Evaluation of time course and predicting factors of progression of paroxysmal or persistent atrial fibrillation to permanent atrial fibrillation.

BACKGROUND: To evaluate time course and predictors of progression of paroxysmal or persistent atrial fibrillation (AF) to permanent AF. METHODS AND RESULTS: We included 460 patients referred for paroxysmal (n = 337) or persistent (n = 123) AF between 1994 and 2012. Mean follow-up was 13.2 ± 6.5 years. AF progression rate was 3.7% per year, 19.7% at 5 years, and 38.1% at 10 years. Lone AF was diagnosed in 217 patients (47%). Predictors of permanent AF were: age, persistent AF, left atrial (LA) size, left ventricular-fractional shortening (LV-FS), lack of antiarrhythmic (AA) drugs, VVI pacing (P < 0.001 for all), and valvular disease (P < 0.02). Independent predictors were age (P < 0.001), persistent AF (P < 0.001), LA diameter (P < 0.005), lack of AA drugs (P < 0.005), and VVI pacing (P < 0.01). When adjusted at means of covariates, persistent AF and age >75 years remained highly significant (P < 0.01). LA dimension >50 mm was highly significant at univariate model (P < 0.001) but to a lesser extent when adjusted (P < 0.05). In patients with paroxysmal AF-with age <75 years-on AA drugs, progression rate to permanent AF was 6.5% at 5 years and 23.7% at 10 years. Among four predictors (age, LA size, LV-FS, and VVI pacing), only age (P < 0.01) and LA size (P < 0.005) remained independently significant, but LA size was not significant when adjusted. CONCLUSIONS: Progression to permanent AF is a slow process. Aging, LA size, VVI pacing, lack of AA therapy, and a persistent form of AF independently increased the progression to permanent AF.

Optimized post-operative surveillance of permanent pacemakers by home monitoring: the OEDIPE trial.

AIMS: The OEDIPE trial examined the safety and efficacy of an abbreviated hospitalization after implantation or replacement of dual-chamber pacemakers (PM) using a telecardiology-based ambulatory surveillance programme. METHODS AND RESULTS: Patients were randomly assigned to (i) an active group, discharged from the hospital 24 h after a first PM implant or 4-6 h after replacement, and followed for 4 weeks with Home-Monitoring (HM), or (ii) a control group followed for 4 weeks according to usual medical practices. The primary objective was to confirm that the proportion of patients who experienced one or more major adverse events (MAE) was not higher in the active than in the control group. The study included 379 patients. At least one treatment-related MAE was observed in 9.2% of patients (n = 17) assigned to the active group vs. 13.3% of patients (n = 26) in the control group (P = 0.21), a 4.1% absolute risk reduction (95% CI -2.2 to 10.4; P = 0.98). By study design, the mean hospitalization duration was 34% shorter in the active than in the control group (P < 0.001), and HM facilitated the early detection of technical issues and detectable clinical anomalies. CONCLUSION: Early discharge with HM after PM implantation or replacement was safe and facilitated the monitoring of patients in the month following the procedure.

Relationship between selected overdrive parameters and the therapeutic outcome and tolerance of atrial overdrive pacing.

There is a paucity of information on the influence of selected overdrive parameters on the clinical efficacy and tolerance of atrial overdrive algorithms to suppress atrial tachyarrhythmias. Data from a completed clinical trial investigating a new DDD+ overdrive algorithm implemented in a permanent pacemaker were analyzed. One-hundred patients with standard pacing indications and atrial tachyarrhythmias were enrolled and followed for 6 months in DDD and 6 months in DDD+ mode in a randomized, crossover fashion. The overdrive step size was programmed at the discretion of the investigators between 4 and 12 beats/min, overdrive plateau length between 10 and 32 beats, and maximum overdrive rate between 100 and 160 beats/min. The effects of DDD+ versus DDD mode on burden and incidence of atrial tachyarrhythmias stored in the mode switch memory were examined as a function of the programmed overdrive parameters. An overdrive step size between 7 and 12 beats/min, and higher a maximum overdrive rate between 121 and 160 beats/min were slightly more effective than lower programmed values, though > 500 randomized, crossover observations would have been necessary to verify statistical significance. Overdrive pacing related symptoms mandated early manual deactivation of overdrive pacing in 4.7% of 85 evaluated patients. Overdrive was disabled without testing tolerability of less aggressive overdrive values. There was no link between patient symptoms and programmed overdrive step size or overdrive plateau length values.

The influence of concomitant drug therapy on the efficacy of atrial overdrive stimulation for prevention of atrial tachyarrhythmias.

Data from the completed "Suppression of Atrial Fibrillation by DDD+ Overdrive Pacing with Inos2 CLS (closed-loop system) Pacemakers" multicenter trial were retrospectively evaluated to examine the influence of concomitant antiarrhythmic drugs on the clinical success of conventional single site right atrial overdrive pacing compared with DDD pacing. The DDD+ overdrive algorithm provided > 90% atrial pacing at a rate slightly above the intrinsic atrial rate. Seventy-five patients with conventional pacing indications and paroxysmal, recurrent atrial tachyarrhythmia have completed the study. They were randomized to 6 months of DDD or DDD+ pacing, followed by mode crossover and an additional 6-month follow-up in the alternate mode. The incidence of atrial tachyarrhythmia during each period was compared using data on sustained (> 60 s) mode switch episodes stored in the pacemaker memory. A stable antiarrhythmic drug regimen was allowed during the study. beta-Adrenergic blockers and Class III antiarrhythmics, prescribed to 54.7% and 40.0% of patients respectively, were linked to minimal or no benefit of overdrive pacing compared with DDD pacing. In contrast, patients untreated with beta-adrenergic blockers or Class III drugs had a significant reduction in atrial tachyarrhythmia burden of > 5 hours/patient per week (P < 0.05) during overdrive. Changes with Class I and Class IV antiarrhythmic drugs, prescribed to 18.7% and 13.3% of patients, respectively, were insignificant. Our data indicate that clinical trials that prohibit the use of beta-adrenergic blockers may record more favorable outcomes with dynamic atrial overdrive algorithms versus conventional DDDR pacing, than studies allowing concomitant beta-adrenergic blockade.

