Quiz 2: EKG Flashcards
What is EKG?
It measures the electrical activity of the heart
What does an EKG determine?
-Heart rate
-Rhythm
What is Phase 0 of EKG?
-Depolarization and rapid entry of Na+
-PR interval
What is Phase 1 of EKG?
-Early depolarization, K+ slowly enters
-QRS (ask Dr. Z)
What is Phase 2 of EKG?
-Plateau continues and slower entry of Ca2+
-ST segment
What is Phase 3 of EKG?
-K+ moves out of the cells
-T wave
What is Phase 4 of EKG?
-Resting phase
-Rest between T and P waves
What are the 4 main electrophysiologic principles?
-Automaticity: pacemaker ability
-Rhythmicity: systematic pattern
-Conductivity: spreads impulse
-Contractility: contraction ability
What is the function of the SA node? What is the intrinsic rate of the SA node?
-Activation of the atria
-Intrinsic rate: 60-100 bpm
What is the function of the AV node? What is the intrinsic rate of the AV node?
-Activation of the ventricles
-Intrinsic rate: 40-60 bpm
What is the intrinsic rate of the Bundle of His and Purkinje Fibers?
Intrinsic rate is 30-40 bpm
How many seconds is 1 large square on an EKG graph?
0.2 seconds
How many large boxes is 3 seconds? How many are 6 seconds?
-15 boxes= 3 seconds
-30 boxes= 6 seconds
How is heart rate calculated with an EKG graph?
-Uses a 6 second tracing
-Count # of QRS complexes in 6 second interval and multiply by 10
What is the P wave on an EKG?
Depolarization of the atria
What is the PR interval on an EKG?
-Onset of P wave to onset of R wave
-Measures the time between onset of atrial depolarization (SA node) and ventricular depolarization (AV node)
How many small squares is a normal PR interval?
3-5 small squares
What is the QRS complex?
-Onset of Q wave to end of S wave
-Measures the depolarization of the ventricles
How many small squares is a normal QRS complex?
1.5-3 small squares
What is the Q wave?
First downward deflection or negative deflection in the QRS complex
What is the R wave?
First upward or positive deflection in the QRS complex
What is the S wave?
Second downward or negative deflection in the QRS complex
What does assessment of the cardiac cycle via EKG include?
-Assessment of P wave
-Assessment of PR interval
-Assessment of QRS complex
-Assessment of QRS interval (duration)
-Assessment of T wave
-Evaluate R to R wave interval (is it regular)
-Evaluate HR
-Observation of pt and any symptoms
What is a term for a normal EKG with a normal HR?
Normal sinus rhythm
What is sinus bradycardia?
Slow HR (< 60 bpm) but normal rhythm
What is sinus tachycardia?
Fast HR (> 100 bpm) but normal rhythm
What are the different types of irregular atrial rhythms?
-Premature atrial contraction (PAC)
-Atrial tachycardia
-Atrial fibrillation
-Atrial flutter
What is a premature atrial contraction (PAC)? How would this look on an EKG?
-Atria contracts prematurely
-Shorter distance between T and P wave of next heart beat
What are causes of PACs? Are they dangerous?
-Often benign and non-lethal
-If underlying cardiac conditions: can be an early sign of CVD
-HTN, caffeine
-Pregnancy
-COPD, asthma
-Metabolic: hyperthyroid disease
-Stress or extreme fatigue
-Some medications for asthma or hayfever
What are symptoms of PACs?
-Patient may not have any symptoms
-A skipped heart beat
-Fatigue or SOB
-Exercise intolerance
-Chest pain (advanced)