaction cardiomyopathy (LVNC) is substantial. Information on prognostic factors, however, is limited. This study was designed to assess the prognostic value of right ventricular (RV) size and function in LVNC patients.

Methods: Cox regression analyses were used to determine the association of indexed RV end-diastolic area (RV-EDAI), indexed end-diastolic diameter (RV-EDDI), fractional area change (FAC), and tricuspid annular systolic excursion (TAPSE) with the occurrence of death or heart transplantation (composite endpoint).

Results: Out of 127 patients (53.2 ± 17.8 years; 61% males, median follow-up time was 7.7 years), 17 patients reached the endpoint. In a univariate analysis, RV-EDAI was the strongest predictor of outcome [HR 1.48 (1.24-1.77) per cm²/m²; p < 0.0001]. FAC was predictive as well [HR 1.44 (1.16-1.83) per 5% decrease; p = 0.0009], while TAPSE was not (p=ns). RV-EDAI remained an independent predictor in a bivariable analysis with indexed left ventricular ED volume [HR 1.41 (1.18-1.70) per cm²/m²; p = 0.0002], while analysis of FAC and left ventricular ejection fraction demonstrated that FAC was not independent [HR 1.20 (0.98-1.52); per 5% decrease; p = 0.0721]. RV-EDAI 11.5 cm²/m²was the best cut-off value for separating patients in terms of outcome. Patients with RV-EDAI >11.5 cm²/m²had a survival rate of 18.5% over 12 years as compared to 93.8% in patients with RV-EDAI <11.5 cm²/m²(p < 0.0001).

Conclusion: Increased end-diastolic RV size and decreased systolic RV function are predictors of adverse outcome in patients with LVNC. Patients with RV-EDAI >11.5 cm²/m²exhibit a significantly lower survival than those <11.5 cm²/m².