Atrial fibrillatory rate in the clinical context: natural course and prediction of intervention outcome (original) (raw)
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Europace, 2006
Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Neither the natural history of AF nor its response to therapy is sufficiently predictable by clinical and echocardiographic parameters. The purpose of this article is to describe technical aspects of novel electrocardiogram (ECG) analysis techniques and to present research and clinical applications of these methods for characterization of both the fibrillatory process and the ventricular response during AF. Atrial fibrillatory frequency (or rate) can reliably be assessed from the surface ECG using digital signal processing (extraction of atrial signals and spectral analysis). This measurement shows large inter-individual variability and correlates well with intra-atrial cycle length, a parameter which appears to have primary importance in AF maintenance and response to therapy. AF with a low fibrillatory rate is more likely to terminate spontaneously and responds better to antiarrhythmic drugs or cardioversion, whereas high-rate AF is more often persistent and refractory to therapy. Ventricular responses during AF can be characterized by a variety of methods, which include analysis of heart rate variability, RR-interval histograms, Lorenz plots, and non-linear dynamics. These methods have all shown a certain degree of usefulness, either in scientific explorations of atrioventricular (AV) nodal function or in selected clinical questions such as predicting response to drugs, cardioversion, or AV nodal modification. The role of the autonomic nervous system for AF sustenance and termination, as well as for ventricular rate responses, can be explored by different ECG analysis methods. In conclusion, non-invasive characterization of atrial fibrillatory activity and ventricular response can be performed from the surface ECG in AF patients. Different signal processing techniques have been suggested for identification of underlying AF pathomechanisms and prediction of therapy efficacy.
Cardiovascular Research, 1998
Ž. Objectives: Atrial fibrillation AF in man has previously been shown to include a wide variety of atrial activity. Assessment of the characteristics of this arrhythmia with a commonly applicable tool may therefore be important in the choice and evaluation of different therapeutic strategies. As the AF cycle length has been shown to correlate locally with atrial refractoriness and globally with the degree of atrial organization, with, in general, shorter cycle length during apparently random AF compared to more organized AF, we have Ž. developed a new method for non-invasive assessment of the AF cycle length using the surface and the esophagus ESO ECG. Methods and Results: From the frequency spectrum of the residual ECG, created by suppression of the QRST complexes, the dominant atrial Ž. cycle length DACL was derived. By comparison with multiple intracardiac simultaneously acquired right and left AF cycle lengths in patients with paroxysmal AF, we found that the DACL in lead V1, ranging from 130 to 185 ms, well represented a spatial average of the right AF cycle lengths, whereas the DACL in the ESO ECG, ranging from 140 to 185 ms, reflected both the right and the left AF cycle length, where the influence from each structure depended on the atrial anatomy of the individual, as determined by MRI. In patients with chronic AF, the method was capable of following changes in the AF cycle length due to administration of D,L-sotalol and 5 min of ECG recording was sufficient for the DACL to be reproducible. Conclusions: We conclude that this new non-invasive method, named Ž. 'Frequency Analysis of Fibrillatory ECG' FAF-ECG , is capable of assessing both the magnitude and the dynamics of the atrial fibrillation cycle length in man. q 1998 Elsevier Science B.V.
Cardiovascular Research, 1999
Objective: Automatic analysis of the frequency content of the fibrillatory baseline on the surface ECG accurately reflects the average rate of atrial fibrillation (AF). This frequency measurement correlates with the behavior of AF and predicts the response to administration of ibutilide, a new antiarrhythmic drug. Neither the temporal pattern of fibrillatory frequency in spontaneous paroxysmal or persistent AF, nor its response to chronic antiarrhythmic medication has been studied so far. Methods and Results: Holter ECG recordings were made in 20 patients during AF. One minute ECG segments were selected for analysis. The frequency content of the fibrillatory baseline was then quantified using digital signal processing. After high-pass filtering, the QRST complexes were subtracted using a template matching algorithm. The resulting fibrillatory baseline signal was subjected to Fourier transformation, displayed as a frequency power spectrum and the peak frequency (f) was determined. In 11 patients (7 male, 4 female, age 62610 years) 31 paroxysmal AF episodes were analyzed. Duration ranged from 1 min to 665 min (1156175 min). Initial mean peak f measured 5.160.7 Hz (range 3.9 to 6.9 Hz). There was a positive correlation between f and AF duration (R50.53, p50.002). AF of less than 15 min duration (n513) showed a lower f (4.860.6 Hz) when compared with longer lasting episodes (n518, 5.360.7 Hz, p50.03). In short AF episodes f was constant, whereas in longer-lasting episodes f increased to 5.860.5 Hz ( p,0.001) within 5 min. In 9 patients (9 male, age 5868 years) with persistent AF oral antiarrhythmic drugs (amiodarone n55, sotalol n53, flecainide n51) were given prior to electrical cardioversion for prophylaxis of AF recurrence. Frequency measurements were obtained at baseline and 3 to 5 days after initiation of drug administration. At baseline mean f measured 6.960.4 Hz. Frequency was reduced by antiarrhythmic drugs to 5.860.4 Hz ( p,0.001). Conclusions: (1) The duration of paroxysmal AF episodes can be predicted using spectral analysis of ECG recordings of AF episodes. (2) An increase in fibrillatory frequency is associated with AF persistence. (3) This technique can be used to monitor the response to antiarrhythmic medication.
