Question

A patient sustained a myocardial infarction 2 days ago. The cardiologist wants to assess left ventricular function. What test should the nurse anticipate the cardiologist will order?

Answer 1

The cardiologist will almost certainly want to get an echocardiogram of the heart.

Explanation:

An echocardiogram is an ultrasound picture of the heart.

The machines generate images and automatically calculate parameters that are of interest to the cardiologist.

Two important numbers are the ejection fraction and the fractional shortening.

Ejection Fraction

Left ventricular function is usually determined by computing the ejection fraction (`"EF"`).

`"EF"` is a measurement of the percentage of blood leaving your heart each time it contracts.

`color(blue)(bar(ul(|color(white)(a/a)"EF" = (V_"ED" - V_"ES")/V_"ED" × 100 %color(white)(a/a)|)))" "`

where

`V_"ED" = "volume at end of diastole"`
`V_"ES" = "volume at end of systole"`

Normal values are `"EF > 55 %"`, while severe damage gives `"EF < 30 %"`.

Fractional Shortening

The ventricle shortens each time the heart beats.

(From 123sonography.com)

Impairment of this shortening is a sign of left ventricular dysfunction.

Fractional shortening (`"FS"`) is a measure of the degree of shortening.

`color(blue)(bar(ul(|color(white)(a/a) "FS" = (LV_"ED" - LV_"ES")/(LV_"ED") × 100 %color(white)(a/a)|)))" "`

Normal values are `"FS > 28 %"`, while severe damage gives `"FS < 14 %"`.