Which artifact is targeted by a 60-Hz notch filter in EKG recordings?

Which artifact is targeted by a 60-Hz notch filter in EKG recordings?

• A. Sweat artifact
• B. Artifact from the EKG
• C. Artifact generated from electrical devices
• D. Muscle artifact

Answer: (B)

The key idea is that a notch filter targets a very narrow frequency, not a broad type of noise. A 60-Hz notch filter is used to remove power-line interference, which comes from electrical devices and runs at the mains frequency of 60 Hz in many regions. This interference shows up as a steady, sinusoidal ripple riding on the ECG trace. Attenuating just that 60 Hz component reduces this noise while leaving the rest of the ECG signal intact, so the heart’s P, QRS, and T waves can be read accurately. Sweat artifacts cause slow baseline drift, not a clean 60 Hz sine wave, and muscle artifacts are typically higher-frequency, irregular noise. Artifact generated from electrical devices is the correct target because it corresponds directly to the power-line noise that a 60-Hz notch filter is designed to suppress.

The key idea is that a notch filter targets a very narrow frequency, not a broad type of noise. A 60-Hz notch filter is used to remove power-line interference, which comes from electrical devices and runs at the mains frequency of 60 Hz in many regions. This interference shows up as a steady, sinusoidal ripple riding on the ECG trace. Attenuating just that 60 Hz component reduces this noise while leaving the rest of the ECG signal intact, so the heart’s P, QRS, and T waves can be read accurately. Sweat artifacts cause slow baseline drift, not a clean 60 Hz sine wave, and muscle artifacts are typically higher-frequency, irregular noise. Artifact generated from electrical devices is the correct target because it corresponds directly to the power-line noise that a 60-Hz notch filter is designed to suppress.