This is pranayama with viparita karani or uttanapadasana.
N = 433
returned to normal sinus rhythm at 1 min
Standard Valsalva Arm: 37/214 (17%) vs Modified Valsalva Arm: 93/214 (43%)Absolute Risk Reduction = 26.2% (p<0.001) NNT = 3.8
This is pranayama. And there are studies on it reducing blood pressure.
Source: Time‐Efficient Inspiratory Muscle Strength Training Lowers Blood Pressure and Improves Endothelial Function, NO Bioavailability, and Oxidative Stress in Midlife/Older Adults With Above‐Normal Blood Pressure | Journal of the American Heart Association