Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
49 Cards in this Set
- Front
- Back
|
3 mechs for bradycardia
|
1. SA disease
2. AV disease 3. his-purkinje disease |
|
|
2 reasons for bradycardia due to SA node disease
|
1. sick sinus syndrome
2. hi vagal activity |
|
|
causes of vagal activity
|
1. coughing
2. vomiting 3. sudden exposure of cold water to face 4. defecation 5. valsalva manoever 6. carotid pressure (press on it) 7. drugs |
|
|
Sick sinus syndrome refers to
|
Any disease that affects SA:
e.g. fibrosis, inflammation, infiltration, circ. problem |
|
|
where is AV node located
|
interatrial septum
|
|
|
etiology of AV node dysfunction
|
fibrosis, ischemia, calcification, drugs, trauma
|
|
|
what are chars of type 1 AV block?
|
slowed conduction (PR > 200 ms)
all impulses from atria are conducted to ventricle |
|
|
what are features of type 2 AV block (general)
|
slowed conduction (PR > 200 ms)
some impulses from atria are not conducted to ventricles mobitz I, mobitz II |
|
|
Difference b/w mobitz I (wenckebach) and mobitz II
|
mobitz I: progressive prolongation of PR interval, followed by a non-conducted atrial beat
mobitz II: PR interval is fixed; sudden non-conduction of atrial activity |
|
|
which is more dangerous, mobitz I or II?
|
mobitz II...
its usually a/w BBB and can lead to 3rd degree heart block |
|
|
3rd degree AV block
|
no communication b/w atria and ventricles
|
|
|
what is an escape rhythm?
|
anything that 'escapes' the SA node (failure of SA node)
inherent rate of depol becomes that of AV or purkinje fibers |
|
|
when is a pacemaker indicated for bradycardia?
|
when bradycardia is
(i) not reversible AND (ii) pt is symptomatic |
|
|
3 general mechs of tachycardia
|
1. automaticity
2. re-entry 3. triggered activity |
|
|
a myocyte's property of automaticity has to do with what aspect of its AP?
|
rate of Phase 4 depol.
|
|
|
what is the most common mech of clinical tachycardias?
|
reentry
|
|
|
in atrial fibrillation, how fast can the atrial depolarization rate be?
|
350-600 bpm
|
|
|
what is the mech of a.fib?
|
multiple micro re-entry circuits
|
|
|
management of A. fib: what is the major long-term decision that needs to be made?
|
rhythm control or rate control
|
|
|
management of a. fib: what are 2 ways that you can control rhythm?
|
ablative techniques (surgically, through catheter ablation techniques)
Drug therapy |
|
|
when do you consider implantation of a AICD (automated implantable cardiac device)
|
ventricular tachycardia
|
|
|
on an ECG, how much time does 1 little square equal?
|
0.04 sec
|
|
|
Sinus arrhythmia - is it normal or abnormal? why?
|
normal - its just that your rhythm is irregular with a pattern (HR is faster on inspiration than expiration) due to increase in preload with inspiration due to negative intrathoracic pressures
|
|
|
As a general rule, rates faster than _____ are not sinus (except in babies)
|
200 bpm
|
|
|
abnormality in 1st degree Heart block
|
increased PR interval (greater than 5 lil' squares)
|
|
|
how do you describe the rhythm for wenckeback heart block?
|
regular with a pattern (prolongation of the PR, then one missed QRS complex)
|
|
|
how do you describe rhythm for type II second degree heart block?
|
regular with random missing QRS complexes
|
|
|
what is the sawtooth pattern characteristic of
|
atrial flutter
|
|
|
what is the atrial rate usually in atrial flutter
|
about 300
|
|
|
is the block in atrial flutter physiological or pathological
|
physiological
|
|
|
what is the rate in atrial fibrillation?
|
usually greater than 80 (not req'd for Dx tho)
|
|
|
what does PSVT or SVT refer to?
|
any narrow QRS complex tachycardia in which teh P waves are not obvious
|
|
|
what is the rate of PSVT or SVT usually?
|
>150
|
|
|
for junctional rhythm, what do the p waves look like?
|
1. burried in teh QRS
2. inverted before QRS 3. occur after QRS in ST segment |
|
|
what happens to the PR interval in jucntional rhythm?
|
PR interval is short or non existant. (b/c the AV node conducts - therefore atria contract just before, simultaneously or just after ventricles)
|
|
|
PVC rhythm
|
regular with an early beat
|
|
|
Ventricular tachycardia rate?
|
100-250
|
|
|
no rate, no rhythm, no p waves, no CO, no pulse, no BP is characteristic of...
|
v. fib
|
|
|
torsades de pointes is a deadly form of
|
ventricular tachycardia
|
|
|
waht changes with each heartbeat in torsade de pointes?
|
the QRS complexes change in amplitude adn direction
|
|
|
why does torsade occur?
|
path of conduction changes with each heart beat
|
|
|
what is the rate in T de P?
|
>100
|
|
|
rate >100, no p waves, no PR, wide QRS, no BP, no pulse, no CO is characteristic of
|
t de p
|
|
|
3 things to check for in a pt with asystole?
|
1. rule out fine v. big by checking amplitude of ECG
2. leads are connected properly 3. check other leads in case one lead isn't reading very well |
|
|
absolute refractory period for working myocardium occurs in what part of the AP?
|
from phase 0 to the middle of phase 3
|
|
|
the relative refractory period for working myocardium will occur in which part of the AP?
|
from phase 0 to the end of phase 3
|
|
|
why is re-entry often triggered by a pre-mature beat?
|
a premature beat occurs when the working myocardium is still partly in refractory period. Some of the tissue will be refractory, while other tissue is ready to accept a new signal. Because we have tissue in 2 different electrical states, this sets us up perfectly for re-entry.
|
|
|
afterdepolarizations are more common with long QT syndrome why?
|
b/c prolonged repolarization gives time for calcium to be pumped back into the SR, and therefore causing small depolarizations during the repolarization phase
|
|
|
if you have 2 pathways that have different electrical properties, will a reentry circuit always result?
|
nope. 99.9% of time time, the signal will just terminate
|
