HOW TO DIAGNOSE AND AVOID THESE COMMON ERRORS WHILE DOING AND INTERPRETING ECG

1. ECG ARTIFACTS AND PITFALLS
DR PADMANABH KAMATH
ADDITIONAL PROFESSSOR
DEPT OF CARDIOLOGY
KMC
MANGALORE

2. STANDARD POSITION OF LEADS

3. 10 COMMANDMENTS
1. YOU SHALL NOT REVERSE THE ARM ELECTRODES
2. YOU SHALL NOT TREAT THE ECG,TREAT PATIENT
3. SHALL NOT REVERSE LG ELECTRODES
4. SHALL NOT REVERSE PRECORDIAL ELECTRODES
5. PATIENT CALM AND QUIET
6. TURN OFF MOBILE PHONE
7. DO NOT PLACE ELECTRODE ON TORSO
8. DO NOT PLACE TELEMETRY ELECTRODES ON ECG
ELECTRODES
9. DO NOT REVERSE ARM AND LEG ELECTRODES
10. PATIENT SHOULD BE LYING DOWN

4. CLASSIFICAION OF ARTIFACTS
INTERNAL(PHYSIOLOGICAL)
1) MUSCULAR
2) MOTION
EXTERNAL(NON PHYSIOLOGICAL)
1. ELECTROMAGNETIC INTERFERENCE
 Light
 Electrocautery
 Electrical devices
2. CABLE AND ELECTRODE MALFUNCTION
 Insufficient gel
 Inappropriate filter
 Loose connection
 Misplaced leads
 Accumulation of static energy

5. LIMB LEAD REVERSAL

6. RA LA LEAD REVERSAL(COMMONEST)
(Technical Dextrocardia)

7. TECHNICAL DEXTROCARDIA
• R wave positive in lead avR
• Extreme axis eviation
• Reverse polarity in all normal deflection in
lead I and avL
• DIFFERENTIAL IS DEXTROCARDIA
• In dextrocardia precordial R wave progression
is reversed
• In technical dextrocardia it is normal.

8. RA AND RL REVERSAL
(pseudoasystole pattern)

9. LEFT ARM AND LEFT LEG REVERSAL
(abdollah sign)

10. REVERSAL OF PRECORDIAL LEADS
(Tall R in V1and deep S in V6)

11. TREMOR ARTIFACT
(Pseudo flutter waves)
When in doubt look at
lead II

12. ERROR OF COMPUTER AVERAGING
(HI TECH ARRHYTHMIAS)

13. PSEUDO VENTRICULA TACHYCARDIA
(SINUS SIGN,SPIKE SIGN,NOTCH SIGN)

14. Differentiating an Artifact from
Ventricular tachycardia
• Huang et al also described 3 signs that may help in differentiating a
tremor-induced pseudo-ventricular tachycardia from true
ventricular tachycardia. Presence of any of these signs is suggestive
of pseudo-ventricular tachycardia:
• "Sinus" sign: One of the frontal leads (I, II and III) may present with
sinus rhythm showing normal P, QRS, and T waves. The reason is
that one of the upper limbs may be free off tremor.
• "Spike" sign: Presence of regular or irregular tiny spikes among
wide-QRS complexes.
• "Notch" sign: Notches superimposed in the wide-QRS-like complex
artifact, coinciding with the cycle length when sinus rhythm was
recorded.

16. • CAUSES:
EXAGGERATED RESPIRATORY MOVEMENTS USUALLY SEEN
IN PATIENTS IN RESPIRATORY DISTRESS .
• SOLUTION:
AVOID PLACING ELECTRODE IN AREAS WHERE
MOVEMENTS OF THE ACCESSORY MUSCLES ARE MOST EXAGGERATED .
PLACE THE ELECTRODES ON THE TOP OF THE SHOULDERS.

17. Baseline drift
• The amplifier in the ECG machine has to re-find the 'mean'.
This often occurs right after lead connection and after electric
cardioversion.

18. ELECTROMAGNETIC INTERFERENCE
(CELL PHONES)

19. Differentiating an Artifact from
Ventricular tachycardia
Sometimes, EKG changes may mimic specific arrhythmias like
ventricular tachycardia and atrial flutter or fibrillation. It is important
to differentiate these, as misdiagnosis can lead to inadvertent use of
medications and procedures in such a patient.
Characteristics that can help in differentiate an artifact from
ventricular tachycardia include:
• Absence of hemodynamic deterioration during the event.
• Normal QRS complexes within the artifact.
• An unstable baseline on the EKG before the event, after the event,
or both.
• Association with bodily movement.

21. • CAUSES:
PATIENT USING ELECTRICAL EQUIPMENT IMPROPERLY GROUNDED
EQUIPMENT LOOSE ELECTRICAL CONNECTIONS OR EXPOSED WIRING.
• SOLUTIONS:
(A) IF PATIENT IS USING ELECTRICAL EQUIPMENT, TO PUT OFF THE
EQUIPMENT.PROBLEM IS TRANSIENT AND WILL CORRECT ITSELF.
(B) IF PATIENT IS NOT USING ELECTRICAL EQUIPMENT
 UNPLUG ALL EQUIPMENT NOT IN CONTINOUS USE
 REMOVE FROM SERVICE AND USE BATTERY CONNECTION
 ASK THE ELECTRICAL ENGINEER TO CHECK THE WIRING.

22. CALM PATIENT!!!!!!

24. THANK YOU