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Difficulty: MediumCardiovascular System

Match each classic cardiovascular physical exam or ECG finding with its underlying pathophysiologic mechanism.

  • Electrical alternansBeat-to-beat variation in QRS amplitude due to the pendular motion of the heart within a large fluid accumulation
  • Pericardial knockAbrupt halt in early diastolic ventricular filling caused by a thickened, inelastic pericardium
  • Kussmaul signParadoxical rise in jugular venous pressure during inspiration due to impaired right ventricular filling capacity
  • Pulsus paradoxusExaggerated inspiratory drop in systolic blood pressure driven by interventricular septal bowing into the left ventricle

Answer

Electrical alternans matches with pendular motion of the heart; Pericardial knock matches with abrupt halt in diastolic filling; Kussmaul sign matches with impaired right ventricular filling causing JVP rise; Pulsus paradoxus matches with septal bowing into the left ventricle.
Each clinical finding uniquely reflects the altered hemodynamics and structural constraints of either cardiac tamponade (electrical alternans, pulsus paradoxus) or constrictive pericarditis (pericardial knock, Kussmaul sign).

Step-by-Step Solution

1
Analyze Electrical alternans
Matched to the swinging motion of the heart in a large effusion.
The altering electrical axis on the ECG is a direct result of the physical shifting of the heart within the fluid-filled pericardial sac.
2
Analyze Pericardial knock
Matched to the abrupt halt in early diastolic ventricular filling.
The rigid pericardium severely limits expansion, causing a sudden stop in rapid ventricular filling that produces this distinct early diastolic sound.
3
Analyze Kussmaul sign
Matched to the paradoxical rise in jugular venous pressure during inspiration.
Normally, jugular venous pressure falls during inspiration. However, a noncompliant right heart cannot accept the increased venous return, causing the pressure to paradoxically rise.
4
Analyze Pulsus paradoxus
Matched to the exaggerated drop in systolic blood pressure due to septal bowing.
External compression from tamponade forces the right ventricle to expand into the left ventricle during inspiration, significantly reducing left-sided stroke volume.

Key Concept

Pathophysiology of physical exam and ECG findings in pericardial diseases (cardiac tamponade and constrictive pericarditis).
Estimated Time:1m 30s
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Topics

Cardiovascular System

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