Digital illustration of a heart with clear and noisy electrical signals, symbolizing the challenges of AFib mapping.

AFib Mapping: Can We Trust the Signals?

Samir D’Costa monogram
Samir D’Costa in Health & Wellness October 2026 • 4 min read.

"New research explores how signal quality and contamination affect the accuracy of heart mapping for atrial fibrillation."


Atrial fibrillation (AFib), characterized by an irregular and often rapid heart rate, is a widespread heart condition affecting millions globally. While not immediately life-threatening, AFib can significantly increase the risk of stroke, heart failure, and other cardiovascular complications. Effective management of AFib often relies on accurately mapping the heart's electrical activity to identify the sources of the arrhythmia, which can then be targeted with treatments like ablation.

Mapping the heart's electrical signals during AFib is a complex task. The heart's signals can be obscured by various sources of contamination, such as poor electrode contact, interference from other electrical devices, and even signals originating from distant areas of the heart. These inaccuracies can lead to incomplete or misleading maps, potentially reducing the effectiveness of treatments.

Researchers are actively developing new methods to assess and improve the quality of electrical signal mapping in AFib. A recent study published in Frontiers in Physiology introduces a novel approach to measure signal fidelity and evaluate the impact of signal contamination on the accuracy of AFib mapping. This article delves into the study's methods, findings, and potential implications for improving AFib treatment.

AI Search Multiple angles on this topic

Mapping Signals Require Careful Interpretation

The available sources do not provide a consistent set of current AFib prevalence or impact statistics. One review notes that bipolar electrogram amplitude can provide rich data under standardized recording conditions, but activation direction, catheter angle, conduction velocity, and tissue thickness can affect voltage mapping’s accuracy in detecting and quantifying fibrosis. The National Cardiovascular Data Registry’s AFib Ablation Registry was created to assess real-world prevalence, patient demographics, procedural management, and outcomes among people undergoing AF ablation.

Activation Mapping and Its Caveats

Atrial mapping evaluates AF through detailed activation mapping of the right and left atria, often using multiple electrode catheters to identify triggers, organized tachycardias, and abnormal substrates. It can use contact or noncontact methods. One source describes activation mapping as the gold standard for diagnosing and interpreting AF, while also warning that fibrillatory activation maps are highly sensitive to far-field effects and can disagree with optical mapping modalities. Comparing mapping methods is important for understanding their respective advantages and disadvantages.

From Trigger Mapping to Ablation

Mapping techniques were central to the development of AF ablation. The UCSF account describes how a physician mapped the origin of AF triggers in patients and found that 95–96% originated in muscle sleeves extending into the pulmonary veins. A historical review notes that AF is now among the most studied arrhythmias, despite its apparently straightforward diagnosis on surface electrocardiography and the many electromechanical mechanisms underlying its origin.

Decoding Signal Fidelity: What Does it Mean?

Digital illustration of a heart with clear and noisy electrical signals, symbolizing the challenges of AFib mapping.

The study's central aim was to develop a reliable measure of signal fidelity, indicating the trustworthiness of electrical signals recorded during AFib. The researchers hypothesized that high-fidelity signals, characterized by clear and distinct deflections, would provide a more accurate representation of the heart's electrical activity. Conversely, low-fidelity signals, with ambiguous or noisy deflections, might lead to mapping errors.

To quantify signal fidelity, the researchers developed a novel metric based on the phase of the electrical signal. This metric assesses the consistency and clarity of deflections in the signal, assigning higher scores to signals with well-defined deflections and lower scores to those with more ambiguous patterns. This measure allows doctors to identify regions where the heart's electrical activity is clearly defined, and where it might be distorted by noise or interference.

