Paced P-wave duration as a significant predictor for atrial high-rate episodes in patients with cardiac implantable electronic devices.

BACKGROUND: Atrial pacing (AP) can unmask or aggravate a preexisting interatrial block (IAB). The aim of our study was to determine whether AP is associated with the development of atrial high-rate episodes (AHRE) during follow-up. METHODS: Patients with dual-chamber cardiac implantable electronic devices (CIEDs), no previous documented atrial fibrillation, and with a 6-month minimum follow-up were included. In all patients, sinus and paced P-wave duration were measured. AHRE was defined as an episode of atrial rate ≥225 bpm with a minimum duration of 5 min, excluding those documented during the first 3 months after implantation. RESULTS: A total of 220 patients were included (75 ± 10 years, 61% male). After a mean follow-up of 59 ± 25 months, 46% of patients presented AHRE. Mean paced P-wave duration was significantly longer than the sinus P-wave duration (154 ± 27 vs. 115 ± 18 ms; p < .001). Sinus and paced P-waves were significantly longer in those who developed AHRE (sinus: 119 ± 20 vs. 112 ± 16; p = .006; paced: 161 ± 29 vs. 148 ± 23; p < .001). A paced P-wave ≥160 ms was the best predictor of AHRE, especially those lasting >24 h (odds ratio [OR] 4.2 [95% confidence interval (CI)] [1.6-11.4]; p = .004). CONCLUSIONS: AP significantly prolongs P-wave duration and is associated with further development of AHRE. A paced P-wave ≥160 ms is a strong predictor of AHRE and should be taken into consideration as a new definition of IAB in the presence of AP.

Comparison of Outcomes of Catheter Ablation in Asymptomatic Versus Symptomatic Preexcitation to Guidelines and Beyond.

Management of asymptomatic subjects with preexcitation remains controversial. Our objective was to analyze the reasons an electrophysiological study (EPS) was performed in an asymptomatic population referred for the procedure, and compare the results of catheter ablation between asymptomatic and symptomatic patients. Patients ≥18 years of age with preexcitation referred for an EPS and ablation were grouped as either symptomatic or asymptomatic. We analyzed in both subsets for (1) reasons for the procedure, (2) EPS results (anterograde effective refractory period of the accessory pathway, tachycardia/atrial fibrillation inducibility, anatomical localization), (3) success of the procedure, and (4) incidence of complications. We included 175 patients, 121 of which were symptomatic (39 ± 16 years) and 54 were asymptomatic (35 ± 14 years, p = NS not significant). The most frequent symptoms were palpitations (87%) and syncope (7%). EPS was performed in 44 of 54 asymptomatic patients mainly because of involvement in sports (60%) or high-risk employment (14%). Anterograde effective refractory period was significantly longer in asymptomatic patients (314 ± 55 milliseconds) than in symptomatic patients (278 ± 46 milliseconds; p <0.001). Orthodromic tachycardia inducibility was significantly higher in symptomatic than in asymptomatic patients (69% and 27%, respectively; p <0.001). A total of 170 accessory pathways (49% left free wall, 12% right free wall, 39% septal) were observed without significant differences in the anatomical location between groups. Catheter ablation was attempted in all patients, succeeding in 98% of symptomatic and 95% of asymptomatic patients, without major complications in either group. In conclusion, the reasons for invasive evaluation of asymptomatic patients with preexcitation may be outside the scope of current guidelines. Catheter ablation produces excellent results without major complications.