Cardiac Vascular Nursing Exam Diagnostic Testing & Interpretation Flashcards

On a rhythm strip, a nurse identifies a pattern where the PR interval progressively lengthens until a P wave fails to conduct (dropped QRS). Which dysrhythmia is this?

Answer: Second-degree AV block, Mobitz Type I (Wenckebach)

Wenckebach block is characterized by progressive PR prolongation due to increasing AV node fatigue until a beat is blocked, then the cycle resets with a shorter PR interval.

During a nuclear stress test, which finding indicates a fixed perfusion defect rather than ischemia?

Answer: A perfusion defect present on both stress and rest images that does not change indicates prior infarction (scar)

A fixed defect (unchanged between stress and rest images) represents non-viable scar tissue from prior MI; a reversible defect (defect on stress, normal at rest) represents inducible ischemia.

Which ECG finding in a post-cardiac surgery patient warrants immediate physician notification due to risk of cardiac tamponade?

Answer: Electrical alternans (alternating QRS amplitude) with sinus tachycardia and low voltage

Electrical alternans—beat-to-beat variation in QRS amplitude—combined with sinus tachycardia and low voltage is pathognomonic for cardiac tamponade, requiring immediate intervention.

A patient's cardiac catheterization report shows 75% stenosis of the left anterior descending (LAD) artery. The nurse understands this supplies which myocardial territory?

Answer: Anterior left ventricular wall, interventricular septum, and apex

The LAD perfuses the anterior wall, anterior two-thirds of the interventricular septum, and the cardiac apex, making it critical to a large amount of left ventricular mass.

A transesophageal echocardiogram (TEE) is preferred over transthoracic echocardiogram (TTE) for which clinical indication?

Answer: Detection of left atrial appendage thrombus in atrial fibrillation prior to cardioversion

TEE provides superior visualization of the left atrial appendage because of its posterior acoustic window, making it the standard of care for ruling out LAA thrombus before cardioversion.

Which cardiac biomarker pattern is most consistent with an acute MI that occurred approximately 24-48 hours before the laboratory draw?

Answer: Elevated troponin I with near-peak CK-MB that is beginning to decline

Troponin I remains elevated for 7–14 days after MI, while CK-MB peaks at 24 hours and returns to normal by 48–72 hours; at 24–48 hours both remain elevated but CK-MB is declining.