Uncertainties in Left Ventricular Hypertrabeculation/Noncompaction

Abstract

We read with interest the article by Sakuma et al of a 65-year-old woman in whom echocardiography revealed left ventricular hypertrabeculation/noncompaction (LVHT), and who died 5 years later from heart failure and ventricular fibrillation. 1 However, we want to mention the following concerns. The authors say that LVHT is exclusively a congenital disorder and do not seem aware that indivdual patients may acquire LVHT during their lifetime. Three members of a family who subsequently developed LVHT did not show characteristic changes on the fetal echocardiographic studies and therefore in those cases LVHT developed either postnatally or was not visible on fetal echocardiography. 2 In a further case, LVHT was not echocardiographically present in the first days of life and manifested at the age of 5 weeks. 3 In another case, LVHT was documented to develop during the subject's lifetime. 4,5 Overall, the etiology of LVHT remains unknown.The authors describe LVHT as a rare disorder, but it has to be mentioned that LVHT is frequently overlooked and that its recognition depends on the awareness of the echocardiographers and the available technology. Thus, the prevalence of LVHT is at present also unknown. According to our experience in an echocardiographic laboratory, the prevalence of LVHT in adults is 0.25%/year. 6 The echocardiographic diagnostic criteria for LVHT are only one of several different definitions of LVHT. 7 Why did the authors chose that particular definition, and would all 9 patients also fulfill the other 2 criteria for LVHT? 8,9 It would be interesting to know how the authors differentiated between trabeculations, papillary muscles and tendinal chords when quantifying the extent of the trabecular meshwork at the level of the mitral valve and at the level of the papillary muscles. Were the intertrabecular recesses measurable and detectable at each location of LVHT?Did the morphology of LVHT change during follow-up, as has been reported in a patient with LVHT in whom after successful pharmacological therapy, an increase in left ventricular ejection fraction and a decrease in both left ventricular volume and end-diastolic pressure were associated with a decrease of the non-compacted myocardial areas? 10 The association of LVHT with embolism is in other's and our experience 11,12 not as high as previously reported. 7 Did the patient suffer from any embolic events during her lifetime? Did she receive oral anticoagulants?The oldest patient with LVHT, so far reported, is 80 years old. 13 It would be of interest to know the previous history of the presented patient, her laboratory and electrocardiographic findings and results of neurologic examinations because neuromuscular disorders are a frequent finding in patients with LVHT. 9 Regarding the pathoanatomic and pathohistological findings, it would be of interest to know the size and age of the thrombi and if conductive structures could be detected in the trabeculations. Did the authors recognize the intertrabecular thrombi already intra vitam by echocardiogra...