Pressure half-time is a time interval, not a velocity. It measures how quickly the transmitral pressure gradient falls in early diastole and is used to estimate mitral valve area (MVA) with the equation MVA = 220 / PHT (in milliseconds). The normal range for PHT is about 40–60 ms. This corresponds to a normal MVA roughly in the 4–6 cm² range. As PHT lengthens, the valve area decreases (more stenotic); as PHT shortens, the valve area increases. The options listed use velocity units (m/s), but PHT is a time value, so those choices aren’t in the correct units. In practice, you’d report PHT in milliseconds and apply it to the MVA calculation to assess mitral stenosis severity.

Qp:Qs is the ratio of pulmonary blood flow to systemic blood flow, used to gauge how large a shunt is. It reflects how much blood is circulating through the lungs compared with the body, which tells you the magnitude of a left-to-right shunt. When the ratio is about 1, there’s no significant shunt; as it rises above 1, more blood goes through the pulmonary circulation than the systemic circulation, indicating a larger shunt. In practice, this ratio is often estimated from Doppler measurements of stroke volumes across the pulmonary and aortic valves: Qp equals the pulmonary valve cross-sectional area times its velocity-time integral, and Qs equals the aortic valve cross-sectional area times its velocity-time integral; the ratio of these two gives Qp:Qs. Accurate measurement is essential because errors in valve size or VTI can skew the ratio.

Left atrial size, expressed as the left atrial volume index (LAVI), reflects how chronically the left ventricle has been under load from filling pressures. Measuring it and indexing to body size makes the value comparable across individuals. A normal LAVI is about 34 mL/m^2 or less. When the LA enlarges, it signals chronically elevated LV filling pressures, often due to diastolic dysfunction or sustained volume overload. This remodeling isn’t just a passive change; it carries prognostic weight—LA enlargement is associated with worse diastolic function, higher risk of atrial fibrillation, stroke, heart failure hospitalizations, and increased mortality. Therefore, the threshold of ≤34 mL/m^2 defines normal, while enlargement indicates adverse cardiovascular risk. The other statements propose incorrect thresholds or deny the prognostic significance of LA size, which contradicts established clinical evidence.

Aortic stenosis creates a pressure overload on the left ventricle, and the heart initially responds with concentric hypertrophy to generate higher systolic pressures needed to push blood through the narrowed valve. On 2D echocardiography this shows up as increased LV wall thickness (LV hypertrophy). Over time, the stiff, hypertrophied left ventricle raises filling pressures, leading to left atrial enlargement. The high-velocity jet through the stenotic valve also distorts flow in the aorta, producing post-stenotic dilation of the ascending aorta and characteristic contour changes such as systolic bowing of the aortic root and an oval-shaped orifice at the valve. Put together, LV hypertrophy, LA enlargement, post-stenotic aortic dilation, and the described aortic root/valve morphology form the pattern most consistent with aortic stenosis on 2D echo. The other patterns don’t fit because they either miss the LV hypertrophy and LA enlargement expected with chronic pressure overload, or they describe findings more aligned with other conditions (for example, normal heart size without LVH, or isolated posterior wall thickening, which isn’t the typical diffuse LVH seen with AS, and findings like pulmonary edema with a dilated right heart point to different pathophysiology).