…AV) nodes. In addition to these direct effects, adenosine antagonizes catecholamine stimulated adenylate cyclase. This inhibition decreases the accumulation of cyclic adenosine monophosphate (cAMP), which…

…tachycardia may arise if the pacemaker records a rapid atrial rate (e.g. during a supraventricular tachycardia) and stimulates the ventricles with the same rate…

…resting potential (phase 4), which is around –90 mV. These cells must be stimulated in order to evoke an action potential. Upon stimulation, sodium (Na+)…

…be considered. For example, Wolff Parkinson White syndrome (WPW), pacemaker stimulated beats, electrolyte imbalance and medications may prolong the QRS complex. References Aro AL, Anttonen…

…not result in myocardial activation. Failure to pace (FTP) , which means that the pacemaker does not stimulate as expected. Oversensing , which means that the pacemaker…

…low dose Rarely used Low dose : 0.5 3.0 μg/kg/min + + + +++++ Low dose dopamine stimulates D1 receptors and induces vasodilation in coronary…

…direct activation of voltage sensitive calcium channels. At lower doses, dobutamine stimulates beta2 and alpha receptors, inducing vasodilation, decreasing aortic impedance and systemic vascular resistance…

…and aggregate through glycoprotein IIb/IIIa mediated fibrinogen bridging. Tissue factor activation stimulates the coagulation cascade, generating thrombin and fibrin and enlarging the occlusive thrombus…

…and one or two leads . The pulse generator generates the electric current needed to stimulate the myocardium. The current is delivered to the myocardium via…

…causes the myocardium to secrete growth factors (particularly VEGF [vascular endothelial growth factor]) which stimulate nearby arteries to grow new vessels into the ischemic zone…

…low dose Rarely used Low dose : 0.5 3.0 μg/kg/min + + + +++++ Low dose dopamine stimulates D1 receptors and induces vasodilation in coronary…

…artery stenosis. Stress can be induced pharmacologically with coronary vasodilatory agents or simulated hemodynamically through exercise or the use of chronotropic and inotropic agents. Radiotracers…

…Beta 1 adrenergic receptors: expressed in the myocardium. Activation results in increased contractility and increased chronotropy (heart rate). Beta 2 adrenergic receptors: expressed in vascular…

…Image acquisition and evaluation Stress Imaging : Initially performed using exercise or pharmacologic agents to elevate myocardial oxygen demand (or simulate increased demand using vasodilatory agents)…

…which result in secondary ST T changes. Such ST T changes may mimic (simulate) or mask ischemia. Simulation of ischemia manifests as ST segment elevations…

…combined with patient denial, often leads to a mistaken impression of indigestion. STEMI pain can simulate pain from acute pericarditis, pulmonary embolism, acute aortic dissection…

…Can you spot them? Note that negative delta waves may simulate pathological Q waves (and thus be confused with previous myocardial infarction). ECG examples of…