Double chambered left ventricle-Two chambers are not better than one.

Abstract

In this month's Journal,1 Ali and colleagues present a case series consisting of two adults who underwent surgical resection for a double chamber left ventricle (DCLV). The first case was an 18-year-old female with several years of progressive chest pain and dyspnea who was ultimately found to have both a double chamber right ventricle (DCRV) and DCLV after transthoracic echocardiography (TTE) and cardiac catheterization. She underwent surgical resection of the fibromuscular bands in both ventricles with an uncomplicated postoperative course. The second case was a 27-year-old male with a history of supravalvular aortic stenosis that had been previously addressed who on TTE was found to have aortic regurgitation, aortic stenosis, and DCLV with elevated left ventricular outflow tract and accessory chamber (AC) gradients. He underwent mechanical aortic valve replacement, ascending aorta replacement, and muscle bundle excision with a course notable for delayed sternal closure and retroperitoneal hematoma. Both patients had technically successful operations with band resection and appropriate biventricular function confirmed on TTE. Both survived their index operations and had resolution of their symptoms, with the second patient dying at 6 months due to complications from anticoagulation. The authors should be congratulated for the successful identification and operative treatment of these patients. DCLV is an incredibly rare diagnosis and is even less common than its counterpart DCRV—which is seen in less than 2% of all congenital cardiac anomalies.2 Ali and colleagues successfully differentiated DCLV from other similar pathologies such as left ventricular aneurysms and left ventricular diverticulum. This is critical given their difference in etiology and overall management. Those with asymptomatic DCLV do not require surgical intervention. Symptoms are rare but can present as fatal tachyarrhythmias or heart failure. Patients can also be found to have mid-ventricular obstructions, particularly those with superior–inferior arrangements according to Bao et al.3 Those who are intervened upon typically undergo resection with patch reconstruction or cardiac transplant for large communications.4 Furthermore, diagnosing DCLV can be a challenge in and of itself. Some patients, including the second case of this study, have previous imaging that does not confirm the presence of DCLV.5 This just reiterates the importance of having a high clinical suspicion. Nevertheless, TTE is typically the first test performed and serves as a fairly reliable starting point. Bao et al.3 showed that in their series of nine patients, eight were correctly diagnosed during their initial TTE. Although a tissue diagnosis would be the best confirmatory test, a second imaging modality is typically used to confirm the diagnosis. The authors used cardiac catheterization and magnetic resonance imaging (MRI) in their first and second case, respectively, as their second modality of choice. The advantages of cardiac MRI are stated throughout the literature. It offers high inherent contrast resolution, good spatial and temporal resolutions, a wide field of view, multiplanar imaging capabilities, and the absence of radiation.4, 6 Gadolinium is particularly useful as a similar enhancement of the AC wall compared to the remainder of the left ventricular myocardium supports the diagnosis of DCLV.7 We (Figure 1) commend the authors on their work with this complex patient population. Both cases presented were unique and challenging. The authors demonstrated the ability to address DCLV in addition to the patient's existing congenital abnormalities. Furthermore, they demonstrate the ability to do so through both a transaortic and transmitral approach. DCLV is an incredibly rare diagnosis, making it difficult to establish practice guidelines. One should always pause when deciding when and how to operate on these patients. Still, Ali and colleagues add to the body of literature that suggests operating on DCLV can be done safely and that patients may derive a meaningful benefit. This work was supported by a research grant from NHLBI/NIH (No. T32HL007849). The content is solely the responsibility of the authors and does not represent the official views of the National Institutes of Health. The authors declare no conflict of interest.