left ventricular noncompaction ( lvnc ) is a rare primary congenital cardiomyopathy arising from intrauterine arrest of myocardial compaction .
it results in persistent prominent ventricular trabeculations and deep intertrabecular recesses and is characterized morphologically by 2 layers i.e. , thin compacted epicardial layer and thickened noncompacted endocardial layer.1 ) the prevalence of lvnc is approximately 0.05%-0.24% in the general population according to echocardiography , the diagnostic tool of lvnc.2 ) the etiology of lvnc is unidentified ; however , possible linkage between the disease and various genetic background is recently suspected.3 ) diverse clinical manifestations previously reported range from no symptom to the development of heart failure , arrhythmias , systemic embolic events or sudden cardiac deaths.3 ) interestingly , several abnormal electrocardiograms ( ecgs ) were reported in lvnc patients but none had the feature of left atrial ( la ) standstill imitating atrioventricular ( av ) nodal block .
we described a 29-year - old man who presented with a symptom of cerebrovascular accident ( cva ) and concomitant asymptomatic lvnc and la standstill .
a 29-year - old man with the history of stroke was transferred from a local medical center to determine whether he should receive pacemaker insertion due to abnormal ecg findings . at first , he was admitted to a local clinic with dysarthria a month prior to the transfer , and was diagnosed as left middle cerebral artery territory infarction .
his brain magnetic resonance imaging ( mri ) demonstrated multiple cortical infarcts implying embolic origin ( fig .
1 ) . magnetic resonance angiography findings showed no evidence of pathologic stenosis or atheroma of the neck and head arteries .
asymptomatic bradycardia was shown on the local ecg with 2:1 av block reported on local holter monitoring ( seer light , ge medical , usa ) .
there was neither specific family history nor past history of specific diseases except the recent stoke .
the initial ecg obtained after transfer showed bradycardia ( 55 beats / min ) , pr prolongation followed by av block characteristic of second degree av block , mobitz type 1 with left axis deviation and poor r wave progression ( fig .
the patient 's vital signs were as follows : blood pressure , 120/80 mmhg ; heart rate , 49 beats / min ; respiratory rate , 20 breaths / min ; temperature , 36.7. he had white blood cell count 802010/l ( neutrophil 68.5% ) ; hemoglobin , 15.1 g / dl ; platelet count , 202000/l ; and serum c - reactive protein , 0.42 mg / dl .
additionally , serum electrolyte , serum creatine kinase - myocardial band , serum troponin i level and n - terminal pro b - type natriuretic peptide were within normal range .
treadmill test was performed for the evaluation of a chronotrophic response ; however , the patient 's maximum heart rate observed during bruce protocol stage 3 was 117 beats / min without reaching the target heart rate of 163 beat / min .
transthoracic echocardiography demonstrated a loss of a wave mimicking atrial fibrillation with peak e wave velocity of 59.72 cm / sec and deceleration time of 183 msec .
global left ventricular ( lv ) ejection fraction was 67% with e / e ' of 5.24 implying normal lv systolic function and filling pressure .
end diastolic diameters of each ventricle were within normal ranges i.e. 51.80 mm on the left and 33.10 mm on the right ventricle .
contrast echocardiography showed flow communication between multiple intertrabecular recesses and lv cavity with noncompacted / compacted ratio of approximately 3:1 ( fig .
3b ) . cardiac mri demonstrated prominent trabeculations and deep intertrabecular recesses with thinner compact epicardial layer of the lv characteristic of lvnc ( fig .
4 ) . mild spontaneous echo contrast in la appendage without definite thrombi and decreased mean la appendage flow velocity of 19.93 cm / sec were observed on transesophageal echocardiography with no definite atherosclerotic change from the aortic arch to thoracic aorta .
eletrophysiologic ( ep ) test was performed to evaluate the cause of arrhythmia and to determine pacemaker insertion .
5a ) ; interestingly , although there was 1:1 av relationship during pacing from high right atrium ( ra ) , there was no atrial signal on coronary sinus ( cs ) bipole with no correlation between atrial and ventricular signal while pacing from ra appendage that implied absence of electrical activity of la on ep study ( fig .
for further corroboration of the results , we carried out an additional ep study using 3 dimensional voltage mapping ( fig .
the map showed no voltage signal of the entire la , septum and body of ra , which explained the capture failure during pacing of ra septum and la .
based on the prior results , we decided to initiate warfarinzation keeping in mind permanent pacemaker insertion ; however , we could not perform the procedure due to the patients ' refusal .
he was discharged from hospital and remained asymptomatic without further complication until the latest follow up visit .
we reported a case of a young male patient with concomitant lv noncompaction and la standstill that has not been reported before .
the etiology of cva in this case can be explained by 2 conditions : firstly , the noncompaction itself as a complication ; and secondly , low velocity in the la appendage .
lvnc was first described as " spongy myocardium " in 1975 by dusek et al.4 ) and is characterized by morphological abnormality of prominent trabeculae representing " persistent sinusoids " and myocardial wall thickening ; the new term " isolated non - compaction of lv myocardium " was introduced by chin et al.5 ) in 1990 emphasizing deep recesses communicating with the cavity of lv and absence of other cardiac deformities .
