My Notes EKG

8/8/2019 My Notes EKG

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Paper Rate:25 mm/s

1mm=.05 sec (each block)

5mm=.2sec (big blocks)

Voltage:1mm=.1mV5mm=.5mV (between 2 dk

horizontal lines)

10mm=1.0mV


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1. Check that waves (P, QRS, T) are + in Lead II Only in aVRis it normal for the complexes to be inverted or negative.

2. Look for Q waves: small Q waves are normal in Leads I,avL, and V6.

3. Look at the T waves in Leads V1-V6: in V2-V6 the Twaves should be +

4. Look for progression of R waves in V1-V6y In V1 there is a small R and a large Sy V4 or V5 usually has the largest R wavesy In V3 or V4 the R and S waves are usually about

equal size

5. Examine the ST segmenty Look for 1mmor more of depression or elevation

6. Dont forget to check the rhythm and rate.7. Look at the P wavesin Leads II and V1

y The P wave will have an amplitude of >2.5 mm =atrial enlg

y The P wave will be biphasic

QRS: .8-.12 sec (2-3 boxes)

Q- first down (not always present)

R-first up

S- first down after R (first up)

R1- upward deflections occurring after S


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ECG waveforms result from the mean vector summation of atrial and ventricular

depolarization---if the mean QRS waveform is directed toward an electrical lead,

the waveform will have a positive deflection and vice versa.

activation sequence of the right and left ventricles

Anterior septal wall of LV: earliest activation posterior septal wallventricular free wall is subsequently

activated.

Rightward Oriented Leads: V1, aVR- initial septal activation accounts for the presence of septal Q waves on the

ECG and is positive in these leads. Negative deflection in the leftward oriented leads (V5, V6 and aVL).These

initial forces are of low amplitude and brief, however loss of septal Q waves may represent infarction, ischemia,

or fibrosis of the septum. The rest of the QRS complex represents activation of the free walls of the right and left

ventricles.

In the precordial leads, there is a clear progression from rS pattern in the rightward leads to a qR pattern in the

left leads. The point where the pattern changes from an rS to a qR pattern is known as the transition zone. Poor

R wave progression may represent left ventricular infarction, fibrosis, or infiltration.


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Axis represents the sum of the vectors of the electrical depolarization of

the ventricles and gives an idea of the electrical orientation of the heart in

the body. In a healthy person, the axis is downward and to the left. The

QRS axis is midway between two leads that have QRS complexes of equal

amplitude, or the axis is 90 degrees to the lead in which the QRS isisoelectric (ie, R amplitude wave equals S-wave amplitude).

y Normal Axis. QRS positive in I and aVF (090 degrees). Normal axisis actually 30 to 105 degrees.

y Left Axis Deviation (LAD). QRS positive in I and negative in aVF, 30to 90 degrees

y Right Axis Deviation (RAD). QRS negative in I and positive in aVF,+105 to +180 degrees

y Extreme RAD. QRS negative in I and negative in aVF, +180 to +270or 90 to 180 degrees

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My Notes EKG