Isolated Finger-Like Left Ventricular Diverticulum in a Stable Boy
A 4-year-old boy was referred to our hospital because he had a finger-like protrusion, or out-pouching, of the anterior abdominal wall. The protrusion was about 3.7 cm in length and had no obvious changes after birth. It beat simultaneously with the left ventricle (Figure 1 and online-only Data Supplement Movie). Between the protrusion and xiphoid process, a tubular structure was found in the abdominal wall that contracted during systole and was best seen during diastole. Systematic questioning of the patient’s parents elicited no description of significant symptoms. Cardiac examination revealed normal peripheral pulse and normal heart sounds. Electrocardiography revealed no abnormal findings except transient arrhythmia when the protrusion was pressed (Figure 2). No clinical features of midline thoracoabdominal defects were noted, such as sternal deficiency, diaphragmatic hernia, diastasis recti, and umbilical hernia (Figure 3). Transthoracic echocardiography showed normal cardiac development, morphology, and left ventricular function (Figure 4). Both transesophageal and transthoracic color Doppler indicated that an accessory muscular vessel was located at the anterior apical portion of the left ventricle. The vessel passed through the diaphragm and attached to the xiphoid process, then the vessel located itself in the anterior abdominal wall. Finally, it protruded out of the wall with normal skin at the anterior midline above the umbilicus. Below the xiphoid process, the maximal inner and outer diameters of vessel were 0.2 cm and 0.5 cm during the cardiac cycle, respectively. Blood flow and arterial spectrum were detected in the vessel (Figure 5). The vessel’s blood pressure and systemic blood pressure were 108/21 (61) mm Hg and 114/81 (88) mm Hg, respectively. On the basis of these findings, the boy was diagnosed as having a congenital left ventricular diverticulum.
Via a median sternotomy, the verticulum was resected and the incision rim was closed with reinforcing felt strips and mattress sutures to plicate the edge. The whole length of vessel was 17.5 cm (Figure 6). Histological examination showed the wall of diverticulum consisting of exclusively cardiac muscle without fibrous tissues, containing all 3 layers of the heart. The distal diverticulum that protruded out of abdominal wall even had normal skin and subcutaneous tissue (Figure 7). The boy was recovered to discharge in 7 days after the operation.
The first recorded successful resection of a ventricular diverticulum was reported by Roessler in 1944.1 The incidence of left ventricular diverticulum has been reported as 0.05% of all congenital heart malformations.2 The pathogenesis of congenital ventricular diverticulum is not clear, although an embryological developmental defect has been proposed. Acquired causes such as infection, ischemia, and trauma can also cause diverticula. Pathologically, congenital ventricular diverticulum has been classified as muscular or fibrous type, according to its histological characteristics. The wall of the diverticulum consists of 3 layers, endocardium, myocardium and pericardium, regardless of which type. The myocardial layer of the fibrous diverticulum seems to have been replaced gradually with fibrous tissues. But in some cases, the inner layers of diverticulum have had both muscular and fibrous tissues. It is uncertain whether these fibrous tissues were secondary to myocardial fibrosis or not.3–4
Most patients with congenital diverticula will remain asymptomatic with no complication during long-term follow-up. Unfortunately, a few patients could have a potential risk for systemic embolism, spontaneous rupture, or cardiac arrhythmia, which might lead to sudden death. To prevent these mortal or morbid complications, early surgical repair is reasonable even in an asymptomatic patient.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/cgi/content/full/119/22/2951/DC1.