European Heart Journal Advance Access originally published online on February 7, 2008
European Heart Journal 2008 29(7):950-951; doi:10.1093/eurheartj/ehn032
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Non-compaction: a distinct cardiomyopathy or non-specific morphological trait?: reply
ErasmusMC
Department of Clinical Genetics
Dr Molewaterplein 50
Rotterdam
The Netherlands
Email: d.dooijes{at}erasmusmc.nl
With great interest I read the letter by Germans et al., as a reaction to our manuscript titled ‘cardiac β-myosin heavy chain defects in two families with noncompaction cardiomyopathy: linking non-compaction to hypertrophic, restrictive and dilated cardiomyopathies’, describing two large non-compaction cardiomyopathy (NCCM) families with β-myosin heavy chain (MYH7) mutations.1
Germans et al. comment that we used only two of the four diagnostic criteria for NCCM and that the use of non-specific definitions and a method of limited imaging quality (echocardiography) in these two NCCM families likely lead to misinterpretation of cardiac morphology and over diagnosis. Subsequently they suggest that cardiac magnetic resonance should be used to determine whether NCCM can be considered a distinct cardiomyopathy or as a non-specific morphological trait.
Echocardiography is considered the reference standard for the diagnosis of NCCM. For the standardization of this diagnosis, four clear-cut echocardiographic criteria (the so-called Jenni criteria) were established and validated in larger series of patients and pathological samples.2 Recently, Petersen et al.,3 using a limited number of seven NCCM patients, developed diagnostic NCCM criteria for the use with MRI instead of echocardiography. They determined that for MRI studies the ratio of non-compacted to compacted myocardium should be >2.3 in diastole to accurately distinguish pathological non-compaction. The higher value of this ratio, when compared with the echocardiographic Jenni-ratio (of >2) to be taken in systole, reflects that the former is determined in diastole.3
For the identification of two large families with NCCM, we used the Jenni diagnostic criteria lege artis, without any modification as is suggested by Germans et al. These authors most likely failed to notice the diagnosis-paragraph in the Methods section explicitly stating the compliance to all four diagnostic Jenni criteria for a diagnosis of NCCM. In both families, we identified multiple patients that fulfilled these diagnostic NCCM criteria. The presence, in family B, of one asymptomatic 11-year-old boy with only mild apical NCCM, as was commented on by Germans et al., most likely reflects partial expression of pathological NCCM. This phenomenon is typical of autosomal dominant conditions and has been reported before in families with NCCM.3,4
The discussion whether NCCM is indeed a distinct cardiomyopathy or a non-specific morphological trait has been ongoing, where the latter view is exemplified by the Biagini paper5 (wrongly cited by Germans et al., correct citation below). Morphological, aetiological and genetic data should be used to gain insight into the pathophysiology of NCCM. Cardiac imaging physicians should be aware of morphological over diagnosis and classification since imaging techniques, whether echocardiography, MRI, ultrasound or CT, may describe various manifestations of the same cardiomyopathy spectrum and the heterogeneous clinical expression may be an example of this phenomenon. The identification of MYH7 defects in HCM, DCM, RCM, and NCCM1 suggests partial common pathophysiological mechanisms for all morphologically classified cardiomyopathies. In fact, the identification of non-compaction-like crypts in asymptomatic HCM mutation carriers by Germans et al.6 supports this very suggestion.
References
- Hoedemaekers YM, Caliskan K, Majoor-Krakauer D, van de Laar I, Michels M, Witsenburg M, Tencate FJ, Simoons ML, Dooijes D. Cardiac {beta}-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] - Jenni R, Oechslin EN, van der Loo B. Isolated ventricular non-compaction of the myocardium in adults. Heart (2007) 93:11–15.
[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] - Sasse-Klaassen S, Probst S, Gerull B, Oechslin E, Nurnberg P, Heuser A, Jenni R, Hennies HC, Thierfelder L. Novel gene locus for autosomal dominant left ventricular noncompaction maps to chromosome 11p15. Circulation (2004) 109:2720–2723.
[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 FM, Rapezzi C. Different types of cardiomyopathy associated with isolated ventricular noncompaction. Am J Cardiol (2006) 98:821–824.[CrossRef][Web of Science][Medline]
- Germans T, Dijkmans PA, Wilde AA, Kamp O, van Rossum AC. Images in cardiovascular medicine. Prominent crypt formation in the inferoseptum of a hypertrophic cardiomyopathy mutation carrier mimics noncompaction cardiomyopathy. Circulation (2007) 115:e610–e611.
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