Stroke Volume

Stroke volume is calculated from two measurements: Left ventricular outflow tract diameter (LVOTd):

  • Measured from the PLA in mid- systole, with active zoom if available.
  • Measured from inner edge to inner edge before the bump of leaflet insertion on LV side.
  • Normal 1.8-2.2 cm.

Left ventricular outflow tract velocity time integral (LVOT VTI):

  • Measured from the AP 5.
  • Place the pulsed wave doppler cursor just before the AV leaflets.
  • Trace the envelope of flow, make sure to start and end at the baseline, from when the valve opens til it closes.
  • Normal 16-35 cm.


Calculated using the following formula: SV = π x (LVOTd/2)2 x LVOTVTI



  • Look closely at the aortic valve for stenosis.
  • Related to BSA smaller people <1.8 cm and larger >2.2 cm.
  • Anatomic fact does not change rapidly in an adult, so only needs to be measured once in an adult.

LVOT VTI Cursor placement

  • Measured from the AP 5.
  • Do not count if angle > 15% from midline.
  • Do not count if passes through septum.

VTI waveform

  • Select largest envelope if heart beat regular or average of 3-5 beats if irregular.
  • Velocity can be underestimated with aliasing.
  • LVOT VTI is not a reliable tool in the presence of aortic valve stenosis.


Figure 1a - how to measure LVOTd

Figure 1b - how to measure LVOTd

Figure 2a - how to measure LV VTI

Figure 2b - how to measure LV VTI

Figure 3 - correct measurement of LVOT VTI

Figure 4 - correct measurement of LVOTd

Figure 5 - erros in measurement of LVOTd

Figure 6 - correct cursor placement for measuring LVOT VTI

Figure 7 - using the ECG to measure the LV VTI

Figure 8 - tracing the LV VTI without the ECG

Figure 9a - poor LV VTI signal

Figure 9b - poor LV VTI signal


American Society of Echocardiography Guidlines: Assessment of Structure and Function.

Quiñones, Miguel A., et al. “Recommendations for quantification of Doppler echocardiography” Journal of the American Society of Echocardiography 15.2 (2002): 167-184.

Orde, Sam, et al. “Pearls and pitfalls in comprehensive critical care echocardiography.” Critical Care 21.1 (2017): 279.