 Good morning. I'm Azeb Meshari. I'm one of the anesthesiologists at Toronto General. This session was actually curated by Dr. Massimo and Mineri, who unfortunately couldn't join us live today. We will have us talk at the end of the session in recorded format. Our first speaker is Dr. Sarka Murovkova. Dr. Murovkova is a consultant cardiothoracic anesthesiologist at the Hereford Hospital, which is part of the NHS trust of the guys in St. Thomas. She will be giving us her introductory talk on the LV assessment, the basics. Dr. Murovkova. Good morning and afternoon. So I'll just share my screen. Okay. Thank you very much, Azeb, for a kind introduction and invitation to participate in the Toronto Parioperative Symposium. I have no financial disclosures. These are the objectives for this talk, left ventricle function and the basics. The quantification of left ventricle function, size and geometry is important for evaluation and management of patients with a heart disease. And we know that left ventricle ejection fraction is associated with high mortality. In this paper published in 2020, Angaran and colleagues showed that the rate of mortality and hospitalization increases in direct proportion with reduction in left ventricle ejection fraction for both cardiac and non-cardiac causes of hospitalization. So what's the function of the heart? The function of the heart is to provide adequate cardiac output and its product of stroke volume and the heart rate. The left ventricle performance depends on preload, which is a diastolic issue. Afterload, which is a systolic issue, myocardial contractility and presence of regional contractile variations. We can measure stroke volume by echo using integration of velocity time interval in LVOT or Arctic valve and calculating the cross section of the area where the VTI was measured. Left ventricle is located posterior to the right ventricle. It has a cone or bullet shaped with long axis is directed from apex to the base. So it has a basal part mid portion and the apex. The apex of the normal size heart project into the fifth intercostal space near mid clavicular line. It has or is made up of an inlet portion, apical trabecula and outlet portion. Left ventricle muscle is a complex structure and it has been studied in many papers. It's arranged in layers and the Francesco Torres gas showed that the ventricle myocardium can be unwrapped into a single muscular myocardial band and the band extends from the pulmonary artery to aorta and in the middle performs 180 degree twist. According to the fibers orientation. There are three layers in soup epicardial location. The fibers are oriented with left handed helix in soup endocardial location. It is a right handed helix and the mid layer has circumferential orientation. The circumferential fibers decrease the minor axis and the oblique fibers, the longitudinal axis. The mathematical models which studied the function of the left ventricle show that this counter directional orientation of fibers is energetically efficient and necessary for the uniform function of the myocardium and distribution of the stress on the heart. The helical arrangement causes twisting and twisting in systole and twisting in a diastole with suction effect. So these are diagrams of the myocardial motion we can actually visually appreciate the longitudinal contraction, right heel contraction and circumferential contraction. Here is a video from the operating room. The apex of the heart is lifted and you can appreciate its twisting motion. Now observe the longitudinal and radial function of the left ventricle on transesophageal echo images. Also hopefully you can see the circumferential sliding of the epicardium in the left, left sided image. So during systole the atrioventricular ring distance towards the apex and the velocity of the myocardial base is higher than in the base is higher than in the apical parts of the left ventricle. And we can measure the velocity of the myocardium using tissue Doppler by placing pulse wave Doppler in lateral or septal mitral valve annulus. The tissue Doppler signal must be aligned with the vector of the velocity. It's a simple method and easy to obtain. The reduced myocardial velocity indicates in per systolic function values below seven and a half centimeters per second are considered abnormal. When the left ventricle loses its longitudinal shortening, it starts remodeling into the more spherical shape. With left ventricle I can be imaged by transesophageal echo in several standard views I will go very quickly through them. So starting from mit esophageal fourth chamber view visualizes a left ventricle anterolateral and intero septal walls. Moving the beam of the ultrasound to 90 degrees visualizing mit esophageal two chamber view with inferior and anterior walls. And rotating the ultrasound been further towards hundred twenty hundred thirty degrees can visualize in flow and outflow of the left ventricle and in ferro lateral and intero septal walls by pushing the probe further in into the stomach. We can visualize the base of the left ventricle by which transgustic basal short axis view and pushing the probe further in or unflexing the tip we can see short axis mid popular review and further unflexing in this in this view we can see more apical parts of the left ventricle. From the mid popularity view rotating the beam to 90 degrees can see transgustic two chamber views with inferior and anterior walls. So the left ventricle dysfunction is associated with changes in the ventricle shape size and wall thickness at the left ventricle enlargement is associated with out of geometry where left ventricle