bundle branch blocks Flashcards

1
Q

what is the direction of the electrical current in the ventricles normally

A

from left (V6 closest) to right (V1), as LV significantly more muscular

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2
Q

normally on an ecg, the QRS in V1 is predominately….

A

negative

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3
Q

on a normal ECG the V6 QRS is predominately……

A

positive

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4
Q

characteristics of a RBBB

A

wide QRS
V1, rSR ( small R then big R)
V1,big negative deflection between the Rs
V6 or lateral leads, slurred S wave, tall R wave
BOTH LEADS: T wave in the opposite direction of the QRS

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5
Q

how to tell if its a left anterior fascicular block

A

wide QRS, T wave discordance

V1-2,3: negative QRS, slurred long S wave

V6 and lateral leads: large positive QRS with slurred, discordant ST segment

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6
Q

how to tell if its a left posterior fascicular block

A

RBBB with right axis deviation ( negative in I and positive in AVF)

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7
Q

cause of RBBB

A

RVH, pulmonary HTN, ischemic heart disease

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8
Q

Q
what causes a LBBB

A

the left anterior descending

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9
Q

Q
why is the QRS slurred in RBBB

A

RBB blocked, RV will depol after the LV, and it occurs slowly, muscle fibre to muscle fibre, thus a slur that draws it out

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10
Q
A
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