ECG 1. Above is a 6-channel ECG from a 35 years-old apparently healthy man with no known heart disase.
Short-lasting baseline drift gives the appearence of wide QRS and hence ventricular premature contraction (VPC) at first glance.
However
these beats are not premature.
The short-lasting baseline drift also has not affected the T wave vector (which is expected in a VPC).
Additionally, lead I is devoid of baseline drift and
the narrow QRS has a normal T wave.
These clues show that
they are not VPCs.

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ECG 2. The ECG above was recorded during treadmill exercise test (stress test).
Short-lasting baseline drift gives the appearence of wide QRS and hence ventricular premature contraction (VPC) at first glance.
However,
these are not VPCs, but baseline drift giving the impression of a VPC.
The adjacent
narrow QRS complexes also show that the normal QRS complexes are present at the usual expected site.

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ECG 3. The ECG above, is from a 22 years-old healthy man with a normal ECHOcardiogram.
Limb leads show
VPC-like artifact.

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