loses its cylindrical shape and becomes more spherical and the spherical enlargement and causes the ring of mitral leaflets and the mitral agurgitation. So it's also important to look for a wall characteristics wall integrity and texture. And intercavital blood flow has a typical low flow characteristic in severely impaired left ventricle the ASC recommends measuring a left ventricle dimensions wall thickness and left ventricle volumes. So starting with the linear dimensions, the left ventricle dimension and wall thickness can be measured in transgustic basal short axis view with using the M mode measuring the left ventricle and diastolic diameter and left ventricle and systolic diameter. Here are the upper normal limits of left ventricle and diastolic diameter for men is 58 millimeters for women is 52 millimeters and the wall thickness the normal wall thickness is between six to 10 millimeters. The dimensions can be also measured using to the echo in a transgustic to chamber view where the measurement is placed just above the popular muscles. Left ventricle dysfunction is often associated with abnormal wall thickness. There is a complex formula calculated in left ventricle mass. Fortunately scan is done for us by by the machine. Basically it's calculating the myocardial volume. It's important for a monitoring of patients with hypertension and in perioperative setting it has as a limited clinical applications. The machine recommends to comment on left ventricle geometry. So two types of left ventricle hypertrophy are recognized eccentric and concentric the eccentric, the left ventricle chamber and largest proportionally with the increasing wall hypertrophy, and the concentrate the chamber size remains normal, but the wall thickness increases. The wall thickness helps distinguish between concentric and eccentric hypertrophy and concentric remodeling. It's defined as a two times inferior wall thickness divided by the left ventricle diastolic diameter, and it is a marker for adverse events in a patients with left ventricle dysfunction. The measurements are 0.32 to 0.42 and they are not dependent on gender or body size. So these are a normal to the echo parameters published by ASC and ESCVI in 2015. The measurements are derived from trans thoracic echo. Cut-off parameters for left ventricle and diastolic diameter, as I said, 58 millimeters for men, 52 for women. The end diastolic volume is 74. It should be indexed for body surface area and for men it is 74 milliliters per meter square for men 61. The left ventricle and systolic volume for men is 31, the cut-off value is 31 meters per meter square for women 24, and the lower number for the normal left ventricle ejection fraction 52% for men and 54% for women. Another assumption that the left ventricle cavity can be divided in the stack of elliptical discs, which they vary in diameter based on the shape of the left ventricle. The computer software calculates the volume of each disc and summates it and give us the total left ventricle volume. The measurements are performed in two orthogonal views. It is the mid esophageal four chamber view and mid esophageal two chamber view. And we can use automated endocardial border recognition. One of the problems during this measurement is that very often the left ventricle is foreshortening, so it doesn't show the true LVA packs, which then leads to underestimation of left ventricle volumes. And because it's usually more effects left ventricle and systolic volumes, the ejection fraction which is calculated from here is then overestimated. The other problem is that the endocardial borders may not be well visualized. So for quantitative assessment of global systolic left ventricle function the ASC recommends measuring ejection fraction fraction area change and global longitudinal strain. The ASC recommends using modified Simpson method of this so the biplane this summation for measuring of ejection fraction ejection fraction is derived from the endostatic volume and at systolic volume measured as showed earlier. And it is a relation between the amount of blood which is expelled during each cardiac cycle or stroke volume relative to the size of the left ventricle. So the normal lower value as said before for men 52% for women 54% are considered below this number considered abnormal. So the problems to avoid during this measurements apart from the foreshortening of the left ventricle is also important that the LV length is perpendicular to the base width. So the picture on the screen. The part which is the on the lateral around the lateral mitral annulus is not included in the measurements and the volumes will be underestimated. The other important thing while tracing the endocardium it's to concentrate on the compact part of the myocardium not under the soft part and not to include popularity muscles or a trap aculation in in the border. And I think it's important to also always include your visual assessment as that as there are bit to bit variations during even in the systolic rhythm. production area change is measured in trans gastric me popularity view tracing the endocardial border in and systolic and and diastolic. So the problems here can be that the endocardial borders of lateral acceptables are often not well distinguished. And because they are parallel to the ultrasound beam. But it is very quick to perform. There are no issues with the foreshortening of the left ventricle. But it's it's only measurement in one plane and it doesn't account for the rest of the ventricle. It's highly loading dependent so relates to the preload and afterload. And it's usually about 10% less value than