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 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