3-1: Ekg Arrhythmias

Front 1

In order of activation, list ectcopic cardiac foci and their inherent rates.

Back 1

Atria: 60-80
AV Jn: 40-60
Ventricles: 20-40

Front 2

What is idioventricular rhythm?

Back 2

Rhythm under control of His-Purkinje System

Front 3

Triplets for determining rate.

Back 3

300, 150, 100, 75, 60, 50

Front 4

If p waves are absent, and heart rate is 60, what foci is setting the heart's pace?

Back 4

No p waves = No SA node activity
60 is in range of atria
Thus: AV Node conduction

Front 5

How do you determine slow rate?

Back 5

Use 3-sec hashmarks on top of EKG:
Cycles per 6 sec (2 hashmarks) x 10 = HR

Front 6

Peak vs Sad Face on EKG

Back 6

Peak = Depolarization (+)
Sad face = Repolarization (-)

Front 7

Draw an EKG and describe all phases.

When does systole begin and end?

Back 7

P wave: atrial depolarization and contraction; forcec blood through AV valves

QRS: ventricular depolarization and beginning of contraction

T hump: Rapid phase of ventricular repolarization (K+ ions out)

Systole begins at QRS and ends at end of T

Front 8

What defines an S wave?

Back 8

Any downward wave with an upward wave in front of it

Front 9

What interval changes with heart rate?

Back 9

QT interval

Front 10

What does a long QT interval singify?

How would you determine if it's long?

Back 10

If QT is long, then there is a rapid ventricular rhythm

QT is greater than 1/2 R to R

Front 11

1 big box vs 1 small box:
Time

Back 11

1 big box = 0.2 sec
1 little box = 0.04 sec

Front 12

Which leads are precordial? Which heart region does each monitor?

How does Q value (positive/negative) differ among the leads?

Back 12

V1-V6 are precordial

V1-2 Right chest leads (RV): mainly negative
V3-V4: Interventricular Septum (R/L BB's); Isoelectric
V5-V6: Left Chest Leads (LV): Mostly positive QRS

Front 13

What heart region is the origin of the mean QRS vector?

Back 13

AV Node

Front 14

What is normal axis range?

Back 14

Between 0 and +90 degrees

Front 15

Effect of hypertrophy on vector and mean QRS shifts.

Back 15

Hypertrophy increases vector and mean QRS in its direction

Front 16

Effect of infarction on vector and mean QRS shifts.

Back 16

Infarction decreases vector and shifts mean QRS away from it.

Front 17

Steps for determining axis deviation.

Back 17

Find quadrant of mean QRS vector
Find limb lead with most isoelectric QRS
Use reference angles

Front 18

Steps for determining axis rotation.

Back 18

Look at precordial leads.
If isoelectric in V1/V2: RIGHTWARD ROTATION

If isoelectric in V5/V6: LEFTWARD rotation

Front 19

Normal range for heart rate.

Back 19

60-100: Normal

<60 = brady
>100 = tachy

Front 20

How do you decide if rhythm is regular?

Back 20

Measure distance between QRS complexes (should always have ventricular contraction). Should be constant.

Front 21

QRS Complex:
Narrow vs Wide:
What do they mean?
What defines narrow/wide?

Back 21

Narrow QRS: Rhythm originates ABOVE ventricle:
so sinus or supraventricular rhythm: Sinus, Atrium, AV Junction

QRS<0.12 sec

Wide QRS: originates from ventricle
QRS >0.12 sec

Note: 0.12 = 3 tiny boxes

Front 22

What is the significance of wide PR interval?

What's the cutoff for a wide interval?

Back 22

Wide PR interval = more than .20 seconds between beginning of P wave and beginning of QRS

0.2 seconds = 1 big box

Signifies AV block (impaired conduction); taking too long for signal to get through AV junction

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