Cardiomyopathy on ultrasound

Case Study: Isolated Left Ventricular Non-compaction of Left Ventricle

Introduction:

Isolated non compaction of the left ventricle is a rare cardiomyopathy. It is relatively recently recognized entity categorized as “unclassified cardiomyopathy” by the World Health Organization1. It is caused by failure of the developing myocardium to become compact thereby resulting in “spongy myocardium”.2 It may occur as a sporadic disease or be familial. This disorder usually presents with signs and symptoms of cardiac failure3.We report a case of a young man, diagnosed at the age of 37 years of age, to have an isolated non compaction of the left ventricle.

Case Report:

The patient presented with a history of progressive shortness of breath for few months and features of congestive cardiac failure without any preceding history of any viral or bacterial infection.  A loud systolic murmur of 4/6 intensity was audible best at the lower left sternal border. There were crepitations in chest and hepatomegaly.

Chest X ray showed cardiomegaly and plethoric lung fields. EKG showed features of left atrial enlargement and left ventricular hypertrophy. Echocardiogram revealed dilated atrias and hypertrophied spongiform and poorly contractile left ventricle with an ejection fraction of 20%. Transmitral inflow pattern was suggestive of restricted left ventricular filling. A moderate insufficiency of tricuspid valve was also seen. No abnormality of pulmonary valve and aortic valve was noted. The diagnosis was “restrictive cardiomyopathy” with a systolic and diastolic dysfunction of the left ventricle. The patient was treated with antibiotics and duiuretics and was discharged.

He was reviewed at six months and continued to have signs of cardiac failure. He was placed on increased anti-congestive therapy with Digoxin, Captopril and Furosemide. An echocardiogram clearly revealed a non compaction type of left ventricular myocardial disorder. View Figure 1 and 2. Blood movement in the intramural recesses of the left ventricular cavity were seen as demonstrated in Figure 3.  There was systolic as well as diastolic dysfunction of the left ventricle. Both atria were enlarged with moderate tricuspid and mitral regurgitation.

Figure 1

Figure 1

Figure 2

Figure 2

Figure 3

Figure 3

 

Discussion:

Isolated non compaction of the left ventricle is a rare disorder of endomyocardial morphogenesis characterized by numerous prominent ventricular trabeculations and deep intratrabecular recesses.3 It is supposed to result from failure of trabecular compaction of loose mesh of muscle fibers in the early stages of the myocardial development. Normally this process is more pronounced in the left rather than the right ventricle, resulting in a smooth and flat endocardial surface. The normal left ventricle has less than 3 trabeculations per imaging field, mostly confined to the lateral wall.4 In this disorder, however, there are abnormal trabeculations resulting from non compaction of myocardium scattered all over the myocardium, but most evident near the attachment of the papillary muscles of the mitral valve.5

Echocardiography is the most valuable tool in the diagnosis of the disorder.6 Although MRI has been used by many clinicians.7

The combined echocardiographic features essential to make the diagnosis include a two layered ventricular myocardium consisting of an outer sub endocardial compact layer and a thick non compact endocardial layer with prominent trabeculations and intratrabecular recesses; continuity between the left ventricular cavity and the recesses with blood flowing in and out from the ventricular cavity and absence of secondary causes of increased trabeculations.4

Clinical severity depends upon the extent of non compacted cardiac segments. Severe systolic heart failure and increased end diastolic pressure with restrictive cardiomyopathy is seen in more than 50% of patients. Bundle branch block, atrial arrhythmias and other serious ventricular arrhythmias are seen in 45% of cases and can cause sudden cardiac death.4

The genetic basis of this disease is not fully known, but both the isolated variety and the variety associated with other malformations are related with a mutation of the G 4,5 gene in Xq 28. The condition may be associated with Barth’s syndrome (neutropenia, impaired growth, increased organic acids in urine, low concentrations of carnitine and mitochondrial anomalies), Emery-Dreifus muscular dystrophy, and myotubular cardiomyopathy. Familial occurrence is high, 44% of cases in the largest series. In the case of our patient, the cause of death of his mother was not determined and cardiological and genetic studies were not made of any other first-degree relative.

The disease is managed with conventional measures for heart failure, including anticoagulation and antiarrhythmic medications. Automatic defibrillator implantation has been reported. Finally, heart transplantation is indicated, in accordance with current guidelines.

References:

  1. Oechslin K, Jenni R. Isolated left ventricular myocardium: increasing recognition of this distinct, yet “unclassified” cardiomyopathy. Eur J Echocardiogr 2002; 3: 301-2.
  2. Stollberger C, Finsterer J. Left ventricular hypertrabeculation/ non compaction. J Am Soc Echocardiogr 2004; 7: 91-100.
  3. Chin TK, Perloff JK, Williams RG, Jue K, Mohrmann R. Isolated non compaction of left ventricular myocardium: a study of eight cases. Circulation 1990; 82:507-13.
  4. Khan IA, Biddle WP, Najeed SA, Abdul Aziz S, Mehta NJ, Salana V, et al. Isolated non compaction cardiomyopathy presenting with paroxysmal supra ventricular tachycardia: case report and literature review. Angiology 2003; 54:243-50.
  5. Varnava AM. Isolated left ventricular non compaction: a distinct cardiomyopathy: 2001; 86: 599-600.
  6. Thuny F, Philip E, Caucino K, Ambrosi P, Jacquier A, Avierinos JF, et al. Isolated non compaction of the left ventricle. Arch Mal Coeur Vaiss 2003; 96:339-43.

 

Authors:

Dr Mohammad Nasir & Dr Sajid Dhakam
Cardiologists
Aga Khan University Hospital
Pakistan

Facebook Comments