Effects of Nonsystemic Ventricular Pacing in Patients with Transposition of the Great Arteries and Atrial Redirection

Overview of Long-Term Outcome in Adults with Systemic Right Ventricle and Transposition of the Great Arteries: A Review

The population of patients with a systemic right ventricle (sRV) in biventricular circulation includes those who have undergone an atrial switch operation for destro-transposition of the great arteries (d-TGA) and those with congenitally corrected transposition of the great arteries (ccTGA). Despite the life expectancy of these patients is significantly increased, the long-term prognosis remains suboptimal due to late complications such as heart failure, arrhythmias, and premature death. These patients, therefore, need a close follow-up to early identify predictive factors of adverse outcomes and to implement all preventive therapeutic strategies. This review analyzes the late complications of adult patients with an sRV and TGA and clarifies which are risk factors for adverse prognosis and which are the therapeutic strategies that improve the long-term outcomes. For prognostic purposes, it is necessary to monitor sRV size and function, the tricuspid valve regurgitation, the functional class, the occurrence of syncope, the QRS duration, N-terminal pro B-type natriuretic peptide levels, and the development of arrhythmias. Furthermore, pregnancy should be discouraged in women with risk factors. Tricuspid valve replacement/repair, biventricular pacing, and implantable cardioverter defibrillator are the most important therapeutic strategies that have been shown, when used correctly, to improve long-term outcomes.

Validation and Feasibility of Echocardiographic Assessment of Systemic Right Ventricular Function: Serial Correlation With MRI

Background: Inherent to its geometry, echocardiographic imaging of the systemic right ventricle (RV) is challenging. Therefore, echocardiographic assessment of systemic RV function may not always be feasible and/or reproducible in daily practice. Here, we aim to validate the usefulness of a comprehensive range of 32 echocardiographic measurements of systemic RV function in a longitudinal cohort by serial assessment of their correlations with cardiac magnetic resonance (CMR)-derived systemic RV ejection fraction (RVEF). Methods: A single-center, retrospective cohort study was performed. Adult patients with a systemic RV who underwent a combination of both CMR and echocardiography at two different points in time were included. Off-line analysis of echocardiographic images was blinded to off-line CMR analysis and vice versa. In half of the echocardiograms, measurements were repeated by a second observer blinded to the results of the first. Correlations between echocardiographic and CMR measures were assessed with Pearson's correlation coefficient and interobserver agreement was quantified with intraclass correlation coefficients (ICC). Results: Fourteen patients were included, of which 4 had congenitally corrected transposition of the great arteries (ccTGA) and 10 patients had TGA late after an atrial switch operation. Eight patients (57%) were female. There was a mean of 8 years between the first and second imaging assessment. Only global systemic RV function, fractional area change (FAC), and global longitudinal strain (GLS) were consistently, i.e., at both time points, correlated with CMR-RVEF (global RV function: r = -0.77/r = -0.63; FAC: r = 0.79/r = 0.67; GLS: r = -0.73/r = -0.70, all p-values < 0.05). The ICC of GLS (0.82 at t = 1, p = 0.006, 0.77 at t = 2, p = 0.024) was higher than the ICC of FAC (0.35 at t = 1, p = 0.196, 0.70 at t = 2, p = 0.051) at both time points. Conclusion: GLS appears to be the most robust echocardiographic measurement of systemic RV function with good correlation with CMR-RVEF and reproducibility.

Cardiac resynchronization therapy for the failing systemic right ventricle: A systematic review

Patients with a systemic right ventricle (SRV) are at high risk for development of heart failure early in life. An SRV is encountered in patients with congenitally corrected transposition of the great arteries (CCTGA) or dextro-transposition of the great arteries (DTGA) with previous atrial switch repair (Mustard or Senning procedure). Progressive heart failure is one of the leading cause of mortality in these patients. Therefore, cardiac resynchronization therapy (CRT) has gained increasing momentum for use in this challenging congenital heart disease (CHD) population. However, current guidelines differ in recommendations for CRT in patients with an SRV as evidence supporting CRT has thus far only been described in case reports and retrospectively in relatively small study populations. In fact, the European Society of Cardiology Guideline for the management of grown-up congenital heart disease consider CRT to be 'experimental' in this population. This systematic review critically summarizes current literature on CRT in SRV patients and provides future perspectives for further research in this challenging and growing CHD population.

