on behalf of the Multicenter InSync ICD II Study GroupBackground-The effects of cardiac resynchronization therapy (CRT) in patients with mildly symptomatic heart failure have not been fully elucidated. Methods and Results-The Multicenter InSync ICD Randomized Clinical Evaluation II (MIRACLE ICD II) was a randomized, double-blind, parallel-controlled clinical trial of CRT in NYHA class II heart failure patients on optimal medical therapy with a left ventricular (LV) ejection fraction Յ35%, a QRS Ն130 ms, and a class I indication for an ICD. One hundred eighty-six patients were randomized: 101 to the control group (ICD activated, CRT off) and 85 to the CRT group (ICD activated, CRT on). End points included peak V O 2 , V E/V CO 2 , NYHA class, quality of life, 6-minute walk distance, LV volumes and ejection fraction, and composite clinical response. Compared with the control group at 6 months, no significant improvement was noted in peak V O 2 , yet there were significant improvements in ventricular remodeling indexes, specifically LV diastolic and systolic volumes (Pϭ0.04 and Pϭ0.01, respectively), and LV ejection fraction (Pϭ0.02). CRT patients showed statistically significant improvement in V E/V CO 2 (Pϭ0.01), NYHA class (Pϭ0.05), and clinical composite response (Pϭ0.01). No significant differences were noted in 6-minute walk distance or quality of life scores. Conclusions-In patients with mild heart failure symptoms on optimal medical therapy with a wide QRS complex and an ICD indication, CRT did not alter exercise capacity but did result in significant improvement in cardiac structure and function and composite clinical response over 6 months.

Background: Left atrial appendage (LAA) occlusion provides an alternative to oral anticoagulation (OAC) for thromboembolic risk reduction in patients with non-valvular atrial fibrillation (NVAF). Since regulatory approval in 2015, the WATCHMAN device has been the only LAA closure device available for clinical use in the United States. The PINNACLE FLX study evaluated the safety and effectiveness of the next-generation WATCHMAN FLX LAA closure device in patients with NVAF in whom OAC is indicated, but who have an appropriate rationale to seek a non-pharmaceutical alternative. Methods: This was a prospective, non-randomized, multi-center FDA study. The primary safety endpoint was the occurrence of one of the following events within 7 days post-procedure or by hospital discharge, whichever was later: death, ischemic stroke, systemic embolism, or device- or procedure-related events requiring cardiac surgery. The primary effectiveness endpoint was the incidence of effective LAA closure (peri-device flow ≤5mm), as assessed by the echocardiography core laboratory at 12-month follow-up. Results: A total of 400 patients were enrolled. The mean age was 73.8{plus minus}8.6 years and the mean CHA2DS2-VASc score was 4.2{plus minus}1.5. The incidence of the primary safety endpoint was 0.5% with a one-sided 95% upper confidence interval (CI) of 1.6%, meeting the performance goal (PG) of 4.2% (P<0.0001). The incidence of the primary effectiveness endpoint was 100%, with a onesided 95% lower CI of 99.1%, again meeting the PG of 97.0% (P<0.0001). Device-related thrombus was reported in 7 patients, no patients experienced pericardial effusion requiring open cardiac surgery, and there were no device embolizations. