Double-chambered right ventricle (DCRV) is a rare condition. Stenosis of DCRV is progressive, and early surgical intervention is recommended for patients whose symptoms and/or pressure overload of right ventricular (RV) inflow are progressive. However, there are few data regarding the postoperative course of DCRV, and the surgical indications for asymptomatic patients remain to be determined. We retrospectively investigated 38 consecutive patients who were diagnosed with DCRV and underwent surgical intervention from 1981 to 2009. Moreover, we identified 29 patients in whom long-term follow-up transthoracic echocardiographic data were available and investigated the postoperative recurrence of DCRV by evaluating the systolic pressure of RV inflow before, immediately, and in the long term after surgical intervention. The mean follow-up period was 11.0 ± 8.8 years. There were no deaths and no surgical reinterventions during the long-term follow-up period. Among 29 patients with long-term follow-up echocardiographic data, there was no recurrence of DCRV. In these patients, the systolic pressure of RV inflow by echocardiography before, immediately, and long-term after surgical intervention was 80 ± 26, 30 ± 11, and 25 ± 6 mm Hg, respectively. In conclusion, the surgical outcomes and postoperative prognosis beyond 10 years of DCRV are favorable, and neither recurrence of DCRV nor fatal arrhythmias develop during the long-term follow-up period.
A double-chambered right ventricle (DCRV) is a rare congenital condition in which one or more abnormal muscle bundles divide the right ventricle (RV) into a proximal high-pressure chamber and a distal low-pressure chamber. The pressure gradient produced in the RV can cause chest pain or heart failure. Approximately 80% to 90% patients with DCRV have the perimembranous type of ventricular septal defect. Most patients are diagnosed with DCRV in childhood or adolescence, but some patients are diagnosed in adulthood. DCRV is a progressive condition, but some patients are asymptomatic in spite of a high pressure gradient. This creates difficulty in determining the optimal timing of surgical intervention for DCRV. Early surgical intervention is recommended for patients who exhibit progressive symptoms and/or RV inflow pressure overloading. Some reports have recommended surgical resection of the bundle and repair of other anomalies as soon as a diagnosis is made. However, the recurrent rate after surgical resection is unknown, and there are no detailed follow-up data by serial echocardiography on the long-term postoperative course of DCRV. The purpose of this study was to clarify the long-term prognosis of DCRV, including the recurrent rate of DCRV and occurrence of arrhythmias beyond 10 years after surgery.
Methods
We retrospectively investigated 38 consecutive patients who were diagnosed with DCRV and underwent a surgical intervention from 1981 to 2009 at Tenri Hospital. The study protocol was approved by the institutional ethics committee at Tenri Hospital. The criteria for the diagnosis of DCRV were according to previous reports.
We investigated the following clinical characteristics before and after surgery: gender; age at the time of surgery; follow-up period; pressure data obtained using cardiac catheterization and transthoracic echocardiography; and co-existing conditions, such as ventricular septal defect, atrial septal defect, persistent left superior vena cava, and infectious endocarditis. The surgical approaches, postoperative mortality rate, and occurrence of cardiac events were also evaluated. All the patients underwent surgical correction through median sternotomy combined with cardiopulmonary bypass. Associated cardiac anomalies were corrected simultaneously. Cardiac events were defined as cardiac death, hospitalization due to heart failure, arrhythmias, or surgical reintervention. Arrhythmias included ventricular tachycardia, frequent ventricular premature contraction, atrial tachycardia, atrial fibrillation, and atrial flutter.
All the patients underwent preoperative evaluations involving cardiac catheterization, and 33 patients (87%) underwent follow-up cardiac catheterization immediately after the surgical intervention. Using the data of cardiac catheterization, the RV outflow tract gradient, pulmonary artery systolic pressure, right atrial pressure, and the ratio of pulmonary to systemic blood flow were evaluated.
Comprehensive echocardiographic assessments were conducted by experienced sonographers using high-quality, commercially available ultrasound systems. Transthoracic echocardiography was performed before and immediately after the surgical intervention and during long-term follow-up. The peak velocity of tricuspid regurgitation flow and the diameter of the inferior vena cava were measured. Systolic pressure of RV inflow was calculated using the modified Bernoulli equation and the inferior vena cava diameter as follows: systolic pressure of RV inflow = 4 × (peak velocity of tricuspid regurgitation flow) 2 + right atrial pressure (estimated from the diameter of the inferior vena cava according to the American Society of Echocardiography’s Guidelines).
We identified 29 patients who underwent follow-up transthoracic echocardiography more than 2 years after surgery. To investigate the frequency of recurrence of DCRV during long-term follow-up, we evaluated the systolic pressure of RV inflow, which was measured using cardiac catheterization before and immediately after surgery and transthoracic echocardiography before, immediately, and in the long-term after surgery. We monitored the recurrence of DCRV by comparing the systolic pressure values of RV inflow obtained before, immediately, and in the long-term after surgical intervention.
Statistical analyses were performed using SPSS for Windows 22.0 (SPSS, Chicago, Illinois). Data are expressed as mean ± standard deviation or median (range) values. Differences in continuous variables between the 2 groups were determined using the Mann–Whitney U test. Statistical significance was set at a 2-tailed p value of <0.05.
