Trial Outcomes & Findings for FLOW-AF: A Study to Evaluate Electrographic Flow™ (EGF) Mapping Technology (NCT NCT04473963)

Results Overview

Acute Procedure Success is defined as successful elimination of significant sources of electrographic flow (EGF) through targeted radiofrequency ablation. EGF-identified sources are significant when their leading source activity is above threshold. Successful elimination is defined as reduction of the source activity of the leading source below threshold upon post-ablation remapping using EGF mapping.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

85 participants

Primary outcome timeframe

During the Procedure

Results posted on

2025-04-10

Participant Flow

5 patients from the run-in cohort declined to return for protocol-mandated EGF re-mapping procedure after the initial blanking period.

Participant milestones

Participant milestones
Measure	Randomized to Treatment: PVI + Electrographic Flow™ (EGF) Guided Ablation Therapy This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold, qualifying them for randomization. Subjects randomized to the "treatment" group first received pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. After this, EGF mapping in AF was conducted and targeted radiofrequency ablation of EGF-identified source(s) was performed in the left and right atrium. The procedure is considered complete once all EGF-identified sources have been eliminated through ablation. If necessary, the procedure were concluded with cardioversion.	Randomized to Control: PVI Only This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold, qualifying them for randomization. Subjects randomized to the "control" group received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Subjects also received EGF mapping while in AF, but no further ablation of the EGF-identified sources. The procedure were concluded with cardioversion.	Not Randomized This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, but exhibited no EGF-identified sources with leading source activity above threshold. Subjects received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Empiric adjunctive ablation could be performed at operator discretion. If necessary, the procedure were concluded with cardioversion.
Overall Study STARTED	22	24	34
Overall Study Intention to Treat	22	24	34
Overall Study Per Protocol	20	22	28
Overall Study Per Protocol With Complete Follow-up	19	21	28
Overall Study COMPLETED	21	23	32
Overall Study NOT COMPLETED	1	1	2

Reasons for withdrawal

Reasons for withdrawal
Measure	Randomized to Treatment: PVI + Electrographic Flow™ (EGF) Guided Ablation Therapy This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold, qualifying them for randomization. Subjects randomized to the "treatment" group first received pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. After this, EGF mapping in AF was conducted and targeted radiofrequency ablation of EGF-identified source(s) was performed in the left and right atrium. The procedure is considered complete once all EGF-identified sources have been eliminated through ablation. If necessary, the procedure were concluded with cardioversion.	Randomized to Control: PVI Only This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold, qualifying them for randomization. Subjects randomized to the "control" group received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Subjects also received EGF mapping while in AF, but no further ablation of the EGF-identified sources. The procedure were concluded with cardioversion.	Not Randomized This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, but exhibited no EGF-identified sources with leading source activity above threshold. Subjects received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Empiric adjunctive ablation could be performed at operator discretion. If necessary, the procedure were concluded with cardioversion.
Overall Study Withdrawal by Subject	1	1	0
Overall Study Not inducible in AF	0	0	2

