Under a canopy of eight heart-monitoring screens in a cardiac catheterization lab on a recent Monday, Mayo Clinic doctors briefly paused a procedure treating atrial fibrillation to inspect a new tool: a long tube with what looked like flower petals made out of wire at its end.

That wiry flower is the focus of a multibillion-dollar innovation race between some of the world's largest medical technology companies.

Medtronic and Boston Scientific, which both have major cardiac-device operations in Minnesota, and Johnson & Johnson MedTech are vying to control the large and fast-growing market for minimally invasive medical devices to treat the widespread heart problem atrial fibrillation with a safer and quicker procedure called pulsed field ablation (PFA).

PFA uses electric pulses instead of extreme heat or cooling to ablate cardiac tissue around pulmonary veins on the heart, blocking bioelectric signals in the tissue that cause the heart's atrial chambers to quiver, or fibrillate. Atrial fibrillation, or AFib, is believed to affect more than 10 million Americans, greatly increasing their risk of having a stroke, the latest scientific estimates show.