Brainscape's Knowledge GenomeTM

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


See full index

CVPR - CV Unit 1 > ECG > Flashcards

ECG Flashcards

1
Q

P wave

A

Atrial depolarization (sum of R + L)

Smaller amplitude due to less total muscle mass

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

QRS Complex

A

Ventricular depolarization; occurs simultaneously as atrial repolarization, obscuring the signal

Upward deflection of R wave corresponds to phase 0 of action potential; isoelectric ST segment links QRS to T wave and corresponds to phase 2 of the action potential (long plateau)

Normal duration is 0.06-0.10s

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

T wave

A

Repolarization of the ventricles, corresponding to phase 3 of the action potential

T wave (hyperpolarization moving away from the lead) should deflect in the same direction as QRS (depolarization moving toward the lead)

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

QT Interval

A

Total duration of ventricular depolarization and repolarization

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

PR interval

A

Spans from the onset of the P wave to the onset of the QRS complex

Represents AV node conduction time

Normal duration is 0.12-0.20s

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

ECG paper speed

A

25 mm/s

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

ECG chronology - small vs. large squares

A

Thin lines (small squares) are spaced 0.04s apart

Thick lines (large squares) are spaced 0.2s apart

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

Unipolar leads

A

Measure the difference in electrical potential between one point on the body and a virtual reference point set at 0 electrical potential, located in the center of the heart

aVR, aVL, aVF
V1-V6

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

Bipolar leads

A

Measure the difference in electrical potential between two different points on the body

Standard Limb Leads I, II, and III

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

ST depression - Interpretation

A

Caused by ischemia due to sudden high oxygen demand in the presence of a fixed coronary obstruction

Resting ST segment is normal but during exercise there is a ST depression due to transient ischemia

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

T wave inversion - Interpretation

A

Caused by ischemia due to acute coronary artery obstruction during low oxygen demand; ischemia may be transient or result in tissue injury

Recall that normally T waves deflect in the same direction as QRS complex

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

ST elevation - Interpretation

A

Sign of transmural cardiac injury in an acute coronary syndrome, usually acute myocardial infarction

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

Significant Q wave - Definition & Interpretation

A

Defined as a Q wave that is:

  1. Greater than or equal to 1/4 the amplitude of the R wave
  2. Greater than or equal to one small box (0.04s) wide
  3. Seen in at least 2 leads reflecting the same region of the ventricle

Absence of normal transmural vector produces a negative deflection in leads over infarcted tissue

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

Lateral Leads

A

I and AVL

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

Inferior Leads

A

II, III, and AVF

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

Right Chest Leads

A

V1 and V2

Monitor the RV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Left Chest Leads

A

V5 and V6

Monitor the LV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

ECG features of transmural myocardial infarction

A

ST elevation with Q waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ECG features of subendocardial myocardial infarction

A

ST depression without Q waves

20
Q

QT Interval - Definition & Causes

A

Defined as a QT interval that is more than half of the RR interval

Caused by: 
Hypocalcemia, hypokalemia, hypomagnesemia
Class 1A or 3 anti-arrhythmic drugs
Hypothermia
Congenital Long QT Syndrome
21
Q

ECG features of Left Ventricular Hypertrophy

A

Big R waves in L-sided leads:

I, aVL, V5, V6

22
Q

ECG features of Right Ventricular Hypertrophy

A

Big R waves in R-sided leads:

V1, V2

23
Q

ECG features of Hypercalcemia

A

Shortened QT interval

24
Q

ECG features of Hypocalcemia

A

Prolonged QT interval

25
Q

U wave

A

A small, variable wave following the T wave; thought to represent repolarization of the Purkinje fibers

26
Q

Sinus Tachycardia

A

Regular, fast heart rate > 100bpm with normal P and QRS features

Commonly occurs during exercise or emotional stress; increased cardiac oxygen demand may precipitate angina in patients with coronary artery disease

