arrhythmias 2 Flashcards
atrial flutter
P wave rate 240-320/min -
often P:QRS ratio 2:1 or 3:1 or 4:1
Atrial tachycardia
abnormal P waves before each QRS
rate 160-220/min
No P waves but QRS complexes present
- atrial fibrillation
- junctional rhythm
- ventricular tachycardia
atrial fibrillation
- irregular QRS beats often with
undulating baseline. - QRS may be narrow or wide
junctional rhythm
- regular rhythm with flat baseline
2. often no P
ventricular tachycardia
wide, regular, usually fast QRS
No P wave and no QRS
- ventricular fibrillation
2. asystole
ventricular fibrillation
wavy, irregular baseline
asystole
flat baseline
sinus tachycardia in pt with coronary artery disease,
the increased cardiac oxygen demand may precipitate angina
also a feature of hyperthyroidism
sinus tachycardia typical rate
101-150
sinus bradycardia may produce
- syncope during intense vagal activation as in fainting (‘Vaso- Vagal event’) for which atropine is effective.
- Often occurs with small inferior wall infarctions which increase vagal tone.
sinus bradycardia can cause
- syncope
- lightheadedness
- fatique in elderly patients with age-related dysfunction
(the ‘sick sinus syndrome’)
First degree AV block is a
benign condition but can proceed to more serious types of block
3rd degree AV block is due to
- AV node or “junctional” failure with aging
2. infarct or disruption during cardiac surgery.
3rd degree AV block may result in
syncope or sudden death
in 3rd degree AV block, you see
- both P and QRS display regular rhythm
- but they are at different rates
- P rate> QRS rate
Atrial flutter has some risk of
- embolic stroke due to clot in the left atrium
2. may result in rapid ventricular rates that are poorly tolerated.
Because of the increased risk of embolic stroke, nearly all Atrial fibrillation patients are treated with _____
anticoagulation, usually with coumadin (warfarin)
Aspirin is less effective but can be used in low risk cases.
Atrial fibrillation rate control can be treated with
- beta blockers
- calcium channel blockers (diltiazem or verapamil)
- digoxin
either alone or in combination.
Because atrial fibrillation has a very high recurrence rate, most patients are managed with
anticoagulation and rate control.
Atrial fibrillation: conversion to sinus rhythm can be achieved with:
electrical cardioversion drugs or with drugs.
However, maintenance of sinus rhythm often requires drugs with high toxic potential.
Arrhythmias can rarely arise from a
single ectopic pacemaker
most ectopic rhythms arise from ____.
reentry
major mechanism of arrhythmias is
reentry
Abnormal reentry pathways can be present in the
atria, ventricles, or the junctional tissue
In a normal heart, arrhythmias are:
self- terminating because depolarization at a junction usually meets tissue which has already been depolarized and is therefore refractory to reentry.
If chamber dilation and/or islands of fibrosis create a long and circuitous path,
the depolarization can continue to find non-refractory myocardium and be sustained.
atrial tachycardia are
- Quite uncomfortable and disturbing.
- easily terminated by adenosine infusion.
- frequently a recurrent problem.
atrial tachycardia recurrence is prevented by
ablation of the reentry pathway.
