Experimental: Intervention arm: Goal-Directed Valsalva maneuver clinical trials

Standardized Goal-Directed vs. Self-Directed Valsalva Maneuver for the Assessment of Patent Foramen Ovale

This study compares two ways of doing a special breathing test (Valsalva maneuver) to find a small hole in the heart called a PFO. We want to see if a guided breathing test is better at finding PFOs, which can cause strokes.