European Heart Journal Advance Access originally published online on February 7, 2008
European Heart Journal 2008 29(7):949-950; doi:10.1093/eurheartj/ehn029
Non-compaction: a distinct cardiomyopathy or non-specific morphological trait?
Department of Cardiology
VU University Medical Center
De Boelelaan 1117
1081 HV Amsterdam
The Netherlands
Tel: +31 20 444 0631
Fax: +31 20 444 3395
Email: t.germans{at}vumc.nl
Interuniversity Cardiology Institute of The
Netherlands
Utrecht
The Netherlands
Department of Cardiology
Academic Medical Center
Amsterdam
The Netherlands
Interuniversity Cardiology Institute of The
Netherlands
Utrecht
The Netherlands
Department of Cardiology
VU University Medical Center
Amsterdam
The Netherlands
Interuniversity Cardiology Institute of The
Netherlands
Utrecht
The Netherlands
With great interest, we have read the article of Hoedemaekers et al.1 on linking non-compaction cardiomyopathy to hypertrophic, restrictive, and dilated cardiomyopathies. The authors extensively describe two families in which variable severities of non-compaction of the myocardium segregated with mutations in the cardiac ß myosin heavy chain gene (MYH7).
Although genetic heterogeneity of traditional cardiomyopathies is well recognized, the identification of non-compaction in patients with dilated, hypertrophic, and restrictive cardiomyopathies suggests that non-compaction may be considered as a non-specific morphological trait rather than a distinct cardiomyopathy.2 In addition, not all non-compaction associated mutations are confined to genes that encode for a specific construct or functional element of the cardiomyocyte, but have been described in genes that encode for sarcomeric, cytoskeletal, and/or cell junctional proteins.1
Also, the genetic heterogeneity of non-compaction may reflect non-specificity of the current criteria for its diagnosis. According to Jenni et al.,3 isolated non-compaction cardiomyopathy is diagnosed with echocardiography when the following criteria are met: (i) coexisting cardiac abnormalities are absent, (ii) the left ventricular wall has a two-layered structure with a non-compacted to compact layer ratio >2 in end-systole, (iii) the trabecular non-compacted meshwork is predominantly located in the apical, lateral, and inferior regions of the left ventricle, and (iv) colour Doppler evidence of deep perfused intertrabecular recesses is present. While left ventricular trabeculae are more easily observed with high resolution imaging techniques such as cardiac magnetic resonance, Petersen et al.4 proposed to use a non-compacted to compact layer ratio >2.3 in end-diastole as a cut-off value to diagnose left ventricular non-compaction cardiomyopathy.
In the echocardiographic study from Hoedemaekers et al., only the second and forth criteria of Jenni et al. were used to diagnose non-compaction cardiomyopathy and ‘mild’ forms were also noted. These modifications of diagnostic criteria will most likely have introduced increased susceptibility to overdiagnosis in this study. Whether the described mutations encode for a pure form of non-compaction cardiomyopathy is therefore debatable.
In general, non-specific definition and/or limited imaging quality may lead to avoidable misinterpretation of cardiac morphology.5 When available, we advocate to use imaging modalities with optimal resolution for more adequate definition of cardiomyopathies in linkage studies, which may give an answer to the question whether non-compaction can be considered as a distinct cardiomyopathy or as non-specific morphological trait.
Tjeerd Germans is supported by the Netherlands Heart Foundation, grant number 2006B213.
References
- Hoedemaekers YM, Caliskan K, Majoor-Krakauer D, Van Der Laan I, Michels M, Witsenburg M, Ten Cate FJ, Simoons ML, Dooijes D. Cardiac β-myosin heavy chain defects in two families with non-compaction cardiomyopathy: linking non-compaction to hypertrophic, restrictive, and dilated cardiomyopathies. Eur Heart J (2007) 28:2732–2737.
[Abstract/Free Full Text] - Biagini E, Ragni L, Ferlito M, Pasquale F, Lofiego C, Leone O, Rocchi G, Perugini E, Zagnoni S, Branzi A, Picchio F, Rapezzi C. Different types of cardiomyopathy associated with isolated ventricular noncompaction. Am J Cardiol (2006) 98:821–824.[CrossRef][Web of Science][Medline]
- Jenni R, Oechslin E, Schneider J, Attenhofer Jost C, Kaufmann PA. Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy. Heart (2001) 86:666–671.
[Abstract/Free Full Text] - Petersen SE, Selvanayagam JB, Wiesmann F, Robson MD, Francis JM, Anderson RH, Watkins H, Neubauer S. Left ventricular non-compaction: insights from cardiovascular magnetic resonance imaging. J Am Coll Cardiol (2005) 46:101–105.
[Abstract/Free Full Text] - Germans T, Dijkmans PA, Wilde AAM, Kamp O, Van Rossum AC. Structural abnormalities of the inferoseptal left ventricular wall detected by cardiac magnetic resonance imaging in carriers of hypertrophic cardiomyopathy mutations. J Am Coll Cardiol (2006) 48:2518–2523.
[Abstract/Free Full Text]
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