The heart cycle: review

The heart is a pump that performs 72 beats per minute, equivalent to 1.2 Hertz, which each beat lasts around 0.830 ms (milliseconds) to boost the blood circulation that transports and distributes nutrients and oxygen, maintains the balance of fluids and body temperature as well as removes carbon dioxide and other metabolic byproducts from all cells of the body. Over a year, the heart beats around 38,843,300 times without taking into account the moments of stress and emotion in which the heart rate normally rises. Hence the importance of a system that works 24 hours a day, pumping about 200 million liters of blood (over a life of 70 years) to keep us alive.1 This work aims to synthesize the physiology of the cardiac cycle as well as to point out the main affections after a failure of this cycle.