The different clinical scenarios of left ventricular non-compaction: report of three cases

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1 Page 1 of 5 Cardiovascular Medicine The different clinical scenarios of left ventricular non-compaction: report of three cases M Bolognesi 1 *, D Bolognesi 2 Abstract Introduction Left ventricular non-compaction is a morphological abnormality of excessive trabeculation of the left ventricle, and often, but not always, complicated by cardioembolism, arrhythmias and ventricular dysfunction. Since its irst mention in the 1980s, left ventricular non-compaction cardiomyopathy has gained increasing awareness and attention. Thirty or more years of research and an ever-increasing number of published articles have improved our understanding of this rare cardiomyopathy, yet many issues remain unresolved. In particular, the phenotypic and clinical expression of the same genetic cardiomyopathy assumes different forms depending on the type of subjects involved. These case reports describe the different clinical evolutions of the same cardiomyopathy independently of the anatomical substrate and illustrate two aspects of the same disease in different types of patients. Isolated left ventricular non-compaction cardiomyopathy has been observed both as a sporadic and a familiar form, but newly diagnosed patients have been strati ied for symptoms found at the time of diagnosis. Conclusion For clinical presentation and genetic heterogeneity, Left ventricular noncompaction seems to be rather a distinct phenotype or phenotypic, morphological expression of different underlying diseases than a distinct cardiomyopathy. *Corresponding author massbolo1@tin.it 1 Sports Cardiology Medicine Centre, ASL 112, District of Cesena, Italy 2 Territorial Medicine Cesena, ASL 112, District of Cesena, Italy Introduction Left ventricular non-compaction (LVNC) is a myocardial disorder characterized by prominent ventricular trabeculations and deep recesses extending from the left ventricular cavity to the sub-endocardial surface of the left ventricular wall with or without left ventricular dysfunction 1 2. LVNC can be diagnosed in all stages of life. It has been identi ied as a distinct entity over the past few decades 3 4. When the disease is irst recognized, which usually occurs in later stages of life, it is often not clear whether the diagnosis represents late recognition of long-standing non-compaction or delayed morphological manifestation of an underlying cardiomyopathy. LVCN may be associated with other diseases such as neuromuscular disorders 2. Although the American Heart Association has classi ied LVNC as a primary genetic cardiomyopathy 5, the European Society of Cardiology refers to LVNC as an unclassi ied cardiomyopathy 6 based on the fact that LVNC is a morphological manifestation of several distinct cardiomyopathies. Currently, there is no de inite evidence to con- irm whether LVNC is a distinct cardiomyopathy, an epiphenomenon or a phenotypic variant of other cardiomyopathies. However, the absence of speci ic genotype phenotype association, the occurrence of LVNC morphology in various metabolic diseases and other cardiomyopathies, and the inding that the LVNC phenotype is not necessary for the development of cardiomyopathy, all suggest it is unlikely that it could be a speci ic cardiomyopathy 7 9. Traditionally, diagnosis of LVNC is based on 2D trans-thoracic echocardiography 3. Although there are three different diagnostic criteria, there is no universally accepted de inition of LVNC. All criteria are based on morphological indings and require the presence of prominent trabeculations with deep intertrabecular recesses communicating with the ventricular cavity and a two-layered appearance of the myocardium (trabecular myocardium as one layer, and compacted myocardium as the second layer) If a ratio of trabeculated to compact myocardium of more than 2.3 is common in a large-population-based cohort, a critical re-evaluation of the current cardiac magnetic resonance (CMR) criteria for LVNC may be needed 13. This article discusses the different clinical scenarios of LVNC. The irst case concerns a 50-yearold female who came to our medical centre. Subject complained of dyspnea and palpitation on effort for several months, which was attributed to her obesity and lack of exercise. The electrocardiography (ECG) showed a sinus rhythm interrupted by frequent ventricular premature beats, aspeci ic interventricular conduction delay (QRS 140 ms) with a left heart axis. Two dimensional trans-thoracic echocardiography performed with MyLab 30 Gold (ESAOTE Instruments) showed a marked dilatation of the left ventricle with global hypokinesis and very poor systolic function (EF 20%), complicated by severe functional mitral regurgitation by tethering and apical displacement of mitral lea lets; also, a moderate left atrial dilatation and mild tricuspid regurgitation was present without an increase in the systolic pulmonary pressure. Prominent trabeculation was evident on the anterolateral wall,

