Sinus node
The intrinsic pacemaker. Cell membrane "leakiness" reasons spontaneous depolarization at a
price of 60-one hundred times a minute.
AV node
Acts like a resistor to sluggish the impulse allowing time for the atria to absolutely settlement
earlier than initiating ventricular contraction. Back up pacemaker if SA fails, pacing at a rate of
forty-60 times a minute.
Bundle of his
"Cable" that passes through the fibrous sheath setting apart atria from ventricles. Divides into
the bundle branches.
Bundle branches
"Wires" that run down the septum and into the ventricles. There are left package branches and
one proper.
Purkinje
Terminal fibers branches from the bundles, dispensing the impulse throughout the ventricles.
Intranodal pathways
"Wiring" that permits fast impulse motion across the atria to coordinate simultaneous atria
contraction
Impulse vectors
SA node
Atria
AV node
, The depolarization wave within the ventricles additionally journey in specific instructions forming
vectors. Because the left ventricle has a bigger muscle tissues, the wave of depolarization
(starts offevolved in mid septum) is extra than the proper and is represented as a larger vector.
Which ventricle has larger muscles
left ventricle
degree of perpendicular
If the current is jogging at an attitude to the sector, the angulation is visible as so much high
quality and a lot negative relying on how parallel and perpendicular the contemporary vector is
to the sphere. The degree of perpendicular also can be visible as a decrease in amplitude most
effective.
Leads
PQRST
P wave
ATRIAL DEPOLARIZATION
Normal: small, round, superb in lead II
amplitude 0.5-2.5 mm, 0.10 seconds or less
p wave amplitude and time
0.5-2.5 mm
zero.10 s
abnormally formed P wave suggests
broken atria (enlarged makes p wave appear to be an "m") or an impulse origin outside of the
SA node (ectopic)
notching in P wave shows
atrial growth (p mitrale)
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