Wandering Baseline Artifact on ECG

Wandering Baseline Artifact

Baseline Wander (BW) Artifact on ECG 

One of the other major/common noise type on surface ecg is the baseline wander (BW).

BW recorded on ECG is mainly caused by the movement and respiration of the patient hence they appears as low-frequency artifacts!!!!

Generally these fluctuations on ECG are not of cardiac origin. And are typically in range below 0.5 Hz 

Issues with Baseline wander 

1. They can distort the ECG shape esp whenever there is body movement inc even deep rapid breathing !!! ( Some data even suggest that BW can even be caused by loose or dry electrodes) 

(To mitigate this issue remember Some techs may be used to ask patients to hold their breath during a 12-lead ECG. Be aware of this as this can also alter the patient’s heart rate) 

2. BW is especially important when subtle changes in the “low-frequency” ST–T segment are analyzed for the diagnosis of ischemia, for which ETT is performed . 

Though The frequency content of baseline wander is usually in the range below 0.5 Hz. However, increased movement of the body during the latter stages of ETT further increases the frequency content of baseline wander !!!

3. Patients unable to perform ETT may still be able to perform a stress test by either sitting or running an ergometer by hand. In such cases, BW related to motion of the arms severely distorts the ECG signal. Remember The bandwidth of such BW is considerably larger than that caused by respiratory activity and perspiration.

Data shows that Removal of BW is very essential and lots of efforts & Reaserch have been put in world wide ,to decrease the changes in beats morphology which do not have cardiac origin. 

(Techniques like linear filtering and polynomial fitting are used to remove baseline wander from ECG signals)

Thanks 😊