Hi, my name is Dr. Jose Hoglar from the University of Texas Southwestern Medical Center and Parkland Health. I'll be talking about navigating the latest atrial fibrillation diagnostic tools, rhythm monitoring tools and methods. I have no disclosures. For the purpose of this talk, I'm going to be discussing in great detail the 2023 NCCHA NCCPHRS guideline for the diagnosis and management of atrial fibrillation and then how is the guideline make recommendations regarding rhythm monitoring tools and methods. So the guideline cover rhythm monitoring tools and methods as the guideline writing committee recognized that this is very important, especially in modern times where wearable monitoring devices are essentially ubiquitous. So we talk about monitoring options for atrial fibrillation include, it can be anything from a 12-lead EKG, continuously recording electrocardiographic monitors, implantable cardiac monitors, cardiac rhythm management devices such as atrial lead detecting, atrial arrhythmias in a pacemaker, handheld devices, smartwatches. So like I mentioned, smartwatches and other consumer wearables are ubiquitous. They use platysmography to infer atrial fibrillation from detecting an irregular pulse and that's usually the technique or the technology used with devices such as smartwatches and that kind of stuff. And then you have the EKG monitors, loop recorders or cardiac devices that record the EKG and then they use algorithms to detect changes in the pattern of the EKGs and variability and randomness as a way to diagnose atrial fibrillation. So in this section, the guidelines recommend that among individuals without a known history of atrial fibrillation, it is recommended that initial atrial fibrillation diagnosis when a device alerts a patient about the potential for atrial fibrillation that the initial diagnosis be made by the clinician using virtual interpretation of the electrocardiographic signals regardless of the type of rhythm or monitoring device. That means that for making an accurate diagnosis, it's important that the physician visually confirms that his actual arrhythmia is present. And then in patients with intracardiac rhythm devices capable of diagnosing atrial fibrillation such as pacemaker lead, a diagnosis of atrial fibrillation only made after visually confirmed by review intracardiac tracing to exclude things like far-field signals or intracardiac artifactual signals like noise, et cetera. So again, it's very important that there is visual confirmation in any device prior to confirming diagnosis. This is the famous upper heart study, the smartwatch study. This was a proof-of-concept study that led to the adoption of smartwatches across the community for surveillance of arrhythmias. This was a proof-of-concept published a few years ago, but you can see what it was. It was a proof-of-concept that the smartwatches are capable of alerting individuals when there is an abnormal signal suggestive of atrial fibrillation. I just want to remind everyone that there were essentially half a million patients were included in the initial study population, and the great majority of them did not receive a signal for irregularity. And those who received arrhythmias for irregular pulse or an irregular pulse notification essentially half of them failed to initiate initial visit. Essentially we have a very small, at the end of the day without going into great details, we had a very small number of patients that ultimately received a smartwatch in whom the diagnosis was confirmed and then also completed a survey. And after the survey, you can see many, 43% of those patients' diagnosis of atrial fibrillation was made. The risk of stroke and TIA was very, very small. Some patients, a very small number got atrial fibrillation or heart failure, and a very small number were taking anticoagulation or aspirin after that. But again, it's a proof-of-concept that a smartwatch can give you irregular pulse notification, but at the end of the day, that needs to be confirmed accordingly by a physician, and then depending on the results, therapies initiated or not. Since then, there have been a lot of studies, depending on the quality of the smart device, sensitivity, you know, in this study, a simple Apple Watch notification can be 41%, but it improved, the sensitivity improved. You can, when the physician has an opportunity to review the PDF of the tracings, and at the same time, since then also, there have been studies of implantable loop recorders reporting a very large number of false positive transmissions. And this is a real-world scenario. This is a study of four weeks of all consecutive remote transmissions in patients with loop recorders implanted for AFib surveillance, a cryptogenescope, a stroke, sorry, or syncope. And you can see that for AFib, true positive versus false positive was 50-50, essentially, when you have cryptogenescope, a stroke, false positive. So depending on the, you know, pre-test possibility of the incidence of arrhythmia in the population, you have a low incidence of arrhythmia in the population, you have a larger percentage of patients in whom the signals are false positive. The same happens with syncope, you're not screening for AFib in this population, so you have a lot of false positive for atrial fibrillation. So again, emphasizing the importance that physicians verify visually prior to making a diagnosis. Certainly, like I said, the pacemaker didn't go to medical school, like I said, they report what is called atrial high-rate episodes, those are pacemakers of the fibrillators, and they're programmed to detect faster than certain rate, for example, 190 bits per minute to 