THE

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THE ELECTROCARDIOGRAM By Dr. Jay Shahed
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THE ELECTRICAL HEART MUSCLE STIMULATION

• The muscles of the heart especially the
  Myocardium are innervated by some of the minerals
  that are present in our cells .
• Potassium ( K ).
• Sodium ( Na ).
• A stimulation of the muscle will lead to its
  contraction.

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• POLARIZATION
• The muscle fiber is at rest.
• DEPOLARIZATION
• The muscle fiber is being charged with an
  electrical impulse that is followed by
  contraction of the muscle.
• REPOLARIZATION
• The muscle returns to the resting stage.

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THE ELECTRICAL PATHWAY OF THE HEART

• SA node then travels down to the AV node to
  Bundle Of His then to the Purkinje fibers
• SA node ( pacemaker) represents the atrial
  depolarization
• AV node represents the initiation of the
  Ventricular depolarization.
• Bundle Of His represents the Interventricular
  septum depolarization
• Purkinje fibers represents the Ventricular
  depolarization

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THE CARDIAC ELECTRICAL CYCLE

• Depolarization of the muscles of the heart
  followed by heart muscle Contraction followed by
  Pumping of the blood out of the heart followed by
  Repolarization then Polarization or resting of
  the heart muscle.

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• THE
• ELECTROCARDIAC LEADS

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Leads ( Vectors )

• Definition
• A lead is the pathway direction of a group of
  electrical charges that moves in.
• It is an electrical connection attached to the
  body to record electrical activity.

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The STANDARD ( BIPOLAR LEADS )

• Leads I ( Vector )
• Impulses that travels in the Right Arm to the
  Left Arm direction.
• Leads II
• Impulses that travels in the direction from the
  Right Arm to the Left Leg
• Leads III
• All impulses that travels in the direction from
  the Left Arm to the Left Leg

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THE AUGMENTED LEADS

• AVR ( Augmented voltage right )
• The Vector that travels midline between the LT.
  ARM / LT. LEG through the RT. Arm
• AVL ( Augmented voltage left )
• The Vector that travels midline between the RT.
  Arm/ LT. Leg through the LT. Arm
• AVF ( Augmented voltage Foot )
• The Vector that travels midline between the RT.
  ARM /LT. arm through the LT. Foot

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THE CHEST LEADS ( PRECORDIAL )

• V1 4th IC RT. Sternal Boarder
• V2 4th IC LT. Sternal Boarder
• V3 mid point B/W Mid way between V2 V4
• 4th IC 5th IC
  
• V4 5th IC Mid Clavicular Line
• V5 5th IC Ant. Axillary Line
• V6 5th IC Mid Axillary Line

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• The
• Electrocardiograph

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• Two parts
• Galvanometer
• Electrical charges that are emitted by the heart
  to the patients skin into Mechanical energy
  through its The impulses are then magnified by
  its
• Amplifier
• In a written pattern.

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The EKG paper

• Horizontal ( Seconds )
• Each horizontal small square 0.04 seconds
• Vertical ( Millimeter )
• Each vertical small square 1 mm
• Large square
• 5 small squares
• Vertical 5mm
• Horizontal 0.04 seconds
• Total 0.2 mm/sec

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Speed of the EKG

• Normal international speed
• ( 25 mm / second ).
• Tachycardia
• Speed 50 is used to extend the EKG wave complex
  twice as much.

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Normal Cardiac cycle

• Wave length
• 0.8 seconds / 20 mm in distance.

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Standardization

• International Calibration
• 1 ( STD)
• 1 mV of electricity causes the Stylus to move 10
  mm high and 2 mm wide
• Standards amplitudes
• 1 STD Normal
• 1/2 STD Used if amplitude of QRS is high
• 2 STD Used if the amplitude of QRS is low

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RECORDING AN EKG

• USING
• A
• 12 LEADS MACHINE

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PROCEDURE

• Ask the patient to disrobe the chest part only
  and give him or her a gown to ware.
• Ask the patient to remove all jewelry attached to
  the chest area, the arms and the legs.
• Ask the patient to lay down on the examining
  table.
• Make sure the patient is comfortable to reduce
  the possibility of ARTIFACT.

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• Place the appropriate leads onto the patient.
• Ask the patient not to move or talk during the
  procedure.
• Record the leads.
• check if the reading contains any artifact , if
  not remove the electrodes from the patient skin
• Mount the EKG if needed.
• Chart it in the patents chart .

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ARTIFACTS

• Somatic Tremor
• Patient is moving, chewing gum or dirty
  electrodes.
• Baseline shift
• Patient changing position when uncomfortable,
  dirty electrode
• Alternating Current interference
• Outside electrical interference
• Wandering baseline
• Loose or disconnected electrode

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HOLTER MONITOR

• Portable heart monitory system.
• Used to monitor the patients heart over 24 hours
  during different daily activities.
• Patient must keep a written diary of all the
  activities.
• Some machines records the patients voice while
  describing their activities.
• The number of electrodes depends on the number of
  channels that the machine has.

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• Suggested locations
• Clavicle ( Left Sternal boarder)
• Clavicle ( Right Sternal boarder)
• 5th Rib ( Right Sternal boarder)
• 7th rib ( Right Mid - Clavicular line)
• 5th rib ( left Anterior Axillary line)

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STRESS TEST

• A test used to check the activity of the heart
  when under stress using a treadmill
• Used to diagnose
• Heart disorders
• Asses cardiac function following heart surgery
• diagnose the possible cause of chest pains.

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Procedure

• 12 leads electrodes
• are placed on the chest area of the body
• Non on the extremities
• Vital signs are monitored
• Heart rate and Blood pressure is continuously
  monitored.

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• Instructions to the patient
• Rest
• Avoid extreme temperature changes
• Avoid stimulants
• Avoid hot showers
• Complications
• Acute MI
• Fatal cardiac arrhythmia
• Physician must be available at all time with
  appropriate emergency equipment.