Serious cardiac arrhythmias can cause sudden death, heart failure, and stroke. Less serious or relatively benign arrhythmias may cause anxiety, affect quality of life, and lead to unnecessary testing. Common symptoms of arrhythmia include palpitations, rapid heart beating, lightheadedness, and shortness of breath. Less frequent symptoms are blackout spells, chest pain, and seizures. The goal is to evaluate these arrhythmias and symptoms in the most cost-effective manner.
Atrial fibrillation (AF) is the most common serious arrhythmia; over 6 million people in the U.S. have AF, and the number is estimated to double to 12 million by 2030 as the population ages. Less common serious arrhythmias include sustained ventricular tachycardia that may trigger circulatory collapse and sudden death, and very frequent premature ventricular beats that can cause heart failure. Physicians routinely prescribe ambulatory ECG monitors to diagnose suspected or symptomatic arrhythmias.
Holter monitoring has been the gold standard of ambulatory ECG monitoring since 1961, but this type of monitor is only worn for 24-48 hours. The Holter’s relatively low diagnostic yield, cost, and patient non-compliance spurred the development of novel wearable patch monitors that record and analyze long-term ECG data. Today’s wearable ECG patch monitors have revolutionized ambulatory cardiac rhythm monitoring. These patient-friendly monitors can be worn for up to two weeks, and they accurately identify serious or troublesome arrhythmias and guide clinical decision-making.
The ECG patch monitor’s long wear time allows more opportunity to capture cardiac arrhythmias that may not be recorded in a standard 24- to 48-hour Holter monitor. While ECG patch and other types of monitors may be worn up to a month, multiple studies suggest that the peak diagnostic yield for arrhythmia detection occurs during the first week of monitoring. As shown in Figure 1, nearly one-third of important arrhythmias occur beyond 48 hours, and the vast majority are detected during 8 days of continuous ECG monitoring.
Thus, wearing an ECG recording device for just a week can significantly improve diagnostic yield compared to a Holter monitor that is worn for just 24-48 hours.
Detecting and Diagnosing Cardiac Arrhythmias in Outpatient Settings
Early detection and prompt intervention for suspected cardiac arrhythmias may prevent life-threatening consequences, and avoid the suffering and expense of a devastating illness. As importantly, accurate identification of a relatively benign or innocent arrhythmia can reassure patients that nothing is seriously wrong and preclude the need for costly diagnostic testing.
Despite multiple studies, the ideal duration of monitoring remains controversial. Two studies suggest that the optimal duration of monitoring depends, in part, on symptom frequency. Patients who have frequent symptoms may be diagnosed during the first 1-2 days, but patients with intermittent or sporadic symptoms may require monitoring for 7-8 days, and the occasional patient may need to be monitored for several weeks or even months.
In my cardiology practice, 24- to 48-hour Holter monitoring frequently failed to record the ECG data that I needed to diagnose the cause of my patients’ symptoms. As studies have shown, 24- to 48-hour Holter monitoring is often associated with a low diagnostic yield, and this does not improve significantly when the Holter monitor is worn for 72 hours. This is especially true for patients with infrequent or intermittent symptoms.
Patient preference may influence the duration of monitoring and the choice of which device to use. In my experience, patients prefer a monitor that is: (1) unobtrusive; (2) may be worn while bathing or showering; (3) does not itch or irritate the underlying skin; (4) can be removed by the patient at the end of the monitoring period; and (5) collects and analyzes the data in the shortest effective time. Patient compliance is best when these five criteria are met, and they prefer a device that is noninvasive (ie, a wearable monitor versus an implantable loop recorder).
