UKMLA PLAB AMC USMLE Prometric MCQ

Question Number 0832
Question:
An 22 year old female premedical student is concerned because she notices that her heart rate is not regular. Her blood pressure is 102/65 and her heart rate is 72 beats per minute and is mildly irregular. An EKG is done and shows upright P waves, a PR interval of .12 seconds, a QRS complex of .08 seconds with a normal configuration. Her EKG shows that there is a slight variation in her heart rhythm during respiration. What is this rhythm called?

a) normal sinus rhythm
b) sinus tachycardia
c) sinus bradycardia
d) sinus arrhythmia
e) junctional rhythm