Adults with more than a twelve (12)-month history of migraines were assigned randomly in a double-blinded study to receive treatment with experimental drug x (10 or 20 mg/day) or placebo. the primary efficacy measure was the reduction in severity of the migraine attacks. enrollment was twelve-hundred (1200) subjects. which of the following best describes the clinical phase of this study?

An 80-year-old woman comes to the urgent care clinic with dyspnoea on exertion. on physical examination, her blood pressure is 100/70, and her pulse is 75. she has no pulsus paradoxus. her jugular veins are distended, and she has distant heart sounds. in addition, she has extra third and fourth heart sounds. her liver is enlarged, and she has pedal oedema. she has occasional premature ventricular contractions on her electrocardiogram. a chest x-ray reveals clear lung fields with a dilated cardiac silhouette. her echocardiogram reveals ventricular walls with a "speckled pattern". which of the following is the most likely diagnosis? - alcoholic cardiomyopathy- amyloidosis- haemochromatosis- tuberculosis- viral myocarditis