although it is defined as a primary cardiomyopathy by the american heart association , it still remains as a " unclassified " cardiomyopathy according to the world health organization.6 ) the etiologies of isolated lvnc are yet obscure , though several genetic mechanisms that might be involved in the arrest of myocardial development during embryogenesis were recently suggested.3 ) the various clinical manifestations of lvnc reportedly include congestive heart failure , systemic embolic events , and arrhythmias .
the degree of symptoms usually depends on the grade of noncompaction and ventricular function.3 ) two representative methods used for the diagnosis of lvnc are echocardiography and cardiovascular magnetic resonance ( cmr ) .
generally , the diagnosis of lvnc largely depends on 2 dimensional/3 dimensional echocardiography , with or without contrast echocardiography due to cost - effectiveness .
we applied 3 different echocardiographic diagnostic criteria by chin et al.,5 ) jenni et al.,7 ) and stllberger et al.8 ) based on parameters of ventricular morphology , although there is no officially established diagnostic criterion ; therefore , multimodal imaging approach inevitably improves diagnostic accuracy . in case of low echocardiographic image quality
, cmr shows better signal to noise ratio , contrast to noise ratio , unlimited imaging planes and ability to use tissue characterization .
there are 2 cmr criteria proposed by petersen et al.9 ) and jacquier et al.,10 ) either using the ratio of noncompact / compact myocardium depth ( > 2.3 ) or trabecular mass ( > 20% ) .
management of lvnc focuses on standard medical therapy for systolic and diastolic ventricular dysfunction and prevention of systemic embolic events.3 ) we applied warfarin for the prevention and treatment of cva .
there is controversy regarding cardioverter - defibrillator ( implantable cardioverter - defibrillator ) implantation in patients with lvnc but should be considered as primary prevention in high risk patients ; alternatively , cardiac transplantation can be considered in these patients.11 ) once lvnc is diagnosed , family screening of first degree relatives is recommended.3 ) the prognosis of lvnc is still controversial .
initial reports showed very poor prognosis in patients with lvnc ; however , recent studies supported a better prognosis.6)12 ) one study showed 15% mortality among lvnc patients during a mean 30 month follow - up.12 ) previously reviewed studies and case reports indicate various ecg findings among the lvnc patients ; for example , normal ecg , atrial fibrillation , bundle branch block , qt interval prolongation , left ventricular hypertrophy , av block , and repolarization abnormality.13 ) there were several cases of both atrial standstill in lvnc patients ; however , our patient showed isolated la standstill that has not been reported previously in lvnc patients .
atrial standstill is an uncommon arrthymia characterized by the absence of electrical and mechanical activity in the atrium.14 ) on egc , atrial standstill is distinguished by the absence of p waves with bradycardia and narrow junctional escape rhythm.14 ) known etiologies of atrial standstill are electrolyte imbalance , familial cause , cardiomyopathies , valvular disease , muscular dystrophy and toxicity of antiarrhythmic agents.15 ) several types of atrial standstill were previously described ; the more frequent transient type , the rare persistent type and total or partial types.15 ) recently , familial atrial standstill was reported in several studies showing tendency of sudden cardiac death with higher probability of cardiomyopathies at a young age .
the genetic causes of familial type are still obscure ; however , cardiac sodium channel gene scn5a was identified as a related gene mutation.16 ) the study patient showed features of isolated la standstill demonstrating electrical silence in the la that is isolated from partially electrically active ra .
isolated la standstill is extremely rare ; it has previously been reported in severe mitral valvular stenosis , dilated cardiomyopathy or following la ablation.15 ) however , none of the possible factors was found in our patient , thus raising the question whether the abnormal ecg finding was correlated with lvnc or occurred independently .
the ep study demonstrated complete electrical block between ra and la , showing no atrial conduction impulse in the cs bipole with no electrical activity in la , which supported la thrombus formation as the etiology of cva . in conclusion , both lvnc and la standstill have risks of embolic events . while the connection between these 2 conditions is still ambiguous , coagulation is a certainty .
here we reported a case of a young man who had lvnc combined with la standstill with cva sequel without any cardiac symptoms .
 isolated left ventricular noncompaction ( lvnc ) is a rare cardiomyopathy with morphologic characteristics of two distinct myocardial layers i.e. , thin compacted epicardial and thick noncompacted endocardial layers . 
 the noncompacted myocardium consists of prominent ventricular trabeculae and deep intertrabecular recesses . 
 it can lead to arrhythmias , heart failure or systemic embolisms . 
 electrocardiographic patterns of patients with lvnc are various and non - specific ; however , the most common findings are intraventricular conduction delay , left ventricular hypertrophy , and repolarization abnormalities . 
 we reported the first case , to the best of our knowledge , of a 29-year - old man who had recent cerebral infarction and incidental lvnc with spontaneous left atrial standstill . 