Tetralogy of Fallot: risk stratification is straightforward. Or is it?

PURPOSE OF REVIEW: Tetralogy of Fallot (TOF) carries a long-term risk of arrhythmias and sudden death after surgical repair. Risk stratification is still less accurate than desired.

RECENT FINDINGS: Several factors have been studied as risk predictors for ventricular arrhythmias and sudden death. Clinical parameters include age at surgery, time since repair, types of previous surgeries, and symptoms such as syncope and palpitations. Electrocardiographic parameters that have been studied include QRS interval, ventricular arrhythmias assessed with Holter monitors, signal averaged ECG, QRS fragmentation, QRS vector magnitude, and microvolt T-wave alternans. Exercising testing has been shown to have prognostic significance. Ventricular function assessment with imaging studies including echocardiography and magnetic resonance imaging (MRI) plays a significant role. Invasive hemodynamic and electrophysiologic studies, in addition to assessment for inducible tachycardia, can provide information regarding the electroanatomic substrate of VT.

SUMMARY: Risk stratification for TOF has improved over the last years with several clinical, electrocardiographic, imaging, and invasive electrophysiologic findings showing promise, but there still a lack of uniformity in approach between various investigators and reproducibility of findings is difficult in larger populations. With use of a combination of factors, a more informed decision can be made.