EKG Deck Flashcards
Why do different leds record different electrical currents coming from the heart?
Different leads record at different positions on the body, each records current at different vecotr angles
If a positive current (aka depolarization) is travelling toward a lead…..
EKG will show
there will be a positive deflection
If a positive current (aka depolarization) is travelling away from a lead…..
EKG will show
there will be a negative deflection
If a negative current (aka depolarization) is travelling away from a lead…..
EKG will show
there will be a positive deflection
Where are all the locations of the 12 leads of an EKG?
What are the four main events in ventricular depolarrization?
What are some of the features of sequences withing the cardiac cycle?
Long PR interval – abnormality in AV nodal function
Long QRS duration – abnormality in bundle branch function
Wat are two defining features of serial cardiac cycles?
rate and rhythm
Two types of ectopic beats?
- Ectopic beats – premature or extra heart beat
- Atrial ectopic beats – morphology of ectopic beat is similar to the normal heart beats
- Ventricular ectopic beats – morphology of ectopic beat is vastly different compared to the normal heart beat (i.e. elongated and elevated QRS complex)
Two types of anomalities of serial cardiac cycles?
ectopic
arrhythmias
what are EKG paper dimensions?
- Small box = 1mm x 1mm = 0.04sec x 0.04sec = 40ms x 40ms
- Big box = 5mm x 5mm = 0.20sec x 0.20sec = 200ms x 200ms
Three ways to measure heart beat from EKG paper?
count off, six second, and divsion method
The “Count Off” Method
- The “Count Off” Method – used with regular rhythms
- HR = 60s / (0.2 x number of big boxes)
- Start at an R wave and count off to next R wave
The Six Second Method
- The Six Second Method – used with irregular rhythms
- HR = number of R-R intervals in six seconds x 10
The Division Method
- The Division Method – used with rapid and regular rhythms
- HR = 1,500 / mm distance between R-R intervals
- HR = 60,000 / ms between R-R intervals
What are normal intervals on the EKG?
- r-r
- p-r
- qrs
What do EKG axis and horizontal/transition analysis indicate?
Provides information on ventricular size, conduction, hypertrophy, and damage
What vector directions indicate normal, left, and right ventricular dominance?
- Ventricular dominance
- Normal – between -30 degrees and +90 degrees
- Left axis deviation – anything more negative than -30 degrees
- Left ventricular hypertrophy
- Right axis deviation – anything more positive than +90 degrees
- Right ventricular hypertrophy
Calculating the QRS Frontal Plane Axis
Isoelectric method?
- Find the isoelectric lead and draw a line
- Find a lead perpendicular to the line
- Place vector in the direction with positive deflecting leads