A nurse is reviewing the results of electrocardiography monitoring for a client who has atrial fibrillation. Which of the following findings should the nurse expect?

Atrial fibrillation is a cardiac dysrhythmia characterized by disorganized electrical activity in the atria, resulting in ineffective atrial contractions. This leads to an irregularly irregular ventricular response and loss of coordinated atrial depolarization. On electrocardiography (ECG), specific changes reflect the absence of normal atrial activity. Recognizing these characteristic findings is essential for accurate diagnosis and appropriate management. A. A prolonged PR interval is typically associated with first-degree atrioventricular (AV) block, where conduction through the AV node is delayed but still organized. In atrial fibrillation, there is no consistent atrial depolarization, so PR interval measurement is not applicable in a regular pattern. Therefore, this finding is not expected. B. A 1:1 ratio of P to QRS waves indicates normal sinus rhythm, where each atrial impulse is conducted to the ventricles in a coordinated manner. In atrial fibrillation, atrial activity is chaotic and uncoordinated, so there is no organized P wave to QRS relationship. This makes a 1:1 ratio inconsistent with atrial fibrillation. C. Absence of P waves is the hallmark finding in atrial fibrillation because there is no organized atrial depolarization. Instead, the baseline appears irregular and may show fibrillatory waves due to chaotic electrical activity. This lack of discrete P waves distinguishes atrial fibrillation from normal sinus rhythm and other dysrhythmias. D. A prolonged QT interval is associated with delayed ventricular repolarization and can increase the risk of ventricular arrhythmias such as torsades de pointes. It is not a defining feature of atrial fibrillation, which primarily affects atrial electrical activity rather than ventricular repolarization. Therefore, this finding is not expected in atrial fibrillation.