Thinning of compact layer and systolic dysfunction in isolated left ventricular non-compaction: A cardiac magnetic resonance study

BACKGROUND

The Petersen' index reflects an excess of myocardial trabeculation which is not a specific morpho-functional feature of left ventricular non-compaction (LVNC) cardiomyopathy, but a "phenotypic trait" even observed in association with other myocardial diseases and over-loading conditions. The present study was designed to evaluate the relation between a critical thinning of compact layer and the development of systolic dysfunction and LVNC cardiomyopathy.

METHODS

We compared CMR morpho-functional features and measurements of LV wall thickness using a 17 segment model of a cohort of patients fulfilling the Petersen criterion for LVNC with LV systolic dysfunction versus those of a cohort of age- and sex-matched controls with LVNC and preserved LV systolic function. All the study patients had an "isolated" LVNC defined as positive Petersen criterion in the absence of other diseases such as hypertrophic and dilated cardiomyopathy, valvular heart disease, or congenital heart disease and over-loading conditions.

RESULTS

he study population included 33 patients with "isolated" LVNC: 11 consecutive index patients with a reduced LV ejection fraction (LVNCrEF) and 22 controls with a preserved LVEF (LVNCpEF). The compact myocardial layer was thinner in patients with LVNCrEF than in those with LVNCpEF patients, both in mid-ventricular and apical LV segments. On linear regression analysis, there was a linear correlation between median thickness of mid-ventricular free wall segments and left ventricular ejection fraction (r = 0.51, p = 0.005). On the ROC curves analysis, ≥2 segments with a compact myocardial layer <5 mm in the free wall mid-ventricular segments showed the best accuracy for reduced LVEF (100% sensitivity and 60% specificity; AUC 0.81, p < 0.01). The negative predictive value for LV systolic dysfunction of <2 free wall mid ventricular segments <5 mm was 100%. On quantitative analysis, the mass of papillary muscles was lower in patients with LVNCrEF [1.2 (0.8-1.4) versus 1.6 (1.1-1.8) g/mq; p = 0.08].

CONCLUSIONS

A thinned compact layer of mid-ventricular segments of the LV free wall was associated with a reduced systolic function and "isolated" LVNC cardiomyopathy.

["Staghorn" heart. The pathology of the explanted heart of a patient with clinical diagnosis and genetic variants of non-compacted myocardiopathy]

Non-compacted myocardiopathy is rare, the prevalence ranging between 0.01-0.26%. in adults. We present the macroscopic, microscopic and electron microscopy findings of cardiac transplant samples from a 36-year-old patient diagnosed with non-compacted myocardiopathy. This condition shows a high genetic and phenotypic heterogeneity, with superposition of different phenotypes and variability in the hereditary patterns. Clinical diagnosis is established by coupling imaging results to clinical characteristics. The clinical manifestations of non-compacted myocardiopathy are variable, including arrhythmic events and variable degrees of cardiac failure, although some patients may be asymptomatic. In certain cases a heart transplant may be necessary. The differential diagnosis should be made with hypertrophic and dilated myocardiopathy. However, only a few reports can be found in the literature that discuss the pathology of this condition.