Figure 1.

Estimation of left ventricular outflow tract (LVOT) area using echocardiography and magnetic resonance imaging. (A) The LVOT diameter was measured at the aortic cusp insertion points (red arrows) in the parasternal long axis view. The LVOT area was estimated from the diameter measured. (B) The stroke volume was calculated as the difference between end-diastolic and end-systolic volumes. Planimetry of the endocardial borders (red contours in end-diastolic and end-systolic frames) was performed including the papillary muscles and minor trabeculations in volume measurements during both phases of the cardiac cycle. Left ventricular mass was calculated by multiplying the total end-diastolic myocardial volume (green and red contours in the end-diastolic frame) by the specific gravity of the myocardium (1.05 g/mL). Papillary muscles and minor trabeculations were excluded in mass measurements, with care taken to avoid right ventricular trabeculations. (C) Planimetry of the LVOT area in the coaxial short axis view on cardiovascular magnetic resonance imaging at mid-systole.