No treatment usually needed; may be treated with beta blockers, if severe

27
Q

Sinus bradycardia

A

Regular, slow heart rate ( seen in the elderly

Treatment with atropine or cardiac pacemaker

28
Q

1st degree AV block

A

Defined as a PR interval > 0.2 seconds; interpreted as delayed conduction through the AV node

Caused by drugs (B-blockers, digitalis) and conduction system disease

29
Q

2nd degree AV block

A

Some P waves conduct normally to the ventricles but others do not and therefore are not followed by R waves

Rate may be too slow to support adequate CO, resulting in syncope or confusion requiring the use of a pacemaker

Caused by conduction system disease and high vagal tone

30
Q

3rd degree AV block

A

P waves and QRS show regular rhythm but occur at different rates with P rate > QRS rate

Caused by AV node failure secondary to severe conduction system disease; may cause syncope or sudden death, usually requires a pacemaker

31
Q

Atrial Flutter

A

P waves flutter at rate of 240-320 bpm; pulse may be regular or irregular and ventricular rates vary but are typically rapid

Some risk of embolic stroke due to clot in the left atrium; treated with Warfarin for anti-coagulation and B-blockers, Ca2+ channel blockers, or Digoxin for rate control

32
Q

Atrial Fibrillation

A

Irregular ventricular rhythm without P waves

Risk of embolic stroke due to atrial thrombi, heart failure due to rapid heart rate and loss of atrial kick

Treatment: Anti-coagulation, cardioversion (electrical or medical), and rate control with drugs

33
Q

Atrial Tachycardia

A

Characterized by rapid HR (>180 bpm) with narrow QRS complexes and abnormal P waves

Terminated by adenosine infusion; recurrence prevented by ablation of re-entry pathway

34
Q

Junctional Rhythm

A

Regular rhythms arising from the AV node; usually characterized by a narrow QRS without P waves, which are buried within the QRS signal

When P waves are present they are usually inverted because the wave is conducted upward from the AV node rather than downward from the SA node

35
Q

Ventricular Tachycardia

A

Ectopic ventricular focus conducted by slow myocardium; caused by fibrosis, infiltrate, dilation - long path allows re-entry

Characterized by repetitive wide-abnormal QRS without preceeding P wave

36
Q

Lead I

A

Standard (Bipolar) Limb Lead

L. arm (+)
R. arm (-)

37
Q

Lead II

A

Standard (Bipolar) Limb Lead

L. foot (+)
R. arm (-)

38
Q

Lead III

A

Standard (Bipolar) Limb Lead

L. foot (+)
L. arm (-)

39
Q

aVF

A

Augmented (Unipolar) Limb Lead

L. foot (+)

40
Q

aVR

A

Augmented (Unipolar) Limb Lead

R. arm (+)

41
Q

aVL

A

Augmented (Unipolar) Limb Lead

L. arm (+)

42
Q

V1 & V2

A

Precordial Chest Leads

R. ventricle + septum

43
Q

V3 and V4

A

Precordial Chest Leads

Septum

44
Q

V5 and V6

A

Precordial Chest Leads

L. Ventricle

45
Q

Evolution of ECG in transmural myocardial infarct

A
  1. Peaked T wave (“hyperacute T wave”)
  2. T-wave inversion - sign of ischemia
  3. ST elevation - sign of transmural, ischemic injury occurring within 1-2 hours of insult
  4. Q wave + ST elevation + T inversion - typical of transmural infarcts

OR

  1. ST depression with no Q wave - typical of subendocardial infarcts
46
Q

Atrial Premature Beats

A

P wave occurs too early following the last T wave and looks slightly different from other P waves; QRS is normal

Mostly benign

47
Q

Premature Ventricular Contraction (PVC)

A

Depolarization originates in the ventricle and contraction occurs via contractile myocytes

Characterized by wide QRS signal without P waves

Common in normal subjects; treatment usually not required

CVPR - CV Unit 1 (13 decks)

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