Age Related Changes that Occur in the Cardiovascular System
In the normal conduction of the heart the electrical impulse starts in the SA node, also called the pacemaker of the heart. The electrical impulse travels through the right atrium and through the Bachmann’s bundle into the left atrium. This stimulates the atria to contract. Next the signal travel to the AV node. The AV node slightly delays the signal. This delay is needed for the heart to beat properly. Without this delay the atria and ventricles would beat at the same time. The electrical signal then travels to the Bundle of His where it is split into the signals going to the right and left ventricle. The signal travels through the left and the right Bundle Branch to contract the ventricles. As the body ages there are changes in the cardiovascular system. Some of these changes include major changes in heart rate, blood vessels become more stiff and thicker, heart valves become thicker and more stiff, the SA node loses cells and developes fibrous tissue. One major change is the decrease in the elasticity of the aorta and great arteries.The normal aorta allows for normal expansion during systole. Left ventricular ejection creates a pressure wave which travels the length of the aorta to the periphery. The pulse generated at a peripheral vessel is the result of this pressure wave and is not a reflection of blood flow. The velocity of the pressure wave is termed the pulse wave velocity. Age-related aortic stiffening causes an increase in the pulse wave velocity. The wave velocity in the elderly results in an elevation in the systolic blood pressure. The pulse wave is faster resulting in the reflected wave reaching the ascending aorta in the late systole rather than early diastole.
Coronary artery disease also called CAD is the leading cause of death in both men and women. CAD is the leading type of heart disease in the United States.
References: 1. Office for National Statistics: General Lifestyle Survey (2007) www.statistics.gov.uk/statbase/product.asp?vlnk=5756 2. Vasan RS, Beiser A, Seshadri S et al. Residual lifetime risk for developing hypertension in middle-aged women and men. JAMA 287, 1003–1010 (2002).