Evaluation Of Left Atrial Dyssynchrony Time And P Wave Indices To Predict Atrial Fibrillation Recurrences Post Pulmonary Vein Isolation In Paroxysmal And Persistent Atrial Fibrillation Patients

Background:Atrial fibrillation (AF) is defined as a cardiac arrhythmia with absolutely irregular RR and no distinct P waves on the surface ECG. AF has several clinical types according to the presentation and duration of the arrhythmia. Paroxysmal AF is self-terminating, usually up to7days. Persistent AF is present when an AF episode either lasts longer than7days or requires termination by cardioversion, either with drugs or by direct current cardioversion.Prediction of atrial fibrillation, controlling its risk factor and management of Af are having a special concern and medical priority. Atrial remodeling which is the main substrate of AF divides mainly into structural and electrical remodeling and is represented clinically by enlargement of the atria and slow atrial conduction velocity. Remodeling of the left atrium (LA) can be evaluated by several methods by using; electrocardiograph (ECG), echocard-iography, tissue Doppler imaging (TDI), or invasively by measuring cardiac intervals through using intracardiac electrodes. TDI allows the measurement of peak systolic velocity of different regions of the myocardium. Moreover, precise timing of peak systolic velocity is possible when the TDI tracings are related to the electrical activity (P wave and QRS complex). Integration of this information allows accurate assessment of electromechanical coupling, and evaluation of inter-and intra myocardial walls dyssynchrony.Radiofrequency catheter ablation (RFCA) of AF is effective in70-80%of the cases but recurrences are frequent. The natural history of AF is characterized by self-perpetuating mechanisms, rate-induced electrophysiogical changes and structural remodeling that involve the atrial myocardium.Objectives:In our study we evaluate left atrial dyssynchrony time and P wave indices to predict atrial fibrillation recurrences post pulmonary vein isolation in paroxysmal and persistent atrial fibrillation patients.Methods:75consecutive patients (57.1±7.8years,57males, and18females) with symptomatic drug-refractory paroxysmal and persistent AF, undergoing PVI were enrolled in our study. PA peak time by tissue Doppler imaging (PA peak-TDI) is defined as the time measured from the start of P wave in lead II to the peak of A wave on the tissue Doppler tracing. Left atrial dyssynchrony was measured by subtracting the PA peak-TDI time measured at the mid inter atrial septum from the PA peak-TDI time measured at the left atrial mid lateral free wall,(LA dyssynchrony=PApeak TDI lateral-PApeak TDI septal). A12-lead electrocardiogram was used to measure P wave duration in lead II, P wave terminal force (PWTF) in lead V1and P wave dispersion.Results:During a mean follow-up of12±3months, recurrences occurred in24out of75patients. Patients with recurrence of atrial fibrillation had larger left atrial dyssynchrony time (26.9±2.2ms vs.23.3±2.5ms, P<0.001). Left atrial dyssynchrony time of25ms has the best combined sensitivity and specificity (83%and67%respectively) along with positive predictive value64.5%and negative predictive value90.9%. LA dyssynchrony time>25ms was found to discriminate patients prone to AF recurrences over time. Multivariate regression analysis showed that left atrial dyssynchrony time (HR per ms:2.05, P<0.001) was identified as independent predictor of AF recurrence. The patients that presented AF recurrence had longer mean P wave duration (40±1.6ms vs.36.5±3.4ms, P<0.001). P wave duration of≥125ms has66%sensitivity,99%specificity, positive predictive value (PPV)80%and negative predictive value (NPV)85.4%, P wave dispersion of≥40ms has87%sensitivity,69%specificity, PPV56.7%and NPV92.1%. Nineteen out of26(72.7%) patients with P wave terminal force≤-0.04mmsecond showed recurrence of AF when compared with5/49(9%) patients with P wave terminal force>-0.04mmsecond (P<0.001). Multivariate cox regression analysis showed that P wave indices were not independent from left atrial size and age.Conclusion:Left atrial dyssynchrony time is good clinical predictor of recurrence of AF after PVI in patients with paroxysmal and persistent AF. P wave duration≥125ms, P wave dispersion≥40ms and PWTF in V1≤-0.04mmsec are good clinical predictors of AF recurrences post PVI in patients with paroxysmal and persistent atrial fibrillation. However P wave indices were not dependent from age and atrial size.