Cardio Rehab (1 of 2)

B. Positive outside/Negative inside

An instrument which measures the difference between voltage levels at any specific point across the heart

I, II, III, aVR, aVL, aVF, V₁, V₂, V₃, V₄, V₅, V₆

• 
• *Look in notes (p37)

• 
• 0 to +90 = Normal
• 0 to -90 = Left axis deviation
• +90 to +180 = Right axis deviation
• -90 to -180 = Degrees of axis deviation

• Speed= 25 mm/sec
• Amplification= 1mV/cm

Atria excitation, originates in SA node

The deflection following the QRS complex

• "Crossing of excitation" over the inter-ventricular septum.
• Enlarged Q could indicate an old MI

Depolarization of the ventricles

• Late phase depolarization of the ventricles.
• Has little/no interpretive significance.

SA (sino atrial) node

A complex (EKG) in lead 2 equals the sum of the corresponding complexes in leads 1 and 3 (2=1+3)

• aVR = Right Arm
• aVL = Left Arm
• aVF = Left Leg (foot)

Just to the right of the sternum in 4th interspace

Just to the left of the sternum in the 4th interspace

Placed in the mid clavicular line (MLL) in 5th interspace

Halfway between leads 2 and 4

Placed at the same level of V₄ in the anterior axillary line (AAL)

Placed at the same level of V₄ in the middle axillary line (MAL)

Placed at the same level as V₄ in posterior axillary line (PAL)

• Lead I = RA vs LA
• Lead II = RA vs LL
• Lead III = LA vs LL

Reduced blood flow relative to needs and results in too little oxygen (0₂)

Lead II, aVF, V₅

Premature ventricular beats or ectopic beats

• Q= first down strike after P wave before R wave
• R= first upward deflection
• S= last downstroke

Nodal delay of AV junction

The delay between completion of depolarization and the beginning of re-polarization of ventricles

Indicating coronary insufficiency