Lecture 07/08: ECG: Enlargement Patterns and Conduction Disturbances Flashcards
ventricular HR counts which wave?
R wave
atrial HR counts which wave?
P wave
Normal sinus arrhythmia during respiration is slow during _______ and fast during ________
inspiration; expiration
In wandering pacemaker, tall P waves are caused by________ and short P waves are caused by _______
tall –> higher sympathetic tone
short –> higher vagal tone
P mitrale
notched P wave. Indicative of LA enlargement
Why does LA enlargement result in P mitrale?
LA takes longer to depolarize because its enlarged. Vector to lead II not as strong because pulls electrical activity to the left instead of straight down towards lead
Which wave must always be present in alive animal?
T wave
Hyperkalemia
High K+
pericardial effusion
fluid in pericardial sac
pulmonary thromboembolism
clot in pulmonary aa.. Can cause lung thickening
Hypoproteinemia
low protein; fluid leaks outside blood vessels which can cause effusion
Causes of low voltage complex (things that dampen electrical signal):
normal variation, obesity, pleural effusion, pericardial effusion, hypothyroidism, pneumothorax, pulmonary thromboembolism, hypoproteinemia
bundle branch block
delay or block of conduction in a bundle branch
which bundle branch is more susceptible to injury?
RBB
Why does RBBB cause deep S?
RV must depolarize by cell to cell conduction with vector pointed away from lead II
Causes of 1st degree AV block
AV node disease, elevated vagal tone (most common), drugs, hyperkalemia, hypothermia
escape rhythm
Areas in ventricles that will fire unless they are superceeded by a normal beat that comes down and depolarized the ventricles first. Right beneath the bundle of His. Take over to “rescue” the ventricles if AV blocked
tx for 3rd AV Block
pacemaker
