ECG of the Month: Tachycardia
A 75-year-old male with a past medical history including type A aortic dissection with surgical repair and mechanical aortic valve replacement, paroxysmal atrial fibrillation, hypertension and hyperlipidemia presented to antiarrhythmic medications clinic for follow-up monitoring of Flecainide. The patient is asymptomatic. ECG 1 (below) is his baseline ECG.
ECG 2 (below) was taken in clinic at the time of the appointment.
Which option best explains the ECG findings in the ECG 2?