Atrial Antitachycardia Pacing Research Articles

Controversies in pacing: Indications and programming

This article reviews controversies in cardiac pacing in four areas: methods to prevent unnecessary right ventricular pacing and optimal ventricular pacing sites in the bradycardia population, pacing for prevention of atrial fibrillation (AF), a novel pacing technique for the treatment of heart failure, and pacing for the treatment of sleep apnea. Frequent right ventricular pacing has been reported to increase the incidence of AF and congestive heart failure. However, many patients with pacemakers for bradycardia have intrinsic atrioventricular conduction most of the time. Optimal programming of pacemakers and new algorithms designed to reduce unnecessary ventricular pacing are discussed. Pacing algorithms for prevention of AF have generally been shown to be ineffective. Atrial antitachycardia pacing has been shown to reduce the burden of atrial tachyarrhythmias in selected patients. Cardiac contractility modulation has recently been reported to be a promising new approach to the treatment of heart failure. Some pacing techniques may be effective in the treatment of sleep apnea but larger, long-term clinical trials are required to demonstrate a significant clinical benefit.

Device-based therapies for atrial fibrillation

Ablation of the atrioventricular conduction system and pacemaker implantation is the preferred procedure for patients with atrial fibrillation (AF) in whom a rate control strategy has been selected but in whom rate-controlling medications are intolerable or ineffective. Selection of standard right ventricular (RV) pacing versus biventricular pacing is individualized, based on the degree and etiology of left ventricular dysfunction. Atrial-based pacing is clearly preferable to ventricular-based pacing in patients with sick sinus syndrome, because it leads to a reduction in the development of AF. Emerging evidence indicates that excess RV pacing is deleterious, increasing AF, heart failure, and possibly mortality. Therefore, physiologic pacing with minimization of RV pacing is desirable. Atrial pacing algorithms that increase the frequency of atrial pacing have shown modest efficacy in the prevention of AF. Use of atrial pacing algorithms is reasonable for patients with a history of AF and standard bradycardia indications for permanent pacing in whom maintenance of sinus rhythm is desirable. Studies assessing novel and multiple site atrial pacing therapies have mixed results, without compelling evidence of clinically important benefit. The exceptions are biatrial and right atrial overdrive pacing immediately after cardiac surgery. Several studies have shown effective suppression of postoperative AF with their use. Device therapy (eg, atrial antitachycardia pacing and defibrillation) for the termination of AF is effective in reducing arrhythmia burden. However, improvement in clinically relevant end points is not established and indications are not clearly defined. If a patient lacks an indication for an implantable cardioverter-defibrillator, we do not offer atrial defibrillation as a treatment option. Atrial arrhythmias may be better prevented by programming to avoid ventricular pacing than by specific atrial interventions.

High atrial antitachycardia pacing therapy efficacy is associated with a reduction in atrial tachyarrhythmia burden in a subset of patients with sinus node dysfunction and paroxysmal atrial fibrillation

Atrial tachycardia (AT) and atrial flutter that occur in association with paroxysmal atrial fibrillation (AF) can be successfully terminated by antitachycardia pacing (ATP) therapy. We hypothesized that atrial ATP therapy reduces AT/AF burden in a subset of patients with symptomatic bradycardia and frequent paroxysmal AT/AF. This study evaluated the effect of atrial ATP therapy on AT/AF burden in a pacemaker population with paroxysmal AF. We compared AT/AF burden in 261 patients who received a Medtronic AT500 pacemaker for treatment of AT/AF in the setting of symptomatic bradycardia based on device-classified atrial ATP efficacy < 60% and > or = 60%. Patients with > or = 10 device-detected episodes of AT/AF before and after atrial ATP therapy initiation were identified from four clinical studies performed in 72 centers worldwide. The high efficacy group comprised 75 patients with atrial ATP efficacy > or = 60%. The low efficacy group comprised 186 patients with atrial ATP efficacy < 60%. AT/AF episode frequency was similar in both groups prior to ATP activation and decreased in the low efficacy group following ATP activation. Following atrial ATP initiation, total AT/AF burden increased slightly in the low ATP efficacy group (median 2.77 [25th-75th percentiles 0.84-5.86] hours/day vs 2.92 [0.59-8.12] hours/day, P = .01). In contrast, total AT/AF burden decreased significantly in the high efficacy group (median 2.46 [0.29-8.88] hours/day vs 0.68 [0.13-2.97] hours/day, P < .001). Up to 30% of patients with frequent episodes of paroxysmal AF and symptomatic bradycardia experience a reduction in AT/AF burden from atrial ATP therapy over time.

