The chance of having a heart attack is higher after the first.
The cardiac cycle consists of two phases; a period where the heart muscle is relaxed, called <u>diastole</u>, and a period of contraction, called <u>systole</u>.
These are then divided into four stages. These are;
1.<u>Ventricular Filling Period (VPF)</u>
2. <u>Isovolumetric Contraction Period (ICP)</u>
3. <u>Ventricular Ejection Period (VEP)</u>
4.<u> Isovolumetric Relaxation Period (IRP)</u>
At rest, cardiac diastole lasts for approximately 0.5 seconds, and cardiac systole lasts approximately 0.3 seconds to complete. However, during exercise, when the heart rate is increased the time period of <u>diastole</u> , especially, is reduced.
Genetics, Pollution, Family history.
