Ischemic stroke represents a major public health issue, leading to significant disabilities and deaths worldwide. When no clear cause for stroke is found following a comprehensive cardiovascular evaluation (no atrial fibrillation, cardiac masses, or atherosclerosis) i.e. cryptogenic stroke, it is recommended to search for a patent foramen ovale (PFO), especially in young patients. It is estimated that cryptogenic stroke accounts for 30% to 40% of ischemic strokes. Transthoracic echocardiography (TTE) with bubble study at rest and during Valsalva maneuver is the reference method for the diagnosis of PFO. The treatment of PFO using a closure device has demonstrated a significant reduction in recurrent stroke events in patients with PFO and cryptogenic stroke. The Valsalva maneuver is currently achieved using self-directed maneuver i.e. patients are instructed to ''bear down'' or ''strain as if attempting to move your bowels.'' These instructions are subjective and depend largely on individuals understanding and effort. A Goal-Directed Valsalva Maneuver using a manometer has been shown to be a more reproducible way to perform the Valsalva achieving more sensitivity in different settings such as hypertrophic cardiomyopathy but its incremental diagnostic value for the detection of PFO has not been yet evaluated. The aim of the present study is to compare the sensibility and specificity of two methods of Valsalva maneuver for the detection of PFO. We hypothesize that Goal-Directed Valsalva Maneuver will significantly increase the detection rate of PFO compared to Self-Directed Valsalva Maneuver.