A client presents to the emergency department reporting chest pain.
Which order should the nurse complete first?

Choice A rationale

Ventricular tachycardia is characterized by rapid, repetitive firing from an ectopic focus or reentrant circuit within the ventricular myocardium. Because the impulse does not follow the rapid His-Purkinje system, ventricular depolarization is slow and inefficient, resulting in QRS complexes wider than 0.12 seconds. The high rate, typically 100 to 250 beats per minute, overrides the sinus node, meaning P waves are buried or dissociated. This severely compromises cardiac output due to reduced filling time.

Choice B rationale

Chaotic electrical activity without any identifiable QRS complexes describes ventricular fibrillation. In this state, the ventricles merely quiver and do not provide any effective contraction or cardiac output. This is a pulseless rhythm that requires immediate defibrillation to restore organized activity. While ventricular tachycardia is also dangerous, it maintains organized QRS complexes, whereas fibrillation is a total loss of electrical and mechanical organization, appearing as a wavy or jagged baseline on the ECG.

Choice C rationale

Early P waves with a different shape followed by a normal QRS are known as premature atrial contractions. These occur when an irritable focus in the atrium fires before the next expected sinus impulse. The resulting QRS is usually narrow because the impulse still travels through the normal ventricular conduction system. This is a common, often benign finding and does not resemble the wide, rapid, and potentially lethal ventricular complexes seen in tachycardia.

Choice D rationale

A progressive lengthening of the PR interval until a QRS complex is dropped is the hallmark of Mobitz Type I or Wenckebach second-degree heart block. This occurs due to a delay at the atrioventricular node that worsens with each beat until conduction fails entirely for one cycle. This is an atrial-ventricular conduction issue, not a primary ventricular arrhythmia. Ventricular tachycardia does not involve PR interval cycles as the ventricles are firing independently.

Choice A rationale

Aspirin and P2Y12 inhibitors like clopidogrel do not have a physiological role in promoting hydration or reducing kidney strain. In fact, the contrast dye used during the PCI procedure itself is what poses a risk to the kidneys, necessitating hydration with intravenous fluids. Antiplatelet medications are focused entirely on the hematologic system. There is no scientific evidence suggesting that these specific drug classes improve renal perfusion or assist in the filtration of metabolic waste products.

Choice B rationale

The primary rationale for dual antiplatelet therapy is to prevent stent thrombosis and arterial restenosis. Aspirin inhibits thromboxane A2, while clopidogrel blocks the adenosine diphosphate receptor on platelets. Together, they provide synergistic inhibition of platelet activation and aggregation. This is vital because the newly placed stent is a pro-thrombotic surface until it is covered by the patient's own endothelial cells. Preventing a clot from forming at the site of the intervention is crucial for survival.

Choice C rationale

These medications are not analgesics or anxiolytics. Aspirin has some anti-inflammatory properties, but at the low doses used for cardiac protection, its effect on pain is negligible. Anxiety is typically managed with nursing interventions, benzodiazepines, or counseling. Using antiplatelet agents is a strictly physiological intervention aimed at blood chemistry and vessel patency rather than the psychological or sensory comfort of the patient. Effective pain control post-PCI is usually achieved by addressing the underlying ischemia.

Choice D rationale

While blood pressure control is important after a myocardial infarction, aspirin and clopidogrel are not antihypertensive medications. They do not affect the systemic vascular resistance or the force of cardiac contraction. Blood pressure management is usually handled with beta-blockers, ACE inhibitors, or calcium channel blockers. Using antiplatelet therapy specifically targets the coagulation cascade to prevent the recurrence of a myocardial infarction by keeping the coronary arteries open and free from obstructive blood clots. .