Left atrial appendage activity translation in the standard 12-lead ECG

Exploiting intracardiac and surface recording modalities for atrial signal extraction in atrial fibrillation

During atrial fibrillation (AF), atrial activity (AA) on the surface ECG consists of a pattern of quasi-periodic oscillations (f-waves), which are related to the electrical activation of the atrial substrate. However, to date no direct comparison between the extracted f-wave pattern in surface recordings and specific activation sites within the atria has been carried out. In the present study, one reference intracardiac modality consisting of a bipolar electrogram (EGM) recorded from the left atrial appendage (LAA) is exploited for the first time to guide the extraction of LAA electrical activity from standard 12-lead ECG recordings. A periodic component analysis (πCA) technique is employed for this task. The performance of the proposed multimodal extraction technique is compared to that obtained employing a noninvasive, fully blind approach, namely, independent component analysis (ICA). On a database of 31 AF patients, results suggest that the estimation of LAA activity is indeed possible, even though its contribution to the ECG total power is relatively low. Interestingly, ICA seems to provide a slightly better estimation of LAA activation rate, expressed in terms of dominant frequency (DF). On the other hand, the multimodal invasive approach performs better QRST complex suppression and provides AA waveforms with narrower spectra.

Measures of spatiotemporal organization differentiate persistent from long-standing atrial fibrillation

AIMS

This study presents an automatic diagnostic method for the discrimination between persistent and long-standing atrial fibrillation (AF) based on the surface electrocardiogram (ECG).

METHODS AND RESULTS

Standard 12-lead ECG recordings were acquired in 53 patients with either persistent (N= 20) or long-standing AF (N= 33), the latter including both long-standing persistent and permanent AF. A combined frequency analysis of multiple ECG leads followed by the computation of standard complexity measures provided a method for the quantification of spatiotemporal AF organization. All possible pairs of precordial ECG leads were analysed by this method and resulting organization measures were used for automatic classification of persistent and long-standing AF signals. Correct classification rates of 84.9% were obtained, with a predictive value for long-standing AF of 93.1%. Spatiotemporal organization as measured in lateral precordial leads V5 and V6 was shown to be significantly lower during long-standing AF than persistent AF, suggesting that time-related alterations in left atrial electrical activity can be detected in the ECG.

CONCLUSION

Accurate discrimination between persistent and long-standing AF based on standard surface recordings was demonstrated. This information could contribute to optimize the management of sustained AF, permitting appropriate therapeutic decisions and thereby providing substantial clinical cost savings.

Comprehensive risk reduction in patients with atrial fibrillation: emerging diagnostic and therapeutic options--a report from the 3rd Atrial Fibrillation Competence NETwork/European Heart Rhythm Association consensus conference

While management of atrial fibrillation (AF) patients is improved by guideline-conform application of anticoagulant therapy, rate control, rhythm control, and therapy of accompanying heart disease, the morbidity and mortality associated with AF remain unacceptably high. This paper describes the proceedings of the 3rd Atrial Fibrillation NETwork (AFNET)/European Heart Rhythm Association (EHRA) consensus conference that convened over 60 scientists and representatives from industry to jointly discuss emerging therapeutic and diagnostic improvements to achieve better management of AF patients. The paper covers four chapters: (i) risk factors and risk markers for AF; (ii) pathophysiological classification of AF; (iii) relevance of monitored AF duration for AF-related outcomes; and (iv) perspectives and needs for implementing better antithrombotic therapy. Relevant published literature for each section is covered, and suggestions for the improvement of management in each area are put forward. Combined, the propositions formulate a perspective to implement comprehensive management in AF.