Heart Rhythms: Normal or Abnormal (Arrhythmias)
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Transcript of Heart Rhythms: Normal or Abnormal (Arrhythmias)
Heart Rhythms: Normal or Abnormal (Arrhythmias)
Anatomy & Physiology L2 and L3
Cardiac Muscle
Electrical Conduction
SA Node Primary “jump-
start” for the heart Creates a beat
approx 70 bpm If faulty, replaced
by artificial pacemaker
AV node Delays/↓
transmission of signal Could only create
approx 40 bpm on its own
NOT strong enough to sustain life (so need the SA node)
Interior anatomy of heart
Bundle of His Collection of cardiac
cells creating the AV bundle
Conduct impulses along septum to the Purkinje fibers in walls of the ventricles
Takes impulse about 0.03-0.04 sec to travel to the ventricles
Purkinje fibers: largest fibers filaments
Located on inner wall of endocardium
Carry electrical impulse from SA and AV nodes
Electrocardiogram (ECG or EKG)
12-lead (multi-angle)
Normal Sinus Rhythm
P wave
QRS complex
T wave
Bradycardia
Tachycardia Notice the sinus
rhythm
Approx 120 bpm
Ventricular Fibrillation Overall: 300 bpm Cannot sustain life
Artificial Pacemakers
Implanted beneath skin Composed of: electrical pulse
generator and lead wires to communicate with the heart tissue
Permanent battery Can be checked over the phone
Pacemakers