telemetry med surg exam 3
sinus node - AnswerThe intrinsic pacemaker. Cell membrane "leakiness" causes
spontaneous depolarization at a rate of 60-100 times a minute.
AV node - AnswerActs like a resistor to slow the impulse allowing time for the atria to
completely contract before initiating ventricular contraction. Back up pacemaker if SA
fails, pacing at a rate of 40-60 times a minute.
Bundle of his - Answer"Cable" that passes through the fibrous sheath separating atria
from ventricles. Divides into the bundle branches.
Bundle branches - Answer"Wires" that run down the septum and into the ventricles.
There are two left bundle branches and one right.
Purkinje - AnswerTerminal fibers branches from the bundles, distributing the impulse
throughout the ventricles.
Intranodal pathways - Answer"Wiring" that allows rapid impulse movement around the
atria to coordinate simultaneous atria contraction
Impulse vectors - AnswerSA node
Atria
AV node
The depolarization wave in the ventricles also travel in specific directions forming
vectors. Because the left ventricle has a bigger muscle mass, the wave of
depolarization (starts in mid septum) is greater than the right and is represented as a
bigger vector.
which ventricle has bigger muscle mass - Answerleft ventricle
degree of perpendicular - AnswerIf the current is running at an angle to the field, the
angulation is seen as so much positive and so much negative depending on how
parallel and perpendicular the current vector is to the field. The degree of perpendicular
can also be seen as a decrease in amplitude only.
leads - Answer
PQRST - Answer
P wave - AnswerATRIAL DEPOLARIZATION
Normal: small, round, positive in lead II
amplitude 0.5-2.5 mm, 0.10 seconds or less
p wave amplitude and time - Answer0.5-2.5 mm
, telemetry med surg exam 3
0.10 s
abnormally shaped P wave indicates - Answerdamaged atria (enlarged makes p wave
look like an "m") or an impulse origin outside of the SA node (ectopic)
notching in P wave indicates - Answeratrial enlargement (p mitrale)
PR interval normal length - Answer0.12-.20s
PR interval - AnswerStart: beginning of P
End: beginning of QRS
atrial depolarization and pause before QRS (AV node delay)
current traveling quickly down the His and purkinjes
shortened PRI - Answerbypass pathway or the impulse origin was ectopic and close to
the AV node
long PRI - Answerdelays at the AV or His
QRS complex normal length and characteristics - Answer0.06-0.12 s
BEGIN: first deflection
END: flattening before the t (j point)
The "classic" QRS complex is composed of three distinct waves: Q wave-the negative
deflection following the PRI. R wave-tall positively deflected wave in lead II. S wave-
negative deflection following the R wave.
abnormal QRS - Answerwide, longer than 0.12 s
QRS complex - AnswerDEPOLARIZATION OF VENTRICULAR MYOCARDIUM
can take many shapes
ST Segment - AnswerVENTRICULAR DEPOLARIZATION and BEGINNING OF
VENTRICULAR REPOLARIZATION
BEGIN: J point
END: start of t wave
should be flat and horizontally lined up with baseline of PRI
important for doing 12 lead EKG
sinus node - AnswerThe intrinsic pacemaker. Cell membrane "leakiness" causes
spontaneous depolarization at a rate of 60-100 times a minute.
AV node - AnswerActs like a resistor to slow the impulse allowing time for the atria to
completely contract before initiating ventricular contraction. Back up pacemaker if SA
fails, pacing at a rate of 40-60 times a minute.
Bundle of his - Answer"Cable" that passes through the fibrous sheath separating atria
from ventricles. Divides into the bundle branches.
Bundle branches - Answer"Wires" that run down the septum and into the ventricles.
There are two left bundle branches and one right.
Purkinje - AnswerTerminal fibers branches from the bundles, distributing the impulse
throughout the ventricles.
Intranodal pathways - Answer"Wiring" that allows rapid impulse movement around the
atria to coordinate simultaneous atria contraction
Impulse vectors - AnswerSA node
Atria
AV node
The depolarization wave in the ventricles also travel in specific directions forming
vectors. Because the left ventricle has a bigger muscle mass, the wave of
depolarization (starts in mid septum) is greater than the right and is represented as a
bigger vector.
which ventricle has bigger muscle mass - Answerleft ventricle
degree of perpendicular - AnswerIf the current is running at an angle to the field, the
angulation is seen as so much positive and so much negative depending on how
parallel and perpendicular the current vector is to the field. The degree of perpendicular
can also be seen as a decrease in amplitude only.
leads - Answer
PQRST - Answer
P wave - AnswerATRIAL DEPOLARIZATION
Normal: small, round, positive in lead II
amplitude 0.5-2.5 mm, 0.10 seconds or less
p wave amplitude and time - Answer0.5-2.5 mm
, telemetry med surg exam 3
0.10 s
abnormally shaped P wave indicates - Answerdamaged atria (enlarged makes p wave
look like an "m") or an impulse origin outside of the SA node (ectopic)
notching in P wave indicates - Answeratrial enlargement (p mitrale)
PR interval normal length - Answer0.12-.20s
PR interval - AnswerStart: beginning of P
End: beginning of QRS
atrial depolarization and pause before QRS (AV node delay)
current traveling quickly down the His and purkinjes
shortened PRI - Answerbypass pathway or the impulse origin was ectopic and close to
the AV node
long PRI - Answerdelays at the AV or His
QRS complex normal length and characteristics - Answer0.06-0.12 s
BEGIN: first deflection
END: flattening before the t (j point)
The "classic" QRS complex is composed of three distinct waves: Q wave-the negative
deflection following the PRI. R wave-tall positively deflected wave in lead II. S wave-
negative deflection following the R wave.
abnormal QRS - Answerwide, longer than 0.12 s
QRS complex - AnswerDEPOLARIZATION OF VENTRICULAR MYOCARDIUM
can take many shapes
ST Segment - AnswerVENTRICULAR DEPOLARIZATION and BEGINNING OF
VENTRICULAR REPOLARIZATION
BEGIN: J point
END: start of t wave
should be flat and horizontally lined up with baseline of PRI
important for doing 12 lead EKG
