The telemetry monitor alarms for your client. The 6 second rhythm strip is seen here. Your first action is to:

A. Erectile dysfunction: This condition is not a direct physiological side effect of nitrate therapy. While phosphodiesterase inhibitors used for this condition are contraindicated with nitrates due to synergistic hypotension, the medication itself does not cause sexual dysfunction. It primarily affects vascular smooth muscle rather than autonomic pathways.

B. Backache: Nitroglycerin lacks a known mechanism for inducing musculoskeletal pain in the spinal region. Common adverse effects are typically related to systemic vasodilation and subsequent compensatory hemodynamic responses. This symptom is not documented as a frequent or characteristic complication of sublingual nitrate administration.

C. Diarrhea: This medication focuses on vascular smooth muscle relaxation rather than gastrointestinal motility. Nitrates do not typically irritate the enteric lining or accelerate peristalsis to cause frequent loose stools. Side effects usually manifest in the cardiovascular and neurological systems due to rapid vasodilation.

D. Dizziness: Rapid systemic vasodilation leads to a transient decrease in blood pressure and cerebral perfusion. This orthostatic effect often follows the administration of potent vasodilators as the body adjusts to decreased venous return. It remains a significant safety concern during acute anginal management.

E. Headache: The dilation of cerebral vessels increases intracranial pressure and activates pain receptors. This is the most common adverse reaction due to the drug's non-specific effect on all vascular beds. The intensity often correlates with the speed of onset of the medication.

A. Obtain manual blood pressure: Assessing the hemodynamic status is the priority when a client reports a racing heartbeat and shortness of breath. An irregular rhythm following conversion of atrial fibrillation requires immediate validation of perfusion and blood pressure stability. Manual measurement provides the most accurate clinical data for determining the severity of the cardiovascular change.

B. Measure airflow via incentive spirometry: Incentive spirometry is used to prevent atelectasis and is not a diagnostic tool for acute shortness of breath or cardiac arrhythmias. It does not provide information regarding the underlying cause of the "racing heartbeat" or the irregular rhythm. Priority must be placed on cardiovascular assessment rather than routine respiratory exercises.

C. Insert indwelling urinary catheter: There is no immediate clinical indication for an invasive urinary catheter based on the client's current symptoms of palpitations and dyspnea. While monitoring output is important in heart failure, it is secondary to stabilizing the client's heart rate and rhythm. Catheterization poses an unnecessary infection risk in this acute assessment phase.

D. Assist the patient to get dressed to work with physical therapy: Engaging in physical exertion while experiencing tachycardia and shortness of breath is dangerous and contraindicated. The client's reports of a "racing heartbeat" and irregular rhythm indicate a potential relapse into atrial fibrillation with rapid response. Physical activity should be deferred until the client is hemodynamically stable.