Reviewing the Evidence
Optimal Monitoring Duration
Table 1 summarizes studies that have investigated the optimal duration of monitoring for suspected cardiac arrhythmias. Briefly:
- Turakhia published an analysis of 26,751 patients who wore an ECG monitoring patch for an average of 7.6 days; 29.9% of all arrhythmias and 51.1% of patient-triggered arrhythmias occurred after 48 hours; 92% of symptomatic and 97.6% of all arrhythmias occurred by day 8.1
- Rosenberg found that extended patch monitoring beyond 48 hours resulted in a change in patient management in nearly one-third of patients.2
- Shinbane reported that the monitoring time to the first clinically relevant arrhythmia averaged 5.8 days.3
- Barrett compared 24-hour Holter monitoring to extended wearable patch monitoring and concluded that “the adhesive patch monitor detected more events than the Holter monitor. Prolonged duration monitoring for detection of arrhythmia events using single-lead, less-obtrusive, adhesive-patch monitoring platforms could replace conventional Holter monitoring in patients referred for ambulatory ECG monitoring.”4
- Solomon reviewed data from 122,815 patch monitors and found that the identification of one-third of life-threatening ventricular tachycardias required ECG monitoring longer than 48 hours.5
- Heckbert found that 27 of 32 (84%) patients with no prior history of AF were found to have newly diagnosed AF during the first 8 days of monitoring, while AF in 5 patients required longer monitoring (9-11 days).6
Decades ago, two studies of patients with palpitations were evaluated with a continuous-loop event monitor; they found the highest diagnostic yield of cardiac arrhythmias occurred within the first week of monitoring. One study found that there were diminishing returns after the first week — in fact, an additional three weeks of monitoring detected just 4% of arrhythmias, and no patients were diagnosed after the second week.
Table 1 also summarizes recent studies reporting both the wear time and diagnostic yield of various ambulatory cardiac monitoring devices. Briefly:
- Balmelli found in patients evaluated for syncope, dizziness, or palpitations, that more than half (54%) of first diagnostic cardiac events would not have been recorded with a 24-hour Holter. However, when monitored for up to 7 days, 82% of clinically relevant arrhythmias were detected.7
- Turakhia reported that for all types of arrhythmias, diagnostic yield increased with monitoring duration longer than 48 hours. By the fifth day of monitoring, 90% of all patients with arrhythmias were identified. Among patients with symptomatic arrhythmias, 92% of arrhythmias were detected by day 8 compared with only 47% in the first 2 days.1
- Rosenberg and colleagues found that among patients without AF on ECG or 24-hour Holter monitor, the median time to detection was 3.7 days, and 90% of first AF events were detected by day 7. The investigators also concluded that “most recurrence of AF in this population was detected within the first week.”2
- Tung and colleagues published the results of 1,171 patients with stroke or transient ischemic attack (TIA) who were evaluated for AF using a cardiac patch monitor. The investigators found that the mean duration before the first episode of paroxysmal AF (PAF) was 1.5 days and 14.3% of first PAF episodes occurred after 48 hours of monitoring. They found the highest rate of AF detection in the first days of monitoring and a marked decline in the yield of AF detection during the second week.8
- Tan observed that ambulatory event monitoring for 7 days may be sufficient in the diagnosis of symptomatic patients, since significant events first detected beyond 10 days were rare.9
Diminishing Returns Reduce Cost-Effectiveness of Cardiac Monitoring
Since prolonged monitoring beyond 8-14 days is unlikely to improve the detection of clinically significant events, it is logical to conclude that cost-effectiveness also erodes over time. Zimetbaum found that there was only “incremental cost-effectiveness of each week of event monitoring.”10 Balmelli also noted that prolonged monitoring produces “very little additional diagnostic yield compared with rapidly rising costs.”7
Multiple studies question the cost-effectiveness of prolonged monitoring in view of its limited diagnostic utility. Importantly, Rockx observed that “cost per diagnosis is important because a definitive diagnosis halts further testing, thus saving health care resources, and leads to appropriate therapy.”11 Brignole noted that while 24- to 48-hour Holter monitoring has relatively low setup costs, it is expensive in terms of cost per diagnosis.12 Moreover, repeat Holter monitoring is fairly common even though Arnold found that repeat monitoring “did not yield a diagnosis and patients continued to experience clinical events at a substantial healthcare cost.”13
Early detection and timely treatment of cardiac arrhythmias is critical for reducing the burden of cardiac disease, improving quality of life, and lowering healthcare costs. Multiple studies indicate that ECG monitoring beyond the standard 24- to 48-hour Holter monitor improves the detection of clinically significant arrhythmias. Prolonged monitoring beyond 8-14 days is generally not cost-effective and should be reserved for special cases. Wearable patch monitors that record at least 8 days of ECG data appear to be the most well-tolerated and cost-effective devices.
Disclosures: Dr. Hauser has no conflicts of interest to report regarding the content herein. Outside the submitted work, Dr. Hauser reports he is Chair of the Cardiac Insight Scientific Advisory Board.
