**6. Conclusions**

correlation was observed between the P-wave dispersion and its maximum duration. Simi‐ larly, a relevant negative correlation was noticed between the P-wave dispersion and its minimum duration. In another publication, the P-wave dispersion also showed to be a sensitive and specific ECG predictor of paroxysmal lone AF. Furthermore, it also provided a significant correlation with the maximum P-wave duration and a weak, although significant, association with age [47]. On the other hand, Dilaveris et al. [69] and Ciaroni et al. [70] revealed the Pwave dispersion as an independent predictor of the onset of PAF in the hypertensive popula‐ tion. Indeed, this metric was found to be significantly higher in hypertensives with a history of PAF than those without history of arrhythmia. Finally, it is interesting to mention that Koide et al. [71] concluded that the P-wave dispersion was a clinically useful predictor of progression from paroxysmal to persistent AF. In this study, more than 200 patients with a diagnosis of

Recent works have shown that the beat-to-beat analysis of the P-wave can reveal clinically relevant information about the altered atrial conduction preceding the onset of PAF as any signal-averaging approach. Furthermore, the main advantage of the individualized single Pwave analysis is the possibility of being easily used in a routine clinical environment, because it can be developed from daily recordings such as short surface ECGs or long-term Holter signals. Hence, this kind of P-wave analysis could be considered as the most practical way to

It is highly relevant to highlight that in recent years, the analysis of PAC has been improved to reach a clinically significant result. Thus, it has been able to identify the imminent onset of PAF with an accuracy very near to 100%. However, it has also been noticed that the frequency of these ectopics is considerably decreased as the distance to the episode onset increases [53, 52]. Therefore, it could be elucidated that this approach is only feasible just before the ar‐ rhythmia starts [31], which is too late for the application of an efficient prophylactic therapy [72, 73]. In contrast, the analysis of the P-wave variability over time has proven to be able to operate with notably more anticipation in the prediction of PAF onset. Indeed, the time evolution of all the studied P-wave features has revealed an interesting ability to predict

Moreover, it is worth noting that all the analyzed P-wave features show a time course variation as a function of how far is the onset of PAF. Indeed, all the analyzed features provided an increased variability trend as the PAF onset approximates. This outcome is in strong agreement with the atrial electrophysiological alterations noticed in clinical studies before the onset of spontaneous or induced AF. To this respect, a common atrial alteration in patients prone to PAF is the presence of decreased and different cell refractory periods in various atrial regions. Sometimes, these site-specific conduction delays can be increased by intracellular or intercel‐ lular factors, such as connections, ion channels, or regulatory proteins [9, 74]. This heteroge‐ neity may provoke irregular atrial conduction which could result in overlapped atrial

PAF were followed for more than 60 months.

perform exploratory investigations about the onset of PAF.

successfully the onset of PAF with, at least, one hour in advance.

**5. Discussion**

46 Abnormal Heart Rhythms

This study aimed to review the most recent advances in the beat-to-beat P-wave analysis to stratify the risk of suffering PAF and how long in advance its onset can be predicted. In recent years, considerable progress has been reached in both purposes, this kind of analysis being able to provide, in an easy and noninvasive way, clinically useful information related to the time progression and regional differences of the atrial conduction alterations preceding the onset of PAF. The use of this information may be helpful in routine clinical practice to improve the diagnostic and therapeutic management of atrial fibrillation.
