Wojciech Zareba, MD, PhD, is a professor of medicine and cardiology at the University of Rochester Medical Center.

Wojciech Zareba, MD, PhD

The KardiaMobile 6-Lead (KM6L) portable electrocardiographic (ECG) recorder has demonstrated its superior ability to detect 

 when self-administered by patients compared to traditional ambulatory monitoring.

Kardia’s 6-Lead ECG Detects More Arrhythmia Events than Guideline-Recommended Devices

Traditionally, ambulatory ECG monitoring has depended on guideline-recommended 24- or 48-hour Holter monitors, which possess limited sensitivity given the inherent infrequency of arrhythmic events. Symptoms such as palpitations, dizziness, and lightheadedness, while prevalent, are often transient, leaving many ECG monitors unable to detect them reliably. To this end, AliveCor’s KM6L allows patients to initiate recordings manually via handheld devices, capturing arrhythmias as they happen. The present study compares the efficacy of the KM6L with that of existing extended ECG monitoring like Holter recordings.

“When we started the study, it took some time to make sure that people were well versed in these recordings, but we learned how to train them better,” Wojciech Zareba, MD, PhD, professor of medicine and cardiology at the University of Rochester Medical Center and a lead investigator in the study, told 

 in an exclusive interview. “And ultimately, the majority of patients provided us with good quality recordings, which were crucial to determine whether there was any cardiac arrhythmia or not.”

Zareba and colleagues conducted a prospective, single-center cohort study including patients recruited from outpatient cardiology clinics at the University of Rochester. Patients were eligible for inclusion if they were ≥18 years of age and had been referred for ambulatory ECG monitoring due to unexplained lightheadedness, dizziness, or palpitations. Patients with a history of unexplained syncope in the past year were excluded.

At the initial visit after each enrollment, patients were supplied with a KM6L device or a Holter monitor and were instructed in its operation and use via the Kardia smartphone app. Patients performed a supervised ECG recording, obtaining a 6-lead, 1-minute recording to ensure correct operation. Additionally, patients were required to complete 4 daily scheduled asymptomatic recordings to establish a baseline.

Follow-up assessments were conducted at 5 +/-2 days, 17 +/- 2 days, and 32 +/- 2 days post-enrollment. The study’s primary endpoint was the detection of clinically significant arrhythmias, defined a priori as atrial fibrillation or flutter lasting ≥30 seconds, supraventricular tachycardia, second- or third-degree atrioventricular block, pauses ≥3 seconds, or wide complex tachycardia.

A total of 350 patients were enrolled in the study, with 40% (n = 140) receiving a 24- or 48-hour Holter and 60% (n = 210) using an extended patch ECG monitor, including 49.7% (n = 105) with a 2-day patch, 14.7% (n = 31) with a 7-day patch, and 35.6% (n = 74) with a 14-day patch. 22.3% of patients had prior arrhythmia, while 24.6% reported having palpitations in the past requiring cardiac monitoring.

Investigators collected a total of 6251 KM6L recordings, with a median of 15 recordings per patient (interquartile range [IQR], 7-150 recordings per patient). Significant arrhythmias were detected in 66 patients (18.9%) using either ambulatory ECG monitoring or KM6L – the former identified arrhythmias in 27 patients (7.7%), while KM6L identified arrhythmias in 52 patients (14.9%). Additionally, 39 arrhythmia episodes (11.1%) were detected exclusively by KM6L (

 = .0008), most commonly atrial fibrillation (n = 23).

Ultimately, Zareba and colleagues concluded that the KM6L device is capable of detecting arrhythmias otherwise frequently missed by Holter monitoring, while being easy to use and engendering high patient satisfaction. Overall, the team notes that the device may improve arrhythmia detection and patient management, as well as reduce healthcare costs, if applied to routine clinical practice.

“Another very important element of this particular device is that you may be able to provide some additional information for patients who might be healthy,” Zareba said. “They might be a bit nervous, they might be anxious, and they don’t have any serious arrhythmia – finding this out here is much better for them than going through the next steps of diagnostic procedures, echoes or invasive procedures.”

Editors’ Note: Zareba reports no relevant disclosures.

Dzikowicz DJ, Aktas MK, Horn R, et al. Symptom-triggered 6-lead ECG monitoring significantly increases arrhythmia detection beyond traditional ambulatory monitoring. 

Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/hrs guideline for the diagnosis and management of atrial fibrillation: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2024;149(1). 

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Wojciech Zareba, MD, PhD, discusses his recent study comparing the efficacy of the KardiaMobile 6-Lead to Holter ambulatory ECGs.

Wojciech Zareba, MD, PhD

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