Echocardiography Structure and contractile function of myocardial fibers The left ventricular wall can be subdivided into several layers. These layers are similar to those seen…

…defined as regional abnormalities in contractile function. Ischemic heart disease is the most common cause of wall motion abnormalities. Assessment of wall motion abnormalities is…

…low concentration of gap junctions in AV nodal cells), which allows for ventricular filling to complete prior to ventricular contraction. In contrast, contractile cells–and…

…function of the following three variables: Aortic resistance (pressure). Left ventricular volume. Ventricular wall thickness (myocardial thickness). The left ventricle must generate sufficient contractile force…

…differences in contractile function. Otherwise, the point of measurement may not be representative. Ventricular activation must be normal. For example, in the setting of left…

…from one contractile cell to another, starting in the endocardium and heading towards the epicardium. As evident from Figure 7 , the vector of the ventricular…

…excitability, and contractile function are all compromised by ATP depletion. Myocardial necrosis (infarction) commences within 20 minutes of circulatory collapse. The electrical phase: Defibrillate It…

…systolic function (contractile function) Several echocardiographic measurements are available to assess left ventricular systolic function. These methods elucidate slightly different aspects of systolic function and…

…may result in abnormal depolarization of the ventricular myocardium. This is presumably due to a mismatch between the expansion of contractile cells as compared with…

…ventricles. When the contractile myocardium receives the action potential, it is activated and contracts. Figure 1 illustrates the relevant components of the conduction system, the…

…conduction and contractile cells—must undergo rapid repolarization to ensure they are excitable when the next action potential occurs. If any component of the ventricular…

…node. Thus, withdrawal of parasympathetic activity results in increased heart rate and increased impulse transmission across the AV node. Sympathetic fibers innervate the entire heart…

…contractile myocardium. When the contractile myocardium receives the action potential, it is activated and contracts. Figure 1 illustrates the sinus node and the components of…

…J point to the onset of the T wave. Because of the long duration of the plateau phase most contractile cells are in this phase…

…heart rate and contractility (i.e contractile force), results in increased metabolism. Cardiac cells are highly capable of matching the supply and demand of ATP…

…zone and contributes to ventricular failure. Mechanisms of Shock The central consequence of extensive infarction is loss of contractile myocardium, with reduced cardiac output and…

…Vasopressors induce vasoconstriction and increase mean arterial pressure (MAP). Inotropes increase cardiac contractile force (contractility). Several endogenous and synthetic agents exist and are frequently combined…

…Vasopressors induce vasoconstriction and increase mean arterial pressure (MAP). Inotropes increase cardiac contractile force (contractility). Several endogenous and synthetic agents exist and are frequently combined…

…coronary artery disease (CAD). It combines echocardiographic assessment of left ventricular (LV) structure and function with exercise or pharmacological stress. The physiological basis is an…

…This makes more calcium available to the contractile proteins which therefore produce stronger contractions. Lowering of the heart rate is due to increased Vagus nerve…

…conduction system allows for rapid spread of the depolarization to the contractile cells. Figure 3 illustrates the components of the conduction system and its temporal…

…progressive, and highly complex lipid driven inflammatory disease of the arterial intima that serves as the fundamental pathophysiological substrate for acute coronary syndromes (ACS), including…

…contractions (PAC) PACEMAKER RELATED Pacing with rapid ventricular response rate The incidence of tachycardia induced cardiomyopathy is 8–10% among patients with atrial tachycardia (Medi…

…of ventricular rhythm and idioventricular rhythm The usual mechanisms are responsible for all ventricular rhythms. Increased automaticity (in His Purkinje fibers), abnormal automaticity (in contractile…

…moderate ischemia may produce post ischemic stunning. In the absence of infarction, contractile recovery can occur rapidly after reperfusion, with recovery generally occurring within one…

…chronic aortic regurgitation gradually leads to impaired contractile function and the development of myocardial fibrosis. Contractile dysfunction further aggravates the regurgitation (the regurgitation volume increases…

…Ejection fraction is routinely examined at rest, which does not reveal the functional (maximum) capacity of the left ventricle, as this would require measuring the…

…g ejection fraction (EF), fractional sorting (FS), etc — do not elucidate regional variations in contractile function, or the effectiveness of longitudinal, radial, and circumferential contraction…

…are components of the myocardial contractile apparatus and are expressed predominantly in cardiac muscle. Troponin I is highly specific for myocardial injury. Interpretation of troponin…

…The action potential in the sinoatrial node and in contractile myocardial cells. Phase 4 of the action potential in the sinoatrial node is called "pacemaker…