Question: A 58-year-old woman enters the Short Stay Medical Unit due to a clinical picture that began with an episode of syncope and then presented feeling of dizziness and dyspnea. On physical examination, she is sweaty, afebrile at 126 beats per minute and at 30 breaths per minute, with a blood pressure of 88/46 and an oxygen saturation of 85% while breathing room air. Cardiac auscultation shows tachycardia without murmurs or gallop and pulmonary auscultation is clean. Which, among the following, seems the most likely diagnosis? 
 Options:  <1> Pulmonary embolism. <2> Acute cerebrovascular accident of posterior territory. <3> Acute coronary syndrome <4> Hypovolemic shock. <5> Acute pulmonary edema secondary to atrial flutter.
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