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despite the large number of studies about left ventricular noncompaction ( lvnc ) , many uncertainties exist .
echocardiography is accepted as the method of choice for lvnc diagnosis . magnetic resonance imaging ( mri )
was used extensively for this purpose as well ; however , artifacts from arrhythmias or breathing and higher cost are its disadvantages .
large areas of hypertrabeculation ( ht ) can be seen in many diseases including dilated cardiomyopathy ( dcmp ) and even in normal subjects .
it is not known whether this hypertrabeculation is a milder form of noncompaction ( nc ) or a different pathology .
three sets of echocardiographic criteria proposed by chin , jenni , and stllberger developed to differentiate lvnc from other diseases . in spite of the existing criteria
this problem may result from the nature of these criteria which depends on the finding of an area with maximal nc , or the number of ht / nc areas in lv .
failure to find the area with maximal nc or all ht / nc areas may result in a misdiagnosis .
measuring the percentage of hypertrabeculated or noncompacted myocardium ( ht / nc% ) may decrease misdiagnosis .
we introduce a method for this measurement by echocardiography and examined it on a cohort of patients with lvnc cardiomyopathy , dcmp , and normal subjects . in order to create a 3-dimensional concept
from september 2009 to june 2011 targeted subjects for this study were enrolled . all children with a diagnosis of dilated or lvnc cardiomyopathy admitted at our hospital or referred to our outpatient clinics
were included and a control group of healthy subjects were also selected in a convenient method . for lvnc cardiomyopathy patients , the study period extended to june 2012 due to the small number of patients . a noncompacted to compacted myocardial
dcmp was diagnosed when a patient had left ventricular ejection fraction ( lvef ) less than 50% ( present or past ) and disease duration of at least 3 months .
the control group consisted of age - matched children referred to our outpatient clinics , with a final diagnosis of innocent murmur or non - cardiac chest pain and normal echocardiogram .
two dcm patients with poor echocardiographic windows were excluded from the study . after obtaining informed consent from the parents , all study subjects were echocardiographically investigated by a single echocardiographer using a single echocardiographic scanner ( micromaxx ultrasound system , sonosite inc .
the main reason for using this scanner was its portability which permitted us to study subjects in both the intensive care unit and outpatient clinics .
echocardiographic parameters including left ventricular ejection fraction ( lvef ) , left ventricular fractional shortening ( lvfs ) , and left ventricular myocardial performance index ( lvmpi ) were obtained .
the nc / c ratio during systole was measured as described by jenni et al .
the ht / nc% was defined as the mean percentages of ht / nc myocardium at three levels : apical , papillary muscles , and mitral valve . at each level ,
short axis view at systole was obtained and three areas were measured : whole myocardium and lv cavity ( a ) , area encompassing only ht / nc myocardium and lv cavity ( b ) , and only lv cavity ( c ) ( fig .
the ht / nc% at each level was calculated by using the following formula : % ht - nc = 100  ( b - c)/(a - c ) the parameters required to calculate the percentage of hypertrabeculated / noncompacted myocardium .
the numbers 1 , 2 , and 3 refer to the apical , papillary muscle and mitral valve levels , respectively the apical level was defined when a small amount of lv cavity can be seen to precisely measure all desired areas ( fig .
1 ) . the papillary muscle level was defined when these muscles were first viewed when sweeping echocardiography probe from the apex toward the cardiac base .
maximal care was undertaken not to include papillary muscles , aberrant chordae tendineae and lv bands in the ht / nc areas .
the study was accepted by the ethical committee board of tehran university of medical sciences and in accordance with good clinical practice and the declaration of helsinki .
descriptive statistics such as mean , standard deviation ( expressed after  ) , and frequency were calculated for each variable .
independent - sample t , chi - square , and pearson correlation tests were used for the statistical analyses .
twenty six patients with dcmp , 4 with lvnc cardiomyopathy and 25 normal subjects were enrolled in the study .
there was no statistically significant difference regarding the sex , age , weight , and body surface area between dcmp and control groups ( table 1 ) . 
  demographic and basic echocardiographic data in three groups * nc / c , noncompacted to compacted myocardial thickness ; dcmp , dilated cardiomyopathy , lvnc , left ventricular noncompaction comparing the averages in dcmp and control groups patients with dcmp had statistically lower ef , fs , mpi , and higher nc / c ratio in comparison to the normal subjects ( table 1 ) .
the%ht / nc% at all 3 levels and its average were significantly higher in the dcmp group than in the normal subjects ( table 2 ) .
the ht / nc% was significantly correlated with the nc / c ratio ( correlation coefficient = 0.543 , p<0.001 ) . 
 
left ventricular hypertrabeculation / noncompaction percentage at three different levels in the left ventricle sd : standard deviation ; dcmp : dilated cardiomyopathy ; lvnc : left ventricular noncompaction comparing the averages in dcmp and control groups
lvnc was accepted as a distinct type of cardiomyopathy by the world health organization . however , there are many controversies regarding its etiology , pathogenesis , diagnosis , and management .
the diagnosis is especially important because the prognosis and management of lvnc differ from those of its differential diagnoses .
the chin criteria was first described and based on x - to - y ratios at 3 levels ( mitral valve , papillary muscle , and apex ) .
x corresponds to the distance between the epicardial surface and trough of a trabecular recess , while y to the distance between the epicardial surface and peak of the trabeculation .
the measurements should be performed at end diastole and a ratio up to 0.5 is required for the diagnosis of lvnc .
