Echocardiography Methods for assessing systolic function (contractile function) Several echocardiographic measurements are available to assess left ventricular systolic function. These methods elucidate slightly different aspects…

…and infarction Myocardial ischemia: cellular changes, ECG signs and development of infarction Like all other cells in the human body, cardiac myocytes use ATP (adenosine…

…wave. Because of the long duration of the plateau phase most contractile cells are in this phase at the same time (more or less). Moreover…

…Other causes include acute mechanical complications—particularly ventricular septal defect (VSD) and papillary muscle rupture with acute severe mitral regurgitation—predominant right ventricular (RV) infarction…

…including: Global and regional LV systolic function LV contractile reserve Valve function and stress related haemodynamic changes Diastolic function Pulmonary hypertension Coronary flow velocity reserve…

…excellent, with the vast majority of patients recovering completely after restoration of sinus rhythm (or any other rhythm with normal ventricular rate and activation). Recovery…

…driven by platelet derived growth factor (PDGF) and other cytokines. Within the intima, SMCs undergo a phenotypic switch from a contractile to a synthetic state…

…rhythms. Increased automaticity (in His Purkinje fibers), abnormal automaticity (in contractile myocardium), re entry (anywhere) or triggered activity (anywhere) may all cause ventricular arrhythmias. Indeed…

…the leads. Some leads may display all waves, whereas others might only display one of the waves. Regardless of which waves are visible, the wave…

…Viable, stunned, and hibernating myocardium Viable dysfunctional myocardium is myocardial tissue whose contractile function improves after coronary revascularization. This functional definition encompasses several physiological states…

Echocardiography Echocardiographic assessment of regional contractile function Systolic ventricular function is one of the strongest predictors of total and cardiovascular mortality. Previous chapters have discussed…

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…

…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…

…discussed, all cardiac cells—both conduction and contractile cells—must undergo rapid repolarization to ensure they are excitable when the next action potential occurs. If…

…capable of transmitting the action potential, albeit at a much lower speed than the conduction cells. The terms contractile myocardium , myocardium, or simply myocardial cell…

…that ultimately intracellular calcium concentration increases. This makes more calcium available to the contractile proteins which therefore produce stronger contractions. Lowering of the heart rate…

…function. This is due to the following reasons: Left ventricular geometry must be normal. There must not be regional differences in contractile function. Otherwise, the…

…ventricular contraction. In contrast, contractile cells–and Purkinje fibers in particular–are rich in gap junctions, enabling rapid impulse conduction through the ventricles. After passing…

…wall thickness (myocardial thickness). The left ventricle must generate sufficient contractile force to overcome the pressure in the aorta. The greater the pressure in the…

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

…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…

…of the ventricular myocardium. This is presumably due to a mismatch between the expansion of contractile cells as compared with conduction cells. Therefore it is…

…Figure 1. The action potential in the sinoatrial node and in contractile myocardial cells. Phase 4 of the action potential in the sinoatrial node is…

…ejection fraction, then it is likely that variations in preload and afterload, rather than changes in contractile function, explains the varying ejection fraction. Ejection fraction…

…particularly the ventricular myocardium. Sympathetic stimulation has a positive inotropic effect (i.e increases contractile force in the myocardium), positive chronotropic effect (i.e increases…

…cells form bundles of fibers that spread the action potential rapidly and sequentially to the contractile myocardium. When the contractile myocardium receives the action potential…

…and Purkinje fibers. The conduction system allows for rapid spread of the depolarization to the contractile cells. Figure 3 illustrates the components of the conduction…

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

…Houtkooper et al). The majority of ATP produced is utilized to fuel the contractile machinery and maintain ion channel function. Neumar et al studied how…