Left ventricular non-compaction and hypertrophic cardiomyopathy: two overlapping diseases or two manifestations of the same cardiomyopathy? Response to the letter concerning the article: “Left ventricular non-compaction associated with hypertrophic cardiomyopathy in the same patient”

published in “Kardiologia Polska” 2017; 75, 4: 397 (doi: 10.5603/KP. 2017.0064)

Marouane Boukhris, Lobna Laaroussi, Nader Ben Salem, Afef Ben Halima, Salem Kachboura

Cardiology Department, Abderrahmen Mami Hospital, Ariana; Faculty of Medicine of Tunis, University Tunis El Manar, Tunisia

Address for correspondence:
Lobna Laaroussi, MD, Université Tunis El Manar, Faculté de Médecine de Tunis, Service de Cardiologie Hopital Abderrahmen Mami, 2008 Ariana, Tunisia,
e-mail: lobna_laroussi@hotmail.com

We thank Dr. Finsterer and Dr. Stollberger for their valuable comments on our paper [1].

First, we agree that both left ventricular non compaction (LVNC) and hypertrophic cardiomyopathy (HCM) can be associated with neuromuscular disorders [2]. Our patient did not report any symptoms suggestive of myopathy. He was also referred to a neurologist, who did not find any abnormality. Of note, creatine kinase serum level was normal.

Second, LVNC and HCM have been accepted as distinct cardiomyopathies and classified as genetic cardiomyopathies by the American Heart Association [3]. We concur that since LVNC was reported to disappear and was even inducible in animal models, its genetic origin could be conflictual and debatable. Recently, Lorca et al. [4] studied three families with both LVNC and HCM diseases, with different common mutations in each family and autosomal dominant inheritance. Within one family, the investigators found the coexistence of both diseases in two patients, with a possible pathogenic candidate described: mutation of sarcomere cardiac b-myosin heavy chain gene (MYH7 L620P). In the two other families, the same mutation was described (MYBPC G263NX) with phenotype variability, and only one case associating both LVNC and HCM in each family [4]. Further genetic studies should be performed to try to answer to the following question: are HCM and LVNC two overlapping diseases or two different manifestations of the same cardiomyopathy spectrum? Unfortunately, we did not perform genetic analysis because the patient’s family refused it.

Finally, regarding complications, our patient showed heart failure symptoms and signs with mildly impaired left ventricular ejection fraction, in addition to episodes of non-sustained ventricular tachycardia on 24-h Holter electrocardiography recording. According to sudden cardiac death score related to HCM, implantable cardiac defibrillator was indicated and thus implanted. Although the left atrium was dilated (area 27 cm2), no atrial fibrillation was found on 24-h Holter electrocardiogram recordings or on different telemetries; therefore, anti-coagulation was not indicated.

To conclude, LVNC can be either primary (congenital) or secondary. When it is primary, LVNC genetic determination is close to that of HCM. Further genetic studies are needed to better elucidate this relationship and to better identify the pathogenic mutations.

Conflict of interest: none declared

References

1. 1. Laaroussi L, Ben Halima A, Boukhris M, et al. Left ventricular non-compaction associated with hypertrophic cardiomyopathy in the same patient. Kardiol Pol. 2017; 75(4): 397, doi: 10.5603/KP.2017.0064, indexed in Pubmed: 28421585.
2. 2. Stöllberger C, Finsterer J, Blazek G. Left ventricular hypertrabeculation/noncompaction and association with additional cardiac abnormalities and neuromuscular disorders. Am J Cardiol. 2002; 90: 899–902.
3. 3. Maron BJ, Towbin JA, Thiene G, et al. Contemporary definitions and classification of the cardiomyopathies: an American Heart Association Scientific Statement from the Council on Clinical Cardiology, Heart Failure and Transplantation Committee; Quality of Care and Outcomes Research and Functional Genomics and Translational Biology Interdisciplinary Working Groups; and Council on Epidemiology and Prevention. Circulation. 2006;113(14):1807–1816.
4. 4. Lorca R, Martín M, Gómez J, et al. Hypertrophic cardiomyopathy and left ventricular non-compaction: Different manifestations of the same cardiomyopathy spectrum? Int J Cardiol. 2015; 190: 26–28, doi: 10.1016/j.ijcard.2015.04.138.