Ebstein’s anomaly is a rare disease that exhibits a wide variety of clinical features, making it difficult for clinicians to consistently accumulate experience.8–11 Generally, neonatal Ebstein’s anomaly is known to be hemodynamically unstable, difficult for surgical correction, and associated with high mortality. However, in the case of non-severe Ebstein’s anomaly, the diagnosis is often delayed because the symptoms perceived by the patient are unclear. In fact, 42.9% of the patients visiting our hospital were diagnosed with the disease only in adulthood, of which 84.7% of the patients had NYHA functional class I or II. As such, patients’ symptoms are often not severe, and as can be seen in Table 3, there have been quite a lot of cases of medical treatment rather than active surgical correction. Another big reason for encouraging the judgment of such medical support is that the experience of follow-up observation with medical support was not bad in terms of survival compared with that of various active surgical treatments (Fig. 1). Until relatively recently, there have been concerns about whether surgical correction for Ebstein's anomaly has an advantage over medical support because of the increase in mortality and morbidity due to repeated reoperations after surgical repair. Indeed, the results of our hospital as well as other centers reveal that the 10-year survival of Ebstein’s anomaly is more than 90%. 5, 9, 12, 13
Many studies have reported the excellence of cone repair,14–18 however, although it is performed in our institution from 2008, only 30 operations have been performed till date. A total of 5 patients required reoperation after cone repair; however, patients who underwent cone repair from 2014 did not require a reoperation (Table 5). Therefore, it can be considered that we have overcome the initial learning period relatively quickly. Remarkably, the proportion of patients with complete AV block occurrence and those with moderate or severe TR remaining after surgery were significantly less in the Cone repair group than in the conventional repair group. In addition, in the case of Cone repair, no mortality was reported (Table 4). Moreover, because the age of the Cone repair group patients was significantly higher at surgery, it may be thought that patients with a relatively mild form of Ebstein’s anomaly were included. However, cone repair was not specifically avoided in patients of young age.
Before the start of treatment, a large number of patients (85 patients, 50%) had already experienced several types of arrhythmias (Table 2). Some patients experienced multiple types of arrhythmias. Of the patients whose arrhythmia was found before starting treatment, 27 patients did not show arrhythmias after treatment. However, among the patients whose arrhythmia was not clearly identified before treatment, 33 cases showed new arrhythmias after starting treatment. This suggests that the burden of arrhythmia is very high in the case of Ebstein’s anomaly.18 It is thought that arrhythmia may develop even after improving the hemodynamic state and that responding with active interest is necessary.
Studies have proved that Ebstein’s anomaly is not a simple tricuspid valve abnormality and is associated with LV or left atrial dysfunction. 19, 20 However, it is not easy to present standardized indicators in clinical practice. It is known than hemodynamic indicators determined by cardiac MRI can be used as relatively objective indicators because there are several limitations in evaluating RV function and TR using echocardiography. Thus, it is difficult to generalize because it was not performed in all patients, but the results of cardiac MRI performed within 6 months and after surgery were reported for 17 patients of the conventional repair group (54.8%) and 18 patients of the Cone repair group (60%). However, no statistically significant difference was noted between the conventional and Cone repair group. After surgery, the degree of TR significantly decreased in both the groups, as well as the right ventricular end diastolic volume (RVEDV), right ventricular end systolic volume (RVESV), and RV ejection fraction (EF) presented a decreasing tendency (Table 4). It seems reasonable to interpret these changes as changes associated with a decrease in TR amount rather than a significant decrease in RV function after surgery. In addition, postoperative aortic stroke volume (SV) increased after surgery in both the groups. This result can be interpreted as after surgery, the overall cardiac output increased. Based on these results, if no mortality is associated with surgery and the frequency of reoperation is significantly lower than that of TVR or conventional TV plasty, it can be expected that chronic low cardiac output can be more actively improved and chronic hepatic congestion or right heart failure can be reduced by Cone repair. In other words, if we actively advance the operation age for Ebstein’s anomaly than the existing age, it can expected that the outcome of patients will be slightly improved.
Study Limitations
This was a single center study with a small number of patients. In addition, limited data were analyzed due to the retrospective nature of the study.