Sample Size: Our sample size is 300 patients per arm (600 total) determined to yield 80% power to detect an absolute difference of 10% in diagnostic yield between the study arms using a chi-squared test at the 5% level of significance assuming a control arm event rate of 17% and accounting for 5% attrition. A difference of 10% is feasible based on previous studies which have reported an 18% increase in diagnostic yield with prolonged monitoring.