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Predictors of Sudden Cardiac Events in Patients With Fontan Circulation
Quick Takes
- Sudden cardiac events (SCE) occurred in 3.5% of patients over a median follow-up time of 4 years; 36% of patients with SCE died.
- Cardiac magnetic resonance (CMR) predictors of SCE included systemic ventricle ejection fraction <50% and systemic ventricle end-diastolic volume index 104 mL/m2.
- Clinical predictors of SCE included NYHA functional class and history of protein-losing enteropathy or plastic bronchitis.
Study Questions:
What is the prevalence of and what are the risk factors for sudden cardiac events (SCE) in patients with Fontan circulation?
Methods:
The study made use of the FORCE (Fontan Outcomes Registry Using CMR Examinations) registry, which collects clinical and imaging data on Fontan patients. SCE was defined as: 1) cardiac arrest from a shockable rhythm, 2) need for emergent cardioversion/defibrillation, or 3) documented sustained ventricular tachycardia (VT). Univariate and multivariate Cox proportional hazards regression models estimated hazard ratios for predictors of SCE.
Results:
The sample included 3,132 patients (41% female). Dominant ventricular morphology was right in 43.6%, left in 38.5%, and balanced or mixed in 16.3%. The median age at first cardiac magnetic resonance (CMR) was 14.6 years. SCE was experienced by 3.5% (n = 109) over a median follow-up time of 4 years, with mortality of 36% in patients with SCE. On multivariable analysis, New York Heart Association (NYHA) functional class >II (hazard ratio [HR], 4.91; p < 0.0001), history of protein-losing enteropathy/plastic bronchitis (HR, 2.37; p = 0.0082), single-ventricle end-diastolic volume index of >104 mL/m2 (HR, 3.15; p < 0.0001), and ejection fraction <50% (HR, 1.73; p = 0.0437) were associated with SCE. Kaplan-Meier analysis demonstrated that in patients with none of the above risk factors, the 4-year freedom from SCE was 99.5%.
Conclusions:
The authors conclude that SCE occurred in 3.5% of the study population. Mild ventricular dysfunction and dilatation by CMR, NYHA functional class, and history of protein-losing enteropathy/plastic bronchitis were associated with SCE.
Perspective:
While we often think of heart failure and chronic illness as the primary drivers of mortality in patients with Fontan circulation, SCE are emerging as an important contributor. This study identified both CMR and clinical predictors for sudden death in a relatively young cohort. Interestingly, history of atrial arrhythmia or nonsustained VT did not quite meet statistical significance as a predictor of SCE on univariate analysis (p = 0.08).
Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, SCD/Ventricular Arrhythmias, Cardiac Surgery and Arrhythmias, Cardiac Surgery and CHD and Pediatrics, Congenital Heart Disease, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Imaging, CHD and Pediatrics and Interventions, Interventions and Imaging, Interventions and Structural Heart Disease, Magnetic Resonance Imaging
Keywords: Death, Sudden, Cardiac, Fontan Procedure, Heart Defects, Congenital, Magnetic Resonance Imaging
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