Heart pressure waveforms distinguish structures

Steps:

• Recall typical right heart pressures: atrium (0-8 mmHg, atrial systole peak), ventricle (0-25 mmHg systolic), pulmonary artery (15-25 mmHg with dicrotic notch), vena cava (near 0 mmHg, low pulsatile).
• Analyze X's waveform: it shows high systolic pressure matching ventricular ejection but with outflow characteristics like incisura after peak.
• Match X to pulmonary artery, as it records arterial pressure post-ventricular systole.
• Rule out others by mismatched pressure ranges and lack of venous or atrial patterns.

Why A is correct:

• Pulmonary artery pressure mirrors right ventricular systolic ejection (15-25 mmHg) with a dicrotic notch from semilunar valve closure, per cardiac physiology.

Why the others are wrong:

• B: Right atrium has low pressure (0-8 mmHg) with only atrial systole peak, not high systolic.
• C: Right ventricle shows end-diastolic rise before systole, unlike X's arterial pattern.
• D: Vena cava exhibits steady low venous pressure without cardiac cycle pulsations.

Final answer: A