Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cardiopulmonary Renal > Application Of ECG > Flashcards

Application Of ECG Flashcards

1
Q

Describe normal sinus rhythm, what does it indicate?

A

Rate: 60-100 bpm, regular R-R interval- 5 small boxes

P waves present, upright in leads I, II, & III

QRS interval (width normal ~ 2.5 small boxes)

P:QRS ratio: every P associated with a QRS

P-R interval normal (<5 small boxes)

Mean electrical axis- normal

Indicates:

  • electrical signal generated by SA node
  • AV functioning (P-R interval)
  • Signal conducted via normal pathways & normal velocity through heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are arrhythmias?

A

Abnormal rhythms of the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What arrhythmias involve the heart rate?

A

Bradyrhythmias(too slow)

Tachyrhythmias(too fast)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can arrythmias be classified on site of origin?

A

Supraventricular (SA node, atria, & AV node) & ventricular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What mechanisms are used to classify types of arrhythmias ?

A

Automatic, triggered, or re-entrant (covered in pathyops)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the causes of arrhythmias?

A

Altered automaticity: SA node, AV node, or ectopic foci (new pacemakers)

Altered conduction: can occur anywhere along the conducting pathways, and may be partial or compelete. Several blocks are due to dysfunction of the AV node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the locations/sources of arrhythmias?

A
  • Sinoatrial node(SA) node)- normal sinus arrhythmias
  • Atrial arrythmias
  • AV node- node/junctional/heart blocks

Since these 3 are above the ventricle, they are called supraventricular arrythmias

Ventricle- typically due to new pathological/ectopic foci generating electrical signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a supraventricular arrythmias ?

A

Change in cardiac rhythm from the “normal sinus rhythm”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is sinus arrhythmia?

A

Change in HR with the respiratory cycle (slight increase in HR in inspiration; slight decrease in HR in expiration). Due to Vagus nerve/parasympathetic effect on SA node), transplanted heart not have this response.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is sinus bradychardia ?

A

Decreased HR. Athletes (increased vagal tone), hypothyroid, hypothermia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is atrial fibrillation?

A

Ectopic foci/ pacemaker signals coming from cells other than the SA node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the supraventricular arrhythmias ?

A

Sinus arrhythmias

Sinus tachycardia

Sinus bradycardia

Atrial fibrillation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a sinus tachycardia?

A

SA node pacemaker generates impulse for HR, but at a faster pace than normal

Due to increased depolarization of phase 4 of SA node action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe sinus tachycardia showings on an ECG

A

Rate above 100 bpm

Rhythm: regular

P-wave: vusubke before each QRS

QRS interval: normal

Exercise, stress, fight, fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the showings of atrial fibrillation

A

Rate: 80-100 bpm

Rhythm: irregularly irregular

P wave: not distinguishable

QRS interval: usually normal

P-R interval: not measurable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the clinical significance if atrial fibrillation ?

A

Multiple sites generating electrical impulses in atria. Due to refractory period of AV node only some signals pass through AV node to ventricles. Thus HR irregular

  • Frequency of generation of action potentials is so high that there is no coordinated contraction of the myocardium
  • Atrial contraction contributes 10-20% of end diastolic blood volume
  • Atrial fibrillation is well tolerated
  • Common in the elderly

Complications: blood pools in parts of the atria forming clots

17
Q

What mechanisms cause increased excitability of ventricular arrythmias?

A

-abnormal passage of signals through conducting pathways, or new/ectopic foci

-Damage to cells make them more excitable and automaticity e.g. ischemia
1. Reduced oxygen delivery to the damaged myocardium.
The decreased ATP synthesis results in the following cascade. Na/K ATPase pump less efficient, & intracellular [Na+] increases. Thus causes the resting membrane potential (RMP) to increase. Thus the RMP is closer to threshold & cells are more excitable

  1. Damaged cell membranes become leaky, allowing more Na+ to enter the cell
18
Q

What are the types of ventricular fibrillation?

A

Tachycardia- very fast. Large/wide, frequent smooth QRS on EKG

Fibrillation—> 350. Many ectopic foci. Thus EKG QRS not regular, and at some times depolarize in direction opposite EKG lead-resulting in some inverted QRS as well

19
Q

Describe ventricular tachycardia showing on ECG

A

Rapid deadly rhythm of the ventricles

Rate: 150-300 bpm

P wave: not seen

QRS shape: only wide, tall bizarre looking complexes. Prolonged QRS interval> 0.12 sec

Complications: can be a DEADLY rhythm

Ventricles cannot maintain thus rate. Poor cardiac output

20
Q

Describe showing of ventricular fibrillation on ECG

A

Rapid, uncoordinated firing of ventricles

Rate: > 300+ bpm

DEADLY RHYTHM- irregular

Rhythm does not generate a pulse

QRS- No discernible QRS complexes. Disorganized electrical signals cause the ventricles to quiver instead of contracting in a rhythmic fashion

All waves are fibrillation waves

21
Q

What occurs in ventricular fibrillation?

