Lecture Slides

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Unformatted text preview: Click to edit Master subtitle style cardiac drugs: antidysrhythmics and angina meds NURS 324 Fall 2010 Dr. Smith cardiac electrophysiology  The heart contains its own electrical conduction system  Specialized tissues within the myocardium generate (SA/AV nodes) and transmit (other pathways) electrical impulses  This electrical impulse is what causes the myocardium to contract  Therefore normal, effective contraction of the heart depends upon quick and correct Conduction pathway Control of cardiac action  Sympathetic nervous system is the biggest player  Parasympathetic nervous system (vagus nerve)  Medications previously discussed? Action potentials  Each electrical signal generated by the SA node creates a wave of depolarization throughout the entire conduction pathway  Called action potentials  Two types of action potentials: fast and slow  Fast potentials happen in the Bundle of His, Purkinje fibers, and atrial and ventricular myocardium Fast and slow potentials The electrocardiogram  An graphical representation of the sum of electrical activity in the whole myocardium  Combinations of positive & negative electrodes create leads or view angles  Positive deflection on the EKG indicates movement of electricity toward the positive lead, negative deflection means away  The EKG ONLY SHOWS the electrical activity, not the mechanical activity (contractions) The EKG dysrhythmias  Normal, happy hearts have a rhythm called sinus  Disturbances or changes in the electrical rhythm of the heart are dysrhythmias  May originate from nodes (automaticity problems) or other electrical tissue (conduction problems)  Dysrhythmias may be tachycardic or bradycardic Common dysrhythmias  Supraventricular dysrhythmias: originate above the ventricles-usually less dangerous b/c AV node usually blocks some of the extra atrial activity, thereby keeping CO fairly normal-atrial flutter, atrial fibrillation, sustained supraventricular tachycardia  Ventricular dysrhythmias: an ectopic focus in the ventricles Antidysrhythmic therapy...
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This note was uploaded on 02/15/2011 for the course NURS 324 taught by Professor Smith during the Fall '10 term at South Carolina.

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Lecture Slides - Click to edit Master subtitle style...

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