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Response to commentary: biventricular non-compaction hypertrophic cardiomyopathy in association with congenital complete heart block and type I mitochondrial complex deficiency

Published online by Cambridge University Press:  01 June 2015

Ranjana Dhar,
William Reardon and
Colin J. McMahon
Ranjana Dhar
Affiliation:
Department of Paediatric Cardiology, Our Lady’s Hospital for Sick Children, Crumlin, Dublin, Ireland
William Reardon
Affiliation:
National Centre for Medical Genetics, Our Lady’s Hospital for Sick Children, Crumlin, Dublin, Ireland
Colin J. McMahon*
Affiliation:
Department of Paediatric Cardiology, Our Lady’s Hospital for Sick Children, Crumlin, Dublin, Ireland
*
Correspondence to: C. J. McMahon, Cardiac Department, Our Lady’s Hospital for Sick Children, Crumlin, Dublin 12, Ireland. Tel: +01 409 6160; Fax: +01 409 6181; E-mail: cmcmahon992004@yahoo.com
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Information

Type
Commentary
Information
Cardiology in the Young , Volume 25 , Issue 5 , June 2015, pp. 1024 - 1025
Copyright
© Cambridge University Press 2015 

We appreciate the comments of Drs Finsterer and Zarrouk-Mahjoub regarding “Biventricular non-compaction hypertrophic cardiomyopathy in association with congenital complete heart block and type I mitochondrial complex deficiency”.Reference Dhar, Reardon and McMahon 1 – Reference Finsterer and Zarrouk-Mahjoub 2

  • ∙ Thank you for highlighting other reported cases of complete heart block and left ventricular non-compaction cardiomyopathy.Reference Scaglia, Towbin and Criagen 3 – Reference Zarrouk Mahjoub, Mehri and Ourda 4 Our case was an antenatally diagnosed case of non-compaction involving both ventricles and was associated with complete heart block.

  • ∙ Analysis of the respiratory chain enzymes in the cardiac muscle revealed low complex 1 activity. Complete sequencing of the entire mitochondrial genome in blood DNA samples did not indicate a mitochondrial point mutation.

  • ∙ Muscle biopsy showed low activities of complex 1 and 3 with normal complex 2 and 4 levels. There was type I muscle fibre atrophy.

  • ∙ We agree it is very important to screen first-degree relatives, parents, and siblings. There was no evidence of cardiomyopathy in the patient’s parents or siblings. There was no history of sudden cardiac death or cardiomyopathy in the extended family. The maternal cousin’s daughter had an ill-defined metabolic condition, but information about the condition was not forthcoming. There was no other history of metabolic or mitochondrial disease in the family.

  • ∙ We agree that it is vital to assess for extra-cardiac manifestations, particularly neurological and skeletal muscle abnormalities. The patient had mild developmental delay, standing at 11 months and walking at 16 months. There was no speech delay. As she developed, there was evidence of mild muscular weakness, which has been stable over the last 8 years. Although she can walk and run, she has poor co-ordination and balance and has had several falls. Her mother has reported a subtle bilateral ptosis as she gets tired during the day. She did manifest initial feeding problems, which resolved in the 1st year of life. The child has no intellectual disability and is performing well in school and is equal to her peers from a cognitive standpoint.

  • ∙ The patient has not developed any atrial or ventricular arrhythmias on Holter monitoring. Of note, the degree of non-compaction and ventricular hypertrophy has remained remarkably stable with no progression or regression of the degree of hypertrophy or non-compaction. To date, the patient has not demonstrated an undulating phenotype often seen in other cases with non-compaction cardiomyopathy.

We agree with the comments that extra-cardiac assessment of patients, thorough screening of first-degree relatives, and ongoing evaluation for undulating phenotype and progression of non-compaction are essential in this disease process.

Acknowledgement

We are grateful to the cardiac and genetics departments in Our Lady’s Children’s Hospital, Crumlin.

Financial Support

The authors have no financial relationships regarding this article to disclose.

Conflicts of Interest

The authors have no conflicts of interest relevant to this article to disclose.

References

1. Dhar, R, Reardon, W, McMahon, CJ. Biventricular noncompaction hypertrophic cardiomyopathy in association with congenital complete heart block and type I mitochondrial complex deficiency. Cardiol Young 2014; 15: 1–3.Google Scholar
2. Finsterer, J, Zarrouk-Mahjoub, S. Implications of non-compaction in association with respiratory chain complex-1 deficiency. Cardiol Young 2014; 18: 1–2.Google Scholar
3. Scaglia, F, Towbin, JA, Criagen, WJ, et al. Clinical spectrum, morbidity, and mortality in 113 pediatric patients with mitochondrial disease. Pediatrics 2004; 114: 925–931.Google Scholar
4. Zarrouk Mahjoub, S, Mehri, S, Ourda, F, et al. Transition m.3308T>C in the ND1 gene is associated with left ventricular hypertrabeculation/noncompaction. Cardiology 2011; 118: 153–158.Google Scholar