Fibrinolytic therapy is initiated for a patient with a STEMI (ST segment elevated myocardial infarction). The nurse explains to the patient that this treatment is performed to

A. Identifies ventricular muscle depolarization: The P wave does not represent ventricular activity; ventricular depolarization is reflected in the QRS complex. Confusing the P wave with ventricular depolarization could lead to misinterpretation of arrhythmias or conduction abnormalities.

B. Reflects atrial muscle depolarization: The P wave represents depolarization of the atria, showing the spread of the electrical impulse through the atrial myocardium. This is important for assessing atrial rhythm, identifying atrial enlargement, or detecting ectopic atrial activity.

C. Indicates electrical impulse beginning in the AV node: The P wave originates from the sinoatrial (SA) node, not the AV node. The AV node serves primarily as a conduction delay to allow atrial emptying, and impulses passing through it are reflected later in the QRS complex, not in the P wave.

D. Reflects electrical impulse beginning at the SA node: The P wave reflects the electrical activity initiated by the SA node, the heart’s natural pacemaker. Proper interpretation of the P wave allows the nurse to assess whether the heart rhythm is sinus in origin and whether atrial conduction is normal.

A. dissolve the clot in the coronary artery and prevent further cellular death: Fibrinolytic therapy, such as alteplase or tenecteplase, is designed to lyse the thrombus occluding the coronary artery. Rapid clot dissolution restores blood flow to ischemic myocardium, limiting the extent of myocardial necrosis and preserving cardiac function, which is critical in acute STEMI management.

B. prevent the development of life-threatening arrhythmias: While restoring coronary perfusion may reduce arrhythmia risk indirectly, fibrinolytic therapy’s primary purpose is thrombus dissolution, not direct arrhythmia prevention. Arrhythmias are managed with antiarrhythmic drugs or supportive interventions.

C. assist ventricular contraction and promote coronary artery perfusion: Fibrinolytics do not directly enhance ventricular contractility. Improved perfusion occurs as a result of reopening the blocked artery rather than stimulating myocardial contraction.

D. prevent the development of further clotting in the coronary arteries: Antiplatelet or anticoagulant therapies are used to prevent new thrombus formation. Fibrinolytic therapy specifically targets existing clots rather than acting as a prophylactic measure against future clotting.