Enhancing Care Strategies for ICD Patients with Atrial Fibrillation

The Findings of the MATRIX Study Could Change Clinical Practice, Says Cardiac Rhythm Expert Dr. Ignasi Anguera Camos

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The clinical requirement to monitor atrial fibrillation (AF) for preventing potential strokes may present a challenge in patients with standard single-chamber implantable cardioverter-defibrillators (ICDs).1 These devices lack the recommended capability to effectively monitor AF,2 which could lead to missed opportunities for timely intervention and stroke prevention.1  

DX Technology, a single-lead ICD system equipped with a floating atrial dipole, overcomes this limitation by enabling AF detection and monitoring, even in patients not indicated for a dual-chamber ICD. This advancement spares these patients from an atrial lead implantation while allowing clinicians to assess and reliably monitor AF burden and disease progression over time.

Earlier this year, a team of leading experts published the MATRIX study – shedding light on the importance of remote monitoring and on the role of DX Technology in the diagnosis and treatment of AF. We interviewed Dr. Ignasi Anguera Camos from Bellvitge University Hospital, Hospitalet de Llobregat, in Barcelona, Spain, one of the study authors, to discuss key findings and how the DX ICD, combined with remote care, is shaping the future of clinical practice. As we observe Atrial Fibrillation Awareness Month, there's no better time to share these valuable insights and help raise awareness about this intricate condition.

Accurate AF Detection and Disease Progression Monitoring

“We have been successfully implanting devices with DX Technology for more than ten years now. The recent results of the MATRIX study confirm what we have experienced over the years – a high detection accuracy of AF without the need for a dedicated atrial lead,” says Dr. Anguera. “The key result [of the MATRIX study] is that this device is able to detect what's going on in the atrium with high accuracy, with detection of very high amplitudes of the right atrial signal, a detection which is very stable over time,” explains Dr. Anguera, adding that, “in the end, the patients were effectively monitored [via HomeMonitoring] more than 90 percent of the time.” 

The quality of AF detection is made possible with good P-wave sensing. Namely, the MATRIX study investigators rated atrial signal detection quality as excellent, good or adequate in more than 95% of cases – at enrollment, at 12-month and at 24-month follow-ups.3

“What's even more impressive is the high positive-predictive value (PPV) for detecting atrial high-rate episodes (AHREs) of longer duration, reaching an astounding 99.7% for episodes lasting one hour or more. This enables reliable remote monitoring of subclinical AF, allowing clinicians to monitor disease progression over time, initiate treatment and tailor treatment plans accordingly,” concludes Dr. Anguera.

Dr. Ignasi Anguera Camos

Perhaps it's time to reconsider our device selection strategy, and the MATRIX study results could be an indication that we should simply implant fewer standard single-chamber devices – opting for the DX ICD system more frequently.

Dr. Ignasi Anguera Camos


Time to Reconsider Device Selection

Further on, the MATRIX study showed that the new-onset AHRE, as detected by the DX ICD system and Home Monitoring, is not rare. Within the two years of follow-up, 8.2% of patients without a former history of AF experienced new-onset AHRE, and 31.1% of them a progression to a stratum of longer duration (for example from 6 min–1 hr to 1 hr–24 hrs).3

“For me, it's important to truly and efficiently detect incident Afib in our ICD patients. In the study, not only Afib was detected in 8.2 percent of the patients, but we also saw that one out of three patients with [subclinical] Afib had a progression in the type of Afib, from seasonal to persistent or from short episodes to long episodes. There is a progression of the type of arrhythmia in a substantial number of patients. That's why it matters to continuously detect the atrial rhythm,” explains Dr. Anguera.

“The MATRIX study results validate the reliability of the signals and the overall stability of the system,” elaborates Dr. Anguera, adding that the observed incidence of new-onset AF reaching 8% cannot be disregarded. “Perhaps it's time to reconsider our device selection strategy, and these results could be an indication that we should simply implant fewer standard single-chamber devices – opting for the DX ICD system more frequently,” he concludes.

AF Burden as Key Factor in Treatment Decisions, but More Research Needed

One major reoccurring question that still arises is whether to initiate anticoagulation for patients with AF episodes. “Currently, there is no definitive unison answer regarding the specific threshold for initiating anticoagulation,” says Dr. Anguera.

Beyond the duration of individual episodes, the overall burden of AF plays a pivotal role in treatment decisions. “Having an isolated episode of AF in a year differs significantly from experiencing multiple episodes. Unfortunately, the impact of AF burden on AF management remains inconclusive, prompting ongoing trials to address this crucial question. Personalizing decisions based on factors like the patient's CHA2DS2-VASc risk profile and the actual AF burden, thanks to the information from the device, becomes essential,” argues Dr. Anguera. "And while this question awaits an answer, we remain hopeful that the MATRIX study has shed some more light on the potential of AF remote monitoring and detection possibilities for ICD patients, as recommended by the current ESC guidelines."

The Largest Clinical DX Evaluation to Date

The MATRIX3 study evaluated the utility of the DX ICD system (atrial signal detection via a floating dipole integrated in the ICD lead) for remotely monitoring AHRE and the evolution of their duration. In addition, the study analyzed the clinical implications, in terms of AF management, of AHRE detection and progression. The international, multicenter registry enrolled 2,054 DX-ICD patients in 119 sites across 24 countries, while patients were followed for 24 months under real-life conditions.


If you are interested in more research on AF management, check out our related blog stories.


Note: The content of this blog is based on research findings and should not replace individualized medical advice. It is recommended that you consult with a health care professional for personalized guidance and treatment decisions.


1. Reinhold T, Belke R, Hauser T, et al. Cost Saving Potential of an Early Detection of Atrial Fibrillation in Patients after ICD Implantation. BioMed Research International, Volume 2018, 14 August 2018, Article ID 3417643.

2. Hindricks G, Potpara T, Dagres N, Arbelo E, Bax JJ, Blomström-Lundqvist C et al. 2020 ESC guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS): the task force for the diagnosis and management of atrial fibrillation of the European Society of Cardiology (ESC) developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC. Eur Heart J 2021;42:373–498.

3. Hindricks G, Theuns DA, Bar-Lev D, et al. Ability to remotely monitor atrial high-rate episodes using a single-chamber implantable cardioverter-defibrillator with a floating atrial sensing dipole, EP Europace, Volume 25, Issue 5, May 2023, Pages 1–10, euad061.