ECG + GERD Flashcards
How many total electrodes does the ECG have, where?
9 electrodes
- 2 on hands
- 1 foot
- 6 chest (horizontal views)
How many leads are are there on ECG
12 leads
In ECG paper what does each represent in seconds
Small square
Large square
5 large squares
Small box: 0.04 sec
Large square: 0.20 sec
5 large squares: 1 sec
What does the following show:
Pwave
QRS complex
S-T wave
P-wave: atrial depolarization (contraction)
QRS complex: ventricular depolarization (contraction)
S-T wave: ventricular repolarization (relaxation)
ECG paper
- what is measured horizontally
- What is measured vertically
Horizontal
- time
Vertical
- voltage
How fast does ECG paper travel?
25mm/sec
What is the 6 second method
Count the QRS complexes and multiply by 10 people
What is atrial flutter characterized by?
Where
2-4 p waves before the QRS complex
- looks like sawtooth pattern in lead II
What is Afib characterized by?
No P-waves
Irregular QRS intervals
Attempt to pace the atria with no single pacemaker in control
What is the following intervals mean:
Which points on the ECG?
PR interval
QRS width
QT interval
P-P interval
R-R interval
PR interval
- from P to start of QRS
- time for pulse to go from SA node, AV node, to the ventricles
QRS width
- Spread of impulse through the ventricles
QT interval
- time for ventricles to depolarize and then repolarize
P-P interval
- rate of atrial cycle
R-R interval
- rate of ventricular cycle
What are normal interval seconds for the following
PR interval
QRS width
QT interval
QTc
PR: 0.12 -0.2 sec
QRS: <0.12 sec
QT: 0.4-0.44
QTc: male: <0.450
female: <0.460
What is bazzet’s equation for QTc
overestimates/underestimates at:
HR > 100
HR <60
QT / Square root RR
HR > 100 = overestimates
HR <60 = underestimates
What indicates a normal QT in comparison to RR?
The QT should be less than half the R-R interval
What is First degree AV block characterized by?
symptomatic/asymptomatic
Long PR interval (greater than 0.2 sec)
- Start of P to start of Q
- asymptomatic
What is 2nd degree type 1 AV block characterized by?
PR interval lengthens with a shorter RR interval
What is 2nd degree type 2 AV block characterized by?
PR interval the same but QRS dropped every few beats
What is 3rd degree heart block characterized by?
P and QRS have no correlation with each other
- symptomatic
- NEED a pacemaker
Drug effects on the QT interval (3)
QT prolongation
Risk of Torsade de pointes
Primary or secondary
- metabolic (hypokalemia)
- metabolic condition (myocarditis)
What are some non-modifiable risk factors
Age 68+
Female
Structural heart disease (HF, LV dysfunction, MI)
Bradycardia
Congenital long QT
Modifiable risk factors
- 2+ QT prolonging medications
- Electrolytes (hypokalemia, hypomagnesemia)
- Drugs that can cause lyte imbalance
- Bradycardia
What drugs are group 1 QT medications
Effect on QT and TdP?
Group 1:
- ibutilide
- procainamide
- sotalol
- haloperidol
- clarithryomycin
- erythromycin
- methadone
Known to prolong the QT
KNOWN risk of TdP when used as directed
What drugs are group 2 QT medications
Effect on QT and TdP?
Group 2:
- levofolaxacin, moxi
- mirtazipine, olanzapine
- risperiodne, quetiapine
Increase QT
- may NOT cause TdP on their own when used as labelled
- possible risk if 2+
What drugs are group 3 QT medications
Effect on QT and TdP?
Group 3:
- amitriptyline
- fluconazole
- cipro
- fluoxetine, trazodone
Known to prolong the QT
Risk of TdP ONLY in EXCESSIVE dosing
In the TISDALE risk score, what is the most points given to (4)
What is considered low, moderate, high total score
Highest risk scores (=3)
- 2+ QTc prolonging drugs
- sepsis
- HF
- 1 QTc prolonging drug
Low: 0-6
Mod: 7-10
High: 11-21
