The principle of continuity (the continuity equation) states that the volume of blood passing the mitral valve must be equal to the volume passing the aortic valve. Stroke volume, the amount of blood ejected into the aorta, is calculated by measuring the area and VTI in the LVOT: SV = areaLVOT • VTILVOT.

Table of Contents

## What is the continuity equation in echocardiography?

The principle of continuity (the continuity equation) states that the volume of blood passing the mitral valve must be equal to the volume passing the aortic valve. Stroke volume, the amount of blood ejected into the aorta, is calculated by measuring the area and VTI in the LVOT: SV = areaLVOT • VTILVOT.

**What is the Gorlin formula?**

The Gorlin equation states that the aortic valve area is equal to the flow through the aortic valve during ventricular systole divided by the systolic pressure gradient across the valve times a constant.

**How is CSA Lvot calculated?**

CSALVOT is the cross sectional area (in cm2) of the LVOT calculated from the LVOT diameter measured in the parasternal long axis view (d in cm) assuming a circular geometry – CSALVOT = π x (d/2)(2.

### What is Pisa in echocardiography?

The proximal isovelocity surface area (PISA) measurement, also known as the “flow convergence” method, can be used in echocardiography to estimate the area of an orifice through which blood flows. It has many applications, but this review focuses only on its use in the intraoperative evaluation of mitral regurgitation.

**How do you calculate Ero?**

ERO = VFR/Vmax Congratulate yourself on calculating EROA.

**What is normal Lvot VTI?**

The VTI reflects the distance that the column of blood travels through the LVOT during systole (also called stroke distance), and can be used to compute LV stroke volume by multiplying the LVOT VTI by the cross sectional area of the LVOT. Normal value for LVOT VTI is typically >18 cm.

#### How do you calculate echo flow rate?

Flow rate can be simply measured during rest and SE, by dividing the SV by the systolic ejection period (SEP), with a normal rate considered to be 200 ml/s (12).

**What is normal AV VTI?**

Normal. Aortic Valve. Aortic Annulus Size 1.8-2.3 cm. Mitral Annulus Size 3.0-3.5 cm. Aortic VTI 18-25 cm.

**What is AV VTI in echocardiogram?**

The aortic velocity time integral (VTI) is an echocardiographic tool used to estimate cardiac output (CO) by multiplying it with the aortic valve (AV) area and heart rate (HR). Inaccurate measurement of AV diameter will lead to squared miscalculation of CO.

## What is a normal Ero?

ERO (mm2) RVol (mL/beat) Mild. <20.

**What is ERO in mitral regurgitation?**

Mitral Regurgitation. Definition: Severe organic MR: Regurgitant volume >= 60 ml, or Effective Regurgitant Orifice (ERO) >= 40 mm2 or 0.40 cm2. But, in functional or ischemic MR, severe regurgitant volume is ERO >= 20 mm2 or 0.20 cm2. ( Heart 88 (Suppl IV:1v1 – 1v4, 2002)

**What does a low Lvot VTI mean?**

Left ventricular outflow tract velocity time integral (LVOT VTI) is a measure of cardiac systolic function and cardiac output. Heart failure patients with low cardiac output are known to have poor cardiovascular outcomes. Thus, extremely low LVOT VTI may predict heart failure patients at highest risk for mortality.

### What does high Lvot VTI mean?

The LVOT VTI (VTI VA) is nearly 30 cm, which, at an HR (FC) of 100 beats per minute, indicates an elevated stroke volume and cardiac output.

**How do you calculate cardiac output echocardiogram?**

Work out the volume of the cylinder – Multiply the area of the LVOT (a circle) by the length the blood travels and you get the stroke volume (ie volume ejected per beat) The stroke volume multiplied by the heart rate gives us the cardiac output (expressed as L/Min).