EKG MASTER CLASS 2014: INTERPRETATION OF AN EKG:

What do you look for in an EKG?

1. VALIDITY : Name on EKG
Indication for EKG
Mirroring of Lead I and Lead aVR
“R” Wave progression in precordial Leads 

2. RHYTHM: Sinus or not, P present or not If P present sinus origin P or not
P married to QRS or not

3. RATE: Regular or not
If irregular, pattern
Same rate or variable rate

4. AXIS: Vertical axis normal. Left or right or intermittent Horizontal axis same as before or now more clockwise or less 

5. INTERVAL: PR normal, short or long
RR constant or increasing
QT normal or long

6. HYPERTROPHY: P waves tall, wide, bifid or normal
Voltage criteria for RVH and LVH met or not

7. CONDUCTION : Normal QRS duration in V1 –V2 or not
Normal QRS duration in V5-V6 or not
Axis & hypertrophy compatible or not ,else should look for Hemi block . 

8. PERFUSION: Ischemia or not (T Inversion)
Injury or not ( ST depression)
Infarction or not (ST elevation or q)
Infarction old or new
LBBB with infarction or not

9. SEGMENTS : Baseline stable or not
PR depressed or not
ST reflecting perfusion or something else

10. EXTRA FINDINGS: RR Prime or Osborne waves
Delta waves or IVCD
CEREBRAL T waves or T inversion etc,...

ECG MASTERCLASS-1 BY NEBHU MOHAMMED

A Female lady in her 30s had fainted the night before with loss of consciousness for about 3 mts , heaviness of chest since morning . History of mitral valve prolapse . Echo done two yrs back was normal . Interpret the EKG in the best way you can

Systemic approach -look for validity , rate, rhythm, interval(PR,QRS,QT), Axis, Hyper trophy , Infarct (QRST changes) . 

STEP 1- DESCRIPTIVE ANALYSIS ( simply describe what's seen on the tracing as per the check list , write out your findings ) CLINICAL IMPRESSION : should only come after STEP #1 has been completed . those specific findings in descriptive analysis should be interpreted in light of the clinical context ( pt Age, presenting complaint , and any additional relevant clinical history ) .

1.VALIDITY - Its a valid EKG , the name , gender and age are hidden. lead placements are correct . 

2. RATE &RHYTHM- 5 parameters we look for are P waves, QRS width, Regular rhythm, Related (P waves related to QRS ) ,Rate (heart rate ) - P waves here is upright in lead II ,then the rhythm should always be SINUS. QRS is narrow that means it is <0.10 second ( not more than half a large box in duration ) Regularity- Rhythm is regular because P Waves are related to QRS . Rate- is calculated by rule of 300 ( divide 300 by the number of large boxes in the R -R interval) so  here there are 4 large boxes in the R-R interval , 300/4= 75/mt Despite the presence of sinus mechanism here we have an irregular rhythm -SINUS ARRHYTHMIA. 

3.INTERVALS- After rate and rhythm we look for interval -3 ECG intervals . a) PR interval b)QRS c) QT interval PR interval is short if it < 0.12 sec and long if it is > 0.20 sec. here we have a PR interval of 0.16 sec -normal . it doesnt matter if PR is 0.16,0.17,0.19, just say the PR interval is normal. QRS interval if it is longer than half a large box in duration -that QRS is wide >0.10sec. here it is within normal limits .(so no inter ventricular conduction delay ) IVCD. QT interval - to measure the QT select a lead where you can clearly see the end of T wave .Select that lead in which the QT appears to be longest . If there is no "q" wave in the QRS complex - measure from the beginning of the R wave . QT is normal if it is not more than half of the R-R interval.here the QTinterval is less than half the R-R interval ( normal QT interval = <410sec) 

4.AXIS - net QRS deflection in I and avF is positive and more positive in avF so we estimate the net axis at between +60-+75. 

5.No BLOCKS. 

6.No LVH or RVH .( No chamber enlargement ) 

7.Assessing QRST changes : Dont initially worry about lead avR. Scan other 11 leads for Q waves - here no q waves . Check for R wave progression : Does transition occurs at the usual place ? here the transition is not that classical but of no significance . Look at all leads for ; changes in the ST segment ( elevation or depression ) and changes in T waves - here nothing significant . 

SO FINAL DIAGNOSIS : SINUS ARRYTHMIA, HR of 75/mt , normal PR/QRS/QT interval, axis +60-75 ,no conduction block or Hypertrophic changes , and no ST-T changes .

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