advanced ekg Flashcards
what is hypertrophy
excessive growth of myocardium in ventricles
what are the criteria for RVH
tall R wave in v1, RAD, T wave inversion
what is the cause of RVH
lung disease, RV bulks up to push blood into high pressure lung system
what are the criteria for LVH
R wave in v5 or v6 (which ever is taller) plus the S wave in v1 must be greater than 35 mm
what causes LVH
hypertension. the LV bulks to push blood to body against abnormally high BP
what is a low voltage EKG
abormally short waves and complexes, caused by conditions that muffle cardiac impulse in electrodes. (obesity, emphysema, hypothyroidism)
what are the clinical implications of hypertrophy
increased oxygen demands by enlarged ventricles increases the likelihood of ischemia
what is necessary for there to be a BBB
QRS wider than 0.12
what is the shape configuration of the QRS with RBBB
RSR’
what does RBBB imply/what is it caused by
heart disease. CAD, condition system lesion, nomral, RVH, congenital heart disease, RV dilation
what shape configurations of QRS are associated with LBBB
wide QS or RS in v1
what is implied with LBBB/what is it caused by
SEVERE heart disease. CAD, conduction system lesion, hypertension.
what is a difficulty that is caused by LBBB
can make MI determination difficult
what do T waves look like with bundle branch blocks
opposite the terminal QRS
what is a hemiblock. what does the QRS look like?
a block in one of the fascicles of the left bundle branch. the QRS is not prolonged.
what does LAHB cause
LAD. this hemiblock is more common.
what does LPHB cause
RAD. this is not concerning unless there is RAD.
what is required for a deflection to be considered a wave
it must cross the isoelectric line
what is the path of electricity through the 4 major vectors
atrial- septal-free wall-basal wall
what does a positive deflection indicate about the path of electricity
electricity is moving towards the positive electrode (exploring lead)
what does a negative deflection indicate about the path of electricity
it is moving away from the positive electrode
what does an isoelectric wave indicate about the path of electricity
that is is moving perpendicular to the positive electrode
what is a normal r wave progression
in the precordial (chest) leads, the R wave should get larger as you move through leads v1-v5
what is electrical axis
the direction of the hearts electrical flow
what causes axis variation
normal, MI (axis will be away from injury), ventricular hypertrophy (axis will be towards), dysrhythmias, obesity/pregnancy (causes LEFT AD), lung disease (causes RIGHT AD), hemiblocks
what indicates an intermediate axis
waves pointing down in lead 1 and avf
what indicates LAD
lead 1 up, avf down, lead 2 down. if lead 2 is up, axis is normal.
what indicates RAD
lead 1 down, avf up