2 Page 2 of 5 with deep intertrabecular recesses communicating with the ventricular cavity, and a two-layered appearance of the myocardium (trabecular myocardium as one layer, and compacted myocardium as the second layer; see Figure 1: Two-dimensional trans-thoracic echocardiography colour Doppler (apical four-chamber view) recorded in a patient with a dilated cardiomyopathy related to ventricular non-compaction showed a prominent trabeculation along the lateral wall as well as severe functional mitral regurgitation and mild tricuspid regurgitation. Figure 2: Cardiac magnetic resonance (CMR) shows the typical inding in the short-axis view of non-compacted to compacted layer ratio of more than 2.3 in diastole on the lateral wall. Figure 1). In addition, intertrabecular space was illed by direct blood low from the ventricular cavity as visualized on colour Doppler imaging. The diagnosis of non-ischemic dilated cardiomyopathy in LVNC was made and subsequently a cardiac magnetic resonance con irmed this disease (see Figure 2). The second case concerns a 35-year-old elite triathlete in good health condition and highly competitive in sports with unremarkable clinical history. No abnormalities in physical examination were found. Resting ECG showed sinus bradycardia, early repolarization and a sign of left ventricular hypertrophy that required further work through twodimensional trans-thoracic echocardiography performed with MyLab 30 Gold (ESAOTE Instruments). This exam showed a non-dilated left ventricle with good systolic function (estimated EF 65%) and absence of valvular disease or other abnormalities, but the presence of a myocardial disorder characterized by prominent ventricular trabeculations and deep recesses extending from the left ventricular cavity to the sub-endocardial surface of the whole anterolateral left ventricular wall (see Figure 3). Mild right ventricular involvement was also shown (see red arrow). Subsequently, a CMR showed the typical morphologic indings of left ventricular non-compaction of the anterolateral wall (see Figure 4) without dysfunction. The third case concerns the incidental inding of non-compacted myocardium in a 48-year-old female cyclist who was asymptomatic. This athlete was subjected to sports screening prior to participation. Subject had no family history of cardiac disease or sudden death. Physical examination revealed the presence of a slight heart murmur. Resting ECG showed normal sinus rhythm, and exercise testing was negative for arrhythmias. Echocardiography examination showed periapical and apical thickening with spongiform appearance

3 Page 3 of 5 of the myocardium and deep intertrabecular recesses with the association of a false tendon inside the cavity (see Figures 5 and 6). The diagnosis of LVNC myocardium was made. In this case, the athlete has refused to undergo MRI. Figure 3: Two-dimensional trans-thoracic echocardiography in the apical fourchamber view showed irregular masses of echoes, predominantly along the anterolateral wall (arrows), with interspersed sinusoidal spaces representing non-compacted myocardium. Figure 4: Cardiac magnetic resonance (CMR) shows a four-chamber end diastolic sequence evidencing the presence of non-compacted and compacted layers of myocardium. Discussion These three case reports describe different clinical scenarios of the same pathology and then three totally opposite sides of the same structural morphological abnormality of the myocardium. In the irst case, the LVNC is related to an important base of cardiomyopathy such as dilated cardiomyopathy, which causes a severe dysfunction of the left ventricle and requires suitable treatments and therapies; in the second case, the same morphological alteration of the myocardium in a subject appears perfectly healthy and suitable to the athletic skills of that subject, who is completely asymptomatic. It follows that prominent left ventricular trabeculation can be found in asymptomatic, healthy athletes as well as in subjects with hypertrophic or dilated cardiomyopathy 14. Thus, the difference between variants and LVNC may often be challenging. What makes the difference, in our opinion, is not the morphology but the function of the myocardium affected and the absence of other associated anomalies that determine the prognosis of these patients. Conclusion The variety in clinical presentation, genetic heterogeneity and phenotype of the irst transgenic animal model of an LVNC-associated mutation question the hypothesis that LVNC be a distinct cardiomyopathy. It seems to be a distinct phenotype or phenotypic, morphological expression of different underlying diseases rather than a distinct cardiomyopathy. We believe that any person can have non-compaction myocardium and that this development is not only about the genetic

4 Page 4 of 5 basis but also about physiological basis, such as exercise, and that this does not exclude sporting activities in which these subjects participate. Consent Informed consent was collected from the patients for the procedures performed. Consent for data publication was also collected from the patients. Written informed consent was obtained from the patients for publication of this manuscript and accompanying images. Figure 5: Two-dimensional trans-thoracic echocardiography (in apical fourchamber view) shows periapical and apical thickening with spongifom appearance of the myocardium and deep intertrabecular recesses with the association of a false tendon inside the cavity. Figure 6: A zoom on the left ventricular apex showed excessive myocardial trabeculation with deep recesses and false tendon (arrows head). References 1. Jenni R, Oechslin E, Schneider J, Attenhofer Jost C, Kaufmann PA. Echocardiographic and pathoanatomical characteristics of isolated left ventricular non-compaction: a step towards classi ication as a distinct cardiomyopathy. Heart Dec;86(6): Stollberger C, Finsterer J, Blazek G. Left ventricular hypertrabeculation/ noncompaction and association with additional cardiac abnormalities and neuromuscular disorders. Am J Cardiol Oct 15;90(8): Engberding R, Bender F. Identi ication of a rare congenital anomaly of the myocardium by two-dimensional echocardiography: persistence of isolated myocardial sinusoids. Am J Cardiol Jun 1;53(11): Pignatelli RH, McMahon CJ, Dreyer WJ, Den ield SW, Price J, Belmont JW, et al. Clinical characterization of left ventricular noncompaction in children: a relatively common form of cardiomyopathy. Circulation Nov 25;108(21): Maron BJ, Towbin JA, Thiene G, Antzelevitch C, Corrado D, Arnett D, et al. Contemporary de initions and classi ication of the cardiomyopathies: an American Heart Association Scienti ic 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 Apr 11;113(14): Elliott P, Andersson B, Arbustini E, Bilinska Z, Cecchi F, Charron P, et al.

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