Evolution of ICMs for Afib and Syncope Management

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An expert in cardiovascular medicine comments on how the technology of ICMs has evolved and evaluates the use of ICMs for patients fibrillation who are at high risk for syncope.

Solomon J. Sager, MD: How has the monitoring technology evolved over the years? For 1 thing, size is a big deal. When the first monitors were implanted in the 2000s, they were a surgical procedure that took 25 to 30 minutes to implant. Over time, they’ve become barely bigger than a matchstick, they’re done in the office, and it takes 60 seconds to insert. Another technology that’s evolved is machine learning, which is really important. It’s the newest, latest, and greatest of the insertable cardiac monitor technology. This allows for enhanced detection of arrhythmias and decreased false detection of arrhythmias. Additionally, the ability to detect extra heartbeats such as PVCs [premature ventricular contractions] has become part of the paradigm of insertable cardiac monitors. Although it’s not indicated specifically to quantify PVCs, it is an additional use of the devices, and that’s just in the past year.

What are the best ways to obtain clinically actionable data on patients? There are a lot of ways to obtain data via monitors. Wearable monitors can be useful, and there’s a variety of wearable monitors. The limitations of wearable monitors is No. 1, they can be worn only for a certain amount of time, and No. 2, many of them do not provide real-time data. You place the monitor for 1 week, 2 week, or up to 4 weeks, and you don’t get the data back until after those data are analyzed. The other limitation is that they can be very cumbersome and can cause rashes as well as local reactions.

How do we monitor patients at high risk for syncope? The original studies were done on patients with unexplained syncope. In some of those studies, they randomized patients to routine clinical monitoring vs long-term monitoring with an insertable cardiac monitor to determine the diagnosis of the unexplained syncope. The patients who had the insertable cardiac monitor were 30% more likely to obtain an appropriate diagnosis at 1 year, and the longer they were monitored, the more likely they were to obtain an appropriate diagnosis.

Today we use insertable cardiac monitors all the time in patients with unexplained syncope. Usually we do at least some sort of wearable monitor beforehand. The reason is that if we can detect something within a couple of weeks on a wearable monitor, sometimes we recommend a pacemaker, in which case an insertable cardiac monitor isn’t indicated. But the vast majority of the time, patients who present with multiple episodes of unexplained syncope—and who’ve had a full work-up without clear explanation—meet criteria for insertable cardiac monitoring and benefit from having this. The long-term likelihood of finding a diagnosis with an insertable cardiac monitor in a patient with unexplained syncope is greater than 30%.

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