Atrial fibrillation: current concepts
International journal of health sciences, 2008
Atrial fibrillation (AF) is the most common arrhythmia which is a focus of newer modalities of treatment, especially ablation techniques using innovative mapping techniques. Its incidence and prevalence increases with aging and presence of structural heart disease, the latter being less than 1% prior to age 40, rising to 8% at age 80. Concomittant morbidity and excessive mortality is related to the increased incidence of stroke and congestive heart failure. Once developed in a clinical setting, it tends to either persist or recur. Pharmacotherapy to control rate or rhythm tends to have a secondary failure, and therefore there is a growing interest in ablation techniques. The use of anticoagulation is also associated with bleeding risks and therefore the management of AF needs to be individualized in every patient. In this article, we shall be discussing clinical types of AF, etiology, the mechanism of genesis, symptoms, complications and approach to treatment in various clinical sce...
Validation of surface atrial fibrillation organization indicators through invasive recordings
2011
Studies related to atrial fibrillation (AF) have shown that surface lead V1 reflects mainly the dominant atrial frequency (DAF) of the right atrium (RA), which has been widely used to analyze this arrhythmia. AF organization and fibrillatory (f ) waves amplitude are two recently proposed noninvasive AF markers, which have not been yet validated with invasive recordings. In this work, these two non-invasive metrics have been compared with similar measures recorded from two unipolar atrial electrograms (AEGs). Results obtained from 38 patients showed statistically significant correlations between the values measured from surface and invasive recordings, thus corroborating the usefulness of the aforesaid markers in the non-invasive study of AF. Precisely, for AF organization, the correlation coefficients between surface and both AEGs were R = 0.926 (p < 0.001) and R = 0.932 (p < 0.001), respectively. For f waves amplitude, slightly lower significant relationships were noticed, the correlation coefficients being R = 0.765 (p < 0.001) and R = 0.842 (p < 0.001), respectively. These outcomes together with interesting linear relationships found among the parameters, suggest that AF organization and f waves amplitude can characterize non-invasively the epicardial activity related to AF.
Current Approaches for the Prediction of Atrial Fibrillation Development and Progression
European Journal of Molecular & Clinical Medicine, 2021
Atrial fibrillation (AF) is the most common arrhythmia inclinical practice. Several conventional and novel predictorsof AF development and progression (from paroxysmalto persistent and permanent types) have been reported.The most important predictor of AF progression ispossibly the arrhythmia itself. The electrical, mechanicaland structural remodeling determines the perpetuationof AF and the progression from paroxysmal to persistentand permanent forms. Common clinical scores such asthe hypertension, age ≥ 75 years, transient ischemicattack or stroke, chronic obstructive pulmonary disease,and heart failure and the congestive heart failure,hypertension, age ≥ 75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74years, sex category scores as well as biomarkers relatedto inflammation may also add important information onthis topic. There is now increasing evidence that even inpatients with so-called lone or idiopathic AF, the arrhythmiais the manifestation of a structural atrial disease whichhas recently been defined and described as fibrotic atrialcardiomyopathy. Fibrosis results from a broad rangeof factors related to AF inducing pathologies such ascell stretch, neurohumoral activation, and oxidativestress. The extent of fibrosis as detected either by lategadolinium enhancementmagnetic resonance imaging or electroanatomic voltage mapping may guide thetherapeutic approach based on the arrhythmia substrate.The knowledge of these risk factors may not only delayarrhythmia progression, but also reduce the arrhythmiaburden in patients with first detected AF. The presentreview highlights on the conventional and novel risk