  • High Fidelity: Clear, distinct deflections in the electrical signal.
  • Low Fidelity: Ambiguous or noisy deflections, potentially obscuring the true electrical activity.
  • Fidelity Score: A quantitative measure assessing the clarity and consistency of signal deflections.
AI Search Multiple angles on this topic

New Mapping Approaches Need Further Testing

A review of STAR-mapping-guided ablation reports superiority over pulmonary vein isolation alone or combined with CFAE/linear ablation for persistent AF, but says the finding needs further evaluation in multicenter randomized trials. The planned ROC-STAR trial is identified as NCT04442113. Separately, a 2024 clinical review describes how recent advances in three-dimensional ultra-high-density mapping have uncovered previously unknown arrhythmia mechanisms, including work aimed at clarifying AF mechanisms.

Signal Contamination Can Obscure Local Activity

Ablation-catheter distal bipolar electrograms include both near-field and far-field signal components, which can obscure the local characteristics most relevant to assessing catheter contact. Research on signal fidelity also reports that rotational patterns observed in phase maps appear most sensitive to far-field activation. FLOW EVAL-AF was a single-center prospective study of 10 AF patients, designed to evaluate electrographic flow mapping with Ablamap v10.0.1 in sinus rhythm and AF and compare its maps with high-density bipolar voltage maps.

Comparisons of Mapping Systems in PFA

The MAP-PFA study is described as comparing standard pulsed field ablation (PFA) using the FARAVIEW mapping system with standard PFA alone. A 2026 report’s figure description compares FARAVIEW with other mapping systems, including an Opal HDx left-atrial electroanatomical map, and indicates comparisons of procedure efficiency, total cost, and procedure and fluoroscopy time per lesion set. The supplied material does not provide comparative results or figures for those outcomes, so it does not support a conclusion that one system performs better.

The signal fidelity measure was used to analyze electrical recordings from patients with persistent AFib. The analysis revealed that regions of low signal fidelity often corresponded to the location of rotational cores, which are areas of the heart where electrical signals circulate and sustain the arrhythmia. This suggests that the complex electrical activity within these cores might lead to signal distortion, making accurate mapping more challenging.

The Future of AFib Mapping

This research highlights the importance of signal quality in AFib mapping and provides a valuable tool for assessing the reliability of electrical signals. By identifying and mitigating the effects of signal contamination, clinicians can create more accurate heart maps, potentially improving the success of AFib treatments like ablation. Further studies are needed to validate these findings and explore the optimal strategies for incorporating signal fidelity measures into clinical practice.

AI Search Multiple angles on this topic

Balancing Targeted Ablation and Added Scar

A review of high-density and resolution epicardial mapping says it has contributed novel insights into AF pathophysiology, while noting the limited efficacy of pulmonary vein isolation for more persistent AF and the need for more substrate-based treatment approaches. Electrographic flow mapping uses spatiotemporal voltage relationships to localize sources and quantify substrate health, but further research is needed to optimize phenotyping and treatment. Mapping atrial ectopy that initiates AF after pulmonary vein isolation may be promising, yet can be limited by trigger suppression from anesthetics and by ablation of ectopy that may not be mechanistically related to the arrhythmia.

Real-World Mapping Evidence and Feasibility

A 2021 study aimed to identify global real-world data sources for heart failure, acute coronary syndrome, and AF, reflecting the importance of transparent and robust real-world evidence in cardiovascular health. A separate study listing describes a feasibility study of personalized, noninvasive mapping-guided ablation for persistent AF in patients considered unlikely to benefit from empirical pulmonary vein isolation alone. Another report says it aims to describe real-world experience with commercially available high-density mapping catheters and compare mapping performance in AF ablation. The supplied snippets do not report results from these studies.