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Randomized to Treatment: PVI + Electrographic Flow™ (EGF) Guided Ablation Therapy n=22 Participants This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold, qualifying them for randomization. Subjects randomized to the "treatment" group first received pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. After this, EGF mapping in AF was conducted and targeted radiofrequency ablation of EGF-identified source(s) was performed in the left and right atrium. The procedure is considered complete once all EGF-identified sources have been eliminated through ablation. If necessary, the procedure were concluded with cardioversion.	Randomized to Control: PVI Only n=24 Participants This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold, qualifying them for randomization. Subjects randomized to the "control" group received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Subjects also received EGF mapping while in AF, but no further ablation of the EGF-identified sources. The procedure were concluded with cardioversion.	Not Randomized n=34 Participants This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, but exhibited no EGF-identified sources with leading source activity above threshold. Subjects received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Empiric adjunctive ablation could be performed at operator discretion. If necessary, the procedure were concluded with cardioversion.	Total n=80 Participants Total of all reporting groups
Age, Continuous	67.2 years STANDARD_DEVIATION 9.5 • n=22 Participants	69.1 years STANDARD_DEVIATION 10.5 • n=24 Participants	62.6 years STANDARD_DEVIATION 7.3 • n=34 Participants	65.8 years STANDARD_DEVIATION 9.3 • n=80 Participants
Sex: Female, Male Female	7 Participants n=22 Participants	11 Participants n=24 Participants	10 Participants n=34 Participants	28 Participants n=80 Participants
Sex: Female, Male Male	15 Participants n=22 Participants	13 Participants n=24 Participants	24 Participants n=34 Participants	52 Participants n=80 Participants
Race and Ethnicity Not Collected	—	—	—	0 Participants Race and Ethnicity were not collected from any participant.
Body Mass Index	27.2 kg/m2 STANDARD_DEVIATION 4.3 • n=22 Participants	29.3 kg/m2 STANDARD_DEVIATION 5.3 • n=24 Participants	30.3 kg/m2 STANDARD_DEVIATION 4.2 • n=34 Participants	29.1 kg/m2 STANDARD_DEVIATION 4.6 • n=80 Participants
Long-Standing Persistent Atrial Fibrillation	5 Participants n=22 Participants	6 Participants n=24 Participants	6 Participants n=34 Participants	17 Participants n=80 Participants
CHA2DS2-VASc score	2.7 units on a scale [scale range: 0-9] STANDARD_DEVIATION 1.5 • n=22 Participants	3.1 units on a scale [scale range: 0-9] STANDARD_DEVIATION 1.4 • n=24 Participants	1.8 units on a scale [scale range: 0-9] STANDARD_DEVIATION 1.0 • n=34 Participants	2.4 units on a scale [scale range: 0-9] STANDARD_DEVIATION 1.3 • n=80 Participants
LA Size (cm)	4.5 cm STANDARD_DEVIATION 0.5 • n=22 Participants	4.4 cm STANDARD_DEVIATION 0.7 • n=24 Participants	4.4 cm STANDARD_DEVIATION 0.5 • n=34 Participants	4.4 cm STANDARD_DEVIATION 0.6 • n=80 Participants
Left Ventricular Ejection Fraction	56 % STANDARD_DEVIATION 6 • n=22 Participants	58 % STANDARD_DEVIATION 6 • n=24 Participants	56 % STANDARD_DEVIATION 7 • n=34 Participants	57 % STANDARD_DEVIATION 6 • n=80 Participants

PRIMARY outcome

Timeframe: During the Procedure

Population: Per protocol population. Outcome Measure is only applicable to the group "Randomized to Treatment: PVI + EGF-Guided Ablation Therapy", because this outcome assesses the ability to eliminate EGF-identified sources through targeted source ablation. Other groups did not receive EGF-identified source ablation, and are therefore not included in analysis.

Acute Procedure Success is defined as successful elimination of significant sources of electrographic flow (EGF) through targeted radiofrequency ablation. EGF-identified sources are significant when their leading source activity is above threshold. Successful elimination is defined as reduction of the source activity of the leading source below threshold upon post-ablation remapping using EGF mapping.

Outcome measures

Outcome measures
Measure	Randomized to Treatment: PVI + EGF Guided Ablation Therapy n=20 Participants This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold (≥26.5%), qualifying them for randomization. Subjects randomized to the "treatment" group first received pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. After this, EGF mapping in AF was conducted and targeted radiofrequency ablation of EGF-identified source(s) was performed in the left and right atrium. The procedure is considered complete once all EGF-identified sources have been eliminated through ablation. If necessary, the procedure were concluded with cardioversion.	Randomized to Control: PVI Only This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold (≥26.5%), qualifying them for randomization. Subjects randomized to the "control" group received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Subjects also received EGF mapping while in AF, but no further ablation of the EGF-identified sources. The procedure were concluded with cardioversion.	Not Randomized This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, but exhibited no EGF-identified sources with leading source activity above threshold (≥26.5%). Subjects received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Empiric adjunctive ablation could be performed at operator discretion. If necessary, the procedure were concluded with cardioversion.	Total All Subjects in ITT population
Number of Participants With Acute Procedure Success	19 Participants	—	—	—

PRIMARY outcome

Timeframe: 7 days

Population: ITT population

Freedom from Serious Adverse Events (SAE) related to the procedure through 7 days following the index procedure.

