Right Atrial Volume is Increased in Corrected Tetralogy of Fallot and Correlates with the Incidence of Supraventricular Arrhythmia: A CMR Study

Myocardial, Valvular and Vascular Abnormalities in Repaired Tetralogy of Fallot

Tetralogy of Fallot is the most common heart defect associated with cyanosis characterized by the co-occurrence of pulmonary stenosis, right ventricular hypertrophy, and ventricular septal defect with over-riding of the aorta. The present review purposed to summarize myocardial, valvular and vascular abnormalities, which were described in a series of patients following repair of tetralogy of Fallot. It was also aimed to describe potential differences in these parameter using different surgical strategies.

Association of cardiovascular magnetic resonance diastolic indices with arrhythmia in repaired Tetralogy of Fallot

BACKGROUND

Patients with repaired Tetralogy of Fallot (rTOF) experience a high burden of long-term morbidity, particularly arrhythmias. Cardiovascular magnetic resonance (CMR) is routinely used to assess ventricular characteristics but the relationship between CMR diastolic function and arrhythmia has not been evaluated. We hypothesized in rTOF, left ventricular (LV) diastolic dysfunction on CMR would correlate with arrhythmias and mortality.

METHODS

Adolescents and adults with rTOF who underwent CMR were compared to healthy controls (n = 58). Standard ventricular parameters were assessed and manual planimetry was performed to generate filling curves and indices of diastolic function. Chart review was performed to collect outcomes. Univariate and multivariable logistic regression was performed to identify outcome associations.

RESULTS

One-hundred sixty-seven subjects with rTOF (mean age 32 years) and 58 healthy control subjects underwent CMR. Patients with rTOF had decreased LV volumes and increased right ventricular (RV) volumes, lower RV ejection fraction (RVEF), lower peak ejection rate (PER), peak filling rate (PFR) and PFR indexed to end-diastolic volume (PFR/EDV) compared to healthy controls. Eighty-three subjects with rTOF had arrhythmia (63 atrial, 47 ventricular) and 11 died. Left atrial (LA) volumes, time to peak filling rate (tPFR), and PFR/EDV were associated with arrhythmia on univariate analysis. PER/EDV was associated with ventricular (Odds ratio, OR 0.43 [0.24-0.80], p = 0.007) and total arrhythmia (OR 0.56 [0.37-0.92], p = 0.021) burden. A multivariable predictive model including diastolic covariates showed improved prediction for arrhythmia compared to clinical and conventional CMR measures (area under curve (AUC) 0.749 v. 0.685 for overall arrhythmia). PFR/EDV was decreased and tPFR was increased in rTOF subjects with mortality as compared to those without mortality.

CONCLUSIONS

Subjects with rTOF have abnormal LV diastolic function compared to healthy controls. Indices of LV diastolic function were associated with arrhythmia and mortality. CMR diastolic indices may be helpful in risk stratification for arrhythmia.

Utility of Cardiac Magnetic Resonance Imaging in Predicting Atrial Arrhythmias in Repaired Tetralogy of Fallot

Arrhythmias are the leading cause of morbidity and mortality in repaired tetralogy of Fallot (TOF), and over 20% of these patients will develop a sustained atrial arrhythmia during their lifetimes. Cardiac magnetic resonance imaging (cMRI) is frequently performed in TOF, although its ability to identify patients at risk of atrial arrhythmias is uncertain. Adult TOF patients (n = 175) with no history of atrial arrhythmia who underwent cMRI between 2003 and 2020 at a single tertiary care center were identified. Clinical characteristics and imaging findings were evaluated to identify a predilection for atrial arrhythmias using Kaplan-Meier survival analysis and log-rank testing. Multivariable Cox regression was used to determine independent predictors of atrial arrhythmias. Over a median follow-up of 3.6 years, 29 patients (17%) developed atrial arrhythmias. Independent predictors of atrial arrhythmia included age (hazard ratio [HR] 1.06 per 1-year increase, 95% confidence interval [CI] 1.02 to 1.09, p = 0.002), diabetes mellitus (HR 4.26, 95% CI 1.26 to 14.41, p = 0.020), indexed right ventricular end-diastolic volume (RVEDVi), (HR 1.20 per 10-ml/m² increase, 95% CI 1.05 to 1.39, p = 0.010), and moderate or greater tricuspid regurgitation (TR) (HR 6.32, 95% CI 2.15 to 18.60, p = 0.001). Utilizing Kaplan-Meier analysis, patients with at least mild right ventricular dilation (RVEDVi >100 ml/m², p = 0.047) and greater than or equal to moderate TR (p <0.001) were found to be significantly more likely to develop atrial arrhythmias. In conclusion, cMRI can help to identify TOF patients at increased risk for atrial arrhythmia beyond standard clinical and imaging data by better quantifying RVEDVi and degree of TR.

