EKG

Question 0

What type of patients get multifocal atrial tachycardia? What’s up with the atrial automaticity foci?

Answer 0

Very ill patients; like those with COPD
Atrial automaticity foci are also I’ll and show early signs of parasystole/entrance block. This is a condition where these cells can not be overdrive suppressed and pace at their own intrinsic rate.

Question 1

Characterize a wandering pacemakers rate rhythm and anything else that makes it unique

Answer 1

Rate normal-if irregular its called multifocal atrial tachycardia
Rhythm irregular-length variation
Waves from multiple atrial foci give distinct and variable P waves on the EKG called P prime waves.

Question 2

What condition is characterized by multiple parasystolic atrial foci?
Is this likely to happen to me?

Answer 2

Atrial fibrillation

NOT a condition of healthy young people

Question 3

A fib is characterized by what?

Answer 3

Rate- tachycardic
Rhythm-irregular
No P waves because no single impulse completely depolarizes both atria.
Random atrial depolarization leading to irregular ventricular rate/QRS rhythum (slow or fast)

Question 4

How can you quickly distinguish between an atrial and junctional escape rhythm?

Answer 4

Atrial escape rhythms will have P prime waves and junctional rhythms won’t have any P waves.

Question 5

What interesting finding might you see on an EKG related to junctional automaticity? What are the various presentations you might observe?

Answer 5

Retrograde atrial depolarization producing inverted P prime waves in leads with upright QRS complexes.

P prime wave will be before, after, or buried in a QRS complex

Question 6

When a premature beat depolarizes the SA node how does the peacemaking activity change?
When a premature beat is unable to do this, how might you detect it on EKG?

Answer 6

When the SA node is depolarizes by a premature beat the peacemaking activity resets in step with the premature beat; though the rate doesn’t change.

When a premature beat is unable to depolarize the SA node (like with a PVC) you can see the P wave continue to fire at the same rate. In this case if will probably be buried in the QRS complex and its firing will likely not result in ventricular depolarization because the ventricles will be in their refractory period.

Question 7

What are the signs of a premature atrial beat with aberrant ventricular conduction? Explain the aberrant conduction

Answer 7

You will see a premature P wave (P prime), and a widened QRS complex.

The aberrant conduction is the result of the right bundle branch repolarizing more slowly than the left, because it is temporarily refractory to depolarization. This non-simultaneous depolarization is what widened a the QRS complex.

Question 8

You’re reading an EKG with a premature P prime wave that isn’t followed by a QRS complex. What is this condition and how will it affect the peacemaking of the heart?

Answer 8

Non-conductive premature atrial beat which will (based on the P prime wave finding) reset the pacemaking in step with this new P wave.

Question 9

What is atrial bigeminy?

Answer 9

This is when an irritable atrial focus fires after each normal cardiac cycle and by doing so depolarizes the SA node (resetting it) resulting in a clear baseline between these two cycles (but could also result in aberrant ventricular conduction). These cycles form a couplet and display group beating.

Question 10

How does aberrant ventricular conduction present on EKG?

Answer 10

Widened QRS complex

Question 11

Inverted P’ waves preceding by, followed by, or buried in a upwardly deflected QRS complex are suggestive of what, assuming they alway follow two normal cycles, and are followed by gaps of empty baseline between these groups?

Answer 11

AV junctional trigeminy

Question 12

Hyperkalemia can be detected on EKG how?

Answer 12

tall peaked T waves, don’t confuse this with MI; with MI there should be more indications

Question 13

Hypokalemia presents how on EKG?

Answer 13

Flat T waves and a U wave

Question 14

What are some causes of an MI?

Answer 14

Narrowed or obstructed coronary artery
Rapid arrhythmia, causing insufficient blood supply
Decreased ventricular output in general leading to decreased coronary perfusion

Question 15

How will the progression of an MI look on EKG?

Answer 15

Hyperacute T waves minutes to hrs
ST elevation or depression 0-12hrs
New Q wave 0-12hrs
ST elevation with T wave inversion 2-5 days
T wave recovery weeks to months
Q wave will persist

Question 16

When would you use emergency coronary reperfusion therapy?

Answer 16

Only with a STEMI (ST elevation MI)

Question 17

How do you measure a STEMI?

Answer 17

J point must be elevated 1 box/0.1mV in 2 contiguous leads. If it looks close then check reciprocal leads to confirm.

Question 18

How does a heart injury vary with a STEMI vs a Non-STEMI?

Answer 18

STEMI is a transmural ischemia which spans a portion of the left ventricle

A Non-STEMI is subenocardial =ST depression and T wave inversion. (subendocardial think depression)

Question 19

What makes a Q wave significant?

Answer 19

Its larger than 1/3 of QRS amplitude and it represents cell death which is why it persists (irreversible damage)

Question 20

If the RCA is damaged, which leads should this be indicated in?

Answer 20

Inferior (II,III,aVF), and posterior (V1,V2)

Question 21

Which are the lateral leads?

Answer 21

I, aVL, V5, V6

Question 22

In which lead do you typically asses rhythum?

Answer 22

II

Question 23

How many contiguous leads do you need to confirm a likely MI and how can you increase your confidence?

Answer 23

2 contiguous leads. (Septal and anterior and grouped together). Use reciprocal leads to confirm: lateral and inferior leads are reciprocal.

Question 24

What information indicates a posterior MI on EKG and which leads should you look at to gather this information?

Answer 24

Large R wave, ST depression, upright T wave

V1,V2

Question 25

How do you identify pericarditis on EKG?

Answer 25

ST segment elevation almost everywhere, without T wave inversion.