Paradoxical contributions of non-compacted and compacted segments to global left ventricular dysfunction in isolated left ventricular noncompaction.

The pathophysiologic mechanisms of left ventricular (LV) dysfunction in isolated ventricular noncompaction (IVNC) remain unclear. Evaluating global and segmental systolic LV function in 65 patients with IVNC, this study found that normal wall motion was more common in noncompacted than in compacted segments. The number of noncompacted segments per patient correlated positively with the LV ejection fraction and negatively with LV end-diastolic volume index. These paradoxical findings support the concept that noncompaction represents a marker of a more generalized (cardio)myopathy rather than the direct pathophysiologic substrate of this still little-understood disease.