…for electrophysiological evaluation (Hasdemir et al, Kawamura et al, Yokokawa et al). Tachycardia induced cardiomyopathy is presumably the main cause of left ventricular dysfunction among…

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…

…His, bundle branches (left and right bundle branch), and Purkinje fibers. The conduction system allows for rapid spread of the depolarization to the contractile cells…

…of the left ventricle (Figure 1; refer to Segments of the Left Ventricle). Regional wall motion abnormalities are defined as regional abnormalities in contractile function…

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

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…

…easily obtained parameters, but fail to provide important insights into left ventricular mechanics. Regional differences in contractile function are of utmost importance, particularly in the…

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

…volume overload. Unfortunately, adaptation implies that the left ventricle dilates, which induces irreversible cellular and extracellular processes that ultimately lead to heart failure. This initially…

…than changes in contractile function, explains the varying ejection fraction. Ejection fraction and left ventricular volume Ejection fraction is also affected by left ventricular volume…

…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…

…fibrosis Reversible ischemic dysfunction Chronic hypoperfusion with hibernating myocardium Post ischemic stunning Adverse left ventricular (LV) remodeling Ischemic cardiomyopathy is the leading cause of heart…

…In the setting of ST elevation myocardial infarction (STEMI), cardiogenic shock most commonly reflects severe left ventricular (LV) dysfunction, accounting for approximately 80% of cases…

…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…

…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…

…little calculation. Sensitivity and specificity vary markedly, as discussed in detail in the articles on left ventricular enlargement, right ventricular enlargement and atrial enlargement. Below…

…third vector: the ventricular free wall The vectors resulting from activation of the ventricular free walls is directed to the left and downwards ( Figure 7 )…

…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…

…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…

…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…

…cellular functions, such as contraction and relaxation. Increasing cardiac workload by increasing heart rate and contractility (i.e contractile force), results in increased metabolism. Cardiac…

…injury. Mechanisms of troponin release Troponin I and troponin T are components of the myocardial contractile apparatus and are expressed predominantly in cardiac muscle. Troponin…

…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…

…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…

…other cytokines. Within the intima, SMCs undergo a phenotypic switch from a contractile to a synthetic state, producing abundant extracellular matrix (ECM) components, primarily interstitial…

…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…

…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…