Requires normal conduction to be slowed

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Unformatted text preview: ents Reentry causing Circus movements Reentry causing Circus movements Reentry Reentry • The same impulse reactivates tissue that it has already stimulated. • Requires: – Normal conduction to be slowed – Refractoriness to be shortened – Both ***Relate to Functional Refractory Period*** Arrhythmias: Arrhythmias: Disorders of rate, abnormal impulse formation, and electrical conduction • Rate and abnormal impulse formation – – – – Bradycardia (under 50-60 BPM) Tachycardia (100-200 impulses/minute) Flutter (200-300 impulses/minute) Fibrillation (probably over 300/minute) - can't measure pulse because contraction non-effective Normal Normal Atrial Flutter Atrial Atrial Fibrillation Atrial Arrhythmias: Arrhythmias: Disorders of rate, abnormal impulse formation, and electrical conduction • Rate and abnormal impulse formation – – – – Bradycardia (under 50-60 BPM) Tachycardia (100-200 impulses/minute) Flutter (200-300 impulses/minute) Fibrillation (probably over 300/minute) - can't measure pulse because contraction non-effective • Conduction – A-V block - from tissue damage, coronary infarction, vagal stimulation • Pulse less than 50-60 beats/minute often a warning sign but depends upon the patient Heart Block Heart First Degree Slow Conduction Rate OK Second Degree Type I Slower until skips Type II Just skips Third Degree Complete v Heart Medications Heart Drugs may change the force, rate, and rhythm of the heartbeat • Inotropic effect - influences contractility or force of contraction – May be positive or negative inotropic effect • Chronotropic effect - influences rate – May be positive or negative chronotropic effect • Dromotropic effect - influences conduction through specialized conducting tissues – May be positive or negative dromotropic effect Objective 2: Objective For each of the following drug groups, explain: – – – – Therapeutic use(s) Mechanism of action (if known) Side or toxic effects Contraindications or cautions ***Note names in Bold Type*** Treating Congestive He...
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This document was uploaded on 02/07/2014.

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