EKG Interpretation Flashcards
6 Steps:
1 Rate 2 Intervals 3 Axis 4 Rhythm 5 Ischemia and Infarct 6 LVH and RVH
Rate:
Calculate using number of boxes in 10 sec x6 or doing 1500 divided by number of small boxes in one RR interval.
Normal rate is 60-100 bpm.
Regular or irregular?
Irregularly irregular?
Intervals:
PR
QRS
QT
PR interval:
Normal is .120-.2 or 3-5 small boxes. Measure in lead II then march across, checking if all intervals are equal. Also note height and width of P wave.
What is RAE?
If P wave greater than 2.5 mm tall.
What is LAE?
If P wave greater than .11s wide
If P wave normal in lead II:
Check biphasic P wave in lead V1. If first part of biphasic wave is greater than 2 mm tall, RAE. If second part of biphasic P wave is greater than 1 mm wide and 1 mm deep, LAE.
QRS Complex:
Normal is less than .120 s. Measure in lead II and or V1.
What is RBBB?
If P greater than .120 s plus V1 more upgoing
What is LBBB?
If P greater than .120 plus V1 more downgoing
QT:
Normal is .35-.45 or about 2 large boxes.
Axis:
Look at QRS in leads I and aVF. If both pos, normal. If both neg, extreme RAD. If lead I pos, LAD. If lead aVF pos, RAD.
What if axis is abnormal?
Find the lead that is most isoelectric, then look at a lead that is perpendicular to it. If that one is positive, then axis is about deg of that lead. If neg, axis is plus or minus 180 deg from that lead.
Rhythm:
1 PRN Interval
2 Ectopy
3 Block
PRN Interval Varies:
…but all P waves look alike, look for blocks.
…and P waves differ: Normal Rate: Wandering Atrial Pacemaker, HR greater than 100, Multifocal Atrial Tachycardia (MAT)
PR Interval Short W:
- Delta Wave- Wolff-Parkinson-White (WPW) Syndrome
- No Delta Wave- Ectopic atrial rhythm (similar to wandering but PR constant)
No P waves and normal rate:
Normal QRS - Afib, Aflutter, or junctional (accelerated jxnl if HR greater than 60)
Wide QRS - Vent Paced or Idioventricular (accel. idioventricular if HR greater than 40)
No P waves and tachycardia and normal QRS:
Regular - Supraventricular tachycardia (SVT)
Irregular (Only 3) - MAT, Aflutter w/variable block, afib
No P waves/wide complex tachycardia - Vtach (80 percent) and wide complex SVT
Others you can’t miss:
Vent fib and torsades
Is there ectopy?
- PAC (atrial), Has p wave and narrow QRS
- PJC (junctional), No p wave and narrow QRS
- PVC (ventricular), No p wave and wide bizarre QRS
Is there a block?
- First AV block - PR greater than .20 but constant and no dropped QRS
- Second AV block, Type I (Wenckebach) - PR lengthens and dropped QRS complex
- Second AV block, Type II - PR constant
- Third AV block - PR changes but PP intervals and RR intervals constant
- Wide QRS equals bundle branch block
- If you have LBBB, can’t interpret anything else.
Ischemia and infarct
ST Elevation - acute infarct
ST Depression - Ischemia
Inverted T waves (but no Q waves) - Ischemia (if w/Q waves then infarct)
Q waves
Infarct, age indeterminate (Q is 1 mm wide of .04 sec or a Q wave one third amplitude of QRS complex
Lateral MI
I, aVL, V4, V5, V6
