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Difficulty: MediumCardiovascular System

Match each classic electrocardiogram (ECG) finding with its most likely associated cardiovascular condition or electrolyte disturbance.

  • Diffuse concave ST-segment elevations and PR-segment depressionsAcute pericarditis
  • Sinus tachycardia with beat-to-beat variation in QRS complex amplitudeCardiac tamponade
  • Prominent U waves, flattened T waves, and ST-segment depressionSevere hypokalemia
  • Peaked T waves progressing to widened QRS complexes and a sine wave patternSevere hyperkalemia

Answer

Diffuse ST elevations and PR depressions match with Acute pericarditis. Beat-to-beat QRS variation (electrical alternans) matches with Cardiac tamponade. Prominent U waves and flat T waves match with Severe hypokalemia. Peaked T waves and widened QRS match with Severe hyperkalemia.
Each cardiovascular condition and electrolyte abnormality alters myocardial depolarization and repolarization in a distinct, highly characteristic manner that can be reliably identified on an electrocardiogram.

Step-by-Step Solution

1
Analyze the first ECG pattern: diffuse ST-segment elevations and PR-segment depressions.
Matches acute pericarditis.
This is the classic ECG hallmark of diffuse epicardial and atrial inflammation seen in acute pericarditis.
2
Analyze the second ECG pattern: sinus tachycardia with alternating QRS amplitudes.
Matches cardiac tamponade.
This phenomenon is known as electrical alternans, caused by the swinging motion of the heart in a large pericardial effusion.
3
Analyze the third ECG pattern: prominent U waves and flattened T waves.
Matches severe hypokalemia.
Low serum potassium prolongs ventricular repolarization, leading to the appearance of U waves and flattened T waves.
4
Analyze the fourth ECG pattern: peaked T waves and widened QRS complexes.
Matches severe hyperkalemia.
High serum potassium profoundly alters cardiac conduction, causing peaked T waves and, as levels rise, progressive QRS widening until a sine wave pattern appears.

Key Concept

Correlation of classic electrocardiographic patterns with specific pericardial syndromes and electrolyte abnormalities.
Estimated Time:1m 30s
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Topics

Cardiovascular System

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