Comments on: Isolated Nonocompaction Suggests Subclinical Myopathy

It is with interest that I read the article by Nappi et al[1] about a fetus with left ventricular hypertrabeculation (LVHT), also known as left ventricular noncompaction (LVNC), at 26 weeks and 4 days of gestation. The fetus was delivered by cesarean section, preterm, at gestational week 31 and died 3 days after delivery for unknown reasons. The autopsy did not reveal any cardiac abnormality in addition to LVHT.[1] Thus, I have a few comments and concerns.

Since LVHT is frequently associated with monogenic disorders or chromosomal defects,[2] it would be interesting to know if the fetus underwent genetic testing and if any previously described mutation or chromosomal abnormality associated with LVHT was detected. In case a genetic defect was detected, I would like to know if the parents were tested for this particular defect and if it could be found in either of the parents as well.

Since LVHT is particularly associated with neuromuscular disorders in up to 80% of the cases,[3] it would also be interesting to know if muscle tissue of the fetus was collected to perform immunohistological, ultrastructural, or biochemical investigations. Neuromuscular disorders may present with only mild manifestations or may remain subclinical; thus, it would be interesting to know if creatine-kinase or serum lactate was elevated in the index patient or his parents.

I do not agree that LVHT is per definition associated with hypoplastic papillary muscles. Usually, papillary muscles are well preserved in patients with LVHT, and there is no indication for hypoplpasia or atrophy of papillary muscles. Papillary muscles may rather give rise to be mixed up with LVHT, particularly on axial views.[4] Only in case LVHT is non-isolated, other cardiac abnormalities, including hypoplasia of the papillary muscles, may be present.[5]

A frequent complication of LVHT not mentioned in the article is ventricular arrhythmias. Ventricular arrhythmias may be the cause of sudden cardiac death. However, if ventricular arrhythmias are detected prior to a fatal outcome, the patient may survive upon adequate therapy. This includes antiarrhythmic medication or implantation of an implantable cardioverter defibrillator. Therefore, it is crucial to mention ventricular arrhythmias, as they are accessible to treatment if detected in due time. Ventricular arrhythmias may have been the cause of death of the the index patient 3 days after delivery.

A further shortcoming of the study is that it is not mentioned that LVHT may not be congenital in all cases. Although LVHT is congenital in the majority of the cases, it may be also acquired, thus developing after birth. Conditions associated with acquired LVHT include neuromuscular disorders, athletism, or pregnancy. Gestational LVHT in a pregnant female may disappear after delivery. Thus, transient LVHT may have a better prognosis than permanent LVHT.

In summary, it is crucial to investigate fetuses with LVHT genetically, to screen patients with LVHT for ventricular arrhythmias, and to investigate patients with LVHT for neuromuscular disorders. Acquired LVHT should be discussed, since it may have implications the outcome of these patients.

• References

• 1 Nappi L, Vasciaveo L, Sorrentino F, Scutiero G, Iannone P, Greco P. Fetal noncompaction cardiomyopathy and histologic diagnosis of spongy myocardium: case report and review of the literature. Rev Bras Ginecol Obstet 2018 •••;. Doi: 10.1055/s-0038-1673677
• 2 Finsterer J. Cardiogenetics, neurogenetics, and pathogenetics of left ventricular hypertrabeculation/noncompaction. Pediatr Cardiol 2009; 30 (05) 659-681 . Doi: 10.1007/s00246-008-9359-0
• 3 Stöllberger C, Blazek G, Gessner M, Bichler K, Wegner C, Finsterer J. Age-dependency of cardiac and neuromuscular findings in adults with left ventricular hypertrabeculation/noncompaction. Am J Cardiol 2015; 115 (09) 1287-1292 . Doi: 10.1016/j.amjcard.2015.02.014
• 4 Cagliyan CE, Akilli RE, Deniz A, Deveci OS, Demir S, Kanadasi M. Atypical form of left ventricular noncompaction resembling mass appearance in papillary muscles. Herz 2015; 40 (01) 76-78 . Doi: 10.1007/s00059-013-3903-2
• 5 Woo JS, Perez-Rosendahl M, Haydel D, Perens G, Fishbein MC. A novel association of biventricular cardiac noncompaction and diabetic embryopathy: case report and review of the literature. Pediatr Dev Pathol 2015; 18 (01) 71-75 . Doi: 10.2350/14-07-1532-CR.1

• References

• 1 Nappi L, Vasciaveo L, Sorrentino F, Scutiero G, Iannone P, Greco P. Fetal noncompaction cardiomyopathy and histologic diagnosis of spongy myocardium: case report and review of the literature. Rev Bras Ginecol Obstet 2018 •••;. Doi: 10.1055/s-0038-1673677
• 2 Ursell PC. Noncompaction in the fetus and neonate: an autopsy study. Am J Med Genet C Semin Med Genet 2013; 163C [phone] . Doi: 10.1002/ajmg.c.31367
• 3 Ge S, Maulik D. Introduction: From fetal echocardiography to fetal cardiology: A journey of over half a century. Echocardiography 2017; 34 (12) 1757-1759 . Doi: 10.1111/echo.13776