Abstract
Background
Adults with repaired tetralogy of Fallot (rtoF) are at risk of ventricular arrhythmia and sudden cardiac death (SCD). Cross-sectional data suggest association of late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) with adverse clinical risk factors
Purpose
We sought to determine prognosis related to LGE CMR.
Methods
In this prospective cohort study the primary composite outcome comprised the first of cardiovascular death (SCD or heart failure-related), aborted SCD (successfully resuscitated cardiac arrest or appropriate AICD shock for ventricular fibrillation), and clinical sustained ventricular tachycardia (VT>30 seconds duration).
Results
In 531 rtoF patients (median age 32; 23–42, 296 (56%) male, NYHA≥II 17%) followed up after LGE CMR for median 5 (1.7–8.9) years, there were 39 primary composite outcomes: 10 SCD, 11 heart failure related deaths (2 perioperative RV failure), 2 aborted SCD and 16 clinical sustained VT events. At study end, there were 28 ventricular arrhythmic events in 28 rtoF patients (10 SCD, 16 clinical sustained VT, 2 aborted VF) that were significantly predicted by RV LGE extent (HR 1.45 CI: 1.3–1.6; P<0.001).
Univariable predictors of the primary outcome were RV LGE score; HR: 1.44 (1.31–1.57; p<0.001), (Figure) together with older age; HR: 1.05 (1.02–1.07; P<0.001), late repair; HR: 1.04 (1.02–1.07; p<0.001), lower RV ejection fraction; HR: 0.92 (0.89–0.95; p<0.001), larger RVOT akinetic length; HR: 1.04 (1.02–1.06; p<0.001) larger right atrial area; HR: 1.2 (1.12–1.29; p<0.001); higher BNP levels; HR: 1.01 (1–1.02; p<0.001), lower peak VO2; HR: 0.89 (0.83–0.96; p=0.001), prior atrial arrhythmia; HR: 5.3 (2.8–10.07; p<0.001), and non-sustained VT; HR: 4.1 (2.1–7.7; p<0.001). Inducible VT did not predict the primary outcome; HR: 2.1 (0.57–8; p=0.25)
In multivariable analysis both RV LGE score and indexed right atrial area (RAAi) only, remained predictive of the primary outcome (HR 1.29 CI: 1.12–1.49; p<0.001 and HR 1.1 CI: 1.02–1.12; p=0.01, respectively). Patients could accordingly be stratified such that supramedian RV LGE score (≥5) and RAAi ≥16cm2/m2 had 5-year event free survival 84% vs 94% for supramedian RV LGE score (≥5) and RAAi <16cm2/m2 or 98% for inframedian RV LGE score with RAAI<16cm2/m2. Figure.
Conclusions
For every unit increase in CMR defined RV fibrosis score there is a 44% increased risk of sudden cardiac death and VT. LGE CMR and maximal right atrial area should therefore be incorporated into risk stratification for sudden death in adults with rTOF.
Acknowledgement/Funding
British heart foundation
Prevention of sudden death after repair of tetralogy of fallot: Treatment of ventricular arrhythmias