A

Electrical chaos: no coordinated ventricular contraction. Due to many ectopic foci generating depolarization signals.

Decreased CO, Decreased MAP, patient becomes unconscious as there in NO cardiac output

May be caused by myocardial infarct

22
Q

What are conduction blocks?

A

Heart blocks/ junctional blocks/ AV blocks

23
Q

Why does the AV node slow the signals?

A
  1. Small cells: the wave of depolarization has to jump many cell membranes and moves slowly. Greater resistance
  2. Few gap junctions between the cells.
  3. High resting membrane potential (RMP, -60mV). Thus most voltage gated Na channels are closed. AV node depolarization due to L type Ca2+ channels- which are slower (less step phase 0 in SA as compared to normal cardiomyocytes)
24
Q

Describe importance AV node & effect on P-R interval

A

The atria are electrically separated from the AV node by a fibrous septum

  • The only normal pathway for SA node signals to get to the ventricles is via the AV node(a window)
  • The AV node delays the signal by 0.1 sec (P-R interval), giving atria time to contract and fill ventricles
25
Q

What are 1st degree heart blocks?

A

Prolonged P-R interval
Conduction delayed through AV node.

PR interval long > 0.2 seconds

Each and every P wave is followed by a QRS wave

Longer interval

26
Q

How is 1st degree heart block treated ?

A

NO treatment indicated for asymptomatic, isolated 1st degree Atrioventricular (AV) heart block

27
Q

What is the cause of 1 st degree heart block?

A

Age, athletic training, surgery, some diseases, electrolyte disturbances, AV node blocking drugs, or normal variabt

28
Q

How can 1st degree heart blocks be identified on ECG?

A

Rate: 60-100 bpm (normal), normal rhythm

P: QRS ratio: each P followed by QRS (1:1)

QRS shape: normal

P-R interval> 0.2 sec> 5 small boxes

29
Q

What are the types of 2nd degree heart blocks?

A

Mobitz type 1p

Mobitz ty9e 2

30
Q

What is a mobitz type 1, 2nd degree heart block?

A

Type- Wenckeback

Progressive lengthening of P-R interval beat dropped

Gradual increase in AV node refractoriness causes conduction block of some; not all atrial impulses get through to ventricles

Defect at AV node: P-R interval progressively longer

Benign condition. Children, athletes with increase vagal tone

In treatment necessary

31
Q

Describe the showing of a mobitz type 1 (wenckback) on ECG

A

Progressive lengthening of P-R interval-beat dropped

Rate: normal or slow

P: QRS ratio: ALMOST every P followed byvQRS

QRS shape: normal

-P-R interval: progressively longer until QRS dropped (QRS and T waves absent)

32
Q

Describe 2nd degree heart block -mobitz type 2 showing in ECG

A

Some beats dropped

Rate: 30-100 bpm depending on conduction ratio (2:1, 3:1, 4:1)

P: QRS ratio: ALMOST every P followed by QRS

P-R interval: constant and normal

Impulses blocked at A-V node- so some P waves stand alone

Defect below AV node- AV node working & P-R interval not change

Dangerous condition need a pacemaker

33
Q

What causes the 2nd degree heart block, mobitz type II?

A

Due to loss of conduction beyond AV node.

P waves on time . Atria regular Ventricles irregular

34
Q

How is a 3rd degree heart block treated?

A

Pacemaker

35
Q

How does a 3 rd degree heart block show on ECG?

A

No relationship between P & QRS

Rate: P wave (atrial) 60-100 bpm (normal. Pacemaker is SA node)

QRS (ventricle) 20-40 bpm (ventricle generate their own impulse through an NON SA node pacemaker (e.g. AV node or conduction system)

P: QRS ratio; complete dissociation of P and QRS relationship

QRS may look narrow or wide and bizarre

P-R interval values because it is completely random and dissociated from QRS

CO & BP are compromised

36
Q

What are bundle branch blocks?

A

Occurs when heart rate > critical level, conduction system fails. Inadequate time for repolarization of conduction system

Impulse spreads slowly through the ventricles- from one myocyte to the next (conducting system not working)

QRS complex is widened. No coordinated spread of APs. Contractions of the heart are weaker

Cardiopulmonary Renal (35 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions