Isolated noncompaction of the myocardium: multiplane transesophageal echocardiography diagnosis in an adult

Left ventricular noncompaction cardiomyopathy: updated review

The first case of noncompaction was described in 1932 after an autopsy performed on a newborn infant with aortic atresia/coronary-ventricular fistula. Isolated noncompaction cardiomyopathy was first described in 1984. A review on selected/relevant medical literature was conducted using Pubmed from 1984 to 2013 and the pathogenesis, clinical features, and management are discussed. Left ventricular noncompaction (LVNC) is a relatively rare congenital condition that results from arrest of the normal compaction process of the myocardium during fetal development. LVNC shows variability in its genetic pattern, pathophysiologic findings, and clinical presentations. The genetic heterogeneity, phenotypical overlap, and variety in clinical presentation raised the suspicion that LVNC might just be a morphological variant of other cardiomyopathies, but the American Heart Association classifies LVNC as a primary genetic cardiomyopathy. The familiar type is common and follows a X-linked, autosomal-dominant, or mitochondrial-inheritance pattern (in children). LVNC can occur in isolation or coexist with other cardiac and/or systemic anomalies. The clinical presentations are variable ranging from asymptomatic patients to patients who develop ventricular arrhythmias, thromboembolism, heart failure, and sudden cardiac death. Increased awareness over the last 25 years and improvements in technology have increased the identification of this illness and improved the clinical outcome and prognosis. LVNC is commonly diagnosed by echocardiography. Other useful diagnostic techniques for LVNC include cardiac magnetic resonance imaging, computerized tomography, and left ventriculography. Management is symptom based and patients with symptoms have a poorer prognosis. LVNC is a genetically heterogeneous disorder which can be associated with other anomalies. Making the correct diagnosis is important because of the possible associations and the need for long-term management and screening of living relatives.

Left ventricular noncompaction

According to the World Health Organization classification of cardiomyopathies, left ventricular noncompaction is still an unclassified cardiomyopathy. In 2006, the American Heart Association classified this entity as a primary cardiomyopathy of genetic origin. In 2008, the European Society of Cardiology updated the classification scheme similar to the World Health Organization classification. At present, there is no consensus on the diagnostic criteria, and diagnosis is based on the morphologic features identified by cardiac imaging studies or at autopsy. Due to lack of standardization of the diagnostic criteria and little awareness of this condition among clinicians, the true prevalence of this disease is not clear. There is no specific therapy for this condition. However, it seems prognosis is much better than initially reported. The current status of diagnosis, prognosis, and management of isolated noncompaction in adults is discussed in this review.

Primary noncompaction of the ventricular myocardium from the morphogenetic standpoint

This review compiles the current knowledge of normal and abnormal myocardial morphogenesis to facilitate an unambiguous diagnosis of primary myocardial noncompaction. During the early stages of development, the formation of trabeculae with the resulting increase in myocardial surface is a adaptation of the rapidly growing heart to improve nourishment by exchange diffusion from the cardiac lumen. Once the coronary vasculature has developed, the switch to cardiac nutrient supply through active circulation from the subepicardial space is paralleled by gradual compaction of the myocardial trabeculae. This results in a decrease of the inner, trabeculated myocardial layer with a parallel increase in thickness of the outer, compact myocardial layer. Similar to the direction of coronary arterial development, this process proceeds from the epicardium toward the endocardium and from the base of the heart to the apex. Based on developmental data, congenital myocardial noncompaction represents a failure of normal embryonic myocardial maturation. The time of arrest of this process will determine the extension of myocardial noncompaction within the ventricle. Whereas disturbances of myocardial microcirculation are frequent in these hearts, direct communications between the myocardial cavity and the coronary arteries (sinusoids) do not belong to this morphogenetic entity.

Isolated noncompaction of the left ventricular myocardium complicated by thromboembolic cerebrovascular accident in a patient with essential thrombocythemia

There are up to 3 prominent trabeculations in the normal left ventricle. Sometimes, left ventricle has excessive trabeculations and intertrabecular recesses. This appearance is called as noncompaction or hypertrabeculation. It may be together with other structural cardiac abnormalities (non-isolated) or without them (isolated). Here we present a rare case with isolated noncompaction of the left ventricular myocardium. Rarity comes from its coexistence with essential thrombocythemia. In addition, it was complicated by thromboembolic cerebrovascular accident.

