ECG ARTIFACTS AND PITFALLS

DR PADMANABH KAMATHADDITIONAL PROFESSSOR

DEPT OF CARDIOLOGYKMC

MANGALORE

STANDARD POSITION OF LEADS

10 COMMANDMENTS1. YOU SHALL NOT REVERSE THE ARM ELECTRODES2. YOU SHALL NOT TREAT THE ECG,TREAT PATIENT3. SHALL NOT REVERSE LG ELECTRODES4. SHALL NOT REVERSE PRECORDIAL ELECTRODES5. PATIENT CALM AND QUIET6. TURN OFF MOBILE PHONE7. DO NOT PLACE ELECTRODE ON TORSO8. DO NOT PLACE TELEMETRY ELECTRODES ON ECG ELECTRODES9. DO NOT REVERSE ARM AND LEG ELECTRODES10. PATIENT SHOULD BE LYING DOWN

CLASSIFICAION OF ARTIFACTS

INTERNAL(PHYSIOLOGICAL)1) MUSCULAR2) MOTION

EXTERNAL(NON PHYSIOLOGICAL)1. ELECTROMAGNETIC INTERFERENCE Light Electrocautery Electrical devices2. CABLE AND ELECTRODE MALFUNCTION Insufficient gel Inappropriate filter Loose connection Misplaced leads Accumulation of static energy

LIMB LEAD REVERSAL

RA LA LEAD REVERSAL(COMMONEST)(Technical Dextrocardia)

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.

RA AND RL REVERSAL(pseudoasystole pattern)

LEFT ARM AND LEFT LEG REVERSAL(abdollah sign)

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

TREMOR ARTIFACT(Pseudo flutter waves)

When in doubt look at lead II

ERROR OF COMPUTER AVERAGING(HI TECH ARRHYTHMIAS)

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

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.

WANDERING BASELINE ECG

WANDERING BASELINE

• 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.

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.

ELECTROMAGNETIC INTERFERENCE(CELL PHONES)

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.

ELECTRICAL INTERFERENCE

ELECTRICAL INTERFERENCE• 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.

CALM PATIENT!!!!!!

THANK YOU