left ventricular noncompaction cardiomyopathy ( lvnc ) is a very rare cardiomyopathy characterized by an increase in the noncompacted , trabeculated myocardium adjacent to compacted myocardium in the left ventricular ( lv ) .
though current research suggests a developmental arrest in embryogenesis as the underlying pathology , the etiology of lvnc are not fully understood .
the patients will often present with a spectrum of disease severity ranging from no symptoms to cardiac arrhythmias , cardiac failure , thromboembolism or even sudden cardiac death .
historically , lvnc has been diagnosed by echocardiography when the ratio of noncompacted to compacted myocardium is > 2 .
echocardiography may not visualize the apical region optimally , leading to underestimation of the degree of lv noncompaction .
however , cardiac magnetic resonance imaging ( cmri ) provides a comprehensive depiction of cardiac morphology in any imaging plane .
recent cmri reports suggest a ratio of the noncompacted myocardium to compacted myocardium of > 2.3 yield the highest sensitivity ( 86% ) and specificity ( 99% ) in diagnosis .
we present a case of lvnc in an adult patient with its clinical and imaging findings .
a 24-year - old female patient was initially referred to our vascular department for investigation of bilateral lymphedema .
her echocardiogram showed mildly impaired lv with evidence of segmental wall motion abnormality and hypertrabeculation in the apex suggestive of noncompaction .
the history of the patient started at birth when she had difficulty swallowing and several delayed milestones such as walking and talking at the age of 5 . due to socioeconomic issues
as the patient matured , there was an additional history of palpitations , which were occasionally associated with syncopal attacks .
lower limbs bilateral nonpitting edema up to the knees , proximal bilateral upper and lower limbs weakness with intact sensation , waddling gait , and easy fatigability with few steps were noted . computed tomography coronary angiogram was performed to exclude coronary artery disease .
results showed segmental wall motion abnormality and revealed normal coronaries , lv dilatation , and lateral wall and apical noncompaction with the noncompacted myocardium to compacted myocardium ratio in the range of 2.53.5 [ figure 1 ] .
her cmri showed mildly dilated lv with mild global hypokinesis and a marked decrease in longitudinal shortening .
end - diastolic volume was 120 ml , end - systolic volume was 61 ml and the ejection fraction was 50% .
in addition , multiple areas of noncompacted myocardium , particularly in the apex and most of the lateral wall extending from apical lateral wall to the mid - to - basal segment were seen .
the ratio of maximum thickness of the noncompacted myocardium to compacted myocardium was more than 2.5 in multiple areas [ figure 2 ] .
gated cardiac computed tomography scan was performed to evaluate the coronary arteries and showed patent coronary arteries of normal anatomy ( not shown ) .
axial image shows left ventricle lateral wall noncompaction with prominent trabeculation ( arrows ) noncompaction cardiomyopathy in a 24-year - old female .
a four chambers view dark blood using horizontal long axis t1 fast spin echo - magnetic resonance imaging .
( a ) apparent thickening of the left ventricle lateral wall ( arrows ) . a static image of four chamber view from cardiac magnetic resonance imaging cine , using the balanced steady state free precession technique .
( b ) shows mild dilatation of the left ventricle , prominent left ventricle wall trabecular network ( arrowheads ) and only a thin compacta ( arrows ) further investigation showed elevated creatine kinase and electromyography findings consistent with myopathy .
thus , the clinical impression was proximal myopathy mostly mitochondrial or congenital , congenital lymphedema , lv noncompaction with lv ejection fraction of 40% , and normal rv function .
as her lv impairment is mild , the decision was made to keep her on beta - blockers and on angiotensin - converting enzyme inhibitor in the form of metoprolol and lisinopril , respectively .
on subsequent follow - up visits , she reported a history of interval improvement apart of occasional palpitations with no history of shortness of breath , syncope or dizziness . she has been advised to do regular physiotherapy and to wear compressive stockings for her lymphedema .
bellet and gouley described the first case of noncompaction in an autopsy of a newborn infant with aortic atresia and coronary  ventricular fistula .
lvnc without other cardiac abnormalities ( isolated noncompaction cardiomyopathy ) was first described by an echocardiogram performed by engberding and bender .
historically , the prevalence of lvnc has been underestimated due to the lack of knowledge about this rare condition and its similarity to other diseases of the myocardium and endocardium .
a study of pediatric patients with primary cardiomyopathy showed that 9% of the patients had lvnc .
the median age at diagnosis of isolated noncompaction cardiomyopathy in the initial case series of isolated noncompaction was 7 years ranging from 11 months to 22 years .
the prevalence of lvnc in the adult population ranges between 0.01% and 0.3% of all adult patients referred for echocardiography studies .
these numbers are mostly extracted from the referred patient for abnormal echocardiographic findings or congestive heart failure ( hf ) . therefore , because of this potential selection bias , the true prevalence is not clear .
male patients are predominately affected accounting for 63% , 70% , and 74% of cases in three different reported series . in 2001 , jenni et al . evaluated seven patients with lv noncompaction with pathologic correlation ( four postmortem patients and three cardiac transplant patients ) .
histologic analysis demonstrated ischemic lesions in the thickened endocardium and thickened trabeculae with accompanying fibrosis .
