Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy

Aim-To determine clear cut echo cardiographic criteria for isolated ventric ular non-compaction (IVNC), a cardiomyopathy as yet "unclassified" by the W orld Health Organization. The disease is not widely known and its diagnosis mostly missed. Methods and results-In seven out of a series of 34 patients with IVNC the i n vivo echocardiographic characteristics were validated against the anatomi cal examination of the heart removed after death in four and due to heart t ransplantation in three patients. Four morphological criteria diagnostic fo r IVNC were found. (1) Coexisting cardiac abnormalities were absent (by def inition). (2) A two layer structure was seen, with a compacted thin epicard ial band and a much thicker non-compacted endocardial layer of trabecular m eshwork with deep endomyocardial spaces. A maximal end systolic ratio of no n-compacted to compacted layers of > 2 is diagnostic. (3) The predominant l ocalisation of the pathology was to mid-lateral (seven of seven patients), apical (six), and mid-inferior (seven) areas. The pathological preparations confirmed the echocardiographic findings. Concomitant regional hypokinesia was not confined to the non-compacted segments. (4) There was colour Doppl er evidence of deep perfused intertrabecular recesses. Conclusions-Four clear cut echo cardiographic diagnostic criteria were esta blished. It is suggested that the WHO classification of cardiomyopathies be reconsidered to include IVNC as a distinct cardiomyopathy.