Basic ECG Flashcards
What does a P wave indicate?
sinus rhythm
What does an ST interval indicate?
ischemia
What do the intervals indicate?
- heart rate
- heart blocks
- electrolytes
Calculating rate?
rate = 300/R-R interval in large squares
rate = 1500/R-R interval in small squares
Calculating rate in atrial fibrillation?
- use the rhythm strip count the number of QRS complexes in 10 seconds and multiply by 6
- give a range for the shortest distance between QRS and the longest
What does a normal sinus rhythm mean?
- P before every QRS (look lead II strip)
AND - Upright P wave in
- I, II, aVF
- Inverted P wave in aVR
Normal cardiac axis?
lead 1 - left thumb up
aVF - right thumb up
NB: Both are positive
Left axis deviation?
lead 1 positive - left thumb up
aVF negative - right thumb down
Right axis deviation?
lead 1 negative - left thumb down
aVF positive - right thumb up
What does QRS mean?
Q = if first NEGATIVE deflection
R = first POSITIVE deflection
S = second NEGATIVE deflection
What is a Q wave?
A Q wave is any negative deflection that
precedes an R wave
- The Q wave represents the normal left-to-right depolarisation of the interventricular septum
Pathological Q waves?
Q waves are considered pathological if:
1. > 40 ms (1 mm) wide
2. > 2 mm deep
3. > 25% of depth of QRS complex
4. Seen in leads V1-3
- Pathological Q waves usually indicate current or prior myocardial infarction
Where to locate lateral ischaemia?
- lead I
- lead aVL
- lead V5
- lead V6
Where to locate inferior ischemia on ECG?
- lead II
- lead III
- lead aVF
Where to locate septal ischaemia on ECG?
- lead aVR
- lead V1
- lead V2
Where to locate anterior ischameia?
- lead V4
- lead V3
Signs of ischaemia on ECG?
- hyperactue T waves
- T wave inversions
- ST deviations (elevation or depression)
- deep Q waves
Right bundle branch block?
- second and larger R-wave
- broad and deep S-wave
Left bundle branch block?
- deep S-wave
- broad and clumsy R-wave
Atrial fibrillation on ECG?
- narrow QRS
- irregular intervals
- undulating or flat P wave
Atrial fibrillation management?
- Manage the UNDERLYING pathology (lung disease, heart failure, sepsis, etc)
- Consider Anticoagulation to prevent stroke
- CHADs-2 VASC and HASBLED - Consider Rate or Rhythm control
- Beta Blocker, Calcium Channel Blocker, digoxin, amiodarone - Likely get Echocardiogram
If patient is unstable in arrythmias what should you do?
cardioversion
Supraventricular tachycardia?
- TACHYCARDIC usually >150bpm
- No discernible P-waves
- REGULAR!! (should not vary much at all on continuous telemetry)
- NARROW!! (this is what makes it “supra” ventricular
SVT management in stable patient?
- Vagal Maneuvers
- Adenosine (12mg, 12mg)
- Beta Blocker or Calcium Channel Blocker
- Direct Synchronized Cardioversion
SVT features in an unstable patient?
- hypotensive
- altered mental status
- severe chest pain
- very short of breath
- syncope
SVT management in unstable patient?
direct synchronized cardioversion
Venricular fibrillation management?
dead patient - start ACLS
1. Immediately Start CPR
2. Immediately Apply the AED pads
3. Immediately defibrillate
4. 1 mg Adrenaline q3-5 min
5. continue until patient is out of Vfib
Ventricular tachycardia treatment in stable patient?
Immediately apply AED pads
If available, amiodarone
Direct Synchronized Cardioversion
Ventricular tachycardia treatment in an unstable patient?
direct synchronized cardioversion
Features of unstable ventricular tachycardia?
hypotensive, altered mental status,
hypoxic, severe chest pain, syncope
Pulseless patient in VT management?
Start ACLS
Immediate CPR
Immediate defibrillation
1 mg Adrenaline q3-5 min
When to do cardioversion?
Afib, Aflutter, SVT, Vtach with pulse,
unstable Vtach but with pulse
Who to do cardioversion on?
ANY patient with a PULSE!
- Hit the SYNCHRONIZE button on AED
- Avoids “R on T” phenomenon
When to defibrillate?
Defibrillate = only TWO situations
1. PulseLESS VTach
2. Ventricular Fibrillation
- Do NOT hit the synchronize button on AED
