Cardiac dynamics

• Stroke volume is the volume of blood ejected from the left ventricle per beat . Units (ml)
• Heart rate is the number of times the heart beats per minute units (bpm).
• Cardiac output is the volume of blood pumped from the heart per minute. units (l/min)
• The average heart rate is 72bpm.
• A lower resting heart rate shows that the heart works more efficiently.
• Heart rate can rise slightly before exercise due to adrenaline. This is termed Anticipatory rise.
• Heart rate under 60bpm is known as bradycardia.
• During exercise heart rate rises proportionately to exercise intensity.
• At submaximal levels HR will plateau when a steady state is reached and O2 demand is met.
• HR increases rapidly at the start of exercise until a steady state is reached.
• Post exercise there is an initial rapid drop in HR due to less oxygen demand. HR then gradually drops to repay oxygen debt.
• Stroke volume occurs during ventricular systole.
• The average resting Stroke Volume is 70ml.
• Diastole: the phase of the heartbeat when the heart muscle relaxes and allows the chambers to fill with blood. (relaxation and filling)
• Atrial systole 


  Contraction and emptying of the atria.
• Ventricular Systole


  Contraction and emptying of the ventricles.