Clinical Research Articale
 

Left Ventricular Non Compaction
A Tertiary Care Centre Experience
I. Sathyamurthy, K. Jayanthi, K. N. Srinivasan, Robert Mao, Pramod Kumar, P. Ramachandran, K. Subramanyan

Department Of Cardiology Apollo Hospitals, Chennai

Abstract

Aim: To analyse the clinical profile of consecutive cases of Left Ventricular Non Compaction (LVNC), a condition characterized by excessive and prominent Left Ventricular (LV) trabeculations which may be associated with LV systolic dysfunction.
Methods: Twenty six consecutive cases from January 2003 to December 2008 with echocardiographic evidence of hypertrabeculation of LV were evaluated by clinical examination, electrocardiographic(ECG) and echocardiographic features. Diagnosis was based on 3 published definitions.
Results: Out of 26 cases of LVNC  (18Males: 8Females) aged between 1 day and 63 years, isolated LVNC was seen in 16 cases  and rest of the cases were associated with congenital heart disease (CHD), Rheumatic Heart Disease (RHD) and Coronary Artery Disease (CAD). All patients were previously undiagnosed cases of LVNC. Left ventricular ejection Fraction ranged from 15 – 60 % in these cases.
Conclusions: This study demonstrates the increased detection of patients fulfilling echocardiographic criteria of LVNC and its association with other disorders. It also shows that milder phenotypes exist and the disease is detected incidentally in some cases.
Key Words: LVNC, Echocardiography

 

INTRODUCTION

Left Ventricular Non Compaction is a myocardial disorder, characterized by excessive and prominent trabeculations associated with deep recesses that communicate with the ventricular cavity but not the coronary circulation 1. Failure of regression of trabeculations during normal embryonic development is the underlying pathogenesis 2. Since most of the  data are based on case reports, the true prevalence of LVNC is unclear. LVNC is a genetically heterogenous disorder with both familial and sporadic forms and linked to mutations in several genes. The disease can present at any age with progressive LV dysfunction and an increased incidence of thromboembolism and arrhythmias 3. Both echocardiography and magnetic resonance imaging (MRI) are diagnostic. Some criteria require a double layered appearance of the myocardium by echocardiogram and others by prominent and numerous trabeculations 4. The rise in the number of reports describing LVNC suggests that its prevalence has been underestimated. We report here a series of such cases and their clinical profile.

 

Methods

Study population comprised of 26 consecutive cases with

 

echocardiographic features of LVNC observed from January 2003 to December 2008. All the patients were previously undiagnosed cases of LVNC. This included 18 males and 8 females with age ranging from 1 day to 63 years.  All were evaluated by history, physical examination, 12-lead ECG and echocardiography. Nine patients had angiography.

Correspondence:Dr. I. Sathyamurthy, Director & Interventional Cardiologist, Department of Cardiology, Apollo Hospitals, Chennai , No: 21, Greams lane off Greams Road, Chennai – 600006
Tele No; 044-28296548, Fax No: 044-28294429
Email: [email protected]

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Patients fulfilling any one of the following criteria by echocardiography (See Figure-1) were diagnosed as having LVNC:

  • Spongy: Defined by inner myocardial layer demonstrating small cavities without appearances of defined recesses by 2D echocardiography
  • Meshwork: Trabeculations interwoven in a meshwork
  • Prominent and numerous trabeculations only

Statistical Analysis

Consecutive cases fulfilling echocardiographic criteria of LVNC studied for their profile and presentation without application of any specific statistical analysis.

 

Results

Isolated LVNC was seen in 16 patients including a Newborn. Six patients had associated congenital heart diseases (Table-1). One male aged 39 years had associated rheumatic aortic stenosis with aortic regurgitation. Three patients had coronary artery disease and were above 53 years of age. 
Among the patients with isolated LVNC, three patients presented in congestive cardiac failure; two patients in left ventricular failure out of which one patient had chronic renal failure and was on dialysis; one patient with ventricular  arrhythmia; five patients presented with class II NYHA symptoms and the rest of the five patients were asymptomatic.
The ECG was unremarkable in all patients with isolated LVNC except 1 patient who had Non Sustained Ventricular Tachycardia.

All patients had echocardiographic evidence of global LV hypokinesia with Ejection Fraction (EF) ranging from 20%-60%. One patient who had suffered anterior wall myocardial infarction exhibited regional wall motion abnormality. One patient with Ebstein’s Anomaly of the tricuspid valve had associated right ventricular noncompaction. There was evidence of thrombus within trabeculations in one patient.

Angiogram was done for all CAD and RHD patients and in 5 of isolated LVNC patients. It was noncontributory in isolated LVNC patients.

