Mobile Cardiac Outpatient Telemetry for Unexplained Syncope

The study will establish the efficacy of ED-based, post-discharge mobile cardiac outpatient telemetry for patients discharged with a diagnosis of unexplained syncope.

Research objectives are to 1) Measure the time to medical intervention in patients with unexplained syncope fitted with a Philips MCOT at the time of hospital discharge compared to patients treated with usual care for unexplained syncope; and 2) Measure the time to arrhythmia diagnosis in patients with unexplained syncope fitted with a Philips MCOT at the time of hospital discharge compared to patients treated with usual care for unexplained syncope.

The hypothesis for this study is that participants who receive the Philips MCOT device upon discharge will experience a shorter time to diagnosis for the cause of their episode of syncope and receive subsequent medical intervention sooner than those who do not receive an MCOT device.

Medical intervention is defined as a change in medical management, escalation of diagnostic testing or device, or medical procedure that might result from diagnostic information obtained from outpatient cardiac monitoring following a syncopal episode. Change in medical management includes, but is not limited to, initiation of a new medication, lifestyle modification recommendations, referral to medical specialist such as cardiology or electrophysiology. Escalation of diagnostic device may include, but is not limited to, ordering of diagnostic studies such as a cardiac stress test, echocardiogram, other cardiac testing at the preference of the treating subspecialist, or placement of a longer duration cardiac monitor such as an implantable loop recorder or cardiac event monitor. Medical procedure is defined as cardiac pacemaker implantation, cardiac heart catheterization, or other invasive cardiac procedure felt to be medically necessary by the treating specialist or subspecialist physician.

An arrhythmia is an abnormal heart rhythm. In some instances syncope/near syncope, or fainting/near fainting, may be the result of an undiagnosed abnormal heart rhythm. Abnormal heart rhythms that might result in a fainting include atrial fibrillation, supraventricular tachycardia, sinus pause, Mobitz Type II heart block, complete heart block, and ventricular tachycardia. Wearing the mobile cardiac outpatient telemetry monitor increases the likelihood of identifying fainting episodes that were caused by abnormal heart rhythms.

Previous studies are variable in the number and type of arrythmias captured that would mandate medical intervention of some type that is measurable (medication, ablation, etc). All comer diagnosis and absolute diagnosis of any arrythmia is much higher than 10%. Thus, we based the pilot study size based on the lowest reported incidence in the literature for arrythmias requiring a change in a patient's medical care of 10% as the lowest suspected incidence for the Na sample size calculation. With a one-sided means test, 1-b at 0.80, and a of 0.05, 8 events in Na requiring medical intervention of some type would be required to demonstrate a 7d difference in time to intervention from the usual care group or 80 patients in the Na and 160 total. The device manufacturer is providing up to 120 devices with monitoring (up to 240 total study enrollees), which will allow for flexibility in the event of loss to follow up or to increase power.

Study participants will be randomized at ED discharge into either the control group, which receives usual care (referrals to follow up with outpatient services), or the experimental group, which receives usual care AND are fitted with a Philips MCOT device and remotely monitored for 30 days along with possible referrals to follow up with outpatient services. Data will be collected from participants' medical records to determine whether additional episodes of syncope or near syncope, diagnosis, and/or treatment occurred. Additionally, participants will be contacted by the study team at 14 and 30 days post-discharge to answer questions to determine whether additional episodes of syncope or near syncope occurred, whether treatment occurred, and whether they complied with follow up referrals. To determine if there is a difference in the time to medical intervention and in time to arrhythmia diagnosis, we will conduct two-sample tests of proportions. Secondary outcome analysis will be descriptive.