ECG Flashcards
Intrinsic rate of the SA node
60-100 bpm
intrinsic rate of AV node
40-60 bpm
intrinsic rate of ventricles
25-40 bpm
What does the P wave represent
depolarization of both atria
What does the P-R interval represent
The electrical transmission from the atria to the ventricles
What does the QRS complex represent
ventricular depolarization
what does the S-T segment represent
early repolarization
What does the T wave represent
repolarization of the ventricles
3 methods to calculate HR
- 1500 method
- Cardiac ruler
- 6-second method
What is the 1500 method
- Calculate R-R interval
HR = 1500/# of squares
What is the cardiac ruler method
- each 5 mm block = 300
What is the 6-second method
- 6 seconds on strip is 30 5mm boxes
- Count number of RR intervals during 6-seconds
- Multiply by 10
what is sinus bradycardia
HR < 60 bpm
what is tachycardia
HR > 100 bpm
The more leads an ECG has, the more….
accurate
the more snapshots of the heart
What are the 6 steps to interpretation of 3 or 5 lead ECG
- calculate rate
- calculate rhythm
- examine the relationship between the P wave and the QRS complex
- Examine the PR interval
- Check for terrible triad of ischemia, injury, and infarction
- What are the hemodynamic consequences of this rhythm
How do you examine atrial rhythm
P-P intervals using pencil + paper
how do you examine atrial rhythm
R-R intervals using pencil + paper
What is a slightly irregular rhythm? Makedly?
< or equal to 0.04s
>0.04
What is the amplitude and duration of a normal p wave
amp: 2-3 mm high
duration: 0.06-0.12 s
What is the amplitude and duration of a QRS complex
- Amp: 5-30 mm
- Duration: 0.04-.11 s
Normal duration of PR interval
0.12-0.20 seconds
What does a peaked or enlarged P-wave indicate
atrial hypertrophy or enlargement associated with COPD, pulmonary emboli, vascular disease or heart failure
What does an inverted P wave indicate
reverse conduction from atriaventricular junction toward atria
What do varying p waves indicate
impulse may be coming from different sites, wandering pacemaker, damage near SA node
What does an absent P-wave indicate
conduction route other than SA node - atrial fibrillation
What do no p waves indicate
complete heart block
What does a deep/wide QRS complex indicate
myocardial infarction
what does an absent QRS complex indicate
atrioventricular block
What does a prolonged PR interval mean
conduction delay from meds or heart block
What does a shortened PR interval indicate
impulse originated from somewhere other than SA node
What are the 3 signs of a terrible triad
- inverted T waves
- Elevated or depressed ST segment
- Q-waves - usually negative deflection
what does an inverted T wave mean
- myocardial ischemia
What does an elevated or depressed ST segment indicate
myocardial injury
What does a Q-wave longer than 0.04s indicated
myocardial infarction or myocardial necrosis
What are the steps to the development of an acute MI
- ST elevation
- T wave inversion
- Start of a Q wave
- Normalization of the ST segment
What does the diagnoses of MI depend on
- Chest discomfort and symptoms (nausea, fatigue, SOB)
- ECG abnormality
In what populations is it important to be aware of a premature ventricular contraction
acute MI & post-op cardiac patient populations
What is an premature ventricular contraction? How does it appear on an ECG
An early beat originating in the ventricles characterized by a premature, wide QRS complex, no associated P wave (typically), ST segment/T wave that slope opposite main QRS complex, followed by a pause
What in the consequence of a premature ventricular contraction
More than 6-minute, runs in 3 or more, needs medical attention
What is the treatment for premature ventricular contraction
antiarrhythmic medication
What are 5 questions/steps to determine your action
- know the MD assessment and recommendations/referral parameters
- Do they have accompanying objective symptoms
- What are the protocold where you are working
- What are the code blue protocols where you are working
- When in doubt notify RN/MS ASAP
