Cardiac and Thoracic Sonographic Evaluation
Standard views and measurements
Know the parasternal long and short axis, apical four-, two-, and three-chamber, subcostal, and suprasternal views. In the parasternal long axis, identify RV anteriorly, LV posteriorly, aortic valve, mitral valve, and the descending aorta as a circle. In apical four-chamber, the LV is on the right of the screen (standard display) and the RV on the left. Understand chamber quantification: LV dimensions, wall thickness, biplane Simpson EF, and Doppler-derived gradients.
Doppler measurements
Apply the simplified Bernoulli equation (ΔP = 4v²) to estimate gradients. Use the continuity equation for valve area and the proximal isovelocity surface area (PISA) for regurgitant severity. Understand tissue Doppler velocities (e′) for diastolic function and the E/e′ ratio.
Traps
A frequent trap is misidentifying the RV versus LV in apical views-use the moderator band and tricuspid annular position. Another: applying the Bernoulli equation without recognizing it estimates peak gradient, not mean. Watch for questions confusing Simpson biplane with M-mode for EF, or misplacing the sample volume for aortic flow (apical five-chamber or right parasternal).
Rule of thumb
If a continuous-wave envelope peaks at 3 m/s, the peak gradient is 4 × 3² = 36 mmHg.
Worked example
Aortic stenosis with peak velocity 4 m/s gives a peak gradient of 4 × 16 = 64 mmHg; the mean gradient requires tracing the envelope, not a single point.