Interview with Robert G. Hauser, MD, FACC, FHRS
Interview by Jodie Elrod
Can you tell me about the Heart Rhythm Management Program at the Minneapolis Heart Institute? What is your former and current role there?
I’m a general cardiologist, and I retired in 2015. My role in the Heart Rhythm Program at the Minneapolis Heart Institute was to run their pacemaker and defibrillator follow-up clinic. I was involved with patients primarily in that clinic after they had a pacemaker or defibrillator implanted, and we did all the follow-up work.
What are your research interests?
My primary research interest is patient safety, particularly from the standpoint of pacemaker/defibrillator reliability in regards to both pulse generators and leads. My research has primarily been on pacemaker/defibrillator technology since 1973.
Why is duration of ambulatory cardiac monitoring important to you both as a study and to write this review topic?
I primarily wrote this review because I had been thinking about the practicality of evaluating patients in the primary care setting. I did a lot of clinical work during my years at the Minneapolis Heart Institute. I traveled all over the state of Minnesota, visiting and consulting in many primary care clinics that were not related directly to the Minneapolis Heart Institute. So I saw literally thousands of patients from all demographics with all sorts of conditions. My greatest frustration as a clinical cardiologist at that time was getting an ECG recorder, which was primarily the Holter monitor. The problem with the Holter monitor was twofold. Number one, our patients didn’t like it so they weren’t always compliant with the requirements with the Holter monitor (eg, not wearing the patches, not showering, not writing down symptoms, etc.). Number two, these clinics, including ours in Minneapolis, had a limited number of Holter recorders because they were expensive.
We also had a limited number of technicians to analyze the recordings and then deliver those reports to us in a reasonable period of time. For example, if I was seeing patients in Hutchinson, Minnesota, which is about 75 miles west of Minneapolis, I would place a Holter monitor in the clinic in Hutchinson, but then that monitor would have to be sent to the city to get analyzed, and the report could take weeks to come back.
Therefore, when I saw the wearable patch design by Cardiac Insight 10 years ago, it immediately resonated with me for two reasons. First, the ECG patch was going to be easy to wear, easy to apply, and you could analyze the recording in the clinic. So instead of ordering a Holter monitor or waiting for a monitor to become available, and then sending that monitor for analysis, all the patient has to do is bring the patch back. The physician can then plug it into a desktop device that directly downloads the data from the electronics within the module, and the software immediately interprets the information on a computer in the clinic.
Do you have any personal experiences with Cardiac Insight’s Cardea SOLO wearable sensor?
I didn’t have this product when I was in practice. However, my wife has atrial fibrillation, so we do periodic monitors on her to see how well her atrial fibrillation is controlled. About two years ago, when the Cardea SOLO became available, I got the system set up in my home, and she wore the device for seven days. When we took off the ECG patch, all I had to do was take the module, which looks similar to a memory stick, and insert it into the computer to view the full seven days of her rhythm interpretation. It turns out that she was having some recurrent atrial fibrillation.
So my motivation for writing this article is to let everybody know that there is a better way than Holter monitoring. Patient compliance is also higher because this ECG patch doesn’t irritate the skin, so patients can shower. Very importantly, when the monitoring is done, all patients need to do is bring the patch monitor back to the clinic. The doctor can plug it in the computer and get the results right away, so there are no gaps in follow-up. It’s a much smoother process.
As head of the Cardiac Insight Scientific Advisory Board, what initially interested you in Cardea SOLO in particular, given the seeming plethora of similar wearable ECG devices available?
About 10 years ago, when Cardiac Insight started, there were not all the patches that there are today — it wasn’t a crowded marketplace at that point in time. So what initially interested me was the simplicity of the ECG patch plus having the on-board diagnostics, which allow the primary care physician, who orders the vast majority of ECG recorders, to instantly have a diagnostic report. Rather than having Holter monitors being strictly within the purview of the specialist, we’re getting it out to more and more primary care providers, including physicians, nurse practitioners and physician assistants, who see a lot of patients in this country. Therefore, it democratizes ECG monitoring and makes it more available. It’s an effective tool that should be in the hands of the primary care physicians.
For more information about the Cardea SOLO, please visit here!
