A client in the coronary care unit is receiving a diltiazem infusion for atrial fibrillation. The nurse observes on the cardiac monitor that the client's heart rate has converted to sinus bradycardia at a rate of 50 beats/minute. Which nursing action should be performed first?

A. Diaphoresis, hypertension: While diaphoresis may occur in response to the discomfort or anxiety caused by a rapid heart rate, hypertension is not a typical feature of atrial flutter. The rapid ventricular response can more often lead to hypotension if cardiac output is compromised.

B. Palpitations, shortness of breath: These are hallmark symptoms of rapid atrial flutter. Palpitations result from the fast, irregular atrial contractions, while shortness of breath may occur due to decreased cardiac output and poor ventricular filling during rapid rates.

C. Systolic murmur, severe anxiety: Atrial flutter is not typically associated with a systolic murmur unless there is a pre-existing valvular condition. Anxiety may be present but is a nonspecific response and not as directly linked to atrial flutter as palpitations and dyspnea.

D. Visual changes, anorexia: These symptoms are not characteristic of atrial flutter. Visual changes may occur with severe hypotension or embolic events, and anorexia may be seen in chronic illness, but neither is directly tied to the acute presentation of atrial flutter.

A. The P-P and R-R distances are equal and regular: Equal and regular spacing between P-P and R-R intervals indicates that both atrial and ventricular rhythms are regular. This is a fundamental aspect of rhythm interpretation, helping to distinguish between regular and irregular rhythms such as atrial fibrillation or sinus arrhythmia.

B. The rhythm rate using a 3-second strip: Assessing the heart rate using a 3-second or 6-second ECG strip helps determine whether the rhythm is bradycardic, tachycardic, or within normal limits, which is crucial for accurate rhythm classification.

C. The duration of the U waves: U waves are typically small and follow the T wave. Although their presence can suggest conditions like hypokalemia, they are not routinely assessed in basic rhythm identification. Evaluating U wave duration is more relevant in electrolyte imbalance analysis than in identifying rhythm type.

D. There is a QRS complex after each P wave: A consistent QRS following every P wave indicates effective conduction from the atria to the ventricles. Each atrial depolarization (P wave) should be followed by a ventricular depolarization (QRS complex) if the signal is being conducted properly through the AV node. This finding supports a diagnosis of sinus rhythm and helps rule out AV blocks, where conduction may be delayed or blocked entirely.

E. P waves are present, upright and rounded: P waves that are upright and rounded in lead II suggest the electrical impulse is originating from the SA node. Their presence and morphology are essential criteria for identifying sinus rhythm and differentiating it from atrial arrhythmias like flutter or fibrillation.