CV Part 2 Flashcards

1
Q

AV node allows for ______ from the _____ to the ______

A

Unidirectional conduction
Atria
His bundle

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2
Q

His-Purkinje is the bridge between _____ and ______

A

AV nodal relay

Ventricular myocardium

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3
Q

The refractory period of Purkinje fiber AP is

A

Inversely related to HR

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4
Q

Order of events starting with SA node → Purkinje

A

SA node → atrial myocardium → AV node → bundle of His → left and right bundle branches → Purkinje fibers

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5
Q

What’s the direction of ventricular depolarization in the myocardium?

A

From apex to base

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6
Q

Upward deflections in ECG mean

A

Depolarization moving towards + electrode

Repolarization moving away from + electrode

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7
Q

Negative deflections in ECG mean

A

Depolarization moving away from + electrode

Repolarization moving towards + electrode

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8
Q

P wave

A

1st half = RA depol

2nd half = LA depol

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9
Q

PR interval

A

Atrial depol

End of ventricular repol

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10
Q

QRS complex

A

Ventricular depol

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11
Q

S

A

End phase of ventricular depol

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12
Q

ST segment

A

End of ventricular depol

Beginning of ventricular repol

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13
Q

T

A

Ventricular repol

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14
Q

TP

A

Isoelectric line

Electrically silent myocardium

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15
Q

The cardiac electrical axis falls between

A

0 and 90 degrees

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16
Q

2 common causes for axis deviation is

A

Hypertrophy

Pregnancy

17
Q

Supraventricular arrhythmias are problems in (3)

A

SA nodal
Atrial
AV junctional

(Anything before hitting the bundle branches)

18
Q

Ventricular arrhythmias originate in (2)

A

Bundle branches

Ventricular myocardium

19
Q

When are narrow QRS complexes formed? Why?

A

Supraventricular arrhythmias

Ventricular depol can still use fast conducting pathways

20
Q

When are widened QRS complexes formed? Why?

A

Ventricular/bundle branch arrhythmias

Signal has to go through the myocardium cell by cell

21
Q

Sinus tachycardia

A

HR > 100 bpm
Decrease P-P interval
Increase SA node AP

22
Q

Sinus bradycardia

A

HR < 60
Increase P-P interval
Decrease SA node AP

23
Q

What is atrial flutter and what is it the result of?

A

Rapid and regular atrial activity

Reentry

24
Q

Ventricular rate depends on

A

Degree of AV delay

25
Q

Premature atrial contractions (PAC) causes

A

Premature depol leading to atrial contraction

26
Q

AV node dysfunction is known as _____ and is based on ______

A

Heart block

Degree of severity

27
Q

Primary heart block:
How is the ECG affected?
What is it caused by?

A

Prolonged PR interval

Longer conduction time in AV node/bundle of His

28
Q

Second degree heart block:
How is the ECG affected?
What is it caused by?

A

Ratio of P:QRS is greater than 1

Increased refractory period of AV node/bundle of His → less excitable

29
Q

Third degree heart block?
How is the ECG affected?
What is it caused by?

A

Messy- P waves can be before, within or after QRS complex

No atrial impulses reach the ventricles

30
Q

What is an escape rhythm?

A

Pacemakers that take control of cardiac rate and rhythm when the relay system doesn’t work properly

31
Q

AV Junctional

A

Escape rhythm if the block is in the AV node
40-50 bpm
Can maintain hemodynamic stability

32
Q

Ventricular (think AV node)

A

Escape rhythm when block is distal to AV node
30-40 bpm
Unstable and slow rhythm

33
Q

What is fibrillation?

A

Arrhythmia hat prevent effectual contraction of atria/ventricles

34
Q

Atrial Fibrillation (4)

A

Rapid twitches or contractions of muscle fibrils
No discernable P wave
Irregularly irregular HR and pulse
Lose atrial contribution to CO

35
Q

Ventricular fibrillation

A

Blood not effectively pumped from the ventricles
Apply electric current to defibrillate myocardium for a brief period of refraction
Hope to get SA node in control again

36
Q

Bundle branch block

A

Cause widened QRS

Have to use myocyte-myocyte conduction

37
Q

Premature ventricular contraction (PVC)

A

Uncoordinated ventricular depol
Widened QRS
No P wave associated with aberrant QRS

38
Q

Ventricular tachycardia

A

Wide QRS complex

Vary in shape and rhythm

39
Q

Antiarrhythmic drugs targets _____ and prevents ________

A

SNS

Activation of Ca, Na or K channels