- Turakhia MP, Hoang DD, Zimetbaum P, et al. Diagnostic utility of a novel leadless arrhythmia monitoring device. Am J Cardiol. 2013;112(4):520-524.
- Rosenberg MA, Samuel M, Thosani A, Zimetbaum PJ. Use of a noninvasive continuous monitoring device in the management of atrial fibrillation: a pilot study. Pacing Clin Electrophysiol. 2013;36(3):328-333.
- Shinbane J, Merkert M, Fogoros R, Mehta V, Cao M, Saxon LA. Wearable wireless arrhythmia detection patches: diagnostic arrhythmia yield, time to first arrhythmia, and patient compliance. Heart Rhythm. 2013;10:5S-S305.
- Barrett PM, Komatireddy R, Haaser S, et al. Comparison of 24-hour Holter monitoring with 14-day novel adhesive patch electrocardiographic monitoring. Am J Med. 2014;127(1):95.e11-17.
- Solomon MD, Yang J, Sung SH, et al. Incidence and timing of potentially high-risk arrhythmias detected through long-term continuous ambulatory electrocardiographic monitoring. BMC Cardiovasc Disord. 2016;16:35.
- Heckbert SR, Austin TR, Jensen PN, et al. Yield and consistency of arrhythmia detection with patch electrocardiographic monitoring: the Multi-Ethnic Study of Atherosclerosis. J Electrocardiol. 2018;51(6):997-1002.
- Balmelli N, Naegeli B, Bertel O. Diagnostic yield of automatic and patient-triggered ambulatory cardiac event recording in the evaluation of patients with palpitations, dizziness, or syncope. Clin Cardiol. 2003;26(4):173-176.
- Tung CE, Su D, Turakhia MP, Lansberg MG. Diagnostic yield of extended cardiac patch monitoring in patients with stroke or TIA. Front Neurol. 2015;5:266.
- Tan ESJ, Seow SC, Kojodjojo P, Singh D, Yeo WT, Lim TW. Optimal duration and predictors of diagnostic utility of patient-activated ambulatory ECG monitoring. Heart Asia. 2018;10(2):e011061.
- Zimetbaum PJ Kim KY, Josephson ME, Goldberger AL, Cohen DJ. Diagnostic yield and optimal duration of continuous-loop event monitoring for the diagnosis of palpitations. A cost-effectiveness analysis. Ann Intern Med. 1998;128(11):890-895.
- Rockx MA, Hoch JS, Klein GJ, et al. Is ambulatory monitoring for community-acquired syncope economically attractive? A cost-effectiveness analysis of a randomized trial of external loop recorders versus Holter monitoring. Am Heart J. 2005;150(5):1065.
- Brignole M, Moya A, de Lange FJ, et al; ESC Scientific Document Group. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J. 2018;39(21):1883-1948.
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- Fung E, Järvelin MR, Doshi RN, et al. Electrocardiographic patch devices and contemporary wireless cardiac monitoring. Front Physiol. 2015;6:149.
- Karaoğuz MR, Yurtseven E, Aslan G, et al. The quality of ECG data acquisition, and diagnostic performance of a novel adhesive patch for ambulatory cardiac rhythm monitoring in arrhythmia detection. J Electrocardiol. 2019;54:28-35.
- Linzer M, Pritchett EL, Pontinen M, McCarthy E, Divine GW. Incremental diagnostic yield of loop electrocardiographic recorders in unexplained syncope. Am J Cardiol. 1990;66(2):214-219.
- Lobodzinski SS. ECG patch monitors for assessment of cardiac rhythm abnormalities. Prog Cardiovasc Dis. 2013;56(2):224-229.
- Moya A, Sutton R, Ammirati F, et al. Guidelines for the diagnosis and management of syncope (version 2009). Eur Heart J. 2009;30:2631-2671.
- Schreiber D, Sattar A, Drigalla D, Higgins S. Ambulatory cardiac monitoring for discharged emergency department patients with possible cardiac arrhythmias. West J Emerg Med. 2014;15(2):194-198.
- Yenikomshian M, Jarvis J, Patton C, Yee C, Mortimer R, Birnbaum H, Topash M. Cardiac arrhythmia detection outcomes among patients monitored with the Zio patch system: a systematic literature review. Curr Med Res Opin. 2019;35(10):1659-1670.