Duración de la onda P en las 12 derivaciones del electrocardiograma y su relación con el tiempo de conducción interauricular en pacientes con taquicardias paroxísticas supraventriculares / P wave duration in the 12 leads of the electrocardiogram and its relationship with interatrial conduction time in patients with paroxysmal supraventricular tachycardias

RESUMEN Introducción: Existen algunos estudios que relacionan parámetros de la onda P con diferentes tiempos de conducción auricular, pero no se han realizado teniendo en cuenta a cada derivación del electrocardiograma. Objetivo: Determinar la duración de la onda P (Pdur) en las 12 derivaciones y relacionarlas con el tiempo de conducción interauricular. Método: Estudio de corte transversal en 153 pacientes adultos con diagnóstico confirmado de taquicardia por reentrada intranodal (TRIN) o vías accesorias mediante estudio electrofisiológico invasivo. Resultados: Al comparar la Pdur entre sustratos arrítmicos por cada derivación, no existieron diferencias significativas, excepto en V6. En las derivaciones DII, DIII, aVR, aVF, V1 y de V3-V6 la Pdur se correlacionó con el tiempo de conducción interauricular en ambos sustratos arrítmicos. En el análisis multivariado, la Pdur constituyó un predictor independiente de tiempos de conducción interauricular ≥ 95 percentil, en las derivaciones de cara inferior y en V3, V5 y V6. Se observaron altos valores del área bajo la curva de la Característica Operativa del Receptor en las derivaciones DII (0,950; p<0,001), DIII (0,850; p<0,001) y V5 (0,891; p<0,001). Conclusiones: No existen diferencias por derivación en la Pdur al comparar casos con TRIN y vías accesorias, excepto en V6. La mayoría de las derivaciones se correlacionaron con el tiempo de conducción interauricular. La Pdur fue un predictor independiente de tiempos de conducción interauricular ≥ 95 percentil. La derivación DII presenta la mayor capacidad discriminativa para encontrar valores prolongados del tiempo de conducción interauricular.

ABSTRACT Introduction: Although some studies relate P wave parameters to different atrial conduction times, they do not consider each electrocardiogram lead separately. Objective: To determine the duration of P wave (Pdur) in the 12 leads of the electrocardiogram and relate it to the interatrial conduction time. Method: We conducted a cross-sectional study in 153 adult patients with confirmed diagnosis of atrioventricular nodal reentry tachycardia (AVNRT) or accessory pathways by invasive electrophysiological study. Results: When comparing the Pdur between arrhythmic substrates by each lead, no significant differences were found, except for V6. In leads II, III, aVR, aVF, V1 and V3-V6, Pdur was correlated with the interatrial conduction time in both arrhythmic substrates. In our multivariate analysis, the Pdur was an independent predictor of interatrial conduction times ≥ 95 percentile in inferior wall leads and in V3, V5 and V6. High values of the area under the receiver operating characteristic curve were observed in II (0.950; p<0.001), III (0.850; p<0.001) and V5 (0.891; p<0.001) leads. Conclusions: The Pdur showed no difference by leads when comparing cases with AVNRT and accessory pathways, except for V6. Most of the leads were correlated with the interatrial conduction time; Pdur was an independent predictor of interatrial conduction times ≥ 95 percentile. Lead II has the greatest discriminatory ability to find prolonged values of interatrial conduction time.

Interatrial conduction times in paroxysmal atrial fibrillation patients with normal atrial volume and their correlation with areas of local prolonged bipolar electrograms.

BACKGROUND: Recent evidence has shown that the presence of abnormal substrate can be demonstrated also among patients with "lone" AF. OBJECTIVES: Interatrial conduction slowing is likely to characterize patients with paroxysmal atrial fibrillation (AF) and it could be correlated to the left atrium area of prolonged local bipolar endocardial electrograms. METHODS: P-wave duration (PWD), amplified PWD and endocavitary interatrial conduction time (IACT), were analyzed in 60 patients; 30 undergoing de novo ablation for paroxysmal AF with normal atrial volumes and without any other cardiac disease and 30 of similar age undergoing electrophysiological study for atrioventricular nodal reentrant tachycardia or atrioventricular re- entrant tachycardia. In patients with AF, voltage maps and local bipolar electrograms (LBE) duration map were evaluated. RESULTS: Although PWD was <120 ms in 28 patients with AF and in 29 controls, patients with AF exhibited longer PWD, amplified-PWD and IACT. Although low-voltage areas (<0.5 mV) were not found in the study population, 28 of them demonstrated areas with LBE longer than 60 ms. These LBE were found mainly in the roof of the left atrium and their extension was correlated to IACT (R = 0.51, p = 0.004). IACT >135.5 ms identified the subjects who experienced AF with 90% sensitivity and 97% specificity. CONCLUSION: A subclinical interatrial conduction disturbance is demonstrable in subjects with paroxysmal AF and normal left atrial volume. IACT has a good correlation to the areas of abnormal LBE in the left atrium. IACT >135 ms identified subjects who have experienced AF.

