Arrhythmias Flashcards
Tachycardia
elevated HR>100 bpm
can be due to increased body temp, SNS activity, toxins, weakening of myocardium
Bradycardia
slow HRincreased vagal tone)
AV block: general
altered conduction b/w atria and ventricles via AV node/bundle/ His
can be caused by ischemia, compression, inflammation, or extreme vagal stimulation of the AV node
First degree AV block
Increases of PR interval>0.2seconds
delay of conduction from atria to ventricles (but not an physical blockage)
Second degree AV block
Increase of PR interval to .25-.45sec
Causes dropping of QRS-T beat
2:1 rhythm (2 atrial contractions:1 ventricular contraction)
Type 1= Increasing delays in each cycle before dropped beat
Type 2= No increasing delays before dropped beat
Third-degree AV block
complete block caused by poor conduction in he AV node or bundle of His
ventricles spontaneously establish their own bead, dissociating QRST (much slower) from P waves
Premature Ventricular Contractions (PVC)
1) elongated QRS complex
2) High voltage QRS
3) Opposite polarity T wave
may be caused by by drugs (coffee, toxins), lack of sleep, emotional irritability or re-entrant signal around the borders of infarcted tissues (ectopic foci)
multiform= several sequential PVCs
Long QT syndrome
Disorders that delay repolarization of ventricles (elongate QT interval)
increases ventricular arrhythmias–> torsades de pointes –> changes shape of QRS
often associated with hypomagnesemia, hypokalemia, and other drugs
may be asymptomatic, but can also cause ventricular arrhythmias–> v-fib–>death
Ventricular fibrillations
Most severe of all
abnormal ventricular depolarization causing out-of control and uncoordinated contractions—> no pumping of blood
**caused by Re-entry–>circus movements
causes low-voltage, irregular waves
can be reset by AED
Atrial fibrillation
same mecha as v-fib
often caused by atrial enlargement–>increased conduction pathway–> increased re-entry–>fibrillation
no blood pumping, but only decreases ventricular pumping by 20-30%–>less serious
absence of P wave, QRS can be normal, but can present with variability in in spacing of heartbeats
Atrial flutter
circus movement in the atria that causes a single electrical signal to travel in one direction around and around
causes rapid rate of atrial contraction (200-350bpm) with decreased blood movement to ventricles 2-3 atrial beats:1 ventricle beat
strong p waves followed by QRS in 2:1 pattern or 3:1 pattern
Ventricular tachycardia
series of ventricular premature beats one after another without a normal beat inb/w
caused by re-entry or ectopic foci , can cause v-fib
look like series of PVCs all in a row, cover up P wave
