What could cause heart rate to jump to 262 bpm for a brief time? i took a quick ecg reading (kardia) and it showed a sharp increase in hr on the graph. pvcs and couplets shown on ecg as well. could noise cause this?

As a non-cardiologist, I would recommend you see a cardiac specialist, as you might indeed have a cardiac arrhythmia, such as Paroxysmal Atrial Tachycardia. Perhaps a Holter monitor will reveal answer. Will refer to appropriate experts here at HT.

Noise in the recording system you mean? Or actual heart rate increase in noise around you? Always check a big jump like this by counting pulse at your wrist with your finder for 60 sec. 262 almost too fast to count.