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Difficulty: HardPhysical Examination Findings

A 6161-year-old woman with a history of advanced lung cancer presents to the emergency department complaining of severe shortness of breath, orthopnea, and dizziness that has progressively worsened over the past 33 days. Earlier today, she felt lightheaded and nearly fainted while walking. Vital signs show a temperature of 37.1∘37.1^{\circ} C (98.8∘98.8^{\circ} F), blood pressure of 84/6884/68 mmHg, heart rate of 124124/min, and respiratory rate of 2424/min. Her extremities are cool and clammy. Bedside electrocardiography demonstrates sinus tachycardia with low QRS voltage and beat-to-beat variation in the amplitude of the QRS complexes. The physician suspects a life-threatening accumulation of fluid in the pericardial space. Which of the following physical examination findings are most likely to be present in this patient? (Select all that apply)

  1. An exaggerated decrease in systolic blood pressure of greater than 1010 mmHg during inspirationAnswer
  2. Distant and muffled heart sounds on precordial auscultationAnswer
  3. Elevated jugular venous pressure with an absent or blunted 'y' descentAnswer
  4. D
    Increased jugular venous distention that worsens during normal inspiration
  5. E
    A low-pitched, early diastolic sound heard shortly after the second heart sound

Answer

The correct findings are an exaggerated decrease in systolic blood pressure greater than 1010 mmHg during inspiration, distant and muffled heart sounds, and elevated jugular venous pressure with an absent or blunted 'y' descent.
The patient's presentation of hypotension, tachycardia, narrow pulse pressure, and ECG findings of electrical alternans with low QRS voltage is classic for cardiac tamponade, likely due to a malignant pericardial effusion. The physical examination findings in cardiac tamponade are driven by the accumulation of pericardial fluid under high pressure, which restricts ventricular filling. This leads to an exaggerated decrease in systolic blood pressure of greater than 1010 mmHg during inspiration, known as pulsus paradoxus. Furthermore, the layer of fluid dampens acoustic transmission, resulting in distant and muffled heart sounds. Because early diastolic filling of the right ventricle is severely impaired by the elevated intrapericardial pressure, the jugular venous waveform typically demonstrates an absent or blunted 'y' descent, while the 'x' descent is preserved.

Step-by-Step Solution

1
Analyze the clinical presentation and diagnostic findings.
The patient has hypotension, tachycardia, and a narrow pulse pressure. The ECG shows low QRS voltage and electrical alternans, highly suggestive of a large pericardial effusion.
Identifying the underlying condition (cardiac tamponade due to malignant pericardial effusion) is necessary to determine the expected physical examination findings.
2
Recall the pathophysiologic hemodynamics of cardiac tamponade.
Cardiac tamponade causes equalized diastolic pressures in all four cardiac chambers, severely restricting venous return and ventricular filling during diastole.
Understanding the hemodynamics helps deduce the clinical signs, such as components of Beck's triad and characteristic jugular venous waveforms.
3
Identify physical examination findings consistent with cardiac tamponade.
Expected findings include pulsus paradoxus (systolic BP drop > 1010 mmHg on inspiration), muffled heart sounds, and elevated jugular venous pressure with a preserved 'x' descent but blunted 'y' descent.
The 'y' descent represents early ventricular filling, which is severely impaired in tamponade due to the high intrapericardial pressure.

Key Concept

Physical examination findings in cardiac tamponade include Beck's triad (hypotension, elevated jugular venous pressure, muffled heart sounds), pulsus paradoxus, and an absent 'y' descent on the jugular venous waveform.
Estimated Time:1m 30s
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Physical Examination Findings

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