Dysrhythmias Flashcards
Properties of Cardiac Cells
Automaticity
Contractility
Conductivity
Excitability
What can EKG detect
Abnormality in
cardiac conduction
ischemia
infarction
hypertrophy
electrolyte abnormalities
Normal Sinus Rhythm
a normal ECG rate and rhythm, generated in SA node
12 lead ECG
10 electrodes placed on chest and limbs, gives 12 views of the heart
Continuous Cardiac monitoring
Only for monitor, not for diagnosis
3 electrodes placed on chest
gives 5 views of heart
Monitor rhythm, ST elevation
ST segment depression
Ischemia caused by partial occlusion of a coronary artery
USA and NSTEMI
ST segment Elevation
Complete occlusion of coronary artery, the entire thickness of the myocardium becomes ischemic: STEMI
Potassium imbalance and ECG
K imbalance slows impulse conduction through the AV node and the myocytes
Hypokalemia and ECG
Prolonged PR,
depressed ST,
low T,
appearance of U
Increase in QT
Hyperkalemia and ECG
Absent P
Widening of QRS
Peaked T
cells become unexcitable
Rapidly progress to cardiac arrest
Premature Atrial Contractions (PAC)
Atria contract earlier than normal
Before the next sinus impulse is due
Cause of PAC and PVC
Stress
Fatigue
Caffeine
Alcohol
Ischemia
Atrial stretch
Electrolyte imbalance
Certain medications
ECG characteristics of PAC
P wave have different shape
Premature Ventricular Contraction
ventricles to contract earlier than normal, leading to an extra heartbeat
ECG characteristic of PVC
Rhythm is irregular, P wave is absent, QRS is wide and distorted
Atrial Fibrillation
Impulse coming from all over the place to cause contract extremely rapid
Multiple ectopic foci - impulse come from somewhere other than SA node
Cause of AF
Heart disease
Thyrotoxicosis
Alcohol intoxicant
electrolyte imbalance
Stress
ECG characteristics of AF
600 bom, ventricular rate varies between 50-180
P wave replaced by wavy baseline
Clinical significance of AF
decrease in CO
Thrombus may form because of stasis of blood due to non-contractility
Treatment of AF
beta-blocker, calcium-channel blocker
