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Difficulty: HardCardiovascular System

Match the following pathophysiological states or clinical conditions with their most characteristic electrocardiogram (ECG) finding.

  • Symptomatic pre-excitation via an accessory atrioventricular pathway (bundle of Kent)Short PR interval (< 120 ms) with a slurred initial upstroke of the QRS complex
  • Critical, highly-unstable stenosis of the proximal left anterior descending (LAD) arteryDeep, symmetric T-wave inversions or biphasic T-waves in leads V2-V3 during a pain-free interval
  • Acute diffuse inflammatory process affecting the fibroserous sac surrounding the heartWidespread concave ST-segment elevation with concurrent PR-segment depression
  • Toxic accumulation of a medication that inhibits the myocardial Na+/K+-ATPase pumpCharacteristic 'scooped' ST-segment depression with a shortened QT interval
  • Severe elevation of extracellular potassium leading to altered myocardial resting membrane potentialTall, narrow, and symmetrically peaked T waves progressing to QRS complex widening

Answer

The correct pairings link specific structural, ischemic, and metabolic derangements to their pathognomonic ECG patterns: the bundle of Kent to a short PR and delta wave; proximal LAD stenosis to anterior T-wave inversions; pericarditis to diffuse ST elevation; Na+/K+-ATPase inhibition to scooped ST segments; and hyperkalemia to peaked T waves.
Each pair correctly matches a fundamental pathophysiological mechanism to its defining electrocardiographic signature, demonstrating a high-level synthesis of cardiovascular pathophysiology and clinical diagnostics.

Step-by-Step Solution

1
Analyze the description of the accessory atrioventricular pathway (bundle of Kent).
Matches with short PR interval and slurred QRS upstroke.
This pathophysiological mechanism defines Wolff-Parkinson-White syndrome, which manifests with early ventricular depolarization (delta wave).
2
Analyze the description of critical proximal LAD stenosis.
Matches with deep, symmetric T-wave inversions in leads V2-V3 during a pain-free state.
This is the classic presentation of Wellens syndrome, indicating an impending anterior myocardial infarction.
3
Analyze the description of acute inflammation of the fibroserous sac.
Matches with widespread concave ST-segment elevation and PR-segment depression.
This describes acute pericarditis, which produces diffuse subepicardial injury patterns on the ECG.
4
Analyze the description of Na+/K+-ATPase pump inhibition.
Matches with scooped ST-segment depression and shortened QT interval.
This describes the cellular effect of digoxin, leading to the characteristic 'digitalis effect' on the ECG.
5
Analyze the description of elevated extracellular potassium.
Matches with tall, symmetrically peaked T waves and eventual QRS widening.
Hyperkalemia alters the action potential duration and resting membrane potential, leading to these sequential, progressive ECG changes.

Key Concept

Recognition of specific electrocardiographic (ECG) manifestations associated with various cardiovascular, ischemic, and metabolic pathologies.
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Topics

Cardiovascular System

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