711 Predictors of atrial antitachycardia pacing efficacy in patients affected by brady-tachy form of sick sinus syndrome and implanted with a DDDRP device

711 Predictors of atrial antitachycardia pacing efficacy in patients affected by brady-tachy form of sick sinus syndrome and implanted with a DDDRP device

214 A randomized comparison between Ramp and Burst+ atrial antitachycardia pacing therapies in patients suffering from bradycardia and atrial fibrillation and implanted with a DDDRP device

214 A randomized comparison between Ramp and Burst+ atrial antitachycardia pacing therapies in patients suffering from bradycardia and atrial fibrillation and implanted with a DDDRP device

214 A randomized comparison between Ramp and Burst+ atrial antitachycardia pacing therapies in patients suffering from bradycardia and atrial fibrillation and implanted with a DDDRP device

214 A randomized comparison between Ramp and Burst+ atrial antitachycardia pacing therapies in patients suffering from bradycardia and atrial fibrillation and implanted with a DDDRP device

Sleep and arrhythmias

Sleep and arrhythmias

521 Atrial antitachycardia pacing is most effective at night

521 Atrial antitachycardia pacing is most effective at night

521 Atrial antitachycardia pacing is most effective at night

521 Atrial antitachycardia pacing is most effective at night

711 Predictors of atrial antitachycardia pacing efficacy in patients affected by brady-tachy form of sick sinus syndrome and implanted with a DDDRP device

711 Predictors of atrial antitachycardia pacing efficacy in patients affected by brady-tachy form of sick sinus syndrome and implanted with a DDDRP device

Comparison of immediate and delayed automatic antitachycardia pacing for the termination of atrial tachyarrhythmias

Automatic atrial antitachycardia pacing (ATP) can terminate atrial tachyarrhythmias (ATs) in patients with an implanted device. We investigated if the programmable delay between AT onset and ATP influences therapy efficacy. Patients with intermittent ATs and an implanted DDDRP pacemaker were randomized to receive ATP either immediately or 30min after AT detection. After four months stored data were interrogated, AT-related symptoms were assessed, and patients crossed over to the alternative treatment arm for another four months. Stored atrial electrograms were analyzed for degree of AT organization and ATP success. In 22 patients (64% male; 72+/-7 years), ATP success rates were higher during immediate than during delayed ATP (device classification: 59+/-7% vs. 22+/-5%, P<0.01; manual analysis: 36+/-6% vs. 12+/-5%, P<0.01). Higher efficacy of immediate ATP was associated with a larger proportion of organized (Type I) AT prior to therapy (71% vs. 44% during delayed ATP). No difference was found in total AT numbers and duration, AT burden or related symptoms. The programmable delay between arrhythmia onset and therapy delivery significantly influences the success-rate of ATP. However, a higher efficacy of immediate compared with delayed ATP does not translate into a reduction of AT burden or related symptoms.

Atrial antitachycardia pacing is most effective at night

Atrial antitachycardia pacing is most effective at night

Ventricular Asystole During Atrial Antitachycardia Pacing by Implanted Cardioverter‐Defibrillator

Ventricular Asystole During Atrial Antitachycardia Pacing by Implanted Cardioverter‐Defibrillator

Simultaneous atrial and ventricular anti-tachycardia pacing as a novel method of rhythm discrimination

Simultaneous atrial and ventricular anti-tachycardia pacing as a novel method of rhythm discrimination

Predictors of Atrial Antitachycardia Pacing Efficacy in Patients Affected by Brady‐Tachy Form of Sick Sinus Syndrome and Implanted with a DDDRP Device

Predictors of ATP efficacy in brady/tachy patients. Recent options to treat atrial tachyarrhythmias (ATA) include implantable devices delivering antitachycardia pacing therapies (ATP). No prospective study selected patients with higher chances of episode termination by ATP or indicated the most effective ATP use. Our aim was to study ATP efficacy in patients with brady-tachy form of sinus node disease (SND), identifying clinical factors, ATA characteristics, and device features predicting ATP efficacy. Three hundred and sixteen patients (105 M, aged 71.1+/-8.8 years) received a DDDRP pacemaker and were prospectively followed. Median follow-up was 18 months: 37,125 ATA episodes occurred in 217 patients; ATP treated 5,536 of them. Overall, ATP efficacy was 50.0%. A multivariate analysis identified longer arrhythmia cycle lengths (OR=1.25; CI=1.07-1.47) and shorter delays to ATP delivery (OR=0.15; CI=0.10-0.22) as independent predictors of ATP efficacy for episodes preceded by >or=5 minutes of sinus rhythm. Additionally, ATP efficacy for all treated episodes was predicted by lower New York Heart Association (NYHA) class (OR=0.64; CI=0.42-0.98), episode classification as nonimmediate recurrence of ATA (non-IRAT) (OR=0.07; CI=0.02-0.33), absence of overlap in the device detection windows (OR=0.54; CI=0.32-0.91), and flecainide treatment (OR=2.22; CI=1.04-4.71). In patients paced for SND, multivariate analysis shows that ATP efficacy is associated to longer arrhythmia cycle lengths, shorter ATP delivery delays, NYHA class I, episode classification as non-IRAT, absence of overlap in the atrial arrhythmia device detection windows, and flecainide treatment.

