Incremental programming of atrial anti-tachycardia pacing therapies in bradycardia-indicated patients: effects on therapy efficacy and atrial tachyarrhythmia burden.

AIMS: Efficacy of pace-termination of atrial arrhythmias (ATP) may depend on atrial cycle length and regularity. Whether device programming of ATP therapies can improve ATP efficacy and alter atrial tachyarrhythmia burden is unknown. METHODS AND RESULTS: ATP efficacy was evaluated in 61 patients (39 males; 66 +/- 10 years) with a standard indication for pacing, 95% with a history of AT/AF. Each patient was implanted with a novel DDDRP pacemaker capable of delivering ATP therapy. ATP efficacy and AT/AF frequency and burden were compared within each patient during a period of nominal ATP programming (NP) followed by a period of aggressive incremental programming (IP). Adjusted ATP-termination efficacy was higher during IP than during NP (54.8% vs 37.9%, P < 0.05). No differences in AT/AF frequency (3.3 +/- 5.9 vs 3.2 +/- 6.9 day(-1)) or burden (18 +/- 28% vs 18 +/- 29%) were observed comparing NP with IP. The majority of episodes during both the NP (81%) and IP (77%) periods terminated within 10 min. Episodes lasting 24 h or more accounted for only 0.4% of the episodes in both groups. but accounted for 38% of the average burden during NP and 51% during IP. CONCLUSIONS: Device programming of ATP therapies can influence the number of treated episodes and the efficacy of ATP therapies although arrhythmic frequency and burden may not change. Total atrial arrhythmia burden is disproportionately influenced by long (>24 h) episodes.

Shock reduction using antitachycardia pacing for spontaneous rapid ventricular tachycardia in patients with coronary artery disease.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) can terminate some ventricular tachycardias (VTs) painlessly with antitachycardia pacing (ATP). ATP has not routinely been applied for VT >188 bpm because of concerns about efficacy, risk of acceleration, and delay of definitive shock therapy. This prospective, multicenter study evaluated the efficacy of empirical ATP to terminate fast VT (FVT; >188 bpm). METHODS AND RESULTS: Two hundred twenty coronary artery disease patients received ICDs for standard indications. Empirical, standardized therapy was programmed so that all FVT episodes (average cycle length [CL] 240 to 320 ms, 250 to 188 bpm) were treated with 2 ATP sequences (8-pulse burst pacing train at 88% of the FVT CL) before shock delivery. A total of 1100 episodes of spontaneous ventricular tachyarrhythmias occurred during a mean of 6.9+/-3.6 months of follow-up. Fifty-seven percent were classified as slow VT (CL>/=320 ms), 40% as FVT (240 ms

Efficacy of pacing therapies for treating atrial tachyarrhythmias in patients with ventricular arrhythmias receiving a dual-chamber implantable cardioverter defibrillator.

BACKGROUND: Although overdrive pacing for treating atrial flutter is well established, the efficacy of device-based atrial pacing for treating spontaneous atrial tachyarrhythmias in patients with implantable cardioverter defibrillators (ICD) is unknown. This study evaluated the efficacy of novel pacing therapies for treating atrial tachyarrhythmias in patients receiving a dual-chamber ICD to treat ventricular tachyarrhythmias. METHODS AND RESULTS: A Jewel AF ICD was implanted in 537 patients with ventricular arrhythmia who were followed for 11.4+/-8.2 months (74% had a documented history of atrial tachyarrhythmias). The device discriminated atrial tachycardia (AT) from atrial fibrillation (AF) on the basis of cycle length and regularity, and it used 3 different methods of overdrive atrial pacing (Ramp, Burst+, and 50-Hz burst) to treat AT episodes and one method (50-Hz burst) to treat AF episodes. Pacing successfully terminated 59% of 1500 spontaneous AT episodes in 127 patients and 30% of 880 AF episodes in 101 patients (P<0.001). With AT and AF episodes combined, pacing efficacy was 48%. Pacing efficacy was significantly reduced at AT cycle lengths

Guadalupe corridor transportation project asbestos health risk assessment, San Jose, California.

A study was conducted to assess health risks and identify a set of appropriate mitigation measures to control airborne emissions of natural asbestos from construction of the Guadalupe Corridor Transportation Project, a highway and light-rail construction project in San Jose, California. This study supported a state-mandated Environmental Impact Report. Communication Hill, along the project route, is known to contain natural chrysotile asbestos-bearing rock. The study described in this paper estimated potential asbestos emissions, identified and evaluated mitigation measures, and evaluated air pathway exposure and health risks. With mitigation, estimated risks were found to be acceptable by the regulatory agency, and construction proceeded.

Dermatoglyphic indicators of congenital heart defects in Down's syndrome patients: a preliminary study.

In a preliminary study fingerprint patterns of Down's syndrome children were examined to determine correlations with congenital heart defects (CHD). The results demonstrate that the left hand digit ridge count minus the right hand digit ridge count, and number of ridges on the fifth digit of the left hand separate patients with CHD from those without heart defects (W/OHD). The method correctly classified 92% of the CHD group and 73% of the W/OHD group.