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85 Cards in this Set
- Front
- Back
Cardiac valves
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thin flaps of flexible tough endothelium lined fibrous tissue.
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AV Valves
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tricuspid and mitral valves. There is overlap of flaps during closure.
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Semilunar Valves
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Aortic & pulmonary subjected to high pressures and a high velocity of blood ejection
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Lub =
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S1 Mitral valve closes
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Dub =
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S2 Aortic semilunar valve closes
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Auscultation
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Listening to the sounds of the body, usually with the aid of a stethoscope
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Heart Sounds
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Result from vibrations created by the moving valves and the moving heart chambers & moving blood.(Lub Dub). Gives indication of condition of the heart. During sedation for dental procedures, you listen to them both before and after procedure.
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S1
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1st sound is lub & corresponds to closure of AV valves. Occurs at the start of ventricular systole.
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S2
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2nd sound is dub & corresponds to closure of semi lunar (aortic and pulmonary) valves. Occurs at the beginning of isovolumetric relaxation.
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S3
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(3rd): turbulence due to ventricular filling.
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S4
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(4th) turbulence due to atrial systole or ventricular filling
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Why do you inhale while your physician listens to your heart?
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Inspiration is linked to 1. increased venous return 2. increased right ventricle stroke volume. 3. decreased pulmonary vascular resistance. These changes amplify murmurs.
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Murmurs
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abnormal heart sounds produced by turbulence of blood flow Ex. A hole in your heart
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Diastolic murmur
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regurgitating aortic valve
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Systolic murmur
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regurgitating mitral valve
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Valve lesions
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systemic diseases e.g. (Rheumatic fever) inflammation of heart valves and becomes scar tissue
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Stenosis
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narrow opening from fusion of valve flaps so blood flow is more turbulent.
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Regurgitation
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when valve flaps are compromised and don’t completely close… there will be back flow.
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Phonocardiogram
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A recording in which heart sounds appear as waves. A microphone that detects low-frequency sound is placed on the chest, and the sounds are amplified and recorded by a high-speed recording apparatus.
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Rheumatic Fever-Dentistry
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Scar tissue formed has a high potential for infection. Dental procedures can cause bacteremia. No longer require prophylactic antibiotics for all cases.
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Echocardiogram
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ultrasound of the heart for structure and function, e.g., measures cardiac output.
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**The beating heart normally makes four sounds. What are they?
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Two (S1 and S2) are audible and two (S3 and S4) are usually inaudible. The heart may make other sounds including murmurs or clicks.
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**S1
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First heart sound is lub and it occurs at the start of ventricular systole-closure of AV valve.
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**S2
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Second heart sound is dub. It occurs at the beginning of isovolumetric relaxation phase of systole when the aortic and pulmonary valves close.
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**S3
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3rd heart sound is a turbulence due to filling of the ventricles.
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**S4
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4th heart sound is a turbulence due to atrial systole or filling of the ventricles
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**Electrocardiogram or ECG are recordings of?
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cardiac action potentials**
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**ECG
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record of voltages from the surface of the thorax produced by the action potential of myocytes. A. - & + electrodes. B. Extracellular electrodes record a potential difference only when part of heart is depolarized or repolarized
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**Normal Sinus Rhythm ECG
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1. The spread of action potential is recorded in an ECG 2. P wave- depolarization of atria 3. QRS complex- depolarization of ventricle 4. T wave – repolarization of ventricle.
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P wave
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depolarization of atria
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QRS complex
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depolarization of ventricle
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T wave
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repolarization of ventricle.
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Atria repolarization is buried in the?
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QRS so you can’t see it
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P-R interval is the conduction of?
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the SA/AV conduction, this increases when Parasympathetic control.
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QRST is the?
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contraction of the ventricles
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Where we place the leads in an ECG (+/-) can have what impact?
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It can change the way the reading projects
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In a Normal ECG. P wave depolarization of atria is end of?
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P wave – all cells depolarized.
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In a Normal ECG. QRS complex depolarization of ventricle shorter than?
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P wave.
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In a Normal ECG. T wave
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repolarization of ventricle from epicardium to endocardium.
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In a Normal ECG. ST-segment
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voltage expected to be flat (MI has current of injury
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In a Normal ECG. R-R interval reflects?
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heart rate (60 sec /RR sec)
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In a Normal ECG. P-R interval is?
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0.12-0.21 s, measured from beginning of p to beginning of QRS & reflects AV-node propagation
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ECG is a diagnostic tool. What are the ways we can use it?
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1. Rate- normal, tachycardia or bradycardia 2. Intervals- evaluates conduction system 3. Rhythm- arrhythmias
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Elevated ST segment indicates?
