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Review: Describe each of the following parts of an ECG
P- wave
QRS- wave
T- wave
PR interval
QRS interval
QT interval
P- wave: atria depolarizing
QRS- wave: ventricles depolarizing
T- wave: ventricles repolarizing
PR interval: measures the conduction system- the SA node through AV node right before ventricles
QRS interval: measures how rapidly we are depolarizing
QT interval: measures how long our action potential takes
Depolarization generates a dipole. How is the net dipole determined?
magnitude of depolarization (how many cells)
orientation of the dipoles (same direction=stronger)
What does the net dipole of atrial depolarization look like?
This net dipole belongs to which of the following?
a. Q wave
b. S wave
c. ST segment
d. R wave
Q wave
This net dipole belongs to which of the following?
a. Q wave
b. S wave
c. ST segment
d. R wave
ST segment (no dipole!)
This net dipole belongs to which of the following?
a. Q wave
b. S wave
c. ST segment
d. R wave
S wave
This net dipole belongs to which of the following?
a. Q wave
b. S wave
c. ST segment
d. R wave
R wave
The mean electrical axis measures the largest dipole during the ___-wave.
R
What are the common causes of left axis deviation?
LVH, right MI
What are the common causes of right axis deviation?
RVH, left MI
An ______________ is an abnormal heart rhythm.
arrhythmia
What arrhythmias are “supraventricular”?
tachycardia (a flutter)
atrial fibrillation
heart block
What arrhythmias are “ventricular”?
bundle branch block
premature ventricular contractions (PVC’s)
ventricular fibrillation
Long QT
myocardial infarction
electrolyte disturbances
In a patient with supraventricular tachycardia, what is seen on the ECG?
P and T waves may overlap
What are the symptoms of supraventricular tachycardia?
dizzy
low BP
What are the 3 causes of supraventricular tachycardia?
SA node over activity
ectopic focus (cells outside SA start to fire)
reentry phenomenon (circus) (abnormal electrical currents)
What is the most likely rhythm in the following ECG trace?
supraventricular tachycardia
the T+P are overlapping
What rhythm is present on the ECG below?
atrial flutter
hallmark sawtooth pattern
no T+P
What rhythm is present on the ECG below?
Atrial fibrillation
P waves not making it to QRS
In sinus tachycardia, the ____ node discharges at a __________ rate.
SA node discharges at a faster rate.
Cause of a fib and a flutter:
a fib- reentry and ectopic
a flutter- usually reentry
A heart block is a conduction block at the _____ node.
AV node
Does a heart block cause tachycardia or bradycardia?
bradycardia
Describe each kind of heart block:
first
second
third
first- slowed conduction thru AV node
second- some but not all signals thru AV node
third- no signals thru AV node
What rhythm is present on the patient’s ECG trace?
1st degree heart block
prolonged PR interval
What rhythm is likely present on the following ECG trace?
3rd degree heart blcok
What rhythm is present on the ECG?
2nd degree heart block
always gonna be a ratio! so 2:1 or 4:1
What rhythm is present on the ECG?
bundle branch block
widened QRS
double R
What is the typical cause of a bundle branch block?
MI
What rhythm is likely present on the following ECG trace?
Premature Ventricular Contractions (PVCs)
huge dip followed by a pause!
What is the cause of PVC’s?
ectopic cells in the ventricle
In ventricular tachycardia, _____________ drive electrical activity.
ectopic foci
Ventricular Tachycardia progresses to….
ventricular fibrillation
What rhythm is present on the ECG?
ventricular fibrillation
What rhythm is present on the ECG?
ventricular tachycardia
What 2 rhythms are present on this ECG?
Long QT syndrome
Torsade de pointes
Long QT syndrome is caused by what?
inappropriate opening of Na+ channels
prolonged closure of K+ channels (maybe by meds)
With what condition is the blood supply to the myocardium interrupted and mainly effects ventricular repolarization?
myocardial infarction
What is seen on the ECG of a STEMI acute MI during the following times:
acute
hours
day 1-2
days later
weeks later
acute- ST ELEVATION
hours- ST elevation, decrease R wave, Q wave begins
day 1-2- T-wave inversion, Q wave
days later- ST normalize, T wave inverted
weeks later- ST and T normal, Q wave persists
What is seen on the ECG of a Non-STEMI Myocardial Infarction?
ST depression
T wave inversion
What electrolyte disturbance would cause the ECG shown?
hyperkalemia
What electrolyte disturbance would cause the ECG shown?
severe hyperkalemia
What electrolyte disturbance would cause the ECG shown?
Hypocalcemia
What electrolyte disturbance would cause the ECG shown?
Hypercalcemia
What electrolyte disturbance would cause the ECG shown?
Hypokalemia
JONES IN CLASS ASSIGNMENT QUESTIONS:
What does ST-elevation suggest?
a. Bundle Branch Block
b. Long QT syndrome
c. Myocardial infarction
d. Second degree heart block
c
JONES IN CLASS ASSIGNMENT QUESTIONS:
Which of the following is a common cause of right axis deviation?
a. Right Ventricular MI
b. atrial fibrillation
c. Right ventricular hypertrophy
d. left ventricular hypertrophy
c
JONES IN CLASS ASSIGNMENT QUESTIONS:
An ECG is performed and reveals a normal PR interval and dropping of QRS complexes at regular intervals. Which of the following is the most likely diagnosis?
a. third degree heart block
b. hyperkalemia
c. first-degree heart block
d. second-degree heart block
d
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. sinus tachycardia
b. atrial flutter
c. atrial fibrillation
d. PVC
a.
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. hypokalemia
b. second degree heart block
c. bundle branch block
d. hypocalcemia
a
JONES IN CLASS ASSIGNMENT QUESTIONS:
Apart from ventricular tachycardia, what is an important cause of wide QRS complexes?
a. AV nodal reentrant tachycardia
b. atrial flutter
c. bundle branch block
d. hypokalemia
c.
(think: if depolarization not occurring at the same time= longer QRS)
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. sinus rhythm
b. second degree heart block
c. STEMI
d. first degree heart block
d
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. complete heart block
b. non-STEMI
c. Atrial fibrillation
d. atrial flutter with 4:1 transmission
c
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. ventricle
b. atria
c. SA node
d. AV node
a
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. second degree heart block
b. complete heart block
c. sinus tachycardia
d. Long QT syndrome
b
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. current angina event
b. severe MI several minutes ago
c. severe MI 2 days ago
d. MI several weeks ago
d
JONES IN CLASS ASSIGNMENT QUESTIONS:
a. Torsades de pointes
b. PVC
c. Ventricular fibrillation
d. bundle branch block
d
JONES IN CLASS ASSIGNMENT QUESTIONS:
SATA:
a. pharmalogical administration of a K+ channel blocker
b. hyperkalemia
c. ectopic ventricular foci firing
d. hypocalcemia
e. reactivation of ventricular muscle Na+ channels
a, d, e