SEVERE AORTIC STENOSIS: THE GRADIENT CAN BE MISLEADING An aortic valve area ≤1.0 cm² suggests severe aortic stenosis (AS), but the mean gradient may be below 40 mmHg. The gradient depends on blood flow, not just valve narrowing. 1. High-gradient AS - AVA ≤1.0 cm² - Mean gradient ≥40 mmHg - Usually preserved or reduced LVEF 2. Classical low-flow, low-gradient AS - AVA ≤1.0 cm² - Mean gradient <40 mmHg - LVEF <50% - Stroke volume index ≤35 mL/m² 3. Paradoxical low-flow, low-gradient AS - AVA ≤1.0 cm² - Mean gradient <40 mmHg - LVEF ≥50% - Stroke volume index ≤35 mL/m² 4. Normal-flow, low-gradient AS - AVA ≤1.0 cm² - Mean gradient <40 mmHg - LVEF ≥50% - Stroke volume index >35 mL/m² Why this matters: Low flow can conceal the hemodynamic severity of a stenotic valve. Discordant findings require careful assessment of Doppler measurements, blood pressure, flow state and valve anatomy. In classical low-flow AS, dobutamine stress echocardiography can help distinguish true severe from pseudo-severe AS. CT aortic valve calcium scoring can help when severity remains uncertain. Clinical pearl: Never grade AS using the valve area or gradient alone. Integrate AVA, mean gradient, peak velocity, stroke volume, LVEF and clinical context. Reference: 2025 ESC/EACTS Guidelines for the Management of Valvular Heart Disease.

19 yo man suddenly collapses while playing soccer and is found to be in ventricular fibrillation. After resuscitation, the ECG shown below. What's your take