QS Study

ESV = End Systolic Volume

It is the volume of Blood remains in each ventricle at the end of ventricular systole is called ESV. It can be used clinically as a measurement of the adequacy of cardiac emptying, related to systolic function. It is about 40 – 50ml.

Factors affecting ESV

It is the lowest volume of blood in the ventricle at any point in the cardiac cycle. The main factors that affect the end-systolic volume are afterload and the contractility of the heart. Clinically, ESV can be measured using two-dimensional echocardiography, MRI or cardiac CT (computed tomography).

Pressure load: It is the pressure, within the aorta. If the aortic pressure is origins physiological limit, the heart can eject all blood.

Myocardial contractility: Heart responds the excitation by Contraction.

The agent which increases the contractility is called inotropic.

Fig: End Systolic Volume Curve

The force of contraction of the heart depends upon –

  • The initial length of muscle fibers
  • Nutrition and oxygen supply
  • Sympathetic stimulation
  • Diastolic period
  • Circulating hormones
  • Ca++ level of blood