Implantable cardiac electronic device therapy for patients with a systemic right ventricle

The systemic right ventricle (SRV), defined as the morphological right ventricle supporting the systemic circulation, is relatively common in congenital heart disease (CHD). Our review aimed at examining the current evidence, knowledge gaps and technical considerations regarding implantable cardiac electronic device therapy in patients with SRV. The risk of sinus node dysfunction (SND) after atrial switch repair and/or complete heart block in congenitally corrected transposition of great arteries requiring permanent pacing increases with age. Similar to acquired heart disease, indication for pacing includes symptomatic bradycardia, SND and high degree atrioventricular nodal block. Right ventricular dysfunction and heart failure also represent important complications in SRV patients. Cardiac resynchronisation therapy (CRT) has been proposed to improve systolic function in SRV patients, although indications for CRT are not well defined and its potential benefit remains uncertain. Amongst adult CHD, patients with SRV are at the highest risk for sudden cardiac death (SCD). Nevertheless, risk stratification for SCD is scarce in this cohort and implantable cardioverter-defibrillator indication is currently limited to secondary prevention. Vascular access and the incidence of device-related complications, such as infections, inappropriate shocks and device system failure, represent additional challenges to implantable cardiac electronic device therapy in patients with SRV. A multidisciplinary approach with tertiary expertise and future collaborative research are all paramount to further the care for this challenging nonetheless ever increasing cohort of patients.

Fontan Conversion

Early survival after the Fontan operation has improved significantly leading to a lifetime of Fontan circulation for patients. There is a natural progression of pulmonary artery pressure during the human lifetime that is easily tolerated in two-ventricle physiology but is deleterious for single-ventricle physiology. Obstructions in the venous to pulmonary artery pathway and pulmonary venous return or ventricular outflow, atrioventricular valve dysfunction (regurgitation), pulmonary arteriovenous malformations, venous thrombosis, and the development of atrial arrhythmias can lead to reduced functional status. These complications have been demonstrated in older patients with largely atriopulmonary connections owing to time accrual and unfavorable flow characteristics. Various surgical and catheter interventions aimed at reducing morbidity and mortality have been attempted to treat these identifiable abnormalities. The purpose of this article is to review the extant literature on Fontan Conversion and to assess the lessons learned over 20 years.

Quantification of systemic right ventricle by echocardiography

Improvements in cardiac imaging have recently focused a great interest on the right ventricle (RV). In patients with congenital heart disease, the right ventricle (RV) may support the systemic circulation (systemic RV). There are 2 different anatomic conditions providing such physiology: the congenitally corrected transposition of the great arteries (ccTGA) and the TGA surgically corrected by atrial switch. During the last decades, evidence is accumulating that progressive systemic RV failure develops leading to considerable morbidity and mortality. Various imaging modalities have been used to evaluate the systemic RV, but echocardiography is still predominantly used in clinical practice, allowing an anatomic and functional approach of the systemic RV function and the potential associated anomalies. The goal of this review is to offer a clinical perspective of the non-invasive evaluation of the systemic RV by echocardiography.

Adverse impact of chronic subpulmonary left ventricular pacing on systemic right ventricular function in patients with congenitally corrected transposition of the great arteries

BACKGROUND

Patients with congenitally corrected transposition of the great arteries (ccTGA) are at high risk of heart block requiring subpulmonary left ventricular (LV) pacing. Long-term right ventricular (RV) pacing in congenitally normal hearts is associated with LV dysfunction. We examined the effects of univentricular subpulmonary LV pacing on the systemic RV in a ccTGA cohort.

METHODS

ccTGA patients with two echocardiographic studies at least 6 months apart were included. Records of 52 patients, 22 with pacing, were retrospectively reviewed. Seven patients with biventricular pacing were included for comparison.

RESULTS

The LV-Paced Group experienced deterioration in the RV fractional area change (RVFAC) (28.7 ± 10.0 vs. 21.9 ± 9.1%; P=0.003), systemic atrioventricular valve regurgitation (P=0.019) and RV dilatation (end-diastolic area 32.7 ± 8.7 vs. 37.2 ± 9.0 cm(2); P=0.004). There was a corresponding deterioration in NYHA class (P=0.013). Multivariate Cox regression analysis showed that pacing was an independent predictor of deteriorating RV function and RV dilation (hazard ratio 2.7(10-7.0) and 4.7(1.1-20.6) respectively). None of these parameters changed significantly in the Un-paced Group. The CRT Group showed improvement in RVFAC (22.0% to 30.7% (P=0.030) and NYHA class (P=0.030), despite having lower baseline RVFAC (22.0±5.7 vs. 31 ± 9.7%; P=0.025) and greater dyssynchrony (RV total isovolumic time 13.4 ± 2.1 vs. 9.3 ± 4.2s/min; P=0.016) when compared to the Un-Paced Group.

CONCLUSIONS

Univentricular subpulmonary LV pacing in patients with ccTGA predicted deterioration in RV function and RV dilatation over time associated with deteriorating NYHA class. Alternative primary pacing strategies such as biventricular pacing may need consideration in this vulnerable group already highly prone to mortality from systemic RV failure.