Magnetic Resonance Imaging Risk Factors for Ventricular Arrhythmias in Tetralogy of Fallot

Clinical Risk Assessment and Prediction in Congenital Heart Disease Across the Lifespan: JACC Scientific Statement

Congenital heart disease (CHD) comprises a range of structural anomalies, each with a unique natural history, evolving treatment strategies, and distinct long-term consequences. Current prediction models are challenged by generalizability, limited validation, and questionable application to extended follow-up periods. In this JACC Scientific Statement, we tackle the difficulty of risk measurement across the lifespan. We appraise current and future risk measurement frameworks and describe domains of risk specific to CHD. Risk of adverse outcomes varies with age, sex, genetics, era, socioeconomic status, behavior, and comorbidities as they evolve through the lifespan and across care settings. Emerging technologies and approaches promise to improve risk assessment, but there is also need for large, longitudinal, representative, prospective CHD cohorts with multidimensional data and consensus-driven methodologies to provide insight into time-varying risk. Communication of risk, particularly with patients and their families, poses a separate and equally important challenge, and best practices are reviewed.

Repaired Tetralogy of Fallot: Have We Understood the Right Timing of PVR?

Despite many advances in surgical repair during the past few decades, the majority of tetralogy of Fallot patients continue to experience residual hemodynamic and electrophysiological abnormalities. The actual issue, which has yet to be solved, is understanding how this disease evolves in each individual patient and, as a result, who is truly at risk of sudden death, as well as the proper timing of pulmonary valve replacement (PVR). Our responsibility should be to select the most appropriate time for each patient, going above and beyond imaging criteria used up to now to make such a clinically crucial decision. Despite several studies on timing, indications, procedures, and outcomes of PVR, there is still much uncertainty about whether PVR reduces arrhythmia burden or improves survival in these patients and how to appropriately manage this population. This review summarizes the most recent research on the evolution of repaired tetralogy of Fallot (from adolescence onwards) and risk factor variables that may favor or delay PVR.

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.

Preventing Arrhythmic Death in Patients With Tetralogy of Fallot: JACC Review Topic of the Week

Patients with tetralogy of Fallot are at risk for ventricular arrhythmias and sudden cardiac death. These abnormalities are associated with pulmonary regurgitation, right ventricular enlargement, and a substrate of discrete, slowly-conducting isthmuses. Although these arrhythmic events are rare, their prediction is challenging. This review will address contemporary risk assessment and prevention strategies. Numerous variables have been proposed to predict who would benefit from an implantable cardioverter-defibrillator. Current risk stratification models combine independently associated factors into risk scores. Cardiac magnetic resonance imaging, QRS fragmentation assessment, and electrophysiology testing in selected patients may refine some of these models. Interaction between right and left ventricular function is emerging as a critical factor in our understanding of disease progression and risk assessment. Multicenter studies evaluating risk factors and risk mitigating strategies such as pulmonary valve replacement, ablative strategies, and use of implantable cardiac-defibrillators are needed moving forward.