In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The atrium (an adjacent/upper heart chamber that is smaller than a ventricle) primes the pump.
https://en.wikipedia.org/wiki/Left_ventricle
The left ventricle is one of four chambers of the heart. It is located in the bottom left portion of the heart below the left atrium, separated by the mitral valve. As the heart contracts, blood eventually flows back into the left atrium, and then through the mitral valve, whereupon it next enters the left ventricle. From there, blood is pumped out through the aortic valve into the aortic arch and onward to the rest of the body. The left ventricle is the thickest of the heart’s chambers and is responsible for pumping oxygenated blood to tissues all over the body. By contrast, the right ventricle solely pumps blood to the lungs.
http://www.healthline.com/human-body-maps/left-ventricle
1 The myocardium is thickest in the left ventricle, as the left ventricle must create a lot of pressure to pump blood into the aorta and throughout systemic circulation.  Cardiac muscle has a high density of mitochondria, and a large blood supply, which keep it functioning continously.
https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/cardiovascular-system-the-heart-18/the-heart-172/myocardial-thickness-and-function-867-10251/
The myocardium, or cardiac muscle, is the thickest section of the heart wall and contains cardiomyocytes, which are the contractile cells of the heart. As type of muscle tissue, the myocardium is unique and distinct compared to all other muscle tissues in the human body.
https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/cardiovascular-system-the-heart-18/the-heart-172/myocardial-thickness-and-function-867-10251/
The left ventricle is thicker and more muscular than the right ventricle because it pumps blood at a higher pressure. The right ventricle is triangular in shape and extends from the tricuspid valve in the right atrium to near the apex of the heart. Its wall is thickest at its base and thins towards the atrium.
https://en.wikipedia.org/wiki/Left_ventricle
The myocardium (cardiac muscle), is the thickest section of the heart wall and contains cardiomyocytes, the contractile cell of the heart. Describe myocardial thickness and function in the heart. Coordinated contraction of cardiomyocytes causes the heart to contract and expel blood into circulation.
https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/cardiovascular-system-the-heart-18/the-heart-172/myocardial-thickness-and-function-867-10251/
Ventricular Contractility Assessment (dP/dt)) The rate (dP/dt max) of left ventricle (LV) pressure rise in early systole is one of the oldest measures of LV global contractility. The greater the contractile force exerted, the greater the rate of increase in left ventricular pressure. This rate can be measured invasively, using high-fidelity micromanometer catheters inside the LV, as well as non-invasively, from a continuous wave Doppler examination of mitral regurgitation jet.
http://www.wikiecho.org/wiki/Ventricular_Contractility_Assessment_(dP/dt))
The right ventricle is equal in size to that of the left ventricle, and contains roughly 85 millilitres (3 imp fl oz; 3 US fl oz) in the adult. Its upper front surface is circled and convex, and forms much of the sternocostal surface of the heart.
https://en.wikipedia.org/wiki/Left_ventricle
Ventricular Contractility Assessment (dP/dt)) From Wikiecho. The rate (dP/dt max) of left ventricle (LV) pressure rise in early systole is one of the oldest measures of LV global contractility. The greater the contractile force exerted, the greater the rate of increase in left ventricular pressure.
http://www.wikiecho.org/wiki/Ventricular_Contractility_Assessment_(dP/dt))
1 Coordinated contraction of cardiomyocytes causes the heart to contract and expel blood into circulation.  The myocardium is thickest in the left ventricle, as the left ventricle must create a lot of pressure to pump blood into the aorta and throughout systemic circulation.
https://www.boundless.com/physiology/textbooks/boundless-anatomy-and-physiology-textbook/cardiovascular-system-the-heart-18/the-heart-172/myocardial-thickness-and-function-867-10251/
what is contractile function of left ventricle
A contractile function of left ventricle is to pumped out the blood through the aortic valve into the aortic arch and onward to the rest of the body. As the heart contracts, blood eventually flows back into the left atrium, and then through the mitral valve, whereupon it next enters the left ventricle. From there, blood is pumped out through the aortic valve into the aortic arch and onward to the rest of the body.