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• Non compaction diagnosis by MR
  Paul Dendale
  Published on: 23 November 2015
• Non-compaction or hypertrabeculation - that's one question.
  C Stollberger
  Published on: 23 November 2015
• Regarding Isolated ventricular non-compaction
  Robert H Anderson
  Published on: 23 November 2015

• Published on: 23 November 2015

  Non compaction diagnosis by MR

  • Paul Dendale, cardiologist
  • Other Contributors:
    • Bernard Paelinck, Bert Suys

  Dear Editor

  In their study, Jenni et al describe the echocardiographic characteristics of a relatively rare cardiomyopathy, isolated ventricular non-compaction. As stated by the authors, this is a disease entity that is difficult to diagnose during life, and the improvement in image quality of modern echocardiography will probably allow to improve its early detection. In the last two years, our group diagno...

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  Dear Editor

  In their study, Jenni et al describe the echocardiographic characteristics of a relatively rare cardiomyopathy, isolated ventricular non-compaction. As stated by the authors, this is a disease entity that is difficult to diagnose during life, and the improvement in image quality of modern echocardiography will probably allow to improve its early detection. In the last two years, our group diagnosed ventricular non compaction by magnetic resonance (MR)imaging in several patients in whom no suspicion of this disease existed after routine echocardiography and cardiac catheterisation. Even in retrospect, it was impossible to detect the abnormalities described by Jenni et al in several of these patients. MR however clearly showed localised thickening of the left ventricular wall ("spongy myocardium" with intramyocardial caverns and excessive trabeculation. Dynamic MR demonstrated the high speed expulsion of blood from the caverns during systole which was not visible on color doppler.

  In our series of 7 patients, the reason for referral was heart failure in 4 and ventricular arrhythmias in 1. One patient was examined because he was the father of a baby with heart failure and proven non compaction. Surprisingly, in 2 other patients, typical signs of ventricular non compaction were found even though the referral diagnosis was myocardial infarction or atrial septal defect. The MR characteristics were increased thickness of parts of the left ventricle of 1.3 up to 1.7 cm in diastole and an irregular endocardial surface with increased trabeculation. In all cases, the thickening was seen in the apex and part of the lateral wall. Basal portions of the ventricle were always normal. On dynamic imaging (gradient echo sequence) blood was seen to be expulsed from caverns in the thickened myocardium. On T1 weighted spin echo imaging, the thickened myocardium had a peculiar aspect comparable to the echo finding of Jenni : the endocardial part of the myocardium showed an important increase in signal intensity in comparison with the epicardial part of the muscle the normal myocardium and the normal myocardiyum. This is typical for imaging of slowly flowing blood : the spin echo images were made in mid diastole, a part of the heart cycle with less movement of blood in these caverns.

  On the basis of these findings, we would suggest to incorporate an MR study in suspected cases of heart failure cardiomyopathy, apical hypertrophy, and important ventricular arrhythmias. Larger cooperative studies are needed to further delineate the role of MR in this difficult diagnosis.

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  Conflict of Interest:
  None declared.

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• Published on: 23 November 2015

  Non-compaction or hypertrabeculation - that's one question.

  • C Stollberger, Cardiologist

  Editor,

  In normal hearts the left ventricle has only up to 3 trabeculations and is less trabeculated than the right ventricle [1]. In 1990, however, it was first described that in rare cases >3 trabeculations occur in the left ventricle (Non-compaction, isolated left ventricular abnormal trabeculation, hypertrabeculation) [2]. The trabeculations consist of myocardium, show the same echogenicity, move synchronously w...

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  Editor,

  In normal hearts the left ventricle has only up to 3 trabeculations and is less trabeculated than the right ventricle [1]. In 1990, however, it was first described that in rare cases >3 trabeculations occur in the left ventricle (Non-compaction, isolated left ventricular abnormal trabeculation, hypertrabeculation) [2]. The trabeculations consist of myocardium, show the same echogenicity, move synchronously with the heart and have echocardiographically to be differentiated from thrombi and intramural haematoma [3]. Hypertrabeculation occurs with or without cardiac malformations in dilated as well as in normally sized hearts, commonly associated with heart failure and ECG abnormalities [4,5,6]. A considerable number of patients with left ventricular hypertrabeculation were found to suffer from neuromuscular disorders like Becker’s muscular dystrophy [7], metabolic myopathy [8], myotonic dystrophy [9], Barth syndrome [10], infantile epilepsy-encephalopathy syndrome [11], Roifman syndrome [12], and skeletal abnormalities like Melnick-Needles syndrome [13] and nail-patella syndrome [14]. Hypertrabeculation can be familial and can develop during lifetime [15]. Hypertrabeculation seems frequently overlooked, and considerable overlap exists between the diagnosis of apical hypertrophic cardiomyopathy, left ventricular involvement of right ventricular dysplasia and endocardial fibroelastosis. To bridge the gap between ignorance and knowledge Jenni at al. propose “clear cut echocardiographic criteria” for “isolated ventricular non- compaction” and, furthermore, suggest that the WHO classification of cardiomyopathies should include non-compaction as a distinct cardiomyopathy [16]. Unfortunately, their suggestions might create more confusion than understanding.