Outcome measures

Outcome measures
Measure	Randomized to Treatment: PVI + EGF Guided Ablation Therapy n=22 Participants This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold (≥26.5%), qualifying them for randomization. Subjects randomized to the "treatment" group first received pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. After this, EGF mapping in AF was conducted and targeted radiofrequency ablation of EGF-identified source(s) was performed in the left and right atrium. The procedure is considered complete once all EGF-identified sources have been eliminated through ablation. If necessary, the procedure were concluded with cardioversion.	Randomized to Control: PVI Only n=24 Participants This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold (≥26.5%), qualifying them for randomization. Subjects randomized to the "control" group received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Subjects also received EGF mapping while in AF, but no further ablation of the EGF-identified sources. The procedure were concluded with cardioversion.	Not Randomized n=34 Participants This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, but exhibited no EGF-identified sources with leading source activity above threshold (≥26.5%). Subjects received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Empiric adjunctive ablation could be performed at operator discretion. If necessary, the procedure were concluded with cardioversion.	Total n=80 Participants All Subjects in ITT population
Number of Participants With Serious Adverse Events Related to the Procedure Through 7 Days	0 Participants	0 Participants	2 Participants	2 Participants

SECONDARY outcome

Timeframe: Index Procedure until Recurrence Procedure

Population: A subgroup of 12 subjects (with a total of 18 Electrographic Flow™ (EGF) identified sources) from the "Randomized to Control," "Randomized to Treatment," or "Not Randomized" groups who returned for a subsequent EGF-guided procedure ≥ 3 months later. Consistency of these sources was evaluated before any randomization/treatment occurred, making inter-group comparisons inappropriate. Groups could be combined as the focus was on source consistency over time, not treatment assignment.

This measure represents the number of Electrographic Flow™ (EGF) identified sources that remained consistent in anatomical location during subsequent EGF-guided procedures. The number and anatomical locations of EGF-identified sources for each subject were compared between the Index procedure and a subsequent EGF-guided procedure conducted ≥ 3 months later. A source was considered consistent if it was visible in the same anatomical location across both procedures.

Outcome measures

Outcome measures
Measure	Randomized to Treatment: PVI + EGF Guided Ablation Therapy n=18 Sources above Threshold This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold (≥26.5%), qualifying them for randomization. Subjects randomized to the "treatment" group first received pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. After this, EGF mapping in AF was conducted and targeted radiofrequency ablation of EGF-identified source(s) was performed in the left and right atrium. The procedure is considered complete once all EGF-identified sources have been eliminated through ablation. If necessary, the procedure were concluded with cardioversion.	Randomized to Control: PVI Only This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, and exhibited EGF-identified significant sources with leading source activity above threshold (≥26.5%), qualifying them for randomization. Subjects randomized to the "control" group received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Subjects also received EGF mapping while in AF, but no further ablation of the EGF-identified sources. The procedure were concluded with cardioversion.	Not Randomized This arm includes subjects who underwent Electrographic Flow™ (EGF) mapping, but exhibited no EGF-identified sources with leading source activity above threshold (≥26.5%). Subjects received standard pulmonary vein isolation (PVI) or PVI touch-up followed by a 20 minute waiting period and PVI confirmation. Empiric adjunctive ablation could be performed at operator discretion. If necessary, the procedure were concluded with cardioversion.	Total All Subjects in ITT population
Number of Electrographic Flow™ (EGF) Identified Sources With Consistent Location Across Subsequent EGF-Guided Procedures	16 EGF-identified Sources	—	—	—

SECONDARY outcome

Timeframe: 90 day - 12 months

Population: Per protocol population with completed 12 month follow-up.

This measure represents the number of subjects with freedom from documented episodes of atrial fibrillation (AF) recurrence lasting longer than 30 seconds from the 90-day post-procedure blanking period through 12 months of follow-up. Follow-up and electrocardiographic monitoring of AF occurred at 3, 6 and 12 months through 7-day Holter recordings and ECGs.