One newborn died of respiratory distress on day-2 after birth. One rheumatic heart disease patient who was subjected to Aortic

Table-1Congenital Heart Disease in LVNC in our series

 a)  CTGV , VSD . PS                            –  1 Patient ( 28 Yrs, M )
b)  Ebstein’s Anomaly                        –  1 Patient ( 22 Yrs, M )
c)   Subaortic VSD and Valvar PS     –  1 Patient ( 15 Yrs, M )
d)  Pulmonary Atresia VSD                –  1 Patient ( 9 Yrs, M )
e)  Subaortic VSD                               –  1 Patient ( 15 Yrs, M )

valve replacement surgery died in the postoperative period due to low cardiac output state. His preoperative EF was 40%. One CAD patient successfully underwent balloon angioplasty and stenting to left anterior descending artery. All others are on medical follow up.

Discussion

LVNC has been described both in children and in adults. At present mutations in q4.5 gene (TAZ gene) on the Xq28 chromosome is the only confirmed disease causing locus 5, though mutations in 7 different genes have been found. X-linked transmission in neonates and autosomal dominant transmission in adults have been proposed.
During the early embryogenesis , the myocardium forms a loose network of interwoven fibres(trabeculations) 2. By 5-8 weeks, vascular network begins to form when trabeculated network compacts - proceeding from epicardium to endocardium and from base to apex, in the same direction as formation of epicardial coronary vessels 1. This process of compaction is completed early in foetal life resulting in prominent outer compact myocardium with few residual subendocardial trabeculae. Ventricular noncompaction results from interruption of this normal process of myocardial morphogenesis. The time of arrest of this process will determine the extent of myocardial noncompaction  in the ventricle.
Based on current reports, incidence is higher in men than in women as seen in our study too. An Australian study 6 on children with primary cardiomyopathy indicated that Isolated LVNC accounted for 9.2 % of all cases of cardiomyopathy and that it was the 3rd most common causes of cardiomyopathy after dilated cardiomyopathy(DCM) and hypertrophic cardiomyopathy(HCM). Similar report is obtained from Texas children’s hospital 7 from U.S.A. In the adult population among patients referred to for echocardiography in 2 series of case reports a prevalence of 1.4-2.6 / 10000 cases was noted.
The clinical presentation of LVNC is highly variable ranging from an incidental echocardiographic diagnosis without symptoms to disabling heart failure. In a comparison of all published adult case series, the prevalence of heart failure is 30-73 % and LV dysfunction is 58-82 %, 8, 9.   In our series heart failure was the presenting feature in 11.5%. The 2 most common clinically significant arrhythmias in patients with LVNC are Atrial fibrillation (AF) (5-29 %) and Ventricular tachycardia (VT) (3-47 %) 8, 10. Nonspecific ECG changes, LV hypertrophy, Left bundle branch block(LBBB), ‘T’ wave inversion have been reported 11. In our series VT was seen in 3.9%, LBBB in 3.9% and AF in 3.9%.

Thrombo embolism occurs in 0-9 % of cases 11 and depends on the severity of LV dysfunction and previous embolic episodes. In our series, none of the patients had embolic episodes though
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thrombus was evident in the trabeculae in one patient.
In paediatric case series facial dysmorphic features have been reported 12. And in adults neuromuscular disorders have been reported 13. In our series we did not find any of these features.
The most commonly involved areas are the LV apex and mid inferior & lateral walls of LV by echocardiography. In our cases also we found similar distribution of noncompaction 4. One patient had evidence of Right ventricular noncompaction in association with Ebstein’s anomaly of the tricuspid valve.
MRI has an emerging role in the diagnosis of LVNC. It was not done in any of our cases. Angiography was done in 9 of our  patients only for delineation of other associated disorders and not to diagnose LVNC.
Prognosis of patients with LVNC is variable. In paediatric case series, LV dysfunction was seen to develop in 10 years period, regardless of presence of symptoms at diagnosis. In adult series 43 % have progressive decline in EF over 3year period. Hospitalisation is needed for heart failure in 50 % of cases 10, 14. Mortality rate is estimated at 2-15 %. In our series 2 patients died – one neonate with heart failure at birth died on 2nd day after birth. & one patient who had RHD with LVEF of 45 %, underwent aortic valve replacement surgery and died in the postoperative period of low cardiac output state.
Many patients had milder phenotypes and lower incidence of symptoms at diagnosis. Improved awareness probably resulted in detection of previously unrecognized cases.
Asymptomatic LVNC needs regular followup by a cardiologist. Anticoagulants and antiarrhythmic drugs are given as per clinical need and routine use of these is controversial. All first degree relatives of patients with LVNC should undergo a screening echocardiography. Implantable cardiovertor defibrillators and cardiac transplantation are some of the options.
In our series, the management of these patients consisted of routine heart failure protocols, treatment of associated cardiac disorders and use of antiarrhythmic drugs and anticoagulants wherever indicated.

 

Conclusions

Evidence from developmental studies, incidental case reports and small clinical series support concept of LVNC as a real disease entity which may in some cases have association with other cardiac and somatic abnormalities. Clinical manifestations of this disease are quite diverse. Increasing awareness of this disease entity probably is the reason of increasing number of reports describing LVNC. More stringent echocardiographic criteria may prevent overdiagnosis of LVNC 15.

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