Left ventricular measurements in M – Mode echocardiography are still popular inspite of advancements in echocardiography. M – Mode echocardiography was one of the earliest modalities of echocardiography to come into clinical use. The inset in the upper part of the image shows the 2-D image in the parasternal long axis view with the position of the cursor which is used to get the M – Mode cut. This image guides us to get better M – Mode echocardiograms than was possible when only M – Mode and no 2-D imaging was available. Left ventricular ejection fraction is calculated from these measurements by an automated computer program which displays the output as EF. LVPWs: left ventricular posterior wall (systole); IVSs: interventricular septum (systole); LVPWd: left ventricular posterior wall (diastole); LVIDd: left ventricular internal diameter (diastole); IVSd: interventricular septum (diastole); EDV: end diastolic volume;
IVS/LVPW: the ratio between the interventricular septal and posterior wall thickness. The ratio is increased in asymmetric septal hypertrophy in hypertrophic cardiomyopathy. The ratio can also be increased when the posterior wall is thinned due to infarction. The ratio is decreased in anterior wall infarction due to thinning of the interventricular septum.
IVS%: percentage of systolic thickening of interventricular septum; ESV: end systolic volume; FS: fractional shortening; EF: ejection fraction; LVPW%: percentage thickening of left ventricular posterior wall. The difference between end diastolic volume and end systolic volume gives the stroke volume. Stroke volume expressed as a percentage of the end diastolic volume gives the ejection fraction or the fraction of end diastolic volume ejected out in each systole. Ejection fraction is an important measure of systolic function and has great prognostic significance.