Right Ventricular Morphology and Systolic Function in Left Ventricular Noncompaction Cardiomyopathy

Abstract

The distinction between normal right ventricular (RV) trabeculations from abnormal has been difficult. We evaluated whether RV volume and function are related to left ventricular (LV) noncompaction (NC) cardiomyopathy and clinical events. Trabeculations or possible LVNC by cardiac magnetic resonance imaging was retrospectively observed among 105 consecutive cases. We measured LV end-systolic (ES) noncompacted-to-compacted ratio, RV ejection fraction (EF), RV apical trabecular thickness, and RV end-diastolic (ED) noncompacted-to-compacted ratio. A control group of 40 subjects was also reviewed to assess the exploratory measures. Comparing those with LVES noncompacted-to-compacted ratio ≥2, those with LVES noncompacted-to-compacted ratio <2, and the normal control group, adjusted means for RV apical trabecular thickness and RVED noncompacted-to-compacted ratio were generated. Logistic regression was used to evaluate the association of composite events traditionally associated with LVNC with RVEF after adjustment for aforementioned covariates, cardiovascular risk factors, delayed enhancement, LVEF, and LVES noncompacted-to-compacted ratio. Analysis of RV morphology found greater apical trabecular thickness among those with LVES noncompacted-to-compacted ratio ≥2 compared with those with LVES noncompacted-to-compacted ratio <2 or normal control group (31 ± 5 vs 27 ± 2.6 vs 22 ± 4 mm; p = 0.03 and p = 0.003, respectively). There was no difference between the groups in relation to the RVED noncompacted-to-compacted ratio. Low RVEF and LVES noncompacted-to-compacted ratio ≥2 had significant association with clinical events in this population even after adjusting for clinical and imaging parameters (p = 0.04 and p <0.001, respectively). In conclusion, RV dysfunction in a morphologic LVNC population is strongly associated with adverse clinical events. LVNC is associated with increased trabeculations of the RV apex.