Discussion

In the aetiopathogenesis of left ventricular non-compaction, pauses in compaction of myocardial fibres during myocardial embryogenesis in foetal life and genetic factors have been held responsible. ^{Reference Suvarna, Deshmukh and Hajela6} Subtypes of left ventricular non-compaction are as follows: isolated or benign, arrhythmogenic, dilated, hypertrophic, mixed, restrictive, biventricular, normal left ventricle with hypertrabeculated left ventricular non-compaction in the right ventricle, left ventricular non-compaction due to CHD. ^{Reference Jefferies5} Left ventricular non-compaction is seen most frequently with isolated, dilated, and hypertrophic subtypes. ^{Reference Mehaney, Haghighi and Embaby4} In a study done with left ventricular non-compaction patients, the symptoms were congestive heart failure (25%), abnormal cardiac examination (19%), abnormal ECG or chest X-ray film (16%), arrhythmia (10%), chest pain (9%), and syncope (5%). ^{Reference Jefferies5} In echocardiography, Chin criteria were defined as any one segment with the ratio of trough of trabeculation-to-epicardium (X): peak of trabeculation-to-epicardium (Y) <0.5 at end-diastole, whereas Jenni criteria as any segment with maximum end-systolic non-compacted: compacted thickness ≥2.4. However, Petersen criteria were defined in CMR as end-diastolic non-compacted: compacted thickness ≥2.3. ^{Reference Vaidya, Lyle and Miranda7}

Genetics plays an essential role in left ventricular non-compaction, as between 17 and 50% of patients have a family member with cardiomyopathy. ^{Reference van Waning, Caliskan and Hoedemaekers8} Left ventricular non-compaction is currently considered a genetically heterogeneous, monogenic disease with autosomal-dominant, autosomal recessive, and X-linked forms reported. ^{Reference Miszalski-Jamka, Jefferies and Mazur9} An autosomal-dominant inheritance pattern in left ventricular non-compaction appears in most families with variable penetration. Left ventricular non-compaction is a heterogeneous disease, and its genetic classification has clinical relevance. In a study, the incidence of mutations in the sarcomere genes was 82%, and the rest were found in non-sarcomere genes. The most frequent mutations in sarcomere genes found in genetic left ventricular non-compaction are MYH7, MYBPC3, and TTN, particularly MYH7. Mutations are more common in children than adults. While TTN was common in adults, it was not seen in children. ^{Reference van Waning, Caliskan and Hoedemaekers8} Studies show that the prognosis is worse in patients with mutations and family history. ^{Reference Jefferies5} Therefore, sequencing patients will help us to better understand and assess the disease prognosis and to identify at-risk family members. ^{Reference Mehaney, Haghighi and Embaby4}

Here we report the first paediatric case of left ventricular non-compaction subtype restrictive cardiomyopathy secondary to a de novo mutation in the cardiac myosin heavy chain gene MYH7. We present a patient with a family history of MYH7 gene mutation who presented with signs of heart failure at the age of 4 and died at 12. The prognosis was poor, and rapid progression was seen. The importance of this case is that the subtype of left ventricular non-compaction is restrictive. While the cardiac findings of patients with left ventricular non-compaction with MYH7 gene mutation usually have a slow course, our patient was diagnosed at an early age, showed rapid progression, and died. The most important features of our patient’s poor prognosis are the presence of a restrictive pattern and signs of heart failure at an early age, along with his family history.

Treatment for left ventricular non-compaction patients should be directed towards preventing and managing heart failure, ventricular arrhythmias, and thromboembolic events. The long-term prognosis of left ventricular non-compaction is poor. ^{Reference Patil and Patil10} The patient in our study had heart failure and received anti-aggregant therapy. Anti-arrhythmics were not prescribed because arrhythmia did not develop. However, while waiting for a heart transplant, he died due to rapidly progressing congestive heart failure.