Left ventricular non-compaction cardiomyopathy in adults – characterisation by cardiac magnetic resonance imaging

Introduction

Left ventricular non-compaction (LVNC) is a congenital cardiomyopathy characterised by left ventricular hypertrabecularisation and thinning of the compacted myocardial layer. Due to its high spatial resolution and precise delineation of the non-compacted layer, cardiac magnetic resonance imaging (cMRI) is a promising method to image and diagnose LVNC cardiomyopathy.

Methods

In 19 patients who underwent cMRI for suspected cardiomyopathy LVNC was diagnosed according to diagnostic criteria such as a ratio of non-compacted to compacted myocardium (NC/C-ratio) of >2.3 in diastole [1] and exclusion of other underlying cardiac pathology or cardiovascular risk factors. We performed cMRI using a clinical 1.5 Tesla scanner (Philips Achieva). Left ventricular (LV) function, dimensions and volumes were assessed using steady-state free precession cine imaging. The NC/C-ratio was assessed in the lateral LV wall in an apical, midventricular and basal short-axis slice. Additionally, delayed contrast enhancement (DCE) imaging was performed.

Results

Of the 19 patients, 6 were women (32%), the mean age was 41.7 ± 16.8 years. Over the whole study group, LV function was impaired with a mean ejection fraction of 41 ± 17%. However, LV ejection fraction was normal in 6 patients (32%). LV volumes were increased with a mean enddiastolic volume of 247 ± 100 ml and a mean endsystolic volume of 155 ± 99 ml, resulting in mean stroke volume of 92 ± 31 ml. Using the 17-segment model, we found a mean number of 11.8 ± 2.6 segments to be affected by LVNC with the typical predomination of the apical segments and the free lateral LV wall. The mean NC/C-ratio was 5.0 ± 1.6 in the apical lateral wall, 3.3 ± 0.7 in the midventricular lateral LV wall and 2.0 ± 1.1 in the basal lateral wall; the basal septum was involved in none of the patients.

DCE was present in 7 patients (37%); in all patients non-ischemic type DCE with an intramural or spotted enhancement pattern and a predilection for the inferior right ventricular insertion zone was observed.

Conclusion

We characterised 19 patients with LVNC cardiomyopathy by cMRI. We observed an impaired LV function in the study cohort along with a dilatation of the left ventricle. The mean number of affected segments was 12 of 17. Apical and lateral segments were most frequently affected. Accordingly, the NC/C-ratio decreased from the apical to the basal segments. Non-ischemic type DCE was observed in 37% of patients.