What signal fidelity can-and cannot-tell us

Repeated maps often placed the leading source at the same electrode position or nearby, but some produced a chaotic pattern. This describes how repeatable the mapping was, not whether the identified source was correct.[1]

Why mapping signals can differ

Voltage readings depend on recording and tissue conditions, including wavefront direction, electrode setup, contact force and filter settings. A voltage map therefore reflects more than the underlying tissue alone.[2]

The close-bipolar local-potential voltage was reported as smaller than the wide-bipolar voltage, but the quoted comparison gives no value for the latter. It supports a difference between configurations, not a complete estimate of its size.[3]

During fibrillation, changing and fractionated signals make activation-time assignment difficult, and choosing a useful time window for a map is also challenging. These issues complicate interpretation independently of whether a signal-fidelity score is available.[4]

What further evidence would need to show

  • How much do signals from adjacent sites alter activation timing, create spurious signals or obscure local activation when wavefronts are out of phase?[5]
  • Can mapping capture activation and recovery across multiple sites at high temporal resolution while avoiding cross-talk from neighboring sites?[5]

Mapping terms in context

Bipolar voltage mapping
A method of mapping atrial substrate using bipolar voltage measurements.[6]

Sources

  1. Electrographic flow mapping of persistent atrial fibrillation: intra- and inter-procedure reproducibility in the absence of ‘ground truth’ (pmc.ncbi.nlm.nih.gov)
  2. Atrial fibrillation substrate mapping with emphasis on voltage-based guidance (pmc.ncbi.nlm.nih.gov)
  3. The influence of the electrodes spacing of a mapping catheter on the atrial voltage substrate map. (pubmed.ncbi.nlm.nih.gov)
  4. Challenges Associated with Interpreting Mechanisms of AF (pmc.ncbi.nlm.nih.gov)
  5. Mechanistically based mapping of human cardiac fibrillation (pmc.ncbi.nlm.nih.gov)
  6. Left atrial voltage mapping: defining and targeting the atrial fibrillation substrate (pmc.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What is atrial fibrillation (AFib), and why is it a concern?

Atrial fibrillation, or AFib, is a common heart condition characterized by an irregular and often rapid heart rate. This occurs because the electrical signals that control the heart's rhythm become disorganized. While AFib isn't immediately life-threatening, it can lead to serious complications such as stroke, heart failure, and other cardiovascular issues. Managing AFib often involves mapping the heart's electrical activity to pinpoint the source of the irregular signals, which can then be treated, often with a procedure called ablation.

2

Why is it challenging to accurately map the heart's electrical signals during AFib?

Mapping the heart's electrical activity during AFib is a complicated process because the signals can be affected by several factors. Poor electrode contact, interference from other electrical devices, and even electrical signals coming from distant areas of the heart can obscure the true signals. These contaminations can lead to inaccurate maps, which can reduce the effectiveness of treatments like ablation. Therefore, ensuring the accuracy of these maps is critical for successful AFib treatment.

3

What does 'signal fidelity' mean in the context of AFib mapping?

Signal fidelity refers to the trustworthiness of the electrical signals recorded during AFib mapping. High fidelity signals are clear and have distinct deflections, providing a more accurate representation of the heart's electrical activity. Low fidelity signals are ambiguous or noisy, potentially leading to mapping errors. A fidelity score is a quantitative measure used to assess the clarity and consistency of these signal deflections.

4

How does the fidelity score work in AFib mapping?

The fidelity score is a novel metric based on the phase of the electrical signal. It assesses the consistency and clarity of deflections, assigning higher scores to signals with well-defined deflections and lower scores to those with more ambiguous patterns. This metric helps doctors identify regions where the heart's electrical activity is clearly defined and where it might be distorted by noise or interference. It is used to analyze electrical recordings from patients with persistent AFib.

5

How does addressing signal quality impact the treatment of AFib?

Identifying and mitigating signal contamination helps create more accurate heart maps, improving the success of AFib treatments like ablation. Research has shown that regions of low signal fidelity often correspond to rotational cores, where electrical signals circulate and sustain the arrhythmia. By focusing on improving signal quality, clinicians can better target these problematic areas during treatment. Further studies are needed to validate these findings and determine the best ways to use signal fidelity measures in clinical practice.

Newsletter Subscribe

Subscribe to get the latest articles and insights directly in your inbox.