- A patient's EKG shows ST segments that appear isoelectric in leads V2-V4, but careful measurement reveals they are actually 1 mm below the baseline. The T waves in these same leads are inverted and symmetric. In leads V5-V6, the ST segments are at baseline with upright T waves. What is the most clinically significant interpretation of this anterior lead pattern?
Answer: Anterior wall ischemia requiring immediate physician notification and continued monitoring
ST depression combined with symmetric T wave inversion in the anterior leads (V2-V4) represents anterior wall ischemia that requires immediate physician notification. This pattern suggests significant cardiac compromise. Choice B is incorrect because symmetric T wave inversion with ST depression is pathologic, not a normal variant. Choice C is wrong because this pattern suggests acute rather than chronic changes. Choice D is incorrect because pericarditis typically shows ST elevation, not this pattern of depression and inversion.
- An EKG shows P waves with varying morphology within the same lead. Some P waves appear normal and upright, while others in the same lead are notched with two distinct peaks separated by a small valley. The PR intervals vary between 0.14-0.18 seconds, and all P waves are followed by QRS complexes. What does this P wave morphology variation most likely represent?
Answer: Wandering atrial pacemaker with the focus shifting between sinus node and ectopic atrial sites periodically
Varying P wave morphology in the same lead with different shapes (normal and notched) and slightly varying PR intervals suggests wandering atrial pacemaker, where the pacemaker site shifts between the sinus node and other atrial locations. Choice A is incorrect because multifocal atrial tachycardia typically has heart rates >100 bpm and more dramatic morphology changes. Choice B is wrong because left atrial enlargement would show consistent notching, not intermittent changes. Choice D is incorrect because atrial flutter shows consistent flutter waves, not varying individual P wave morphologies.
- During stress testing, a patient's EKG shows ST segments that are 1.5 mm elevated in leads II, III, and aVF with reciprocal ST depression in leads I and aVL. The patient reports mild chest tightness. After 2 minutes of recovery, the ST elevation decreases to 0.5 mm but has not completely resolved. What is the most appropriate immediate action?
Answer: Notify the physician immediately due to concerning ST elevation during exercise testing
ST elevation ≥1 mm in multiple leads during stress testing with delayed recovery indicates a significant abnormal response requiring immediate physician notification. The persistent elevation after 2 minutes of recovery is particularly concerning. Choice B is incorrect because ST elevation during exercise is abnormal. Choice C is wrong because the delayed resolution requires immediate attention, not just documentation. Choice D is incorrect because restarting the test would be dangerous with these findings.
- A patient's EKG demonstrates P waves with normal morphology in leads I and II, but in lead aVR, the P waves appear inverted while maintaining the same timing relationship with QRS complexes. The PR interval is consistent at 0.16 seconds across all leads. What does this P wave morphology pattern most likely indicate?
Answer: Normal sinus rhythm with appropriate P wave polarity reflecting the electrical axis relative to lead positions
In normal sinus rhythm, P waves should be positive in leads I and II, and negative in lead aVR due to the electrical axis of atrial depolarization relative to these lead positions. This is normal and expected. Choice B is incorrect because ectopic atrial rhythms typically show abnormal P wave morphology in multiple leads. Choice C is wrong because junctional rhythm would show inverted P waves in leads II, III, and aVF, and the PR interval would likely be shorter. Choice D is incorrect because lead misplacement would affect multiple leads and QRS morphology would also be abnormal.
