After Undergoing Aortic Valve Replacement, a 70-Year-Old Male Complains of Palpitations

After undergoing aortic valve replacement, a 70-year-old male complains of palpitations and dizziness. The nurse records his blood pressure as 110/70 mm Hg. The nurse also records an EKG. Which of the following EKG findings would prompt the nurse to consider a diagnosis of atrial fibrillation?

A) Presence of abnormal P waves with irregular R-R intervals
B) Absent P waves with regular R-R interval
C) Absent P waves, irregular R-R interval, and fibrillatory waves
D) Inverted P waves, regular R-R interval