Results
Table 1 provides baseline characteristics and pressure data before surgical intervention. Of the 38 patients, 4 (11%) were aged >20 years at the time of the surgical intervention. Systolic pressure of RV inflow of the 4 patients who were aged >20 years at the time of surgical intervention was 91 ± 27 mm Hg. All the surgical interventions were successful, and there were no major complications during the hospitalization period or the early follow-up period. All the patients, except for 1 patient, had a documented ventricular septal defect. All of them underwent ventricular septal defect closure with a Dacron patch or direct suturing. Concomitant cardiac anomalies are also provided in Table 1 . The surgical approaches for DCRV are as follows: right ventriculotomy was used in 9 patients (23.7%), right atriotomy was used in 19 patients (50.0%), combined pulmonary arteriotomy and right atriotomy was used in 8 patients (21.1%), and combined right ventriculotomy and right atriotomy was used in 2 patients (5.3%). Longitudinal right ventriculotomy was used in most patients before 1989. Subsequently, right atriotomy or a combination of pulmonary arteriotomy and right atriotomy were used if possible.
| Variables | (n=38) |
|---|---|
| Clinical characteristics | |
| Men | 18 (47%) |
| Follow-up period, years | 11.0 ± 8.8 |
| Age at surgical intervention, years (median, range) | 5 (0-60) |
| Age at surgical intervention (years) | |
| 0-10 | 28 (74%) |
| 11-20 | 6 (16%) |
| 21-30 | 1 (3%) |
| 31-40 | 1 (3%) |
| 41-50 | 0 |
| 51-60 | 2 (5%) |
| Concomitant cardiac anomalies | |
| Ventricular septal defect | 37 (97%) |
| Perimembranous type | 33 (87%) |
| Subarterial type | 4 (11%) |
| Atrial septal defect | 5 (13%) |
| Persistent left superior vena cava | 2 (5%) |
| Discrete type subvalvular aortic stenosis | 1 (3%) |
| Cardiac complications | |
| Infective endocarditis | 2 (5%) |
| Cardiac catheterization data before surgical intervention | |
| RV inflow systolic pressure (mm Hg) | 82 ± 32 |
| Pulmonary artery systolic pressure (mm Hg) | 30 ± 13 |
| Right atrial pressure (mm Hg) | 3.6 ± 2.5 |
| RV outflow tract gradient (mm Hg) | 48 ± 34 |
| Qp/Qs | 2.0 ± 1.1 |
Of the 38 patients, 4 could not be followed up more than 2 years. Therefore, the long-term prognosis and occurrence of cardiac events were evaluated in 34 patients ( Table 2 ). There were no deaths during the long-term follow-up period beyond 10 years. Moreover, there were no cardiac deaths, no hospitalization due to heart failure, and no surgical reintervention. Cardiac arrhythmias developed in 2 patients during the long-term follow-up.
| Long-term prognosis | (n=34) |
|---|---|
| All cause death | 0 |
| Cardiac events | |
| Cardiac death | 0 |
| Hospitalization due to heart failure | 0 |
| Arrhythmias | 2 (6%) |
| Ventricular tachycardia | 0 |
| Atrial fibrillation/atrial tachycardia | 0 |
| Common atrial flutter | 1 (3%) |
| Frequency of premature ventricular contraction | 1 (3%) |
| Surgical reintervention | 0 |
In the 38 patients, systolic pressure of RV inflow was 34 ± 12 mm Hg immediately after the surgical intervention. This finding indicated that the surgical interventions were successful and resulted in sufficient reduction of the patients’ pressure gradient.
Clinical characteristics, clinical data, and chronologic changes in systolic pressure of RV inflow of 29 patients with long-term follow-up were provided in Table 3 . These data of the 29 patients with long-term follow-up were similar to those of all the patients. Systolic pressure of RV inflow immediately after the surgical intervention was markedly decreased compared with that before the surgical intervention (p <0.01). At the long-term follow-up, systolic pressure of RV inflow revealed no increase compared with that immediately after the surgical intervention (p = 0.35). The chronologic changes in systolic pressure of RV inflow of each patient are shown in Figure 1 . None of the patients exhibited systolic pressure of RV inflow of >50 mm Hg at the long-term follow-up or marked increases (>30 mm Hg) compared with values observed immediately after the surgical intervention. Preoperative and postoperative echocardiographic images of a representative case are shown in Figure 2 .
| Variables | (n=29) |
|---|---|
| Clinical characteristics and cardiac catheterization data before surgical intervention | |
| Men | 14 (48%) |
| Follow-up period, years | 11.7 ± 8.2 |
| Age at surgical intervention, years (median, range) | 4 (0-60) |
| RV inflow systolic pressure before surgical intervention (mm Hg) | 84 ± 32 |
| RV outflow tract gradient before surgical intervention (mm Hg) | 50 ± 32 |
| Qp/Qs | 1.9 ± 1.1 |
| Chronological changes in systolic pressure of RV inflow by echocardiography | |
| Before surgical intervention (mm Hg) | 80 ± 26 |
| Immediately after surgical intervention (mm Hg) | 30 ± 11 |
| Long term after surgical intervention (mm Hg) | 25 ± 6 |
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