50. And there's also a lot of false positive for a variety of reasons, so it is important that it is visually confirmed, but the faster the episodes, and you can see here, the longer the duration, the more accurate the diagnosis is, atrial fibrillation is a very fast signal. But you can see the shorter episodes tend to be associated with a slower episode with a higher incidence of false positive here in this graph. So with that in mind, the atrial fibrillation guidelines also recommend that for patients who have had a systemic thromboembolic event without known history of atrial fibrillation, in whom maximum sensitivity to detect atrial fibrillation is sought, an implantable cardiac monitor is reasonable. So the more frequent the longer monitor for AFib is deployed, the greater the sensitivity for detecting AFib. Previous trials have shown that, especially in a patient with cryptogenic stroke. So essentially, the longer you monitor, the more AFib you detect. No questions about that. And you can see some of the studies of embolic stroke of a known source that compare monitor duration. You can see that the longer the duration, 30 days versus 24 hours, you have a higher incidence of AFib. Prolonged monitor with a loop recorder versus just a 24-hour holter, you also detect more AFib. You look at a meta-analysis. When you do a loop recorder in patients with embolic stroke of a known source, you can expect over one or two years to get 20% to 30% incidence of atrial fibrillation, greater than five minutes. Having said that, we have to be careful because subclinical atrial fibrillation is very common, especially in older patients. This is a study in circulation by Healy, where the authors implanted loop recorders in patients older than 65 years of age attending cardiovascular or neurology outpatient clinics with no history of AFib. But they had a CHAS-VAS score of two or greater, sleep apnea or body mass index greater than 30 kilograms over a meter square. So they also had large LA elevated antiprobium. The point is that there were high risk for arrhythmias. And then the rate of subclinical atrial fibrillation in those with a history of stroke or systemic embolism was 39%, but it was 30% in patients without AFib. So essentially, subclinical atrial fibrillation is very common in older patients with risk factors without history of atrial fibrillation. So the clinical significance of that is unclear. So among patients with diagnosis of atrial fibrillation, it's reasonable to infer AFib frequency, duration, and burden using the automated algorithms available from EKG monitors, implantable devices with an atrial lid, for example, with periodic review where the diagnosis is confirmed. And then we recommend also that those devices and consumer accessible EKG devices can be used also to detect recurrences of arrhythmia in patients in whom the diagnosis already has been confirmed and they have been already a good correlation between the patient rhythm abnormalities and the findings in the consumer wearable. In patients with a stroke or TIA of undetermined cause, initial cardiac monitoring and if needed extended monitoring with a loop recorder are reasonable to improve detection of AFib. So we're not detecting AFib, however, I want to emphasize that Crystal AFib study showed that you detect more AFib with a loop recorder in patients with stroke, but we don't know. The study was never designed to look at whether the interventions lead to risk reduction or recurrent stroke or post-stroke mortality. So again, data have shown you detect more atrial fibrillation, but the studies were not designed to look at the effects of therapy on outcomes. These are a couple of examples I included. Devices can monitor atrial arrhythmias and AFib are widespread. So an Apple Watch, for example, can alert a patient about a pulse that is irregular, but it will require confirmation of diagnosis. But once that's confirmed and the patients understand and can correlate symptoms with findings, then the Apple Watch can be used to monitor for recurrences, for example. You have also these devices available for the cardiomobile, similar devices that can print a tracing, and it's essentially a two-lead EKG monitor. So it's actually an actual EKG lead. Those can also be useful for the patients to own, to take home, and that way they can monitor long-term for recurrences of arrhythmias, for example. Like I mentioned, implantable loop recorders can be used to screen for AFib after cryptogenic stroke, but be mindful that you can have a lot of false positives. So it has to be read and confirmed visually. And then pacemakers can be used to track AFib burden once the diagnosis is confirmed also, or essentially is implied. So in conclusion, devices that can monitor arrhythmias and atrial fibrillations are widespread. Accuracy of monitor is variable. The initial diagnosis, then, should rely on healthcare professionals' examination of the electrocardiographic traces. Positive predictive value depends on arrhythmia duration rate and the atrial fibrillation prevalence of the population. The lower prevalence pre-test probability, the higher the incidence of false positives. There's a role for use of consumer wearables in specific scenarios, such as for detecting arrhythmia recurrences or response to therapy, and when maximum sensitivities prefer, such as to screen for atrial fibrillation after an embolic stroke of unknown source, implantable monitors are an option, although the effect of atrial fibrillation screening on outcomes have not been demonstrated. Thank you so much.

AFib diagnostics

wearable technology

2023 guidelines

visual confirmation

implantable monitors