Twenty minutes after the onset of symptoms, an adult client presents to the emergency department with slurred speech and right-sided weakness. After a computerized tomography (CT) scan reveals a non-hemorrhagic stroke, the nurse administers alteplase. Which assessment finding warrants immediate intervention?

A. Frequent premature ventricular contractions: While abnormal heart rhythms are a concern, they may not warrant immediate intervention in this context unless they are causing significant hemodynamic instability. B. Paroxysmal supraventricular tachycardia: This cardiac dysrhythmia may require intervention but is not directly related to the administration of alteplase. C. Lower extremity edema: Lower extremity edema may indicate venous insufficiency or other underlying conditions but is not directly related to the administration of alteplase. D. Headache with blurred vision: This could be indicative of worsening cerebral edema or increased intracranial pressure, which are potential complications of alteplase administration and require immediate intervention.