the left ventricle ejection fraction so normally it's between 40 to 60%. In the period of the setting it's useful because it's. It's very quickly to perform and easy. And it can give us scenarios for different clinic hemodynamic scenarios and evaluation of the status. Longitudinal strain is obtained with spectral tracking but also with tissue Doppler. It's basically a relative length change of left ventricle myocardium between and diastolic and and systolic. The measurement of the global systolic function using three standard views and then the average normal value is above minus 18%. These pictures are from Phillips machine using contact software. It is easy to easy to measure. Another measurement of myocardial function which is not in a recommendation but I can I find it quite useful is the PDT measurement which is measuring the isobalumetric contraction of the left ventricle. And it also has several issues one is that you can only measure it if you have a good quality signal of myocardial agitation. Also, if there's any conduction issues, they can decrease the value of the PDT, the value below 500 indicates severe dysfunction. With procedure. It's common not to have time to perform complex calculations and measurements and therefore eyeballing assessment by experience of a cardiograph is essential. There are several papers which showed a good correlation between eyeballing and quantitative measurements. And it is not recommended as a sole method of evaluation of the left ventricle. So for the assessment of the regional left ventricle function the ventricle is divided into segments reflecting coronary perfusion. Commonly used is a 17 segment model. The regional wall motion is assessed on the basis of observed myocardial wall thickening and the inward movement of the endocardium. The easiest and quickest method is eyeballing, and there is a semi quantitative method of a wall motions score index given, which gives the each segment points depending on the motion so one point is for the ventricle ventricle. So then it is the sum is divided by a number of segments. So the score of one correlates with the good LV ejection fraction and the index score of three with very poor ventricle. And a quantitative assessment by tissue Doppler or spectral tracking. So bear in mind that there can be also non ischemic causes of regional wall movement abnormalities such as pacing or conductive tissues, or interference, the interaction of the between the ventricle, or compression by a fusion or restriction. But the systolic function is sort of more intuitive to understand after systolic miocardium muscle relax and refill with the blood. There so there still is an important aspect of left ventricle function. The driving force for ventricle filling is the left atrial to left ventricle pressure gradient. So comprehensive grading algorithms to evaluate the astolic function. These can be quite consuming to obtain, especially in a theater. And also it is unusual for all parameters to be in agreement, making it hard to create a diastolic function in individual patient. So a specific assessment starts with the 2D characteristics patient with left ventricle hypertrophy increase left ventricle mass increase left atrial size and volume will often have a degree of diastolic dysfunction. The left ventricle volume higher than 34 miles per meter square of body surface area measured by trans thoracic echo is a predictor of an increased mortality and morbidity in patients which don't have atrial fibrillation or valvular heart disease. And as a federal echo, the left atrium measurements can be done in a fourth chamber. As a federal view, the studies show that there is a good correlation but consistently showing a lower values by average about 10 milliliters. So the ventricle filling depends on left atrial left ventricle pressure gradient, which also determines the diastolic velocity profile across the mitral valve. Thanks to the recommendation published in 2016, the quantitative information on left diastolic function includes at least transmittal EQA ratio and e velocity deceleration time, e prime velocity which either average or the absolute values for atrial side of the mitral annulus using pulse tissue Doppler, e to e prime ratio, and the estimation of systolic pulmonary artery pressures derived from tricuspid recogitation velocity. In the study, sort of cut off for severe diastolic dysfunction in thoracic surgery journal in 2011, Schwaminathan and colleagues published a study where they try to assess a utility of ASC algorithm for measuring the diastolic function in a repetitive period and they found that they could only assess a grade to two thirds patients. So they also use a simplified algorithm using only two variables. And that's a measurement starting with a measurement of lateral annulus velocity, e prime, if it is below 10 centimeters per second and they created the diastolic dysfunction according to the e to e prime ratio and find out that it was easy to perform and were able to a great majority of the patients. So in summary of to the echo disadvantages and limitations so to the echo is dependent on a geometric assumption. It is not accurate if the ventricles are distorted and have a reasonable movement abnormalities a way of the of the views where we are using for measurement. It also might not be adequate and little border definition the left ventricle views need to be centered and on axis and be aware of foreshortening and the true apex is often not will visualize even if there is a good quality image and the Doppler measurement needs to be aligned with the flow or vector of velocity. Thank you.