Impact of a prolonged interatrial conduction time for predicting the recurrence of atrial fibrillation after circumferential pulmonary vein isolation of persistent atrial fibrillation.

There are some cases that are difficult to cure with only circumferential pulmonary vein isolation (CPVI) of persistent atrial fibrillation (PerAF). Recently, prolonged interatrial conduction times (IACTs), which seem to be associated with progressive remodeled atria, have been reported as a predictor of new-onset AF. This study aimed to investigate the prognostic value of a prolonged IACT for predicting AF recurrences after CPVI of PerAF. One hundred thirteen patients who underwent CPVI without an empirical substrate modification of PerAF were retrospectively analyzed. The IACT was defined as the interval from the earliest P-wave onset on the ECG to the latest activation in the coronary sinus and was measured after achieving the CPVI and conversion to sinus rhythm. During a mean 22.7-month follow-up after the initial procedure, 56 patients (50%) had AF recurrences. Patients with AF recurrence had a longer IACT than those without AF recurrence (p < 0.001). The best discriminative cut-off value for the IACT was 123 ms (sensitivity 53%, specificity 85%). In a Cox multivariate analysis, a prolonged IACT of ≥ 123 ms was the only independent predictor (hazard ratio: 2.38; 95% confidence interval: 1.36-4.16, p = 0.002) of being associated with the incidence of an AF recurrence. Even after multiple CPVI procedures, patients with an IACT ≥ 123 ms had a higher AF recurrence rate than those with an IACT < 123 ms (p = 0.002). In conclusion, a prolonged IACT of ≥ 123 ms may be a useful marker for predicting AF recurrences after both initial and multiple CPVI procedures for PerAF.

Interatrial Conduction Time Can Predict New-Onset Atrial Fibrillation After Radiofrequency Ablation of Isolated, Typical Atrial Flutter.

INTRODUCTION: Many patients with successful atrial flutter (AFL) ablation will develop atrial fibrillation (AF) during follow-up. This study aimed to determine whether prolonged interatrial conduction time (IACT) is associated with risk for new-onset AF after ablation of isolated, typical AFL. METHODS: Participants were 80 consecutive patients who underwent successful radiofrequency ablation of isolated, typical AFL from 2004 to 2012. Patients with any history of AF prior to AFL ablation were excluded. IACT was defined as the interval from the earliest onset of the P-wave on the ECG to the latest activation in the coronary sinus catheter during sinus rhythm measured after AFL ablation. New-onset AF was identified from 12-lead ECGs, 24-hour ambulatory monitoring, and device interrogations. RESULTS: During a mean follow-up of 4.1 ± 2.5 years after successful AFL ablation, 22 patients (27.5%) developed new-onset AF. Cox regression multivariate analysis demonstrated that IACT was the independent predictor of new-onset AF after AFL ablation (hazard ratio: 1.03; 95% confidence interval: 1.00-1.06; P = 0.02). IACT was accurate in predicting new-onset AF (AUC = 0.70). The optimal cut-off point of IACT for predicting new-onset AF was 120 milliseconds (sensitivity 47.6%, specificity 89.8%). Kaplan-Meier curves showed that new-onset AF after AFL ablation was significantly higher in patients with IACT ≥120 milliseconds than in patients with IACT< 120 milliseconds (P = 0.0016). CONCLUSION: Prolonged IACT predicted new-onset AF after ablation of isolated AFL. This finding may contribute to guiding decisions regarding the maintenance of anticoagulation after AFL ablation.

Interatrial conduction time and incident atrial fibrillation: a prospective cohort study.

BACKGROUND: Atrial electrical conduction properties have been implicated in atrial fibrillation (AF) pathogenesis. OBJECTIVE: The purpose of this study was to prospectively assess the potential association of interatrial conduction time (IACT) with incident AF. METHODS: The study included persons referred for invasive electrophysiologic study (EPS), aged ≥50 years, without AF history or valvular disease. IACT was defined as the interval between the high right atrium electrogram and the distal coronary sinus atrial electrogram. RESULTS: Six hundred twelve subjects were included (median follow-up 43 months, interquartile range 40-47). AF incidence was 21.7 cases per 1000 person-years. IACT was a significant predictor of AF with a c-statistic of 0.770 (95% confidence interval 0.702-0.838). In time-dependent analysis, IACT was a significant stratifier of AF risk (log-rank 28.0, P <.001). The corresponding incidences of AF in each tertile of IACT were 3, 17, and 46 per 1000 person-years, respectively (all differences between tertiles were significant). IACT remained significant in multivariable Cox regression analysis, after adjustment for age, sex, hypertension, and left atrial diameter, with each millisecond of prolonged IACT corresponding to 7% (95% confidence interval 2%-12%) higher adjusted risk of incident AF. CONCLUSION: IACT is independently associated with incident AF. The invasive nature of the measurement is a limitation for its use as a clinical risk stratifier (although it could be used in patients referred for EPS), but these results are of interest in themselves because they suggest a strong pathophysiologic connection between atrial conduction times and substrate alterations ultimately leading to AF.