Chaoter 19 Exam 4 Flashcards
1
Q
Reentry
A
- associated with most tachydysrhythmias
- cardiac impulse continues to depolarize in a part of the heart after the main impulse finished its path and the majority of the fibers have repolarized
- caused by myocardial ischemia and electrolyte abnormalities
- can have wavelets or chase its tail
2
Q
Dysrhythmia Analysis (normal ECG)
A
- ECG recordings allow measurement of waveform amplitude, duration, and heart rate.
- called a normal sinus rhythym
- originates in sino atrial node
3
Q
Characteristics of Normal sinus rhtythym
A
- 60 - 100 BPM
- Charchterized by P wave followed by QRS followed by T wave
- P wave is the atrial contraction
- QRS wave is ventricular depolarization
- T wave is ventricular repolarization
- QT interval (prolonged predisposes to ventricular arrhythmias)
- P to Q or PR interval determines if patient has a heart block
4
Q
Sinus Tachycardia
A
- abnormaly fast heart rate of greater than 100 bpm
- often a compensatory response to increased demand for CO or reduced SV
- Usually Occurs from SNS activation
- treatment is aimed at treating correccting underlying cause, sympatholic agents or calcium channel blocking agents may be indicated
5
Q
Sinus Bradycardia
A
- heart rate lower than 60 bpm
- may be normal in physically trained individuals with large resting SVs
- usually from parasympathetic activation
if slow hr precipitates low CO, treatment includes sympathomimetic or parasympatholytic
6
Q
Sinus Arrhythmia
A
- Associated with fluctuations in autonomic influence and respiratory dynamics
- may be particularly pronounced in children
- must be differentiated from sick sinus syndrome (may need a pacemaker)
- sinus arrhythmia is normal and needs no treatment
- sinus arrhythmias (a) vs sick sinus syndrome (b)
7
Q
Sinus Arrest
A
- absence of impulse initiation in the heart results in electrical asystole
- escape rhythm: a slower pacemaker will generally begin to fire after several seconds of sinus arrest
- pacemaker may be required
- flat line
8
Q
Junctional Escap rhythym
A
- lack of a p wave
- originates in the AV node
9
Q
Ventricular Escape Rhythym
A
- originates in the purkinje fibers
10
Q
Premature Atrial Complexes (PACs)
A
- Originate in the atria but not the SA node
- PACs occur earlier than normal, preceded by a P wave, and have a normal QRS complex configuration
- Frequent PACs may indicate underlying pathophysiologic process and be precursors to more serious dysrhythmias
11
Q
Paroxysmal Focal atrial tachycardia
A
12
Q
Atrial Flutter
A
- Futter is typically manifested by a rapid atrial rate of 240-350 bpm with a sawtooth pattern
- type 1: 240 to 350 BPM
- type 2: over 350 BPM
- recieve anticoagulates due to risk of stroke
13
Q
Atrial Fibrillation
A
- fibrillation is a completely disorganized and irregular atrial rhythym accompanied by an irregular ventricular rhythym
- cause of thrombi
- treated with anticoagulants due to risk of stroke
14
Q
Premature Ventricualr Complexes (PVCs)
A
- arise from the ventricular myocardium
- do not activate the atria or depolarize the sinus node
- Bizarre QRS
- compensatory pause is common
- Bigeminy (every other beat) or trigeminy (every third beat)
- with high frequency (greater than pvc in a row) CO may be compromised
- low magnesium and low potassium can lead to PVCs
15
Q
Ventricular Tachycardia
A
- three or more consecutive ventricular complexes at a rate greater than 100 BPM
- ECG depicts a series of large, wide, undulating waves
- P waves are not associated with the QRS complexes
- May be fatal if not rapidly managed with antiarrhythmia drugs, CPR, or electrical cardioversion
16
Q
Ventricular Fibrillation
A
- rapid, uncoordinated cardiac rhtythym resulting in ventricular quivering and lack of effective contraction
- ECG is rapid and erratic, with no identifiable QRS complexes
- results in death if not reversed within minutes using defibrillation, CPR, or antiarrhythmia drugs
