Dextroversion and Noncompaction

Cardiomyopathies / pathology; Heart Failure; Stroke; Dextrocardia

Dear Editor,

With interest we read the article by Gonçalves et al¹ about a patient with dextrocardia and left-ventricular hypertrabeculation/noncompaction (LVHT)¹. We have the following comments and concerns.

Dextrocardia in association with LVHT has been repeatedly reported².

The exact pathomechanism of LVHT has not been discovered. Though the failing compaction process may play a role, there are also patients in whom LVHT developed during lifetime (acquired LVHT).

Which was the cause of collapses and presyncope? Did the patient undergo cerebral magnetic resonance imaging (MRI) to rule out cardioembolic stroke originating from the inter-trabecular spaces, a complication repeatedly reported in LVHT? Which were the results of carotid ultrasound investigations?

The patient required implantation of an implantable cardioverter defibrillator (ICD) because of inducible ventricular fibrillation. Did the ICD ever discharge during follow-up?

LVHT is frequently associated with neuromuscular disorders (NMDs). Was the patient ever seen by a myologist to rule out a NMD? Neuromuscular disorders, such as periodic paralysis or Marden-Walker syndrome, were associated with dextrocardia.

LVHT is frequently familial. Were other family members investigated for LVHT? Was LVHT found in any of the first-degree relatives? Did any of the family members develop cardiac symptoms?

The patient received gadolinium for cardiac MRI. Did radiologists observe late enhancement, which may indicate myocardial fibrosis? Myocardial late enhancement can be typically found in dystrophic NMD patients with myocardial affection³.

The diagnostic criterion of at least four LV trabeculations on echocardiography for diagnosing LVHT on echocardiography has not been provided by Jenny et al⁴ but by Stöllberger et al⁵.

The figure of 24% of LVHT patients to experience embolic stroke from inter-trabecular thrombi is high and not referenced.

Though cardiac MRI is useful to detect LVHT, it is not diagnostic in each case. Vice-versa echocardiography may not always detect LVHT, most frequently due to poor image quality, due to marked LV dilatation, or due to severe myocardial thickening⁶.

There are a number of sporadic LVHT cases in which mutations in single genes, such as the SCNA5 or G4.5 gene, have been reported, suggesting that not only familial LVHT is associated with mutated genes.

Overall, LVHT remains an enigmatic condition with several practical implications for the management of these patients. In LVHT it is essential that all clinical and scientific aspects are considered not only to improve the outcome of these patients but also to contribute to the clarification of the pathogenetic background.

There is no financial support or other benefits from commercial sources for the work reported in the manuscript, or any other financial interest of the authors, which could create a potential conflict of interest or the appearance of a conflict of interest with regard to the work.

Referências

• ¹
  Gonçalves LF, Souto FM, Faro FN, Mendonça RD, Oliveira JL, Sousa AC. Dextrocardia with situs inversus associated with non-compaction cardiomyopathy. Arq Bras Cardiol. 2013;101(2):e33-6.
• ²
  Baskurt M, Kalyoncuoglu M, Kucukoglu S. Noncompaction cardiomyopathy and dextroversion of the heart. Herz. 2011;36(1):33-6.
• ³
  Binder JS, Weidemann F, Schoser B, Niemann M, Machann W, Beer M, et al. Spongious hypertrophic cardiomyopathy in patients with mutations in the four-and-a-half LIM domain 1 gene. Circ Cardiovasc Genet. 2012;5(5):490-502.
• ⁴
  Oechslin EN, Attenhofer Jost CH, Rojas JR, Kaufmann PA, Jenni R. Long-term follow-up of 34 adults with isolated left ventricular noncompaction: a distinct cardiomyopathy with poor prognosis. J Am Coll Cardiol. 2000;36(2):493-500.
• ⁵
  Stollberger C, Kopsa W, Tscherney R, Finsterer J. Diagnosing left ventricular noncompaction by echocardiography and cardiac magnetic resonance imaging and its dependency on neuromuscular disorders. Clin Cardiol. 2008;31(8):383-7.
• ⁶
  Finsterer J, Stöllberger C. Apical noncompaction in metabolic myopathy may be missed on echocardiography but visible on cardiac MRI or misinterpreted as apical hypokinesia. Int J Cardiol. 2012;160(2):e15-7.

Reply

In response to the letter, we agree that noncompacted cardiomyopathy is an enigmatic condition with several pathophysiological aspects not completely elucidated, making its characterization by the use of the major diagnostic tools, echocardiography and cardiac magnetic resonance imaging, difficult. Thus, as highlighted in the case report, the use of both methods has been postulated as often required to either confirm or exclude the diagnosis of that condition.

a) The patient underwent neither neurological assessment nor cerebral magnetic resonance imaging, because the episodes of lipothymia and presyncope were attributed to bradyarrhythmia, and the patient became asymptomatic after cardioverter defibrillator implantation. Duplex carotid ultrasound showed no significant atherosclerotic lesion;

b) One single inappropriate discharge was identified in the presence of atrial flutter;

c) The patient has no symptoms of neuromuscular disorders; however, he has not been examined by a myologist;

d) There is no report of cardiac symptoms of other family members, although, despite the high interest of the assisting team, no systematic cardiological investigation has been conducted in all first-degree relatives;

e) As reported in the article, after gadolinium administration, no late enhancement, indicating fibrosis, was identified;

f) The occurrence of thromboembolic events, due to thrombi from the atria and intertrabecular recesses, in up to 24% of patients with noncompacted myocardiopathy has been reported by Friedman et al¹ and Baskurt et al², references cited in the case report, as well as by Oechslin et al³.

Fernanda Maria Silveira Souto
Joselina Luzia Menezes Oliveira
Antônio Carlos Sobral Sousa

• ¹
  Friedman MA, Wiseman S, Haramati L, Gordon GM, Spevack DM. Noncompaction of the left ventricle in a patient with dextroversion. Eur J Echocardiogr. 2007;8(1):70-3
• ²
  Baskurt M, Kalyoncuoglu M, Kucukoglu S. Noncompaction cardiomyopathy and dextroversion of the heart. Herz. 2011;36(1):33-6.
• ³
  Oechslin EN, Attenhofer Jost CH, Rojas JR, Kaufmann PA, Jenni R. Long-term follow-up of 34 adults with isolated left ventricular noncompaction: a distinct cardiomyopathy with poor prognosis. J Am Coll Cardiol. 2000;36(2):493-500.

Publication Dates

• Publication in this collection
  Mar 2014

History

• Received
  17 Sept 2013
• Reviewed
  21 Oct 2013
• Accepted
  21 Oct 2013