(6) Electrocardiogram

See paper notes ECG

What are the uses for ECG?
(just know of tbh)

-Monitor cardiac electrical activity

Gain insight into:
- anatomical orientation of heart
- chamber sizes (heart chamber hypertrophy)
(takes time for electrical activity to go through)
- disturbance in rhythm and conduction
- extent, location, progress of ischemic dmg to myocardium (scar tissue, no electrical activity)

1) Electrode pairing is known as a __

2) We can a view of the electrical activity of the heart along the __

1) Lead

2) Reference line

1) Lead 1,2,3 combined are known as the __

2) Which lead most closely aligns w/ dispersal of electrical activity through the heart?

1) Einthoven’s triangle

2) Lead 2

Describe the components of an ECG.

1) Isoelectric line = NO cardiac vector detected by lead (remains 0)

2) Upward deflection
- electropositive pole oriented TOWARDS positive electrode

3) Downward deflection
- electropositive pole orientated AWAY from positive electrode

General info about Lead 2

(quite intuitive but think about it as additional info)

1) cardiac vector is PARALLEL w/ lead 2
→ maximal upward deflection (i.e., electropositive pole is pointing toward positive electrode)

2) if NOT PARALLEL, lead 2 will only pick up the vector components parallel to lead 2

3) if PERPENDICULAR (cross), NO deflection

4) if PARALLEL but electropositive pole is pointing towards neg electrode = MAXIMAL DOWNWARD DEFLECTION

(don’t really memorize)

Point #3: Rz towards positive electrode = downward deflection (regular cell)

Point #4: Rz AWAY from positive electrode = upward deflection (seen in ventricular cells)
- b/c the epicardium Rz first before the endocardium (Rz goes opposite of the reference line/lead 2)

I didn’t really draw this

(don’t really memorize)