clinical manifestations are highly variable , ranging from no symptoms to disabling congestive hf , arrhythmias , and systemic thromboemboli . according to a french registry , the diagnosis of lvnc diagnosis was confirmed in 105 cases through the use of echocardiogram performed in a laboratory between 2004 and 2006 . in that study ,
lvnc was first detected in 12 patients with rhythm disorders , 45 patients with hf symptoms , and eight patients through familial screening . during the follow - up study
, patients suffered several complications including hf occurring in 33 of the patients , ventricular arrhythmia in seven , embolic events in nine , and nine of the patients received heart transplantation while death occurred in 12 of the patients .
a swiss registry recorded a total of 34 cases over 15 years among a patient population who underwent echocardiogram . in this study ,
major complications included hf ( 53% ) , ventricular tachycardia ( 41% ) , thromboembolic events ( 24% ) , and death ( 35% ) .
six of the reported 12 deaths were sudden and four due to end - stage hf in four and the other two cases were due to unrelated causes .
the presented case had a family history of sudden death in two brothers , with one of them presumed to have an unknown type cardiomyopathy .
sporadic and familial forms of noncompaction have been described . in the original report of isolated noncompaction
ventricular cardiomyopathy that predominantly affected children , half of the patients had a familial recurrence .
however , a larger reported adult population with isolated noncompaction ventricular cardiomyopathy showed only 18% familial recurrence .
lower percentage compared with the earlier report might be attributed to incomplete screening of siblings in oechslin et al .
this patient has a progressive myopathy , which raised the question of other association with her left ventricular noncompaction cardiomyopathy .
about 82% of lv noncompaction cases were found to be associated with neuromuscular disorder including becker muscular dystrophy , metabolic myopathy , myotonic dystrophy , barth syndrome , and other rare genetic disorders .
the ratio of noncompacted myocardium to compacted myocardium at the end of systole is > 2:1 is the most often used echocardiographic criteria that were proposed by jenni et al .
the criteria also include presence of segmental thickening of the myocardial wall of the lv with two layers : prominent trabeculations and deep recesses with a thin epicardial layer and a thick endocardial layer .
the absence of coexisting cardiac abnormalities is required to fulfill the criteria . lv diastolic dysfunction , reduced global lv systolic function , abnormal structure of papillary muscles , and lv thrombi are nonspecific findings that can be seen on echocardiography . cardiac magnetic resonance ( cmr ) can be used in correlation with an echocardiogram to localize and quantify the extent of noncompaction .
cmr offers a detailed view of the cardiac morphology of the noncompacted myocardial layer in the lv in any image plane including the apical and lateral segments - segments , which are not well visualized by echocardiogram .
recent reports suggest that echocardiography diagnostic criteria are strict and mri enhances the detection of more subtle forms of noncompaction .
further , cmr identifies a higher rate of two - layered structures in segments such as the anterior , inferior , anterolateral , and inferolateral segments compared with echocardiogram . however , contraindication after implanted devices , cost and availability of cmr are considered barriers on the way of implementing cmr . according to the american heart association , 1.5
tesla is the minimum acceptable magnet strength to perform cardiac imaging in order to be able to visualize both short and long axis views in approximately 17 segments . acquiring three diastolic long axis views best identifies the nc / c ratio of the most prominent myocardial trabeculations segment .
the nc / c ratio in cmr is measured at the end of diastole and should be more than 2.3 , more than echocardiography , which is 2.1 .
stagnant blood flow , within the myocardial trabeculae may be detracted as a high signal in cmr black blood imaging , supporting the diagnosis lvnc .
the efficacy of cmr was evaluated in a report of seven patients with lvnc in whom other features supported the diagnosis ; the results were compared with 170 healthy volunteers , athletes , or patients with dilated cardiomyopathy or hypertrophic cardiomyopathy , aortic stenosis , and hypertensive heart disease .
the most distinguishing feature was a ratio of noncompacted to compacted myocardium during diastole ( sensitivity 86% and specificity 99% ) .
direct imaging of myocardial fibrosis is possible with the use of an inversion recovery prepared t1-weighted gradient - echo sequence and the extracellular fluid tracer gadopentetate dimeglumine .
this technique has been termed  delayed hyperenhancement  and shows nonviable tissue as hyperenhanced or bright .
nevertheless , the early and precise diagnosis is mandatory to rule out other underlying diagnoses and to allow a timely start of standard hf and anticoagulation therapy , thus preventing further complications .
some trabeculae show delayed hyperenhancement despite having a normal compacted to noncompacted myocardial ratio , suggesting that lv noncompaction may be a more diffuse disease process than previously suspected .
the use of delayed hyperenhancement sequences improves the correlation between cmri and the parameters of the clinical stage of the disease .
cmri follow - up examinations would be helpful to assess a potential change of noncompacted or compacted mass in a chronological sequence . in conclusion
, cmr can distinguish lvnc from other cardiomyopathies and normal hearts with high sensitivity and specificity .
 left ventricular noncompaction cardiomyopathy is a very rare condition , yet believed to be often overlooked . 
 it is thought to be caused by the developmental arrest in embryogenesis and characterized by an increase in the noncompacted , trabeculated myocardium adjacent to compacted myocardium in the left ventricular . 
 the clinical presentations of this type of cardiomyopathy are of variable severity . 
 echocardiography used to be the diagnostic modality , but recent reports suggest that cardiac magnetic resonance imaging has higher sensitivity and specificity by showing a ratio of the noncompacted myocardium to compacted myocardium of > 2.3 . 