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Dysrhythmias Part 1

Terms in this set (24)

Sinus Node
•Normally the primary pacemaker of the heart
•Rate: 60-100 bpm
AV Node
•Normally the only way an electrical impulse moves from the atrium to the ventricles
•Rate: 40-60 bpm
Bundle Branches and Purkinje Fibers
•Bundle Branches:
•3 branches on the left and 1 on the right
•
•Purkinje Fibers:
•"finger like" projections that innervate the ventricles
•Rate: 20-40 bpm
P Wave
atrial depolarization (contraction)
QRS wave
Ventricular Depolarization
Causes of Sinus Bradycardia
-Hypothermia
-Hypothyroidism
-Medications
-Heart Attack (MI)
Manifestations and Treatment of Sinus Bradycardia
Manifestations
-Hypotension
-Pale, cool skin
-weakness
-angina
-dizziness or syncope
-confusion or disorientation
-SOB

Treatment
-Atropine
-Pacemaker
-Stop Offending Drugs
Sinus Tachycardia Causes
-hypertension
-fever
-stress
-excess alcohol
-caffeine
-nicotine
-electrolyte imbalance
-Hyperthyroidism
-compensatory mechanism
Sinus Tachycardia Manifestations and treatment
Manifestations:
-dizziness
-dyspnea
-hypotension
-angina in patients with CAD

Treatment:
-treat the cause
Atrial Fibrillation example
Atrial Fibrillation (A-Fib)
-Causes a decrease in CO and an increased risk of stroke

Treatment:
-Drugs to control ventricular rate and or convert to sinus rhythm (amiodarone)
-Electrical cardioversion
-anticoagulation
-Radiofrequency ablation
Supraventricular Tachycardia example
Characteristics of supraventricular Tachycardia
-HR 150-220bpm
-The P wave is often hidden in the preceding T wave, QRS is usually normal
Supraventricular Tachycardia
•Clinical Associations:
•Normal Heart: Associated with overexertion, emotional stress, deep inspiration, and stimulants such as caffeine and tobacco.
•Diseased Heart: Rheumatic heart disease, digitalis toxicity, CAD and heart failure.

•Clinical Significance: Depends on the symptoms and the heart rate. HR greater than 180bpm will cause decreased cardiac output with hypotension, palpitations, dyspnea, and angina.
•
•Treatment:
•Vagal stimulation
•Medications: Adenosine, B-blockers and Calcium Channel blockers (diltiazem)
Valvular Heart Disease Stenosis
(constriction/Narrowing)
-valve orifice is smaller
-forward blood flow is impeded
-pressure differences reflect degree of stenosis
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