Another source of information is genetic. Long QT syndrome is caused by defects in ion channels, proteins that maintain heartbeat by controlling the flow of ions across the membrane of heart cells.

Ion channels sit in a cell's outer membrane and let electrically charged atoms (ions, as they are known in chemical jargon) in and out of the cell.

Infrared radiation heats up the pit membrane tissue, and TRPA1 channels open when a threshold temperature is reached, allowing ions to flow into the nerve cells and triggering an electrical signal.