A nurse is reviewing a client's cardiac rhythm strips and notes a constant P-R interval of 0.35 seconds. Which of the following dysrhythmias is the client displaying?

A. Atrial fibrillation: Atrial fibrillation is characterized by absent P waves and an irregularly irregular ventricular rhythm. A constant P-R interval is not observed in this dysrhythmia. B. Complete heart block: Complete heart block (third-degree AV block) shows no relationship between P waves and QRS complexes, with atrial and ventricular rhythms independent of each other. A constant prolonged P-R interval is not present. C. First-degree atrioventricular block: First-degree AV block is defined by a consistently prolonged P-R interval (>0.20 seconds) with all atrial impulses conducted to the ventricles. A P-R interval of 0.35 seconds indicates delayed AV conduction consistent with first-degree AV block. D. Premature atrial complexes: Premature atrial complexes present as early P waves with abnormal morphology, often followed by a normal QRS. The P-R interval may be normal or slightly altered, but a consistently prolonged P-R interval is not characteristic.