Posted: March 24th, 2023

Cardiac Cycle

In the article Physiology, Cardiac, authors Rob Oberman; Abhishek Bhardwaj outlines why medical practitioners should understand mechanisms of cardiac physiology. The authors discuss how cardiac physiology manifests as an essential foundation in medical knowledge. From this perspective, cardiovascular physiology has continued to adapt to maintain biological body functions such as homeostasis.¹ As the human cardiac system adapts through different variables of stroke volume, such as heart rate, systole, and diastole, the cardiac cycle creates the pathway for determining the effective functions of the heart.

The article explores different issues of concern that stem from the basic understanding of the cellular system, the tenets of the cardiac cycle, cardiac myocyte action potential, and cases of heart failure. As a result, the cellular physiology of the heart is complex.¹ The authors indicate two sections of action potential and electrophysiology to understand the unique features of health and its role in the human body.

The authors focus on action potential by indicating the five phases of the cardiac myocyte for changing the heart rate through depolarization and repolarization. The ultimate conclusion of the action potential is the contraction of the cardiac myocyte. Similarly, the author emphasizes the cardiac pacemaker cell.¹ These unique bundles allow the cells to undergo an automatic response mechanism for the heart rate. Thus, the authors indicate that every action potential in the heart corresponds to the beat and inherent frequency. As a result, it is the frequency in the cells that determine the proper heart rate control. The three phases in pacemaker action include minor depolarization, rapid depolarization, and repolarization.

Oberman and Bhardwaj make the critical call on understanding how every peacemaker cells are different from their inherent rate. All the normal heart rates under normal conditions depend on the pacemaker phases. Thus, the phases work uniformly to maintain the heart through nodes. Therefore, atrial fibrillation creates concerns through its inconsistent rapid firings.¹ As a result, the failure in the cardiac cycle increases the heart rate, thus interfering with the heart’s normal function.

The article recognizes the electric circuit in the heart. Electrophysiology is a critical circuit that allows the heart to communicate through distinct pathways with the central nervous system. Oberman and Bhardwaj believe that from the right atrium through the heart’s ventricles, the electrical circuit determines the rate of depolarization and transmits the correct data for effective functioning. Any delays in the electrical circuit contribute to lapses in the bundle brand. Therefore, the article reiterates that the adequate flow through the cardiac electrical system requires the Bachman’s bundle and the nodes.

The physiology of the heart requires a concise understanding of the diastole and systole. The authors indicate that diastole is the phase of the cardiac cycle that triggers the relaxation of the supply of the ventricles with blood. On the other hand, the systole phase consists of the constriction of ventricles to eject blood. Thus, this flow has a preload of blood volume in the heart at the end of diastole.

From the article, the cardiac cycle necessitates the flow of blood through the cardiovascular system. According to Oberman and Bhardwaj, this cycle breaks into the lung and the body. The right side of the heart takes non-oxygenated blood from the body and sends it into the lungs through the pulmonary artery.¹ On the other hand, the left side of the heart carries oxygenated blood from the lungs through the pulmonary artery. It pumps this blood to the tissues throughout the body using the aorta. Thus, the article is critical in explaining the different phases of the cardiac cycle and determining the heart’s effective functioning. Failure in the process contributes to heart problems.