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True diverticulum of the left ventricle is very rarely seen in adults: the condition typically occurs in children and can be associated with other anatomic defects that involve the thoracoabdominal midline. Left ventricular diverticulum, which is usually asymptomatic and typically discovered incidentally, can pose a substantial challenge to the surgeon.
Herein, we report the case of a 46-year-old man who presented with worsening exertional angina and ST-segment elevation in the inferior electrocardiographic leads. After a stent was deployed in the patient's occluded right coronary artery, left ventriculography revealed outward pouching of the left ventricular inferior wall, suggesting an aneurysm or a contained free-wall rupture. Transesophageal echocardiography showed a sizable defect and a possible intracavitary thrombus. The presumptive diagnosis was a postinfarction subacute pseudoaneurysm of the left ventricle. However, during surgery, we saw no clots, intrapericardial blood accumulation, or perforation. A localized area of thinned muscle in the region of the posterior descending coronary artery was consistent with a ventricular diverticulum. The left ventricular epicardial surface was reinforced with a small bovine pericardial patch. The patient's recovery was uneventful. We discuss the forms of congenital left ventricular diverticulum and offer considerations regarding differential diagnosis.
True congenital diverticulum of the left ventricle (LV) is seen very rarely in adults. We report a case of congenital LV diverticulum in an adult patient, in whom clinical findings and imaging studies suggested a postinfarction pseudoaneurysm.
In September 2008, a 46-year-old man presented at our institution with a weeklong history of exertional angina that had become worse during the preceding night. He had experienced a similar prolonged episode 7 days before. An electrocardiogram showed ST-segment elevation in the inferior leads. Urgent coronary angiography revealed nonobstructive lesions on the left side and a 99% occlusion of the right coronary artery. Percutaneous coronary intervention was performed, and a stent was deployed in the distal right coronary artery. There was no residual stenosis. However, at the end of the procedure, left ventriculography revealed outward protrusion of the inferior wall, which suggested a LV aneurysm or a contained free-wall rupture (Fig. 1). Transesophageal echocardiography showed a sizable defect of the LV inferior wall and an echodense structure that suggested an intracavitary thrombus (Fig. 2). However, the presence of a muscle band could not be excluded.
On the basis of these findings and the likelihood of a contained free-wall perforation after an inferior myocardial infarction, the patient was taken to the operating room with the presumptive diagnosis of a postinfarction subacute pseudoaneurysm of the LV. Intraoperative transesophageal echocardiography showed the same findings as before (Fig. 3). During surgery, entry into the pericardium revealed no accumulation of blood or clots. The patient was placed on cardiopulmonary bypass, and the heart was arrested with use of antegrade and retrograde administration of blood cardioplegic solution. Inspection of the heart revealed no evidence of perforation. A localized area of thinned muscle in the region of the posterior descending coronary artery was consistent with a ventricular diverticulum (Fig. 4). Upon the removal of the cross-clamp and the resumption of spontaneous cardiac activity, the diverticulum was seen to have normal-appearing myocardium with no evidence of fibrosis or scar, and its contraction seemed normal, with no paradoxical movement. Because this anomaly was benign, congenital, and without characteristic aneurysmal appearance, it was decided that resection or plication would pose unnecessary risk. Instead, the epicardial surface of the ventricular wall was reinforced with a small patch of bovine pericardium. The rest of the procedure and the patient's postoperative recovery were uneventful.
First described in the 1800s,1 LV diverticulum is a very rare condition in adults2–5; it is seen in just 0.4% of cases at autopsy. Left ventricular diverticulum occurs chiefly in children and is often associated with other anatomic defects that involve the thoracoabdominal midline. As described by Cantrell and colleagues in 1958,6 these defects can involve structures other than these in the ventricular region and can present a substantial challenge to the surgeon. In 30% of cases, LV diverticulum is not associated with other congenital defects. The anomaly itself is usually asymptomatic, and it is typically discovered incidentally during diagnostic procedures.4
Congenital diverticulum of the ventricle is classified into 2 types. The muscular type usually originates at the apex and comprises mainly muscular fibers that contract synchronously with the ventricle. This type is often associated with other congenital defects. The other type is the fibrous diverticulum, which is composed of mostly fibrous tissue. The base of this diverticulum is usually wide and situated at the inferior or basal surface of the ventricle; therefore, it can be mistaken for an aneurysm of the LV.7–11
The possible presence of LV diverticulum should be considered during the evaluation of patients whose clinical findings suggest a postinfarction aneurysm. Early use of multiple cardiac imaging methods, coupled with a high index of suspicion, can lead to the differentiation of congenital LV diverticulum from aneurysmal formations.
Address for reprints: Hisham M.F. Sherif, MD, FACS, Department of Cardiac Surgery, Christiana Hospital, Christiana Care Health System, 4755 Ogletown-Stanton Rd., Suite 1E50, Newark, DE 19718