Diaphragmatic downward excursion as a novel metric for assessing Valsalva maneuver efficacy in patent foramen ovale detection by contrast transthoracic echocardiography

DDE provides a simple and objective method for assessing VM efficacy under c-TTE, showing superior diagnostic performance compared with conventional intracardiac parameters. As this represents an initial attempt, further studies incorporating invasive validation are needed to confirm its clinical value.