A nurse is caring for a client who has pericarditis and reports feeling a new onset of palpitations and shortness of breath. Which of the following assessments should indicate to the nurse that the client may have developed atrial fibrillation?

D. Atrial fibrillation can lead to irregular and often rapid heart rates, resulting in discrepancies between the apical (heart) and radial (peripheral) pulses. In atrial fibrillation, the atria fibrillate instead of contracting effectively, leading to irregular and sometimes asynchronous ventricular contractions. This irregularity may result in a pulse deficit, where the number of apical beats exceeds the number of radial pulses felt at the wrist.

A. Different blood pressures in the upper limbs may indicate conditions such as aortic dissection or arterial stenosis, but they are not typically associated with atrial fibrillation. Atrial fibrillation primarily affects the heart rhythm rather than blood pressure distribution.

B. Differences in upper and lower lung sounds may indicate conditions such as pneumonia or pleural effusion, but they are not specific to atrial fibrillation. Atrial fibrillation primarily affects the heart's electrical activity rather than respiratory findings.

C. Differences between oral and axillary temperatures may indicate localized variations in temperature, such as infection or inflammation, but they are not specific to atrial fibrillation. Atrial fibrillation primarily affects cardiac rhythm rather than body temperature regulation.

B. Muffled heart sounds, often described as distant or indistinct, are classic findings in cardiac tamponade. The accumulation of fluid in the pericardial sac dampens the transmission of sound from the heart to the chest wall, resulting in muffled heart sounds on auscultation. This finding is known as Beck's triad, which also includes hypotension and jugular venous distention.

A. Bradycardia is not a typical finding in cardiac tamponade. In fact, tachycardia is more commonly observed due to the compensatory response to decreased cardiac output and decreased stroke volume. The sympathetic nervous system is activated, leading to an increase in heart rate as a compensatory mechanism to maintain cardiac output.

C. Flattened neck veins are not consistent with cardiac tamponade. In cardiac tamponade, jugular venous distention (JVD) is typically observed due to increased venous pressure resulting from impaired right ventricular filling. The presence of JVD is an important clinical finding in cardiac tamponade and can help differentiate it from other causes of shock.

D. Sudden lethargy can occur in various medical emergencies, including cardiac tamponade, but it is not a specific or diagnostic finding for this condition. In cardiac tamponade, symptoms may include dyspnea, chest pain, hypotension, and signs of decreased cardiac output such as cool extremities and altered mental status. However, sudden lethargy alone may not be specific enough to confirm cardiac tamponade.