Original-clinicalClinical predictors and relationship between early and late atrial tachyarrhythmias after pulmonary vein antrum isolation
Introduction
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with a prevalence between 0.9% and 2.5% in the general population and an increasing incidence with age.1, 2 The clinical significance and financial impact of AF management create a need for effective treatment. Antiarrhythmic drugs for prevention of AF recurrences frequently are ineffective and often are associated with adverse and toxic effects that may nullify the possible benefit of sinus rhythm maintenance. In the last 10 years, left atrial catheter ablation aimed at pulmonary vein (PV) isolation and/or elimination of the arrhythmic substrate has been proposed as a definitive cure for this arrhythmia.3 Some investigators have examined the incidence of AF after ablation and found that early arrhythmic recurrences (i.e., within the first 2 weeks to 3 months after the procedure) are common, occurring in as many as 50% of patients.4, 5, 6, 7, 8, 9 However, these recurrences often disappear after the initial period and do not necessarily indicate failure of the procedure over time. It is important to realize that these data derive from small series of patients with relatively short-term follow-up. Furthermore, the factors predictive of both early (EAT) and late atrial tachyarrhythmias (LAT) and their clinical relevance have not been thoroughly investigated.
The aim of the present study was to identify the clinical variables associated with EAT and LAT and to assess the relationship between these arrhythmias in a very large cohort of patients undergoing PV antrum isolation.
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Patient population
Consecutive patients referred to Cleveland Clinic Foundation, Cleveland, Ohio, USA, or Umberto I Hospital, Mestre-Venice, Italy, for treatment of AF by PV antrum isolation between September 2001 and June 2005 were included in the study. On referral, all patient data were prospectively recorded in a computerized database.
All patients selected for PV antrum isolation had a history of symptomatic, drug-resistant paroxysmal, persistent, or permanent AF. Before the ablation procedure, all patients
Patient characteristics
The study enrolled 1,298 patients (1,088 at Cleveland Clinic Foundation and 210 at Umberto I Hospital). The baseline characteristics of these patients are summarized in Table 1. AF was paroxysmal in 699 (54%) patients, persistent in 230 (18%), and permanent in 369 (28%). Hypertension was present in 33% of cases and structural heart disease in 32% of cases. Left atrial diameter was >4 cm in 891 (69%) patients. Mean left ventricular ejection fraction was <40% in 115 (9%) patients.
PV antrum isolation
All four PV
Incidence, predictors, and clinical implications of EAT
Previous studies have examined the incidence of EAT, defined as the recurrence of AF or the development of new-onset left atrial flutter/tachycardia occurring within 2 weeks to 3 months after ablation.4, 5, 6, 7, 8, 9 According to these studies, the incidence of EAT ranges between 35% and 46%.4, 5, 6, 7, 8, 9 In the present study, we found a similar percentage (40%). EAT in our patients occurred more frequently within the first month after ablation, and the incidence progressively decreased
Study limitations
All patients were treated by the same ablation technique; therefore, we cannot exclude the possibility that using different techniques might yield different results. Nevertheless, the data reported in the literature seem to indicate that the ablation technique used does not influence the incidence of EAT, which is reported to be similar among the focal (39%),6 segmental (35%–41%),4, 6, 8 circumferential (46%),7 and antral (40%) approaches. However, considering the differences in long-term
Conclusion
The results of this study confirm that EAT are very frequent and demonstrate that such arrhythmias have an unfavorable prognostic significance in that they are strong predictors of LAT. This is especially true for EAT that occur in the second and third months after ablation. However, because nearly half of patients with EAT will not develop LAT, a conservative strategy is warranted during the first months postablation. Both EAT and LAT are significantly associated with longer duration of AF,
Acknowledgments
We thank Ms. Michelle Williams-Andrews, Dr. Mohamed Kanj, from the Cleveland Clinic Foundation, Dr. Andrea Corrado, and Dr. Michela Madalosso from Umberto I Hospital for contributions in data collection. We also thank Dr. Jennifer E. Cummings and Dr. Mauricio Arruda from the Cleveland Clinic Foundation for reading the manuscript and making several helpful suggestions.
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