Isolated Congenital Left Ventricular Diverticulum: A Case Report and Differential Diagnosis.

We describe a case of an incidental finding of diverticulum in a patient presented to the Emergency Department for atypical chest pain, and we analyze the challenging differential diagnosis with aneurysm, pseudoaneurysm, and ventricular cleft.

INTRODUCTION

The isolated congenital left ventricular (LV) diverticulum is a rare cardiac abnormality with a reported prevalence of 0.4%;[12] however, this is the first case observed in our institution in about 25,000 transthoracic echocardiographic examinations performed over the last 5 years. Usually following an asymptomatic course, in some patients, it may cause heart failure, thrombus formation, arrhythmia, rupture, or chest pain.

CASE REPORT

A 35-year-old male presented to the Emergency Department with the complaint of an atypical chest pain. He had no known cardiac risk factors, neither previous cardiologic history. There was no family history of any heart disease. Physical examination was unremarkable; his blood pressure was 120/80 mmHg, and heart rate was 75 bpm. The routine blood and biochemical tests results were within the normal range. The 12-lead electrocardiogram (ECG) showed sinus rhythm without any ischemic changes. A transthoracic echocardiogram was carried out revealing a two-cavity formation communicating with the left ventricle, in the context on septum and inferior wall, with a narrow neck and a large cavity, whose external layer was normal contractile myocardium. In addition, the patient underwent a contrast–echocardiography (Bracco International B.V. Strawinskylaan 3051, NL-1077 ZX, Amsterdam, Netherlands) confirming the previous findings and showing no thrombus in the cavity of diverticulum; a three-dimensional-echocardiography showed a double–entrance to this formation with an incomplete septum in the cavity and normal contractility of the surrounding myocardium. These findings identify this formation as a cardiac diverticulum [Figure 1]. A stress echo was performed not revealing inducible ischemia; the ECG-monitoring was also negative for arrhythmias.

Figure 1

Image of diverticulum in transthoracic echocardiography (a), Contrast-echocardiography (b), and three-dimensional echocardiography (c)

DISCUSSION

Isolated congenital LV diverticulum is a rare, nonhereditary cardiac abnormality, with a reported prevalence of 0.4%;[12] however, this is the first case observed in our institution in about 25,000 transthoracic echocardiographic examinations performed over the last 5 years. LV diverticulum is defined as an outpouching containing the endocardium, myocardium, and pericardium.[3] It is commonly detected among children along with midline thoracoabdominal defects. Based on its histological composition and location, a ventricular diverticulum can be classified as fibrous or muscular. The fibrous congenital diverticulum is usually subannular (submitral or subaortic) and frequently causes aortic or mitral regurgitation[4] and is not associated with cardiac and somatic abnormalities. The muscular congenital diverticulum includes all three cardiac layers and is usually located in the apex; it may occur in association with cardiac and/or extracardiac defects (such as Cantrell's syndrome) and has all the cardiac layers. They arise due to defects in cardiac development or due to congenital myocardial thinning. It is worth noting that diverticula contract with systole are narrow-mouthed, with a wide outpouching extending beyond the confines of the anatomic LV cavity and myocardial margin;[5] this is a morphological feature that helps to differentiate diverticulum from clefts. The main differential diagnoses are ventricular cleft, pseudoaneurysms, and aneurysms. Congenital myocardial clefts are fissures commonly seen in the basal inferior wall of the left ventricle and the middle of apical segments of the interventricular septum. These regions are prone to developmental myocardial disarray, a histological abnormality of the crossing and interdigitation of the myocytes. A cleft is localized in the compacted layer of the myocardium. Clefts are contractile and may obliterate during systole. They can be seen either single or pairs with no apparent relationship to age, gender, LV function, or mass. Myocardial clefts are congenital anomalies that probably have no prognostic significance. While clefts can be relatively easily diagnosed during a magnetic resonance imaging scan, echocardiographic visualization can be challenging, particularly if the cleft location does not coincide with standard acquisition planes.[6] LV aneurysms and pseudoaneurysms usually occur as a late complication of myocardial infarction or a consequence of cardiac trauma. A narrow neck and synchronous contractility along with all three ventricular layers indicate a diverticulum.[7] In contrast, aneurysm (congenital or acquired) or pseudoaneurysm shows akinesia or paradoxical contractility. The wall of an aneurysm is characterized by a thinned myocardium while the wall of a pseudoaneurysm contains only a pericardial layer. LV diverticula are often clinically silent but may be associated with systemic embolism, arrhythmias, heart failure, and cardiac rupture. The prognosis of such cases is not clearly defined. A series of 108 patients with LV diverticulum with a mean follow-up of 50 months was reported.[8] The incidence of adverse events in symptomatic patients with isolated LV diverticulum has increased during long-term follow-ups. None of the presented patients, however, experienced cardiac death. Considering the inadequacy of data for universal guidance, most authors advocate surgery only for patients who are symptomatic and for those who have a large diverticulum or are believed to be at high risk for rupture. Interestingly, Jain et al. recently reported the first transcatheter closure of an isolated congenital LV diverticulum in a 12-year-old symptomatic girl.[9] This case demonstrated that transcatheter device closure of LV diverticulum is a safe and acceptable option in suitable cases. However, the prospective evidence is needed to investigate the safety of this procedure in the management of this condition. In the case described, because of the lack of specific symptoms, we have planned a periodical follow-up to evaluate the possible enlargement of the diverticulum; moreover, we have planned a computed tomography that is useful for better anatomical definition and differential diagnosis. In conclusion, isolated congenital LV diverticulum is a rare congenital cardiac abnormality. Echocardiography is useful for diagnosis and differential diagnosis. Its clinical course and therapy are not well defined but, due to its generally benign prognosis, surgical treatment can be considered only in symptomatic patient.

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Conflicts of interest

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