Electrocardiography Flashcards

1
Q

Fascicles

A

three conducting fiber bundles (right branch of bundle of HIS + anterior and posterior hemibranches)

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2
Q

unifascicular block of conduction through one of the three bundles

A

still allows impulse from atria into ventricles

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3
Q

bifascicular block

A

still allows impulse from atria into ventricles

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4
Q

trifascicular block

A

same effect as AV node blockade…prevents signals from atria to ventricles

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5
Q

trifascicular block causes

A

myocardial scarring from infarction
amyloidosis
sarcoidosis in the heart, esp. in young AA

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6
Q

A cardiac arrhythmia (esp. heart block) in young african american suggests…

A

possible cardiac sarcoidosis

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7
Q

Each heartbeat is reflected on EKG by 3 major deflections

A
  1. P wave
  2. QRS complex
  3. T wave
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8
Q

PR interval

A

onset of P to end of QRS

represents length of time for signals to propagate from SA node through AV node and ventricles

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9
Q

Normal PR interval

A

120-200ms

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10
Q

first degree AV block (1st degree heart block)

A

PR>200ms but w/ all impulses from atria getting through

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11
Q

QRS interval

A

less than or equal to 100ms

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12
Q

longer QRS intervals

A

aberrantly conducted impulses or impulses from abnormal places

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13
Q

If the QRS interval is not widened, QT interval represents…

A

ventricular repolarization

needs correction for heart rate to be helpful, since faster HRs mean faster repolarization

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14
Q

QTc

A

QT interval corrected for heart rate

normally less than or equal to 440ms

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15
Q

prolonged QT…most common cause

A

dangerous!

myocardial ischemia

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16
Q

other causes of prolonged QT

A

blood electrolyte abnormalities (i.e. hypokalemia, hypocalcemia, hypomagnesemia)

channelopathy

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17
Q

reflect anatomic site of heart disease w/in organ

A

abnormalities in 12-lead EKG

18
Q

Disease of the anterior LV served by LAD coronary artery

A

Abnormalities in leads V1-V4

19
Q

disease of lateral left ventricle served by left circumflex coronary artery

A

abnormalities in V5-V6

20
Q

disease in right coronary artery territory, the inferior left ventricle

A

Abnormalities in leads II, III, and aVF

21
Q

acute blockage of a major epicardial coronary artery

A

elevation of ST segment (end of QRS and beginning of T wave)

T wave commonly inverted

22
Q

large transmural myocardial infarction

A

permanently misshapen QRS complex w/ abnormally large, long, deep initial downward deflection (pathologic Q wave)

23
Q

innocent Q waves

A

some heart murmurs

some S3s and S4s

24
Q

abnormalities in 12-lead EKG

A

reflect anatomic site of heart disease w/in organ

25
Abnormalities in leads V1-V4
Disease of the anterior LV served by LAD coronary artery
26
abnormalities in V5-V6
disease of lateral left ventricle served by left circumflex coronary artery
27
Abnormalities in leads II, III, and aVF
disease in right coronary artery territory, the inferior left ventricle
28
elevation of ST segment (end of QRS and beginning of T wave) T wave commonly inverted
acute blockage of a major epicardial coronary artery
29
permanently misshapen QRS complex w/ abnormally large, long, deep initial downward deflection (pathologic Q wave)
large transmural myocardial infarction
30
Differentiate b/w sinus tachycardia and tachyarrhythmia
sinus tachycardia knows its limits and will not go over rate of 220 minus pt's age
31
a 20 yr old w/ sinus tachycardia of 200 (who has not just sprinted) is...
critically ill, but not likely from intrinsic heart disease ``` look for: anaphylaxis PE cocaine occult bleeding sepsis SIRS thyroid storm ```
32
many tachyarrhythmias that orriginate from above ventricles (supraventricular) are...
sort of innocent examples: **atrial fibrillation atrial flutter supraventricular tachycardia
33
atrial fibrillation
easy to spot rhythm is irregular rate is high or normal (60-220) no P waves
34
atrial flutter
results from reentrant circuit around tricuspid valve two P waves for each QRS HR around 150
35
Supraventricular tachycardia
reentrant pathway in atria right near AV node can respond to home remedy vagal maneuvers such as Valsalva maneuver, carotid sinus massage, immersion of face in a pan of ice water
36
Ventricular tachyarrhythmias
dangerous
37
2 major types of ventricular arrhythmias
ventricular tachycardia | ventricular fibrillation
38
QRS complex wide (over 120ms) and HR usually less than 200
ventricular tachycardia - -If all QRS look alike...monomorphic - -if QRS complexs vary in morphology...polymorphic
39
ventricular tachycardia
can degenerate into ventricular fibrillation
40
ventricular fibrillation
immediately life-threatening totally diordered rapid stimulation of ventricles due to fragmentation of wave of depolarization into numerous tiny wavelets going every which way
41
chaotic pattern w/out discrete QRS complexes
Ventricular fibrillation
42
Treatment for v fib
elecrical defibrillation or punch to the sternum if not available (RARE: punch to sternum in healthy individual can cause fatal arrhythmia...commotio cordis)