  1. The term “isolated – without coexisting cardiac abnormalities” is misleading, since it ignores the finding of decreased left ventricular function or left ventricular wall thickening in nearly all patients with hypertrabeculation [4,5,6]. Additionally, hypertrabeculation may have the same pathogenetic background in both these forms.

  2. The term “noncompaction” suggests that the pathogenesis of the abnormality is known and due to an disturbed compaction process of the myocardium. A scientific proof, however, that this abnormality results from an embryonic defect in the compaction process of the myocardium, is still lacking. On the contrary, development of hypertrabeculations in a normally compacted left ventricle in adulthood has been described [15].

  3. The given definition “numerous, excessively prominent trabeculations” is not clear cut as it does not give a number above which the phenomenon is abnormal. On the contrary, we suggest the anatomically confirmed definition of >3 trabeculations within one imaging plane, apically from the insertion of the papillary muscles, as a practically useful diagnostic criterion when performing echocardiography, but also magnetic resonance imaging or computed tomography [1,4,7].

  4. The definition of hypertrabeculation based on the relation between volume recessuses and volume of trabeculations is weak, as volume and depth of the recessuses are difficult to assess echocardiographically and might be dependent on the hemodynamic status of the patient. Similarly, the ratio between non-compaction and compaction layer >2 is also dependent at which location and volume status measurements are performed.

  5. Since the follow-up studies of patients with hypertrabeculation are rare and conflicting data are available about the embolic risk of patients with hypertrabeculation, the general recommendation for oral anticoagulation in all patients with hypertrabeculation does not seem to be justified [5,6,7]. Overlooking patients with hypertrabeculation over 6 years we did not find an increased rate of stroke or embolism in them.

  6. Facing all the uncertainties and open questions regarding genetics, pathogenesis, aetiology, clinical manifestations and prognosis of left ventricular hypertrabeculation, there is a need to collect all the available data. Unfortunately, Jenni at al. have completely ignored any indications reported in the literature about an association of non-compaction with systemic disorders.

  In conclusion, our present knowledge about left ventricular hypertrabeculation is too poor to recommend it to the WHO as a distinct cardiomyopathy. Left ventricular hypertrabeculation may be due to a frustrated attempt of an impaired myocardium due to an inborn error to hypertrophy, that either manifests congenitally or in adulthood. Instead of creating unnecessary borders and ignoring valuable contributions there is a need to concentrate on common research about hypertrabeculation. Too many questions are awaiting an answer.

  References

  (1) Boyd M T, Seward J B, Tajik A J, et al. Frequency and location of prominent left ventricular trabeculations at autopsy in 474 normal human hearts: Implications for evaluation of mural thrombi by two-dimensional echocardiography. J Am Coll Cardiol 1987; 9:323-6.

  (2) Chin T K, Perloff J K, Williams R G, et al. Isolated noncompaction of left ventricular myocardium. A study of eight cases. Circulation 1990; 82:507-13.

  (3) Stöllberger C, Finsterer J, Waldenberger F R, et al. Intramyocardial hematoma mimicking abnormal left ventricular trabeculation. J Am Soc Echocardiogr 2001; 14:1030-2.

  (4) Stöllberger C, Finsterer J, Blazek G. Isolated left ventricular abnormal trabeculation: Follow-up and association with neuromuscular disorders. Can J Cardiol 2001; 17:163-8.

  (5) Oechslin E, Attenhofer Jost C H, Rojas J R, et al. Long-term follow-up of 34 adults with isolated left ventricular noncompaction: a distinct cardiomyopathy. J Am Coll Cardiol 2000; 36:493-500.

  (6) Ichida F, Hamamichi Y, Miyawaki T, et al. Clinical features of isolated noncompaction of the ventricular myocardium. J Am Coll Cardiol 1999; 34:233-40.

  (7) Stöllberger C, Finsterer J, Blazek G, et al. Left ventricular non-compaction in a patients with Becker’s muscular dystrophy. Heart 1996; 76:380.

  (8) Finsterer J, Stöllberger C. Hypertrabeculated left ventricle in mitochondriopathy. Heart 1998; 80:632.

