A 55-year-old man with dyslipidemia and hypertension is referred to the cardiac clinic by his family physician because of a change of his ECG findings and atypical chest pain. His ECG had been previously normal:

• Sinus bradycardia, 55/min.
• Right bundle branch block (RBBB) 
• Left anterior fascicular block (LAFB)
• RBBB plus LAFB (Bifascicular block)