A nurse is assessing an electrocardiogram rhythm strip. The P waves and QRS complexes are regular. The PR interval is 0.16 seconds, and QRS complexes measure 0.06 seconds. The overall heart rate is 64 beats per minute. The nurse assesses the cardiac rhythm as:
1
Normal sinus rhythm
2
Sinus bradycardia
3
Sick sinus syndrome
4
First-degree heart block