Evident, but poorly defined: left ventricular hypertrabeculation/noncompaction and its diagnostic criteria

Claudia Stöllberger

2nd Medical Department
Krankenanstalt Rudolfstiftung
Juchgasse 25
A-1030 Wien
Österreich, Austria
Tel: +43 1 713 98 70
Fax: +43 1 713 98 70
E-mail address: claudia.stoellberger{at}chello.at

Josef Finsterer

Neurological Department
Krankenanstalt Rudolfstiftung
Juchgasse 25
A-1030 Wien
Österreich
Austria

We read with interest the article by Murphy et al.1 about the natural history and familial characteristics of left ventricular hypertrabeculation/noncompaction (LVHT). In 45 patients with LVHT, they observed a survival from death or transplantation of 97% and conclude that LVHT is associated with a better prognosis than previously reported.

That LVHT is a disorder of endomyocardial morphogenesis, as stated by the authors, is only one of several hypotheses. Actually, the etiology of LVHT is not known. Arguments against the ‘embryonal’ hypothesis are patients in whom LVHT developed during life: three members of a family who subsequently developed LVHT did not show LVHT-characteristic changes by fetal echocardiography.2 In a further case, LVHT was echocardiographically not present in the first days of life, but only at the age of 5 weeks.3 In two further cases with muscular dystrophy, LVHT was documented to develop during life.4,5 Disappearance of LVHT has been observed 2 years after a Coxiella burnetti infection.6

Which criteria were applied for making the primary diagnosis of LVHT, and remained the criteria unchanged during the study period? Were echocardiograms of all 518 patients with idiopathic dilative cardiomyopathy reviewed and screened for LVHT? Were interobserver variability studies performed? When using Jenni's criteria in the short axis view, how did the authors distinguish between papillary muscles and trabeculations? We want to stress that further criteria of LVHT, applied in the largest series of 77 patients, overcome this problem by preferentially using the apical four-chamber view.7 These echocardiographic diagnostic criteria for LVHT are (i) more than three trabeculations protruding from the left ventricular wall, apically to the papillary muscles, visible in single image plane and (ii) intertrabecular spaces perfused from the ventricular cavity, visualized on colour Doppler imaging. Trabeculations are defined as structures with the same echogenicity like the myocardium and moving synchronously with the ventricular contractions.8

It is reported that no patient had clinical evidence of skeletal myopathy. It is not known whether all patients were investigated by a neurologist. LVHT has not only been described in association with mutations in the G4.5, {alpha}-dystrobrevin and Cypher/ZASP gene, but also in Becker and Duchenne muscular dystrophy, myotonic dystrophy, myoadenylate-deaminase deficiency, and metabolic myopathies.7,9

The authors present the largest ever-reported follow-up study of LVHT patients. Did they identify any baseline parameter as indicator for deterioration or death? Did the prognosis differ between patients in whom LVHT was associated with left ventricular dilatation and systolic dysfunction and patients with normal systolic function? How to explain the maximum follow-up time of 179 months, if the study period was only 126 months? Were any patients lost to follow-up? How thoroughly were those patients investigated who developed embolic events, and were other causes of embolism excluded?10

We agree with the authors that LVHT does not seem to be a distinct cardiomyopathy, but a multifactorial cardiac abnormality occurring in dilated and hypertrophic ventricles and commonly associated with neuromuscular disorders.7 Possibly, the prognosis of LVHT depends on the underlying disease. Research about LVHT could be facilitated by uniformly accepted and practically applicable diagnostic criteria.

References

  1. Murphy RT, Thaman R, Blanes JG. Natural history and familial characteristics of isolated left ventricular non-compaction. Eur Heart J 2005;26:187–192.[Abstract/Free Full Text]
  2. Bleyl SB, Mumford BR, Brown-Harrison M-C, Pagotto LT, Carey JC, Pysher TJ, Ward K, Chin TK. Xq28-linked noncompaction of the left ventricular myocardium: prenatal diagnosis and pathologic analysis of affected individuals. Am J Med Genet 1997;72:257–265.[CrossRef][ISI][Medline]
  3. Hussein A, Schmaltz AA, Trowitzsch E. Isolierte Fehlentwicklung ("Noncompaction") des Myokards bei drei Kindern. Klin Pädiatr 1999;211:175–178.[ISI][Medline]
  4. Finsterer J, Stöllberger C, Blazek G, Spahits E. Cardiac involvement in myotonic dystrophy, Becker muscular dystrophy and mitochondrial myopathy: a five-year follow-up. Can J Cardiol 2001;17:1061–1069.[ISI][Medline]
  5. Finsterer J, Stöllberger C, Schubert B. Acquired left ventricular hypertrabeculation/noncompaction in mitochondriopathy. Cardiology 2004;102:228–230.[CrossRef][ISI][Medline]
  6. Pfammatter JP, Paul Th, Flik J, Drescher J, Kallfelz HC. Q-Fieber-assozierte Myokarditis bei einem 14-jährigen Jungen. Z Kardiol 1995;84:947–950.[ISI][Medline]
  7. Stöllberger C, Finsterer J. Cardiologic and neurologic findings in left ventricular hypertrabeculation/non-compaction related to wall thickness, size and systolic function. Eur J Heart Fail 2005;7:95–97.[CrossRef][ISI][Medline]
  8. Stöllberger C, Finsterer J, Blazek G. Left ventricular hypertrabeculation/noncompaction and association with additional cardiac abnormalities and neuromuscular disorders. Am J Cardiol 2002;90:899–901.[CrossRef][ISI][Medline]
  9. Finsterer J, Schoser B, Stollberger C. Myoadenylate-deaminase gene mutation associated with left ventricular hypertrabeculation/non-compaction. Acta Cardiol 2004;59:453–456.[ISI][Medline]
  10. Stöllberger C, Finsterer J. Left ventricular hypertrabeculation/noncompaction and stroke or embolism. Cardiology 2004;103:68–72.[CrossRef][ISI][Medline]




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