EKG Flashcards
(36 cards)
Review lead placement
What is an ECG
12 lead ECG provides information about rate, rhythm, conduction, areas of ischemia and infarct, hypertrophy, electrolyte imbalance, and systemic pathologies
P wave
arterial depolarization
Always the same
P-R interval time
required for impulse to travel from atria through conduction system to Purkinje fibers
0.12 - 0.2 sec
QRS Wave
Ventricle depolarization
0.04 - 0.1 sec
ST segment
beginning of ventricular depolarization
T wave
ventricular repolarization
QT interval
time for electric systole
Counting heart rate by ECG
-count intervals between QRS complexes in 6 second strip and multiply by 10
Possible etiology of arrthymias
- ischemic conditions of myocardium, electrolyte imbalance, acidosis or alkalosis, hypoxia, hypotension, emotional stress, drugs, alcohol, caffeine
ventricular arrhythmia
- originate from an ectopic focus in the ventricles (outside the normal conduction system)
- significant in adversely affecting cardiac output
what is a premature ventricular contraction
- a premature beat arising from the ventricle
- occurs occasionally in the majority of normal population
How does PVC look on ECG
- no P wave
- A bizarre and wide QRS that is pre-mature followed by a compensatory pause
Serious PVCs
- > 6 per minute
- paired or in sequential runs
- multifocal
- very early PVC (R on T phenomena)
Ventricular tachycardia
- A run of four or more PVC’s occurring sequentially
- very rapid rate (150-200 bpm)
-may occur paroxysmally (abrupt onset) - usually the result of an ischemic ventricle
What does ventricular tachycardia look like on ECG
- wide, bizarre QRS waves, no P wave
- very compromised cardiac output
Non-sustained ventricular tachycardia (NSVT)
a run of four or more consecutive beats in duration, terminating spontaneously in less than 30 seconds
Sustained ventricular tachycardia (VT)
VT > 30 seconds in duration and/or requiring termination due to hemodynamic compromise in less than 30 seconds
Ventricular fibrillation
- a pulseless, emergency situation requiring emergency medial treatment (CPR, defibrillation), and medication
- characterized by chaotic activity of ventricle originating from multiple foci
- unable to determine rate
how does V-Fib look on ECG
Bizarre, erratic cardiac output without QRS complexes
- no effective cardiac output
- clinical death within 4-6 mins
Atrial Arrhythmia (supraventricular)
- rapid and repetitive firing of one or more ectopic foci in the atria (outside the sinus note)
- cardiac output usually maintained if rate is controlled; may precipitate ventricular failure in an abnormal heart
how does atrial arrhythmia look on ECG
- P waves are abnormal (variable in shape) or not identifiable (a-fib)
- rhythm may be irregular: chronic or occurring paroxysmally
- Rate: rapid w/ arterial tachycardia (140-250 bpm), atrial flutter (250-350 bpm), fibrillation (>300 bpm)
AV Blocks
abnormal delays or failure to conduct through normal conducting system
- First, second, or third (complete) degree blocks; bundle branch blocks
- if ventricular rate is slowed, CO is decreased
Third degree heart block
- complete heart block
- life threatening
- requires medication (atropine), surgical implantation of pacemaker