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injury. lead is diagnostic through vector analysis.
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A heart with an ischemic region on its inferior surface. The injured region causes a current of injury that shifts the?
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ST segment above the baseline. The location of the injured region can be determined by vector analysis of the ECG traces.
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Hypertrophy
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cells grow and fill in
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Sinus Tachycardia
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100 beats or more per minute
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Sinus Bradycardia
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60 beats or less per minute
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The athlete's heart pumps a large stroke volume output per beat even during periods of rest. The excessive quantities of blood pumped into the arterial tree with each beat initiate?
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feedback circulatory reflexes or other effects to cause bradycardia when the athlete is at rest. This is not dangerous.
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The causes of cardiac arrhythmias are abnormalities caused by ischemia - scar tissue – calcification – inflammation. This leads to what?
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1. Abnormal rhythmicity of the pacemaker 2. Shift of pacemaker from sinus node 3. Blocks at different points in the transmission of the cardiac impulse 4. Abnormal pathways of transmission in the heart 5. Spontaneous generation of abnormal impulses from any part of the heart
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Relationship of P to QRS waves: 1st degree block- PR interval is?
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↑ (>0.21 s).
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Relationship of P to QRS waves: 2nd degree block
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P wave not always followed by QRS complex . (refractory period of Purkinje fibers limits rate to <200/min)
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Relationship of P to QRS waves: 3rd degree block
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dissociation of P & QRS complex.
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Relationship of P to QRS waves: A Short PR interval is indicative of?
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Wolf Parkinson White Syndrome (<0.12 s).
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AV Block 1st degree
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little wave to small wave becomes longer
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AV Block 2nd degree
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p wave not followed by QRS
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AV Block 3rd degree
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dissociation of p waves and QRS’s
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PR interval is an index of?
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atrioventricular depolar?
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Abnormal conditions of the ventricles: Prolonged QRS complex
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Purkinje fibers - bundle branch block and ventricular muscle damage.
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Abnormal conditions of the ventricles: ST segment elevation
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ischemia and myocardial infarction.
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Abnormal conditions of the ventricles: T wave
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abnormal when repolarization does not occur normally.
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Premature ventricular contractions (PVC) are often wider than normal QRS have no p wave and see a compensatory pause. Ventricular tachycardia (V-tach) is a?
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high rate originating in the ventricles.
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Lidocaine used to decrease arrhythmias is in the same class of drugs as the?
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“novacaines”
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Current of Injury
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Damaged cardiac muscle remains partially or totally depolarized all the time. Injured muscle emits negative charges throughout each heart beat.
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What are the Causes of current of injury?
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(1) local ischemia (2) mechanical trauma (3) infection.
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Relative Refractory Period prevents?
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defibrillation.
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Circus Pathway to Fibrillation.
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Increased pathway of conduction due to heart dilation. Decreased conduction rate through the AV node….ischemia/damage to conduction pathway. Shortened refractory period: epinephrine nor-epinephrine
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Heart disease à circus movement takes longer to get through the whole heart and the heart muscle quivers instead. Can happen in?
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atrium and ventricles
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Fibrillation
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there are no p waves and the SA node isn’t working right.
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Atrial fibrillation
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there is no rhythm
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Ventricular fibrillation
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you pass out and if lasts 4-5 seconds you will die if something isn’t done.
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Atrial Fibrillation
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The P waves are absent and see irregular low voltage wavy record. R-R interval & HR are irregular.
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Ventricular fibrillation
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loss of QRS and see wavy record. In 4-5 sec patient becomes unconscious. Ventricle does not contract & so no cardiac output. All coordinated electrical activity is lost.
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Defibrillation
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passes large currents through the heart to make all cells refractory so Normal Sinus Rhythm can resume.
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Astystole
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no Heart rhythm
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**Deflections in the ECG correspond to?
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electrical events on the heart. Action potentials in cardiac cells create extracellular voltages which are conducted to the body surface.
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**The P wave represents atrial depolarization. the QRS complex represents?
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ventricular depolarization; the T wave represents ventricular repolarization.
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**The PR interval is influenced by?
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the conduction time in the AV node.
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**The QT interval is influenced by?
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the duration of ventricular action potentials and conduction time over the ventricle.
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**Myocardial ischemia can produce a current of injury that moves the ST segment?
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off of the baseline.
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**The heart rate can be determined from?
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the R-R interval.
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**Failure of conduction through the AV node causes?
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heart block.
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**Ectopic foci cause?
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premature contractions of the heart.
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**Electrical Impulses can reenter to cause?
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fibrillations.
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Defibrillation
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large DC current applied through thoracic cavity stops fibrillation as entire heart is put into refractory period
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