A nurse is caring for a client who is alert and oriented and is receiving continuous ECG monitoring. The cardiac rhythm strip shows a wavy baseline, no distinguishable P waves, and an increased heart rate. The nurse should identify the cardiac rhythm as which of the following?

A. Sinus tachycardia: Incorrect. Sinus tachycardia shows a regular rhythm with identifiable P waves, not a wavy baseline. B. Atrial fibrillation: The wavy baseline and absent P waves are characteristic of atrial fibrillation, a common arrhythmia that results from rapid and irregular electrical activity in the atria. C. Second-degree heart block: Incorrect. Second-degree heart block would show P waves with intermittent conduction of the QRS complex, not a wavy baseline. D. Ventricular asystole: Incorrect. Ventricular asystole would show no electrical activity, which is different from a wavy baseline.