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Flashcards in Bradycardia Deck (21):
1

What are some modulators of heartrate?

age, gender, physical training, activity of pharmacologic agents

2

intrinsic causes of sinus node dysfunction

disorder of impulse formation

failure of conduction

causes: age associated fibrosis, coronary atherosclerosis, fibrosis due to hypertension and diabetes, cardiovascular disease, familial disease, pericardial disease, amyloidosis

3

extrinsic causes of sinus node dysfunction

increased vagal tone

medications

electrolyte abnormalities

severe hypotension or hypoxemia

4

pharmacologic agents that can suppress sinus node function

beta-blockers, calcium blockers, digoxin, antiarrhythmic drugs, and psychotropic medications

5

treatment of external dysfunction

removing offending stimulus

6

treatment of internal dysfunction

pacemaker implantation

7

estimation of maximum sinus rate

220 - age

8

sinus bradycardia ECG

normap p-wave axis with heart rate of <60 bpm

 every P wave is followed by a QRS complex

9

sinus arrest

normal P-wave axis

every P-wave followed by a QRS complex

pauses of >3 seconds without atrial activity

10

SA exit block

normal P-wave axis

progressive shortening of PP interval until one P wave fails to conduct or sinus pause is an exact multiple of the baseline PP interval

11

bradycardia-tachycardia syndrome

alternating periods of atrial tachycardia and bradycardia

12

types of AV block

first-degree

second degree - mobitz I and II

2:1 AV block

high-grade

complete heart block

13

symptoms of bradyarrhythmia

syncope

presyncope/dizziness

poor exercise tolerance/fatigue

congestive heart failure

can also have no symptoms

14

What is the depolarization rate of the AV node?

40-60 bpm

15

What is the depolarization rate of the ventricles?

20-40 bpm

16

first-degree AV block

delay, no dropped beats

17

second degree AV block - Mobitz Type I (Wenckebach)

progressive delay with dropped beats

18

2nd degree AV block - Mobitz Type II

fixed delay with dropped beats

block is in the His-Purkinje system, which is more severe than the Type I block

19

3rd degree AV block

complete AV block, no conduction from atria to ventricles

20

right bundle branch block

left bundle and left ventricle depolarize normally and rapidly

right ventricle depolarizes slowly via cell-to-cell mechanism

leads to a wide QRS complex and rabbit ears phenomenon

21

left bundle branch block

right bundle and right ventricle depolarize normally and rapidly

left ventricle depolarizes slowly via a cell-to-cell mechanism

wide QRS, low and lobbing in lead V1