It is important to understand that M-mode provides no spatial information beyond the width of one ultrasound beam

Conversion of M-mode data to area or volume estimates should be done with caution

The image below shows a typical M-mode recording of the left ventricle in the parasternal long axis view with:

– 2D reference image on top (red box)

– M-mode recording at the bottom (yellow box)

Notice that the greyscale value is the same so that the white in the 2D image remains white in the M-mode recording and vice versa

Because the ultrasound is emitted from the top of the sector (red box) the anatomical structures close to the transducer are displayed at the top of each box and deeper structures are displayed closer to the bottom of each box (yellow and red)

As time is depicted along the horizontal axis dynamical changes can be observed

In this case 4 cardiac cycles are displayed

Eyeballing is a simple visual qualitative method to evaluate the overall function of the heart chambers

All imaging views can be used for the eyeballing and combined information from different views is recommended

The result of eyeballing the 4 basic FATE views below is normal ventricular function of all chambers

The images below show PSAX views of 4 hearts with hypovolaemia

Observe the small volume of the left ventricle in systole – almost emptying the ventricle
The walls of the LV touch each other
This pattern is often called “kissing ventricle”

The myocardial function is good, and the EF is high
EF alone is of no clinical value
Identification of the real problem/s (here hypovolaemia) is the solution

Keep this image in your mind, and when you recognise it in your patient think of hypovolaemia and treat the condition with volume or norepenephrine or both – not inotropes (beta-1 stimulation)

The EF equation entails:

– That reduced diastolic chamber dimension (reduced EDV) will alter EF – progressive blood loss will often reduce EDV and thus increase the EF

– When EF increases – under these circumstances – the stroke volume will decrease concomitantly

– Thus the EF can go up to almost 100% without providing any clinically useful information about myocardial deformation or adequacy of circulation

– Recognition of the hypovolaemic state is the key to understanding and solving the problem in these patients

It is important to notice that different pathologies may confound the interpretation of left ventricular systolic function

For example:

– Pericardial effusion (A)
– Adjacent chamber dilatation (B)
– Left ventricular dilatation (C)
– Hypovolaemia (D)

M-mode is an abbreviation of

Diastolic cardiac function describes the filling of the ventricles

Impaired diastolic function – also known as diastolic dysfunction – is characterised by reduced filling of the ventricles despite increased filling pressure

As diastolic impairment induces stiffness of the left ventricle, reduced systolic function often accompanies diastolic dysfunction especially as reduced longitudinal deformation

2D ultrasound characteristics of left ventricular diastolic dysfunction are:
– Left ventricular myocardial hypertrophy and concomitant reduced LV cavity size
– Enlarged left atrium (the enlargement is proportional to the severity of the diastolic dysfunction)

Ejection fraction (EF) is considered the gold standard for assessment of left ventricular systolic function in daily clinical practice

EF can be reported either qualitatively or semi-quantitatively

Simple qualitative judgment:
– Eyeballing – probably the most commonly used method for assessment of EF
– EF is normal or reduced (mildly, moderately or severely)

Quantitative and semi-quantitative assessment of dynamic changes during the cardiac cycle:
– Fractional shortening (FS), mitral septal separation (MSS), mitral annular plane systolic excursion (MAPSE)

The images below are explained in the following topics

Several methods exist for the measurement of EF, with eyeballing as the most frequently used method

A high EF is not a bullet proof marker of adequate circulation, because certain clinical circumstances can impact the circulation dramatically without reducing the calculated value of the EF

EF is solely a measure of the LV function, and not a measure of adequate circulation

EF does not take into account the importance of pathological conditions that impair circulation

Several life-threatening pathological conditions – where the myocardial deformation is normal – may invalidate the EF as a measure of the adequacy of circulation