Burden and Impact of Arrhythmias in Repaired Tetralogy of Fallot

PURPOSE OF REVIEW

Arrhythmias are a leading cause of morbidity and mortality following repair of tetralogy of Fallot (TOF). This review will highlight current understanding of arrhythmia pathogenesis in this patient population and review novel therapeutic options.

RECENT FINDINGS

Risk factors for developing ventricular arrhythmias in repaired TOF have thus far been better defined than for atrial arrhythmias. Growing understanding of the pathophysiology of arrhythmias, development of risk stratification models, and novel techniques such as electrophysiologic ultrahigh-density mapping should help to better identify patients that benefit from advanced therapies such as ablation and implantable cardioverter defibrillators. Atrial and ventricular arrhythmias are common in TOF patients. Methods of risk stratification and therapeutic approaches are rapidly evolving, leading to ever improving clinical outcomes in this patient population.

Favorable Atrial Remodeling After Percutaneous Pulmonary Valve Implantation and Its Association With Changes in Exercise Capacity and Right Ventricular Function

Background

Right atrial (RA) dilatation and impaired right ventricular (RV) filling are common in patients with RV outflow tract dysfunction. We aimed to study potential correlations between atrial function with clinically relevant hemodynamic parameters and to assess the predictive impact of atrial performance on the recovery of exercise capacity and RV pump function after percutaneous pulmonary valve implantation (PPVI).

Methods and Results

Altogether, 105 patients with right ventricular outflow tract dysfunction (median age at PPVI, 19.2 years; range, 6.2–53.4 years) who underwent cardiac magnetic resonance imaging before and 6 months after PPVI were included. RA and left atrial maximal and minimal volumes as well as atrial passive and active emptying function were assessed from axial cine slices. RA emptying function was inversely related to invasive RV end‐diastolic pressure, and RA passive emptying correlated significantly with peak oxygen uptake. After PPVI, a significant decrease in RA minimum volume was observed, whereas RA passive emptying function improved, and RA active emptying function decreased significantly. Patients with predominant right ventricular outflow tract stenosis showed more favorable changes in RA active and left atrial passive emptying than those with primary volume overload. None of the RA and left atrial emptying parameters was predictive for recovery of peak oxygen uptake or RV ejection fraction.

Conclusions

In patients with right ventricular outflow tract dysfunction, impaired RA emptying assessed by cardiac magnetic resonance imaging was associated with increased RV filling pressures and lower exercise capacity. PPVI leads to a reduction in RA size and improved passive RA emptying function. However, RA function was not associated with improved exercise performance and RV pump function.

Clinical significance of right atrial volume in patients with repaired tetralogy of Fallot

OBJECTIVES

Atrial arrhythmia and right ventricular (RV) diastolic dysfunction are associated with increased morbidity and mortality in patients with repaired tetralogy of Fallot (TOF). This study was performed to determine whether the preoperative right atrial (RA) volume can predict the development of atrial arrhythmia after pulmonary valve replacement (PVR) in patients with TOF.

METHODS

Forty-seven consecutive adult patients with repaired TOF underwent PVR from 2003 to 2018. Seventeen patients showed preoperative atrial arrhythmia and underwent the Maze procedure concomitantly. The preoperative RA volume was evaluated with computed tomography and image analysis software.

RESULTS

The median follow-up period after PVR was 6.8 years. Among 17 patients who underwent the Maze procedure, recurrent atrial arrhythmia developed in 8 patients. Among 30 patients without preoperative atrial arrhythmia, novel atrial arrhythmia developed in 2 patients. The RA volume index was a significant predictor according to the multivariate analysis (P = 0.003). The RA volume index showed a significant positive correlation with the RV end-diastolic pressure (P < 0.001).

CONCLUSIONS

The RA volume predicts the development of atrial arrhythmia after PVR in patients with repaired TOF. RA volume measurement is strongly recommended in the management of this patient population.