Bigeminy pacing: a new protocol to unmask atrial vulnerability.

INTRODUCTION: One of the most exciting developments in our understanding of atrial fibrillation (AF) mechanisms has been the recognition that "AF begets AF" in a process termed atrial remodeling. Little information is available about the events that mediate short-term remodeling. In a bigeminy atrial pacing protocol that produces a continuous extrasystole-postextrasystole cycle length, we sought to evaluate the electrophysiologic consequences of irregular atrial pacing. METHODS AND RESULTS: This study included 22 consecutive patients with documented paroxysmal AF and 10 control subjects. After evaluating the effective refractory period (ERP) and functional refractory period (FRP), bigeminy atrial pacing was performed for 5 minutes. The S1-S2 coupling interval during bigeminy pacing was programmed to a mean value of 275 +/- 45 msec, i.e., 45 msec longer than the basic ERP measured at 100 beats/min. During bigeminy pacing, AF that lasted longer than 1 minute occurred in 12 AF patients and in none of the control subjects (group I). Short salvos of AF occurred in 5 patients and 3 controls (group II). No arrhythmia occurred in 5 patients and 7 controls (group III). Sensitivity, specificity, and negative and positive predictive values of sustained AF induced by bigeminy pacing were 54%, 100%, 50%, and 100%, respectively. No differences were observed between different pacing rates during bigeminy, the premature coupling interval S1-S2, or the conduction parameters S2-A2 and A2. Group I had the shortest basic ERP (222 +/- 38 msec) and group III the longest ERP (242 +/- 21 msec, P < 0.05); group II was intermediate. Atrial ERPs and FRPs measured immediately after termination of 5 minutes of bigeminy pacing were shorter than during baseline. The degree of shortening was similar in AF patients and in controls. The locoregional conduction delay A2 did not change after the bigeminy protocol. CONCLUSION: This study demonstrates that atrial bigeminy pacing highly increases atrial vulnerability. This protocol appears interesting because its sensitivity and specificity are higher than those of the conventional extrastimulation test. This makes it attractive for routine diagnosis of undocumented paroxysmal AF. Because it may induce atrial arrhythmias independently of the classic mechanisms of wavelength shortening, this study emphasizes the need for new modalities in the prevention of atrial arrhythmias.

P wave duration and morphology predict atrial fibrillation recurrence in patients with sinus node dysfunction and atrial-based pacemaker.

P wave duration and morphology have never been systematically evaluated as markers of AF in patients with a conventional indication to pacing. This study correlated sinus P wave duration and morphology and the incidence of AF in patients with sinus node dysfunction (SND), previous history of AF before implant, and atrial-based pacemaker. Included were 140 patients (86 men, 54 women; mean age 71.8 +/- 10.4 years) with recurrent paroxysmal AF and who received a DDD (128 patients) or AAI (12 patients) pacemaker for SND. Forty-nine patients had structural heart disease. Sinus P wave duration and morphology was evaluated in leads II, III. Twenty-two patients had an abnormal P wave morphology, diphasic (+/-) in 5 and notched (+/+) in 17. The basic pacemaker rate was programmed between 60 and 70 beats/min. Rate responsive function was activated in 65 patients. During a follow-up of 27.6 +/- 17.8 months, AF was documented in 87 patients. Forty-four patients developed permanent AF, following at least one episode of paroxysmal AF in 26 cases. Statistical analysis used Cox model regression. Univariate predictors of AF (P < 0.10) were drugs (mean: 2 +/- 1.4) and DC shock before pacing (16/140 patients), P wave duration (mean 112.5 +/- 24.6 ms), basic pacemaker rate (mean 68 +/- 5 beats/min), and drugs in the follow-up (mean 1.2 +/- 0.94). Multivariate analysis showed that P wave duration (b = 0.013, s.e. = 0.004; P = 0.003), and drugs before pacing (b = 0.2; s.e. = 0.08; P < 0.01) resulted in a significant independent predictor of AF. Actuarial incidence of patients free of AF at 30 months was 35%: 56% in patients with a P wave < 120 ms, and 13% in those with P wave > or = 120 ms (P < 0.01 by Score test). Univariate predictors of permanent AF were drugs and DC shock before pacing, left atrial size (mean 39 +/- 6 mm), P wave duration, abnormal P wave morphology (22/140 patients), and drugs in the follow-up. Multivariate analysis showed that P wave morphology was the most important predictor of permanent AF (b = -0.56, s.e. = 0.2; P = 0.008). Incidence of patients free of permanent AF at 30 months was 69%: 74% in patients with normal P wave, compared to 28% in the case of abnormal P wave morphology (P < 0.01). P wave duration and morphology are good markers of postpacing AF recurrence in patients with SND and an atrial-based pacemaker. This observation suggests that intra- and interatrial conduction disturbances be extensively evaluated before implantation, and the indication for atrial resynchronization procedures be reevaluated.