An asymptomatic 32-year-old man has the ECG shown performed as part of a routine work medical examination.
A. This ECG shows right bundle branch block
The ECG shows pre-excitation. Even though the patient is asymptomatic there is a risk of SCD due to pre-excited AF. There is no consensus on the best way to risk stratify patients, but if non-invasive testing is preferred a 5-day monitor could be performed. However, its main use is to see whether the pathway is intermittent with a sudden loss of pre-excitation which would place the patient in a lower risk category. In answer C there is no loss of pre-excitation during the 5-day monitor and therefore it would not be reasonable simply to discharge him. EP studies allow risk stratification and then the possibility of ablating a high-risk pathway at the same time.