the jenni criterion postulates a systolic ratio of nc myocardial thickness to the adjacent compacted myocardium of more than 2 at the thickest part of myocardium , confirmation of blood flow in the recesses , absence of any cardiac abnormality , and the presence of characteristic trabeculations and deep recesses between the trabeculations .
pignatelli et al suggested that a ratio of at least 1.4 is sufficient for the diagnosis of lvnc in children .
jenni criterion is the most accepted among these three sets and used for the diagnosis of lvnc in this study .
the stllberger criteria require the presence of at least 4 trabeculations distal to the papillary muscles at one plane and intertrabecular spaces filled from the ventricular cavity .
definite diagnosis is present when the patients fulfill both jenni and stllberger sets of criteria , while probable corresponds to the fulfillment of just one , and possible to the situation where the number of trabeculations is less than 4 or the nc / c ratio is lower than two .
kohli et al studied a cohort with heart failure and investigated all these 3 sets of diagnostic criteria .
, 78.7% met the chin criterion , 63.8% the jenni criterion , and 53.2% the stllberger criteria .
only one set of criteria was fulfilled by 36.2% of the patients , while only 29.8% met all sets .
only 3 out of these 8 patients were diagnosed accurately by 2-dimensional echocardiography using jenni criterion .
the idea of lvnc quantification by area measurement was first introduced by belanger et al .
we introduced a new method for the quantification of ht / nc of lv and examined it on patients with dcmp , lvnc cardiomyopathy and normal subjects .
the echocardiographer should investigate at least 3 levels in the myocardium and the result is based on an average rather than the areas of maximal involvement .
we showed that this ht / nc% is well correlated with a carefully measured maximal nc / c ratio .
petersen et al measured the nc / c ratio during diastole and showed that a value greater than 2.3 could be 86% sensitive and 99% specific for the diagnosis of lvnc .
alhabshan et al measured the end - systolic nc / c ratio by both mri and echocardiography .
they found that mri can found a higher nc / c ratio than echocardiography in some subjects .
they found a diastolic value of 22% in their unique lvnc patient and a mean of 11.3% ( range 1.5 - 19 ) in 10 dcm patients .
fernndez - golfin et al studied the same method on a larger cohort of ischemic heart disease , dcm , valvular heart disease , and left ventricular hypertrophy patients , and normal subjects .
they found relatively higher values in their patients ( 17.24.9 in normal subjects , 23.36 in dcm patients ) .
they studied patients with lvnc , dcm , hypertrophic cardiomyopathy ( hcm ) , and normal subjects they found that mean percentages were 3210 in lvnc , 114 in dcm , 124 in hcm , and 125 in controls .
they reported that a percentage of more than 20% can be 93.7% specific and similarly sensitive to predict the presence of lvnc .
in our cohort , only two dcmp subjects had a percentage higher than 17% while our 4 lvnc patients had values of 73 , 24 , 17 , and 24% .
this means that the threshold value of 17% can distinguish lvnc from dcmp with 92% specificity and 100% sensitivity and from normal subjects with 100% specificity and sensitivity .
color doppler echocardiography confirmation of direct blood flow from the ventricular cavity into deep intertrabecular recesses seems to be necessary for the diagnosis of lvnc , as it is a unique feature of this disease .
our suggested echocardiographic threshold value of 17% is very close to the mri threshold of 20% which was suggested by jaquier et al , and korcyk et al . in summary ,
our suggested method is the echocardiographic equivalent of mri ht / nc% measurement while the jenni criterion is the equivalent of mri nc / c ratio measurement .
second , the study was performed in a pediatric setting ; therefore , this method was not examined on adult patients .
in addition , it was impossible to blind the echocardiographer to the diagnosis of the studied subjects .
although the echocardiographer tried his best , there may be some bias in the echocardiographic measurements .
second , the study was performed in a pediatric setting ; therefore , this method was not examined on adult patients .
in addition , it was impossible to blind the echocardiographer to the diagnosis of the studied subjects .
although the echocardiographer tried his best , there may be some bias in the echocardiographic measurements .
we introduced a new echocardiographic method to measure ht / nc% and tested it on patients with dcm or lvnc , and normal subjects .
we showed that the percentage had a statistically significant correlation with the noncompacted to compacted lv ratio .
objectivealthough there are several echocardiographic criteria , there is not yet a general consensus about the diagnosis of left ventricular noncompaction . 
 the current criteria are mostly based on the areas with maximal noncompaction in the heart . 
 the echocardiographer may miss this maximal point leading to a misdiagnosis . 
 accordingly , we suggested a new method to measure the percentage of myocardial noncompaction using two - dimensional echocardiography.methodsin this study , the new method was examined on 4 noncompaction and 26 dilated cardiomyopathies , and 25 normal subjects . 
 the percentage of noncompaction was measured at 3 levels ( apical , papillary muscle and mitral valve ) and averaged.findingsthe mean percentages of myocardial noncompaction were 3.592.27 , 8.865.52 and 34.726.1 in the control , dilated cardiomyopathy and noncompaction groups , respectively 
 . a value of 17% or greater could distinguish left ventricular noncompaction from dilated cardiomyopathy with 92% specificity and 100% sensitivity and from normal subjects with 100% specificity and sensitivity . 
 this percentage had a statistically significant association with noncompacted to compacted myocardial thickness ratio ( p<0.001).conclusionthis method showed good correlations with the existing echocardiographic and magnetic resonance criteria . 
 however , it is not dependent on finding the area of maximal involvement . 
 being comparable to magnetic resonance imaging in accuracy , it is easier to perform and more available .