Cellular Basis of Diastolic Dysfunction - Term Paper Example

Download file to see previous pages Blood flows through the pulmonary valve into the pulmonary artery, going into the lungs to get oxygen. Blood returns to the heart bypassing the pulmonary veins again enters the left atrium and pass through the mitral valve into the left ventricle. The left ventricle pumps out the oxygen-rich blood through the aorta into the body’s general circulation. This is the complete cardiac cycle.
The process of systole starts from the closure of the mitral valve to the closure of the aortic valve. The rest of the cardiac cycle is called the diastole, although the diastole could also include portions of the systole if basing on myocardial physiology (Brutsaert & De Keulenaer, 2006). During the diastole, the heart relaxes after contraction as it prepares to refill with circulating blood. The ventricular diastole occurs when the ventricles are relaxing, while atrial diastole means that the atria are relaxing. The pressure in the left and right ventricles decreases from the peak observed during the systole. The blood pressure measured in the arm is actually the blood pressure in the left ventricle. When the left ventricle drops to a pressure lower than that in the left atrium, the mitral valve will open and fill with the LV with blood. The same holds true for the right ventricle and right atrium. These events are regulated and coordinated by a series of electrical impulses from specialized heart cells. The cardiac muscles or myocytes initiate their own contraction independently of external nerves.
Heart disease and heart failure have been correlated with deficiencies in the diastole (ability to fill) and systole (ability to eject). In 30 to 50 percent of patients with heart failure, most have a normal or almost normal ejection fraction in the left ventricle. Heart failure is attributed to left ventricular diastolic dysfunction, a condition that has received less attention compared to systolic dysfunction (Vasan & Benjamin, 2001).   ...Download file to see next pagesRead More