That is EKG. It records the electrical activity or rhythm of the heart.
No
Noninvasive means not invasive. It means you don't get anything invading you or whatever is being looked at. For instance, a sonogram (the so-called ultrasound) is a noninvasive medical imaging...
No complications from this procedure have been observed
The English word 'noninvasive' means relating to a technique that does not involve puncturing the skin or entering a body cavity