Left ventricular noncompaction cardiomyopathy (LVNC) : a case report

 

Left ventricular noncompaction cardiomyopathy (LVNC) : a case report

Introduction

LVNC is a relatively rare congenital disorder  characterized by prominent trabeculations and intertrabecular recesses that communicate with the ventricular cavity rather than the coronary circulation [1,2]. The American Heart Association classified it as a primary genetic cardiomyopathy. In a recent analysis [3] it was determined that 18% to 42% of left ventricular noncompaction cases were familial. However, the phenotype of patients with noncompaction can vary even within familial cases and range from clinically benign to fatal [4]Genetic and imaging studies are justified in first-degree relatives of affected individuals, to identify potential risks and the possibly causative genes [5,6].The clinical presentations varied ranging from asymptomatic patients to patients who develop ventricular arrhythmias, thromboembolism, heart failure, and sudden cardiac death[ 7]

 Here, we described the case of a man who presented with heart failure for the first time at 55 years of age. We discussed the diagnosis of this case.

Case report

In October  2020, a 55-year-old man was admitted to our hospital because of congestive heart failure during the previous twelve days. He had no chest pain, palpitations, or syncope. Physical examination revealed bilateral crackles in the lower-lung fields and edema of lower extremity.Neurologic findings were unremarkable.The results of routine biochemical tests were within normal limits. An electrocardiogram showed ST-T changes and (LBBB)(Figure 1).chest x-ray showed cardiomegaly(Figure 2)   The trabeculae were located on the posterolateral wall of the left ventricle (Figure 3). The blood flow into the intertrabecular recesses could be visualized by color Doppler (Figure-4). The ratio of non-compacted myocardium to compact myocardium at the end of the systole was > 2:1 (Figure 5). The patient also had mild systolic dysfunction and an ejection fraction of 40% (Figure 6). Moderate mitral and tricuspid regurgitation and Mild pulmonary hypertension were noted (peak systolic pulmonary artery pressure,40  mmHg). Morphologically, the heart valves were normal, and no coexisting congenital anomaly was found. These findings led to the diagnosis of LVNC. The patient had no significant arrhythmias during her hospital stay. After medical management with β-blockers, ACEI, a loop diuretic, spironolactone and digoxin, he was asymptomatic at the 1-month follow up examination.

ECG

(Figure 1) LBBB with non specific ischemic changes 

CX-R

Figure 2 Cardiomegaly 

Figure 3

Left ventricular with more than 3 trabeculations protruding from the posterolateral wall visualized by two-dimensional echocardiography.

Figure 4

Left ventricular trabeculations and blood flow into the intertrabecular recesses  visualized by Color Doppler flow imaging.

Figure 5

The ratio between noncompacted and compacted walls was more than 2 in the diastole.

Figure 6

The result of the left ventricular ejection fraction measured  indicated that the systolic function was impaired.

Discussion

LVNC is a structural abnormality of the left ventricular (LV) myocardium of uncertain etiology and mechanism but is generally considered genetic in nature. In some patients, neuromus-cular disorders and chromosomal defects are noted.[8,9].LVNC cardiomyopathy (OMIM No. 604169) was first described at the time of autopsy because current imaging mo-dalities were not available. Feldt et al [10].The first report of an echocardiographically diagnosed case of LVNC was by Engberding and Bender[11] in 1984. In 1990, the term noncompaction was first introduced by Chin et al[12] In 1997, cardiac magnetic                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   resonance imaging (CMR) was initially used to identify LVNC by Hany et al.[12]The etiology of LVNC is uncertain, but it is speculated that it results from a disturbed compaction process during early development of the LV myocardium.[13].It is believed that LVNC result from a failure of the final phase of cardiac development, the myocardial compaction process. Failure of the compaction process results in deep intertrabecular recesses between the abnormal trabeculations. Mutations in the murine genes Casz1,[14]  LVNC have been considered to be rare. However, Andrews et al 30  reported that 9% of 104 children with primary cardio-myopathy had LVNC. In adults referred for echocardiogra-phy, the prevalence of LVNC reportedly ranged from 0.01% to 0.3%, [15,16,17].  We have described the diagnosis of LVNC in a 55-year-old man. The patient had been asymptomatic until mild symptoms of congestive heart failure developed during twelve days before initial presentation. He  responded well to medical management of this relatively rare cause of heart failure. Tools for the diagnosis of LVNC are echocardiography, contrast ventriculography, computed tomography (CT) and magnetic resonance imaging (MRI) [18] .Widely accepted diagnostic criteria by Jenni et al. [19,20] were as follows: (1) Absence of coexisting cardiac abnormalities. (2) Segmental thickening of myocardial wall of left ventricle with two layers: a thin epicardial layer and a thick endocardial layer with prominent trabeculations and deep recesses. The ratio of non-compacted myocardium to compact myocardium at the end of systole is > 2:1. (3) The trabeculae are usually located on the apical/lateral, middle/bottom walls of the left ventricle. Most non-compacted segments are hypokinetic. (4) The flow between the intertrabecular recesses can be identified by using the color Doppler method.  In patients with LVNC, treatment options vary on an individual basis, ranging from medical management in mild cases to heart transplantation in patients with refractory symptoms [4] Besides treatment for congestive heart failure and antiarrhythmic therapy, if indicated, anticoagulation therapy is recommended because of the risk of systemic embolism. [2]Monitoring asymptomatic patients is encouraged, whether diagnosis is incidental or the consequence of familial screening, because of possible future complication in those individuals [3,15] Interestingly, LVNC can be identified with overlapping features of other car-diomyopathies, as well as with congenital heart disease.(2,4,5)The diagnosis may be made at any age and in either sex.[18]The prognosis of patients with LVNC is determined by the degree and progression of heart failure, presence of thromboembolic events and arrhythmias [9].Our patient’s mild symptoms responded well to medical therapy, and her short-term prognosis was excellent.

Therefore, we suggested that the diagnosis of suspected myocardial noncompaction should be carefully evaluated by imaging methods to avoid inappropriate and exaggerated diagnoses.

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Dr. Tofayel uddin ahmed

Associate professor and head Department of cardiology

Community Based Medical College, Bangladesh

Phone: +8801711906682

Email: tuahmed@gmail.com