…activation of the ventricular myocardium. The ventricles should be depolarized (activated) by impulses spreading through the left and right bundle branch, which branches out into…

…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…

…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…

…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…

…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…

…discussed in detail in the articles on left ventricular enlargement, right ventricular enlargement and atrial enlargement. Below follows a discussion on the principles and differences…

…7 ). The explanation for this is as follows: The vector resulting from activation of the right ventricle does not come to expression , because it is…

…intrinsic automaticity The sinus node is a small oval structure located near the entrance of the superior vena cava in the right atrium (Figure 1)…

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…

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…

…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…

…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…

…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…

…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…

…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…

…ischaemia should instead be classified as acute myocardial injury. Mechanisms of troponin release Troponin I and troponin T are components of the myocardial contractile apparatus…

…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…

…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…

…to consider loading conditions when evaluating the measured ejection fraction. Ideally, ejection fraction should be assessed during normal, with regards to the patient, loading conditions…

…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…

…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…

…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…

…ejection fraction (LVEF). This is accompanied by myocardial remodeling. The remodeling is accompanied by diminishing myocardial contractile function. Central venous pressure, pulmonary capillary wedge pressure…

…interventions are time sensitive, and to maximize the likelihood of restoring spontaneous circulation, interventions should be adapted to the current phase. However, current guidelines do…

…1. Ventricular rhythm. One exception to the rule above should be noted. If an ectopic focus arises in or near the bundle of His, the…