Ultrasound Teaching Atlas
Draft — not yet peer-reviewedcoreThorax / HeartFoCUS

Cardiac — Subxiphoid (Subcostal) 4-Chamber

The go-to view in cardiac arrest and trauma: all four chambers and the pericardium through the liver window.

This module is a content/teaching-structure draft. Images shown are illustrative schematics — real, de-identified, license-verified ultrasound clips replace them before peer review.

Learning objectives

  • Obtain a subxiphoid 4-chamber view using the liver as an acoustic window.
  • Identify all four chambers and the pericardial space.
  • Recognize a pericardial effusion and signs of tamponade (RV diastolic collapse).

Maps to

  • Resident: ACEP Emergency Ultrasound — Cardiac: Subxiphoid acquisition
  • Resident: ACEP Emergency Ultrasound — Cardiac: Effusion / tamponade
  • Tech: ARDMS Adult Echocardiography (AE) — subcostal views

Acquisition — getting the view

Probe
phased-array
Patient position
Supine; bend the knees to relax the abdominal wall.
Orientation convention
cardiology
Probe placement
Just inferior to the xiphoid, probe nearly flat against the abdomen
Marker direction
Indicator to patient's left, beam aimed toward the left shoulder

Probe placement (3D)

Just inferior to the xiphoid, probe nearly flat against the abdomen

Structures in the imaging plane (near → far): Abdominal wall · Left lobe of liver (acoustic window) · Right ventricle · Right atrium · Left ventricle · Left atrium · Pericardium

Step by step

  1. Place the phased-array probe just below the xiphoid, nearly flat, indicator to the patient's left.
    Why: A flat angle uses the liver as a window up to the heart.
  2. Aim the beam toward the patient's left shoulder and press gently to slide under the costal margin.
    Why: Brings all four chambers into a single plane.
  3. Identify the pericardium and assess for effusion and chamber collapse.
    Why: Subxiphoid is the most reliable view for tamponade physiology.

Troubleshooting

Heart is too far / poor window.
Flatten the probe further and slide slightly to the patient's right to use more liver as a window.
Bowel gas obscures the view.
Have the patient take and hold a deep breath to bring the heart inferiorly toward the probe.

Findings: normal

Normal subxiphoid 4-chamber

All four chambers seen through the liver, with the pericardium as a bright line and no fluid in the pericardial space.

Schematic of a normal subxiphoid 4-chamber view
Schematic: four chambers through the liver window.
Original schematic, dedicated to the public domain (CC0).

Findings: pathology

Pericardial effusion / tamponade

Anechoic fluid in the pericardial space. Diastolic collapse of the right ventricle or right atrium indicates tamponade physiology.

Signs: Anechoic pericardial fluid; RV/RA diastolic collapse = tamponade

Schematic of a pericardial effusion on subxiphoid view
Schematic: pericardial effusion with RV collapse.
Original schematic, dedicated to the public domain (CC0).

Interpretation practice

On the subxiphoid view there is anechoic fluid surrounding the heart and the right ventricular free wall buckles inward in diastole. What does this indicate?

Pericardial effusion with right ventricular diastolic collapse
Fluid + RV diastolic collapse — interpret.
Original schematic, dedicated to the public domain (CC0).

Check your understanding

Why is the subxiphoid view favored in cardiac arrest?

Which finding indicates cardiac tamponade?

References

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