Mod 3 - EKG Analysis & Interpretation Flashcards
what is the most precise method to use to calculate heart rate
1500 method
what are the 3 ways to find heart rate from ekg
1500, sequence, and 6-second
how do you find the ventricular rate using the 1500 method
1500 divided by # of small boxes between R waves
how do you find the atrial rate using the 1500 method
1500 divided by # of small boxes between p waves
aka sequence method
300 method or R-R method
how do you use the sequence method
300 divided by # of large boxes between R waves
how do you use the 6 second method
number of QRS complexes in 6 seconds x 10
what do the hashmarks at the top of an ekg strip signify
3 second intervals
how do you calculate maximum heart rate
220 - pt age
how do you calculate target heart rate
(220 - pt age) x percent of maximum
what is the range for percent of maximum
60-85%
the QRS complex represents
ventricular depolarization
irregular intervals in Q waves can signify
ventricular dysfunction
which is the best method to find heartrate when it is fast or irregular
1500
what is the best method to calculate heart rate when it is slow
300
what is not visible but happens during ventricular depolarization
atrial repolarization
where does the QRS complex end
J point
QRS complexes normally range from
0.04-0.1 seconds
define J POINT
exact point in time where ventricular depolarization stops and ventricular repolarization starts
how can the j point be represented in an ekg during myocardial ischemia
elevate or depress below baseline
what does the T wave represent
ventricular repolarization
what does the U wave represent even if it is not always visible
repolarization of bundle of His and Purkinje fibers
the normal PR interval range is
0.12-0.2 seconds
what does the P-P interval represent
amount of time between atrial depolarization cycles
what does the R-R interval represent
amount of time between ventricular depolarization cycles
what does the QT interval represent
1 complete ventricular cycle (ventricular depolarization and repolarization)
how is the QT interval measured
beginning of Q wave to end of T wave
where is the PR interval located
beginning of P wave and ends at beginning of Q wave
what does the PR segment represent
end of atrial contraction and beginning of ventricular contraction
where is the PR segment located
end of P wave to beginning of Q wave
what does the ST segment represent
early phase of ventricular repolarization (end of ventricular depolarization to beginning of ventricular repolarization)
where is the ST segment
end of S wave to beginning of T wave
P wave and PR interval abnormalities indicate
atrial dysfunction
QRS and T wave abnormalities can demonstrate
ventricular dysfunction
how should T waves be shaped and oriented
peak toward end of wave and deflected in same direction as QRS complex
how does low potassium levels impact heart function
decreased heart rate
how does high potassium levels impact heart function
abnormal rate or rhythm
low concentrations of calcium can cause
slowed heart rate
high concentrations of calcium will cause
longer than normal contractions
what are the signs of normal sinus rhythm
- p wave present, upright, and rounded
- p wave has amplitude less than 2.5 mm
- p wave duration less than 110 milliseconds
- QRS complex usually narrow
sinus bradycardia can be normal in these pts
- athletes
- pt’s with hypothyroidism
- older adults with sedentary lifestyle
tachycardia is expected under these conditions
- during exercise
- with pt’s who have hyperthyroidism
define SINUS DYSRHYTHMIA
slight irregularity in rhythm
sinus dysrhythmia is most likely associated with
normal breathing patterns
sinus arrest is not significant unless it is longer than
6 seconds
what is the cause of sinus arrest
failure of SA node to fire
define ATRIAL FLUTTER
atria contract faster than ventricles
define ATRIAL FIBRILLATION
atria quivering without organized contraction