The authors describe the case of a newborn presenting with a pulsatile abdominal mass that was subsequently diagnosed as a large congenital muscular left ventricular diverticulum. This case illustrates the role of multimodality imaging in the diagnosis and surgical planning of this rare congenital heart disease. The diverticulum was managed with surgical resection without the use of cardiopulmonary bypass. Unlike in previous case reports, this patient did not have any associated intracardiac defect.
Congenital left ventricular (LV) out-pouching may result from LV aneurysms, LV diverticula, and double-chambered left ventricle. LV diverticula have been classified as either fibrous or muscular. Muscular diverticula are defined as structures originating from the LV apex that have narrow connections to the left ventricle, contain all 3 layers of cardiac tissue, and contract synchronously with the rest of the left ventricle.
Case Presentation
A full-term female newborn was noted to have a pulsatile abdominal mass ( Figure 1 , Video 1 ). The prenatal course and delivery were unremarkable. By auscultation, her cardiac examination was normal, and she was acyanotic. A pulsatile mass that originated from the inferior portion of the sternum was seen extending along the abdominal midline to the umbilicus. The sternum was intact by palpation. The apex of the pulsatile mass was attached to the umbilical cord by a fibrous strand. The umbilicus was enlarged. However, the abdominal wall appeared intact.
Transthoracic echocardiography showed mesocardia with a pulsatile mass originating from the LV apex extending toward the abdomen ( Figure 2 A , Video 2 ). By color Doppler, there was unrestricted to-and-fro flow into the diverticulum ( Figure 2 B, Video 3 ). The remainder of the intracardiac anatomy was normal, with the exception of a small patent foramen ovale and a patent ductus arteriosus.
To better define the tissue characteristics and extent of the mass, cardiac magnetic resonance (CMR) imaging was performed and revealed a long tubular diverticulum arising from the LV apex, which then exited the thoracic cavity at the inferior aspect of the sternum. It then coursed anterior to the abdominal musculature, terminating in a blind pouch approximately 1cm cephalad to the umbilicus. The diverticulum measured 5 cm in length and 8 mm in its widest dimension. The LV entrance of the diverticulum measured 6 mm. The entire length of the diverticulum was contractile, without any evidence of thrombus or dyskinesia ( Figures 3 A and 3 B). The patient was referred for surgical resection of the diverticulum in light of the potential for traumatic rupture or thrombus formation.
Intraoperative findings were consistent with CMR imaging, demonstrating the diverticulum anterior to the abdominal wall covered by only a thin layer of skin and subcutaneous tissue ( Figure 4 ). The thin serosal layer covering the diverticulum appeared to be an extension of pericardium, and there was no obvious pericardial defect. The sternum was thin, and the xiphoid process was absent. There was no sternal cleft. The diverticulum was dissected from the surrounding tissue, and 3 sutures were placed at the LV opening to isolate the diverticulum. After the diverticular origin was suture closed, real-time transesophageal echocardiography was used to confirm no significant change in LV chamber size and preserved biventricular systolic function. The diverticulum was then resected.