Comparison of Induced and Spontaneous Atrial Tachyarrhythmias in Patients with a History of Spontaneous Atrial Tachyarrhythmias

This retrospective study investigated whether induced episodes could be used to predict the morphology of future spontaneous atrial episodes. Eighty-two patients (64 +/- 12 years; 77% male; CAD in 60%; left ventricular ejection fraction 45 +/- 16%) with a history of atrial tachycardia or atrial fibrillation (AT/AF) were implanted with a dual-chamber implantable cardioverter defibrillator (ICD) and followed for 6 months. A total of 224 episodes of induced and spontaneous AT/AF were classified into type I, II, and III according to the method of Israel et al. and then compared based on average cycle length (CL) and atrial amplitude. Episodes were also grouped as "pace-terminable" or "nonpace-terminable" based on the CL definition of Gillis et al. The analysis of 121 induced episodes (from 80 patients) and 103 spontaneous episodes (from 43 patients) showed that within each arrhythmia type, there were no significant differences in CL or mean amplitude between induced and spontaneous episodes. Additional analysis of patients that had both induced and spontaneous episodes (n = 41) showed 78% had at least one spontaneous episode that matched the induced episode. Fifty-seven percent of spontaneous episodes were considered to be pace-terminable based on CL. Our data suggest that there is no significant difference between induced and spontaneous episodes of AT/AF of the same type. The majority of patients had at least one spontaneous episode of the same type as the induced episode, showing that induced atrial arrhythmias may be useful in predicting the morphology of future spontaneous episodes and in identifying patients potentially benefiting from atrial antitachycardia pacing.

Role of Permanent Pacing to Prevent Atrial Fibrillation

This advisory summarizes the current database on pacing modalities and algorithms used to prevent and terminate atrial fibrillation (AF). On the basis of the evidence indicating that ventricular pacing is associated with a higher incidence of AF in patients with sinus node dysfunction, a patient who has a history of AF and needs a pacemaker for bradycardia should receive a physiological pacemaker (dual chamber or atrial) rather than a single-chamber ventricular pacemaker. For patients who need a dual-chamber pacemaker, efforts should be made to program the device to minimize the amount of ventricular pacing when atrioventricular conduction is intact. Many pacemakers and implantable defibrillators have features designed to prevent AF and to terminate AF with rapid atrial pacing. The evidence to support their use is limited, although these algorithms appear to be safe and usually add little additional cost. For patients who have a bradycardia indication for pacing and also have AF, no consistent data from large randomized trials support the use of alternative single-site atrial pacing, multisite right atrial pacing, biatrial pacing, overdrive pacing, or antitachycardia atrial pacing. Even fewer data support the use of atrial pacing in the management of AF in patients without symptomatic bradycardia. At present, permanent pacing to prevent AF is not indicated; however, additional studies are ongoing, which will help to clarify the role of permanent pacing for AF.

1091-225 Atrial antitachycardia pacing efficacy based on time and rhythm

1091-225 Atrial antitachycardia pacing efficacy based on time and rhythm

Clinical trials of pacing for maintenance of sinus rhythm.

Several prospective randomized clinical trials have demonstrated that atrial-based pacing prevents the development of paroxysmal and persistent atrial fibrillation (AF) in patients with symptomatic bradycardia as the indication for a pacemaker. The greatest benefit appears to be in patients with sinus node dysfunction as the primary indication for pacing. Studies of site specific atrial pacing have not shown a consistent benefit for prevention of AF. A number of prospective studies have been undertaken to assess the role of selective atrial pacing algorithms designed for prevention of AF. These studies suggest that these AF pace prevention algorithms have modest to minimal incremental benefit compared to atrial based pacing alone for the prevention of AF. Atrial antitachycardia pacing (ATP) algorithms have been incorporated into some pacemakers and defibrillators. Overall, atrial ATP therapy has not been shown to substantially reduce the burden of AF in one randomized trial. However, there are subsets of patients e.g. those with atrial flutter as well as AF who are likely to benefit from this therapy.

New method for real-time discrimination and management of ventricular and supraventricular tachyarrhythmias applicable to patients with dual-chamber cardioverter-defibrillators

In this study we describe a highly sensitive and specific method for discriminating between ventricular and supraventricular tachyarrhythmias based on the response to simultaneous atrial and ventricular antitachycardia pacing. This new method, which can terminate supraventricular tachycardias in >50% of patients, can be easily implemented in a new generation of dual-chamber defibrillators.