Non-compaction of the ventricular myocardium

Non-compaction of the left ventricle (LVNC) is a disorder of endomyocardial morphogenesis that results in multiple trabeculations in the left ventricular (LV) myocardium. This rare disorder is characterized by an excessively prominent trabecular meshwork and deep intratrabecular recesses. This idiopathic cardiomyopathy is characterized by an altered structure of the myocardial wall as a result of intrauterine arrest of compaction of the myocardial fibers in the absence of any coexisting congenital lesion. It can be associated with neuromuscular disorders and can co-exist with other cardiac malformations, and it is accompanied by depressed ventricular function, systemic embolism and ventricular arrhythmia. Echocardiography is the method of choice for diagnosing LVNC, but the correct diagnosis is often missed or delayed due to a lack of knowledge concerning this uncommon disease and its similarity to other diseases of the myocardium and endocardium. There is a two-layered structure of the myocardial wall consisting of a thin compacted epicardial layer and a thick non-compacted endocardial layer with prominent trabeculations and deep recesses.

Wide spectrum of presentation and variable outcomes of isolated left ventricular non-compaction

OBJECTIVES

To investigate diagnostic routes, echocardiographic substrates, outcomes and prognostic factors in patients with isolated ventricular non-compaction (IVNC) identified by echocardiographic laboratories with referral from specialists and primary care physicians.

PATIENTS AND DESIGN

Since 1991, all patients with suspected IVNC were flagged and followed up on dedicated databases. Patients were divided into symptom-based and non-symptom-based diagnostic subgroups.

RESULTS

65 eligible patients were followed up for 6-193 months (mean 46 (SD 44). In 53 (82%) patients, IVNC was associated with variable degrees of left ventricular (LV) dilatation and hypokinesia, and in the remaining 12 (18%) LV volumes were normal. Diagnosis was symptom based in 48 (74%) and non-symptom based in 17 (26%) (familial referral in 10). The non-symptom-based subgroup was characterised by younger age, lower prevalence of ECG abnormalities, better systolic function and lower left atrial size, whereas the extent of non-compaction was not different. No major cardiovascular events occurred in the non-symptom-based group, whereas 15 of 48 (31%) symptomatically diagnosed patients experienced cardiovascular death or heart transplantation (p = 0.01, Kaplan-Meier analysis). Independent predictors of cardiovascular death or heart transplantation were New York Heart Association class III-IV, sustained ventricular arrhythmias and left atrial size.

CONCLUSIONS

IVNC is associated with a broad spectrum of clinical and pathophysiological findings, and the overall natural history and prognosis may be better than previously thought. Adult patients with incidental or familial discovery of IVNC have an encouraging outlook, whereas those who have symptoms of heart failure, a history of sustained ventricular tachycardia or an enlarged left atrium have an unstable course and more severe prognosis.

Incidence and characteristics of left ventricular false tendons and trabeculations in the normal and pathologic heart by second harmonic echocardiography

We sought to review echocardiographic incidence of anomalous images (AI) as false tendons and trabeculations of the left ventricle (LV) in light of recent advancements in echocardiographic evaluation of heart anatomy. In 1580 patients the presence of false tendons, trabeculations, or thrombi was evaluated with transthoracic echocardiography and correlated to clinical characteristics and echocardiographic parameters. Incidence of AI was 46.7% (75% false tendons, 23% trabeculations, 2% thrombi), slightly higher in pathologic (48.9%) than in normal hearts (40.8%). AI were more frequent in male patients (52%) than in female patients (39.7%) and associated with LV dilatation, hypertrophy, and systolic dysfunction. False tendons and trabeculations were not related to age. Male sex was the most significant independent predictor of AI. In 2 patients, isolated LV noncompaction of myocardium was diagnosed and confirmed by magnetic resonance imaging. This study shows a high prevalence of AI for patients with and without pathologic hearts suggesting the need of updating LV echocardiographic anatomy. It also emphasizes the necessity for an awareness of these anatomic variants when evaluating patients for mural thrombi and cardiomyopathies.