  (9) Finsterer J, Stöllberger C, Wegmann R, et al. Left ventricular hypertrabeculation in myotonic dystrophy type 1. Herz 2001; 26:287-90.

  (10) Bleyl S B, Mumford B R, Thompson V, et al. Neonatal, lethal noncompaction of the left ventricular myocardium is allelic with Barth syndrome. Am J Hum Genet 1997; 61:868-72.

  (11) Hussein A, Schmaltz A A, Trowitzsch E. Isolated abnormality of the myocardium in 3 children. Klin Pädiatr 1999; 211:175-8.

  (12) Mandel K, Grunebaum E, Benson L. Noncompaction of the myocardium associated with Roifman syndrome. Cardiol Young 2001; 11:240-3.

  (13) Wong J A, Bofinger M K. Noncompaction of the ventricular myocardium in Melnick-Needles syndrome. Am J Med Genet 1997; 71:72-5.

  (14) Finsterer J, Stöllberger C, Wanschitz J, et al. Nail-patella syndrome associated with respiratory chain disorder. Eur Neurol 2001; 46:92-5.

  (15) Finsterer J, Stöllberger C, Blazek G, et al. Cardiac involvement in myotonic dystrophy, Becker muscular dystrophy and mitochondrial myopathy: A five-year follow-up. Can J Cardiol 2001; 17:1061-9.

  (16) Jenni R, Oechslin E, Schneider J, et al. Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy. Heart 2001; 86:666-71.

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  Conflict of Interest:
  None declared.

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• Published on: 23 November 2015

  Regarding Isolated ventricular non-compaction

  • Robert H Anderson, Joseph Levy Foundation Professor of Paediatric Cardiac Morphology

  Editor,

  I read with great interest the article by Jenni and colleagues [1], and the accompanying editorial by Varnava [2]. I agree with them that this entity is deserving of more attention, but if it is to be accorded special status within the group of cardiomyopathies, then I would suggest that much more work needs to be done to establish the phenotype.

  Thus, Jenni et al [1] argue that the non-compacted layer o...

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  Editor,

  I read with great interest the article by Jenni and colleagues [1], and the accompanying editorial by Varnava [2]. I agree with them that this entity is deserving of more attention, but if it is to be accorded special status within the group of cardiomyopathies, then I would suggest that much more work needs to be done to establish the phenotype.

  Thus, Jenni et al [1] argue that the non-compacted layer of the myocardium needs to be twice as thick as the compact layer to justify the diagnosis. They also indicate, however, that the bilaminar arrangement is not uniformly distributed throughout the left ventricular walls. The autopsied examples they show in Figure 4 illustrate the problems which might arise in applying their definition. To my eyes, the heart illustrated in Figure 4B at no site shows a non-compacted layer twice as thick as the compact layer.

  Indeed, the trabeculations at the apical part of the ventricle look relatively normal, with most of the ventricular wall seemingly having a compact appearance. There is then a further problem in that, in the normal heart, the compact myocardium is of no more than 1-2mm thickness at the apical thin point. Have the team from Zurich taken this into account when making their correlations? And why did they not measure the thickness of the compact and non-compact layers in their autopsy specimens, in this way providing objective rather than subjective evidence to establish this important phenotype?

  I am not meaning to devalue the importance of their work, since this is by far the largest and best documented series establishing the existence of this diagnostic entity. But we need to establish whether it is the trabeculations themselves which are abnormal, or the ventricular myocardium related to the origins of the papillary muscles of the mitral valve. In fact, in all the examples shown, the area of maximal non-compaction is at the site of the origins of the papillary muscles from the lateral ventricular wall. And, as is shown by Figure 3, this is the site of maximal abnormality in all seven patients in which echo-pathological correlations were made.

  This feature is also worthy of consideration by Varnava [2], who uses the beautiful illustrations by my friend David Sedmera to illustrate the points made. To the best of my knowledge, however, there is no evidence as yet to substantiate the claim that the entity represents "an arrest in cardiac embryogenesis". In this age of evidence-based medicine, one had rather hoped we had passed the stage of using speculative armchair embryology to support scientific data. Examination of Sedmera's scanning electron microscopic preparations shows that the normal process of compaction is confined largely to the apex and the mid-anterior ventricular wall, findings which do not correlate well with the observations of Jenni et al [1] for isolated left ventricular non-compaction.

  (1) Jenni R, Oeschslin E, Schneider J, Attenhoffer Jost C, and Kaufmann P A. Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classification as a distinct cardiomyopathy. Heart 2001; 86:666-671.

  (2) Varnava A M. Isolated left ventricular non-compaction: a distinct cardiomyopathy? Editorial. Heart 2001; 86:599-600.

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  Conflict of Interest:
  None declared.

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