LVOT VTI (A5C, PW Doppler): Place sample volume in LVOT ~5 mm proximal to AV. Trace the spectral envelope. Measure at least 3 traces (SR) or 5 (AF); average.

Cardiac output: CO = HR × LVOT VTI × π(LVOT diameter / 2)². LVOT diameter measured in PLAX during systole at the aortic annulus. Never <2 cm in adults — if your measurement is, remeasure.

LVEF (Simpson’s biplane — new in 2026 curriculum): Trace endocardial border in A4C and A2C at ED and ES. Machine calculates EDV and ESV. LVEF = (EDV−ESV)/EDV × 100.

Respiratory LVOT variation (>12% = responsive): Only valid with sinus rhythm, full mechanical ventilation (no spontaneous breaths), TV ≥8 ml/kg, normal intra-abdominal pressure. Formula: % variation = 100 × (Vmax − Vmin) / [(Vmax + Vmin) / 2].

IVC distensibility index (>12% = responsive): Same caveats as above.

Passive leg raise (PLR): Most versatile test — works in AF and spontaneous breathing. Raise legs to 45° and measure LVOT VTI before and after (within 60–90 s). >10% increase = fluid responsive. No fluid given — fully reversible.

Mini-fluid challenge: 100 ml rapid IV bolus; >10% LVOT VTI increase = responsive.

Aortic root (PLAX): Measure at sinotubular junction in end-diastole. Normal <4 cm. Also measure ascending aorta 2 cm distal. >4 cm = refer for expert scan/CT.

Dissection flap: Mobile intimal flap within the aortic root = Type A dissection. Surgical emergency. Look for associated pericardial effusion and aortic regurgitation.

Aortic arch (suprasternal): Probe in suprasternal notch, indicator to left. Arch and major branch vessels visible.

Descending thoracic aorta (modified PSAX at MV level): Circular cross-section posteriorly. Fan caudally.

Abdominal aorta (epigastric, longitudinal): Aorta lies left of midline, anterior to vertebral body. Normal <3 cm. AAA ≥3 cm. Surgical threshold ≥5.5 cm. Scan from diaphragm to bifurcation at umbilicus.

Dimensionless index (DI) for aortic stenosis: DI = VTI_LVOT / VTI_AV. DI = 1 is normal. DI <0.25 = severe AS. Independent of cardiac output.

Valvular recognition: Identify severe leaflet immobility (stenosis) or large turbulent regurgitant colour jets. Refer for endocarditis, acute MR from papillary rupture, or acute AR from dissection — all surgical emergencies.

LVOTO and SAM:

• SAM in PLAX: mitral valve leaflet moves toward septum in mid–late systole — freeze and scroll frame-by-frame
• Colour Doppler: posteriorly directed MR jet + turbulence in LVOT
• PW: normal velocity proximally in LVOT, then aliasing distally
• Treatment: fluid, beta-blockade, vasopressors — NOT inotropes or vasodilators

Normal wall motion: endocardial excursion >5 mm and wall thickening >30% in systole. Grading: normokinetic → hypokinetic → akinetic → dyskinetic → aneurysmal.

Coronary territories (simplified):

• LAD: Anterior wall, septum, apex
• RCA: Inferior wall, inferior septum
• LCx: Lateral, posterolateral wall

Takotsubo: Apical and mid-segment akinesis with preserved basal function — beyond one coronary territory. Treatment requires stopping beta-agonists/inotropes (counter-intuitive).

Step 1 (rapid): Bilateral B-lines on lung US + IAS bowing into RA throughout cardiac cycle = raised LA pressure. Highly likely. No Doppler needed — proceed to treatment.

Step 2 (Doppler, if Step 1 negative/equivocal):

• TDI of mitral annulus: Measure lateral and septal e′ in A4C. Average e′ = (lat + sep) / 2.
• E/e′ ratio: Measure E-wave from mitral inflow (PW at leaflet tips).

TR velocity (CW Doppler): RVSP = 4V² + estimated RAP. Normal TR Vmax <2.8 m/s. >3.4 m/s = likely raised PAP. Optimise the TR jet window using colour Doppler to guide placement.

TAPSE: Normal ≥17 mm. <17 mm = impaired longitudinal RV function.

RV-PA coupling (TAPSE/RVSP ratio): <0.55 mm/mmHg = RV-PA uncoupling — the RV is failing to adapt to its load.

Builds on FUSIC Heart findings (RV collapse, RA collapse, dilated IVC) with Doppler confirmation of respiratory variation:

• Mitral inflow (PW): E-wave drops >25% on inspiration = exaggerated pulsus paradoxus
• Tricuspid inflow: Paradoxical E-wave increase on inspiration >40%
• LVOT velocity variation: >25% respiratory variation

Venous congestion causes end-organ injury independently of arterial hypoperfusion. VExUS (Venous Excess Ultrasound) grades systemic congestion using abdominal vein Doppler.

IVC screen first: IVC <2 cm + collapsible = low RA pressure; congestion unlikely. IVC ≥2 cm + plethoric = assess hepatic and portal veins.

Hepatic vein (PW Doppler, subcostal):

• Normal: triphasic (S wave, D wave, small AR)
• Mild congestion: S:D reversal (S < D)
• Severe: S wave absent or reversed

Portal vein (PW, RUQ):

• Normal: continuous, <30% pulsatility
• Moderate: pulsatile (>30% variation)
• Severe: biphasic or reverse flow

Renal vein (PW, intercostal):

• Normal: continuous
• Moderate: biphasic
• Severe: monophasic or discontinuous; renal RI >0.7