Left ventricular hypertrabeculation/noncompaction

In normal human hearts the left ventricle (LV) has up to 3 prominent trabeculations and is, thus, less trabeculated than the right ventricle. Rarely, more than 3 prominent trabeculations can be found at autopsy and by various imaging techniques in the LV. For this abnormality, different synonyms are used such as spongy myocardium, LV noncompaction, and LV hypertrabeculation (LVHT). In this review it is stated that: (1) LVHT has a higher prevalence than previously thought and the prevalence of LVHT seems to increase with the improvement of cardiac imaging; (2) because LVHT is most frequently diagnosed primarily by echocardiography, echocardiographers should be aware and trained to recognize this abnormality; (3) LVHT is frequently associated with other cardiac and extracardiac, particularly neuromuscular, disorders; (4) there are indications that the cause of LVHT is usually a genetic one and quite heterogeneous; and (5) controversies exist about diagnostic criteria, nomenclature, prognosis, origin, pathogenesis, and the necessity to classify LVHT as a distinct entity and cardiomyopathy by the World Health Organization.

Noncompaction of the ventricular myocardium: report of two cases with bicuspid aortic valve demonstrating poor prognosis and with prominent right ventricular involvement

Noncompaction of the ventricular myocardium is a rare, unclassified cardiomyopathy due to an arrest of myocardial morphogenesis. The characteristic echocardiographic findings consist of multiple, prominent myocardial trabeculations and deep intertrabecular spaces communicating with the left ventricular (LV) cavity. The disease typically involves the LV myocardium, but right ventricular (RV) involvement is not uncommon. The clinical manifestations include heart failure (HF) signs, ventricular arrhythmias and cardioembolic events. Noncompacted myocardium may occur as an isolated cardiac lesion, as well as it can be in association with congenital anomalies. We describe two illustrative cases of noncompaction of the ventricular myocardium, a 19-year-old male with bicuspid aortic valve and progressive worsening of HF, and a 61-year-old male with marked RV involvement in addition to LV apical involvement, both with the typical clinical and echocardiographic features of the disease.

Isolated noncompaction cardiomyopathy presenting with paroxysmal supraventricular tachycardia--case report and literature review

Isolated noncompaction cardiomyopathy is an exceedingly rare congenital cardiomyopathy. A case of isolated noncompaction cardiomyopathy is reported and the literature on the subject collected through a comprehensive literature search is reviewed. Fewer than 100 cases of this condition have been reported. Isolated noncompaction cardiomyopathy is caused by a defect in cardiac morphogenesis resulting in an arrest of compaction of loose interwoven meshwork of myocardial fibers during intrauterine life, which results in severe systolic dysfunction as well as undue hypertrophy of the involved walls of the ventricles. Although the most frequent sites involved are left ventricular apex and inferior wall, involvement of other left ventricular walls and right ventricle has also been reported. Etiology of the isolated noncompaction of myocardium is not clear. Familial cases have been reported and the mode of inheritance is heterogeneous. In X-linked form of the disease, a locus has been found on Xq28, and mutations have been reported in G4.5 gene. The age of onset of symptoms ranges from infancy to the geriatric age. Patients with isolated noncompaction cardiomyopathy have a high incidence of heart failure, arrhythmias, and thromboembolism. The most common presentation is congestive heart failure. Arrhythmias include atrial arrhythmias, ventricular tachycardia, and sudden cardiac death. The patient reported in this article presented with paroxysmal supraventricular tachycardia. Echocardiography is the procedure of choice to establish diagnosis. Due to the lack of associated cardiac anomalies, antenatal detection is difficult. The treatment is that for congestive heart failure, arrhythmias, and thromboembolism. The end-stage congestive heart failure is managed with heart transplantation and potential life-threatening ventricular tachyarrhythmias with an implantable cardioverter defibrillator. Prognosis is poor and the common causes of death are intractable heart failure and sudden cardiac death.

Noncompaction of the ventricular myocardium: the use of contrast-enhanced echocardiography in diagnosis

We describe a case of noncompaction of the ventricular myocardium diagnosed in the preoperative evaluation of a patient undergoing renal transplantation. Ventricular noncompaction is characterized by numerous prominent trabecular recesses with intratrabecular blood from the ventricular cavity. Color Doppler was suggestive of intramyocardial flow. With contrast-enhanced echocardiography the endocardial borders were clearly demarcated, allowing for visualization of trabecular recesses and intratrabecular flow. Contrast-enhanced echocardiography facilitates the diagnosis of noncompaction of the ventricular myocardium, circumventing the need for invasive diagnostic testing.