NURS 444 week 6 arrhythmias Flashcards
(41 cards)
Properties Cardiac Cells
Automaticity- ability to initiate impulse
Excitability- ability to be electrically stimulated
Conductivity- ability to transmit an impulse in an orderly manner
Contractility- ability to respond mechanically
U wave
if present;
repolarization of purkinje fibers OR hypokalemia
Normal QRS interval in seconds
What rhythms can be defibrillated
v fib
pulseless v taach
v tach
1mm square
0.04 sec
5mm box
0.2 seconds
Sinus Bradycardiaa
SA nodes fires less than 60 seconds
Can be sleeping or from an athlete
Associated with some disease states
Can occur with response to parasympathetic nerve stimulation and certain drugs
Sinus Bradycardia:
Clinical associations
Occurs in response to;
-Carotid sinus massage
-hypothermia
-increased vagal tone
-meds.
Occurs in disease states;
>hypothyroidism
> ^ intracranial pressure
>obstructive jaundice
>inferior wall MI
Sinus Tachycardia
- Discharge rate from SA node is increased (>100 bpm)
- caused by vagal inhibition or sympathetic stimulation
- physiologic or psychological stressors
- drugs can increase rate
Sinus Tachycardia: Clinical associations
_ exercise
_ hypotension
_ hypovolemia
_ myocardial ischemia
_ CHF
_ anxiety
normal PR interval
0.12 (3 boxes) - 0.2 (5 boxes)
- if it’s longer it may be a block
- if it’s shorter it is called a junctional rhythm
Normal QRS interval
< 0.12
- if greater, you can have a disturbance in the ventricles (block)
Elevated ST segment
What does a depressed ST segment mean?
unusual T wave?
Premature Atrial Contractions
- contraction starts from ectopic focus in the atrium
- travels across the atria by abnormal pathway –> distorted P wave
- impulse may be stopped or delayed
PAC: clinical associations
> emotional stress
physical fatigue
caffeine
tobacco
alcohol
hypoxia **
electrolyte imbalances
disease states: infection, inflammation, COPD, valvular disease **
Paroxysmal Supraventricular Tachycardia (PSVT)
Starts or stops abruptly
- originated in ectopic focus anywhere above bundle of HIS (QRS interval is normal, less than 3 boxes) **
-paroxysmal means an abrupt onset and termination
- usually a PAC triggers a run of repeated premature beats **
PSVT: clinical associations
- overexertion
- stress
- deep inspiration
- stimulants, disease
- digitalis toxicity
- can occur in presence of Wolff- Parkinson- White Syndrome (onset during childhood)
Atrial Flutter
^ atrial tachyarrhythmia
^ identified by recurring, regular, sawtoothed-shaped waves
^ from single ectopic focus
^ associated with slower ventricular response. (ex. atrial rate 200-350, vent. rate generally <100
^ vent. rate may be regular or irregular
Atrial fibrillation
total disorganization of atrial activity w/out effective atrial activity
chronic or intermittent; Paroxysmal or Persistent
most common dysrhythmia
prevalence increases with age
usually occur with underlying heart diseases
atrial rate 350 -600, ventricular response variable/ irregular (CVR 60-100, rapid ventricular response RVR)
A. flutter: clinical associations
- CAD
- htn
- mitral valve disorders
- cardiomyopathy
- pulmonary embolus
- chronic lung disease
- Cor pulmonale
- hyperthyroidism
- Drugs: digoxin, quinidine, epinephrine
A. fib: clinical association
> CAD or cardiac surgery
htn
valvular heart disease
cardiomyopathy and/or HF
pericarditis
thyrotoxicosis
alcohol intoxication and/or caffeine
electrolyte imbalances
stress
First Degree AV block
PR interval prolonged (> .20)
Associated with increasing age, disease states, and certain drugs
usually not serious; patients asymptomatic
no treatment
monitor for changes in heart rhythm
