Fibrillatory wave amplitude and thromboembolic risk in non-anticoagulated patients with atrial fibrillation

Abstract

Background

The benefit of oral anticoagulation in atrial fibrillation (AF) is well established for patients at elevated stroke risk, but less clear for those at intermediate risk. We investigated whether analysis of electrocardiogram (ECG) derived fibrillatory waves (F-waves) could help identify patients at risk for stroke and systemic embolism (SSE).

Methods

The Finnish Cardioversion (FinCV) study included patients not on permanent anticoagulation therapy who underwent cardioversion for an acute AF episode. We identified 739 individuals with a valid ECG and complete follow-up data. The maximum amplitudes of the F-waves in leads II and V1 were manually measured from the pre-procedure ECG. Patients were categorized into fine and coarse F-wave groups. The optimal lead and amplitude threshold for grouping were found in an events per person-years analysis. SSE were identified from the patient medical records until either anticoagulation was prescribed, AF was deemed chronic, the patient had deceased, or the end of follow-up.

Results

Overall 37 (5.0%) patients suffered SSE during the median follow-up time of 5.4 years (1.9–10.8). Measured from lead V1 the SSE rates per 100 person-years were 1.5 and 0.7 in fine and coarse F-wave groups, respectively. Fine F-waves were observed in 112 (15.2%). Baseline characteristics were similar between the groups. Fine F-wave predicted SSE in a competing risk analysis (SHR 2.34, 95%CI 1.12–4.87, p = .023). Analyses from lead II did not provide significant results.

Conclusion

Electrocardiographic F-wave amplitude may provide additional information on stroke risk in patients with paroxysmal AF and borderline indications or contraindications for anticoagulation.

Keywords:

• Atrial fibrillation
• electrocardiogram
• F-wave
• stroke

Acknowledgements

The authors thank BM Malla Mononen for her contribution in data acquisition.

Authors contributions

AR contributed to the study design, data analysis and interpretation, and drafting of the manuscript. SJ, TV, IN, KEJA, and TK had a substantial role in the conception of the study and in reviewing the manuscript. HV and EN played a major role in data acquisition and reviewing the manuscript. All authors have made substantial contributions to the work and agree to be accountable for all aspects.

Ethics statement

The study received approval from the Medical Ethics Committee of the Hospital District of Southwest Finland (identifier: T02/005/19, 14.3.2019). This study conforms to the principles of the Declaration of Helsinki. Informed consent was not required owing to the retrospective nature of the study.

Disclosure statement

K.E. Juhani Airaksinen has received research grants from The Finnish Foundation for Cardiovascular Research; speaker fees from Bayer, Pfizer, and Boehringer-Ingelheim; and is a member of the advisory boards of Bayer, Pfizer, and Astra-Zeneca. Tuomas Kiviniemi reports personal fees from MSD, Boehringer Ingelheim, Bayer, BMS-Pfizer, and Astra-Zeneca. Other authors have nothing to declare.

Disclaimer

Portions of this manuscript has been presented in the form of an abstract at the 2022 annual meeting of the Finnish Cardiac Society. Simultaneously, the abstract was published in the respective journal Sydänääni.

Data availability statement

The data underlying this article are available upon reasonable request from the corresponding author. Authors AR and TK had full access to the study data and take responsibility for its integrity and data analysis.

Additional information

Funding

This work was supported by grants from the Finnish Medical Foundation, Finnish Foundation for Cardiovascular Research, State Research Funding by the Hospital District of Southwest Finland, and Ida Montin Foundation. The funding sources had no role in the study design and conduct, including collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; or the decision to submit the manuscript for publication.