Jeffrey Irwin
Argosy University Twin Cities
ECH215-Cardiovascular Principles II
Zach Traverse
7-24-2015
Systolic Function and Dysfunction In this paper I will discuss systolic function and systolic dysfunction. I will first define systolic function from physical as well as from physiological aspects: from mechanical and electrical systole, to preload and afterload. From there I will describe four modalities in which systolic function is measured and assessed. This will also include any formulas used to determine needed volumes and percentages. Lastly I will cover three causes of systolic dysfunction. Systolic function in its simplest terms is, how well the ventricle contracts. However, …show more content…
Contractility is affected by a number of components, three of which are: heart rate, preload and afterload. Heart rate is a factor when calculating cardiac output and cardiac index. Preload is the stretching of cardiac myocytes prior to contraction. With preload comes a law of physiology called Frank Staring’s law. Starling’s law describes how the higher intensity of the initial stretch of the myocardium creates a larger contraction, this has a great effect on preload and stroke volume. Preload has a direct relationship with stroke volume, increasing preload also increases stroke volume. Afterload occurs thought the ejection phase, this describes the amount of tension in the ventricle walls. After load has an inverse relationship with stroke volume, as afterload increases the stroke volume …show more content…
“Myocarditis is an inflammation of the myocardium, the middle layer of the heart wall. Myocarditis is usually caused by a viral infection. Signs and symptoms of myocarditis include chest pain, heart failure and abnormal heart rhythms.”(Mayo Clinic, 2012). Another cause of systolic dysfunction is valvular stenosis. Valvular stenosis is defined as a thickening or blockage to one or possibly more heart valve. In example, if a patient has aortic valve stenosis, their left ventricle would have great difficulty pumping blood efficiently. One other cause of systolic dysfunction is coronary heart disease or CHD. This cause of systolic dysfunction is from plaque that builds up in the coronary arteries and reduces blood flow to the heart, this is called