Coarse fibrillatory waves in atrial fibrillation predict success of electrical cardioversion

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

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.

Diastolic Dysfunction and Atrial Fibrillation: Recognition, Interplay, and Management

Diastolic dysfunction occurs when the left ventricle loses its ability to relax normally, impairing ventricular filling during diastole. This most commonly occurs as a pathological sequela of left ventricular hypertrophy and remodeling due to chronic hypertension and/or age-related sclerotic changes of the aortic valve. This can subsequently deteriorate to diastolic heart failure or heart failure with preserved ejection fraction. There is a substantive interplay between atrial fibrillation and diastolic dysfunction, as atrial fibrillation can cause, exacerbate, or be a direct result of diastolic dysfunction and vice versa. In this review, we first independently define diastolic heart failure and atrial fibrillation while discussing the diagnostic guidelines, which encompass various modalities such as medical history, electrocardiography, echocardiography, and laboratory tests. We subsequently examine their interplay and pathophysiological links drawing on recent evidence in the literature. Finally, we discuss management approaches, including pharmacological interventions targeting rate and rhythm control, diuretics, and addressing comorbidities.

Predictors of long-term outcomes in patients with persistent atrial fibrillation undergoing electrical cardioversion

Introduction

Cardioversion for atrial fibrillation (AF) is routinely implemented in daily practice; however, it can be associated with the development of recurrent AF. In this study we aimed to evaluate the predictors of AF recurrence after electrical cardioversion, and to compare the outcomes of patients with or without AF recurrence during follow-up.

Methods

Patients with persistent AF were enrolled from March 2015 to September 2018. Patients with recurrent AF within 6 months after the index cardioversion were considered as AF recurrence (AFR) group, and those with normal sinus rhythm were defined as normal sinus rhythm (NSR) group. Thereafter, all patients were followed up for the incidence of adverse events, including death, requiring dialysis, coronary artery intervention/surgeries, cerebrovascular events, heart failure, and recurrent AF beyond 6 months.

Results

Of 129 patients, 11 patients had failed cardioversion and 7 patients lost to follow-up. So, 34 and 77 patients were categorized as the NSR and the AFR groups. During a median follow-up time of 54 (46-75) months, there was a trend for a higher incidence of major adverse events in the AFR group compared to the NSR group (P=0.063). Lower body mass index (odds ratio [OR] 0.885, 95% confidence interval [CI] 0.794-0.986, P=0.027) and coarse AF before the index cardioversion (OR 3.846, 95% CI 1.189-12.443, P=0.025) were the independent predictors of recurrent AF.

Conclusion

In patients with persistent AF undergoing cardioversion, the presence of coarse AF and the lower values of body mass index were found to be associated with the AF recurrence.

F Wave Amplitude as a Predictor of Thromboembolism and Success of Electrical Cardioversion in Patients with Persistent Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is classified according to the amplitude of fibrillatory waves (f) into fine waves (fAF) and coarse waves (cAF).

OBJECTIVES

To correlate the amplitude of f waves with clinical, laboratory, electrocardiographic, and echocardiographic variables that indicate a high risk of thromboembolism and to assess their impact on the success of electrical cardioversion (ECV).

METHODS

Retrospective, observational study that included 57 patients with persistent non-valvular AF who underwent ECV. The maximum amplitude of f waves was measured in lead V1. cAF was defined when f ≥ 1.0mm and fAF when f < 1.0mm. The findings were correlated with the indicated variables. Values of p < 0.05 were considered statistically significant.

RESULTS

cAF (n = 35) was associated with greater success in ECV (94.3% vs. 72.7%, p = 0.036) even after adjusting for variables such as age and BMI (p = 0.026, OR = 11.8). Patients with fAF (n = 22) required more shocks and more energy to revert to sinus rhythm (p = 0.019 and p = 0.027, respectively). There was no significant association between f-wave amplitude and clinical, echocardiographic, and laboratory parameters.

CONCLUSIONS

The amplitude of f wave was not associated with echocardiographic, clinical and laboratory parameters that indicate a high risk of thromboembolism. cAF was associated with a higher chance of success reverting to sinus rhythm employing ECV. A greater number of shocks and energy were required for reversion to sinus rhythm in patients with fAF.

Multi-scale Entropy Evaluates the Proarrhythmic Condition of Persistent Atrial Fibrillation Patients Predicting Early Failure of Electrical Cardioversion

Atrial fibrillation (AF) is nowadays the most common cardiac arrhythmia, being associated with an increase in cardiovascular mortality and morbidity. When AF lasts for more than seven days, it is classified as persistent AF and external interventions are required for its termination. A well-established alternative for that purpose is electrical cardioversion (ECV). While ECV is able to initially restore sinus rhythm (SR) in more than 90% of patients, rates of AF recurrence as high as 20-30% have been found after only a few weeks of follow-up. Hence, new methods for evaluating the proarrhythmic condition of a patient before the intervention can serve as efficient predictors about the high risk of early failure of ECV, thus facilitating optimal management of AF patients. Among the wide variety of predictors that have been proposed to date, those based on estimating organization of the fibrillatory (f-) waves from the surface electrocardiogram (ECG) have reported very promising results. However, the existing methods are based on traditional entropy measures, which only assess a single time scale and often are unable to fully characterize the dynamics generated by highly complex systems, such as the heart during AF. The present work then explores whether a multi-scale entropy (MSE) analysis of the f-waves may provide early prediction of AF recurrence after ECV. In addition to the common MSE, two improved versions have also been analyzed, composite MSE (CMSE) and refined MSE (RMSE). When analyzing 70 patients under ECV, of which 31 maintained SR and 39 relapsed to AF after a four week follow-up, the three methods provided similar performance. However, RMSE reported a slightly better discriminant ability of 86%, thus improving the other multi-scale-based outcomes by 3-9% and other previously proposed predictors of ECV by 15-30%. This outcome suggests that investigation of dynamics at large time scales yields novel insights about the underlying complex processes generating f-waves, which could provide individual proarrhythmic condition estimation, thus improving preoperative predictions of ECV early failure.

Coarse fibrillatory waves in atrial fibrillation predict success of electrical cardioversion

BACKGROUND

To determine whether the presence of "coarse" fibrillatory waves (Fw) seen on surface ECGs of patients with persistent atrial fibrillation (AF) predict maintenance of sinus rhythm (SR) at 6 weeks after electrical cardioversion (ECV).

METHODS

Preprocedure ECGs from 94 consecutive patients with persistent AF scheduled to undergo ECV at a single centre were classified as having coarse Fw (≥0.1 mV) or fine Fw (<0.1 mV) in leads II or V₁ . The primary outcome was ECG rhythm at 6-week clinical follow-up. Demographic and echocardiographic data were also collected.

RESULTS

Thirty-two patient ECGs (34%) had coarse Fw on baseline ECG in either or both leads II or V₁ with no significant differences in baseline demographics compared to those patients with fine Fw. At 6 weeks post-ECV, in the coarse Fw group 72% of patients maintained SR vs. 42% in the fine Fw group (χ² , p = .006) with the odds ratio (OR) of maintaining SR at 6 weeks in the presence of coarse Fw being 3.5 (95% CI: 1.4-8.9, p = .007). Across the overall study population, there were no other significant univariate predictors of SR at 6 weeks post-ECV.

CONCLUSION

Classifying persistent AF using the maximal Fw amplitude on a surface ECG is a simple and reproducible method of predicting medium-term success of ECV, independent of traditional risk factors.