ECG Flashcards
Normal sinus rhythm
begins in SA node travels to rest of heart. 60-100bpm
sinus bradycardia
<60bpm. normal rhythm
Sinus tachycardia
> 100bpm. normal rhythm
sinus arrhythmia
sinus rhythm but quickening/ slowing of implus from SA node that produces beat to beat variation in rate
Sinus Arrest
sinus rhythm but with intermittent failure of impuls in SA or AV node that results in loss of P or QRS waves
premature atrial contraction
ectopic focus in atrium initiates pulse before SA node. p wave is premature. very common but may lead to atrial flutter, tachycardia or fib
atrial flutter
ectopic very rapid tachycardia. 250-350bpm. occurs with valvular disease, ischemia, MI, hypertension, COPD, etc. get palpitations, lightheaded, angina
Atrial fibrilation
common arrhythmia where atria are depoloraized 350-600x/min. palpitations, fatigue, dyspnea, syncope, chest pain
1st degree AV block
PR interval longer than 0.2 sec. no real symoptoms or change in cardiac funciton
2nd degree AV block
AV conduction disturbance where impulses btwn atria and ventricles fail intermittently.
3rd degree AV block
all impulses blocked at the AV node and none a transmitted to ventricles. atria and ventricles are paced independently with atria >vent. medical emergency requiring pacemaker
Premature ventricular contractions
ectopic ventricle focus. p wave absent QRS has wide aberrant shape. common from anxiety caffeine, stress, smoking, heart disease
V-tach
3 or more PVCs at ventricular rate >150bpm. longer than 30sec is life threatening, can progress to V-fib. caused by MI, cardiomyopathy, valvular disease
V-Fib
ventricles do not beat n coordinated fashion, quiver/ fibrillate. No cardiac ouput, unconscious. required defibrillation
Ventricular asystole
ventricular standstill with no rhythm. ECG =straight line, requires defibrillation.
ST segment depression
sign of ischemia, digitalis toxicity, hypokalemia
ST segment elevation
earliest sign of MI. can also indicate benign early repoloraization in normal heart
Qwave
marker of infarction; loss of positive electrical voltage from necrosis. Q wave longer than .04 msec and larger than 1/4 amplitude of the R wave
T wave inversion
occurs hours or days after MI as a result of delay in repolarization produces by injury. also occurs after R/L BBB, after CVA.
indications for terminating exercise stress test
- Drop in SBP >10mmHg despite inc in workload
- mod/severe angina (3/4)
- increasing nervous system symptoms (ataxia, dizziness)
- poor perfusion (cyanosis, pallor)
- v tach sustained
1. 0mm elevation in ST segment
exercise stress test interpretation
neg test= low probability of CAD
pos test= high probability of CAD
normal PR interval
.12-.20 sec
Normal QRS
.04-.10 normal ventricular conduction
Rate pressure product (RPP)
index of myocardial O2 consumption and coronary blood flow. can correlate to onset of angina. RPP=HRxSBP. Can be used to prescribe exercise below level that would produce angina.
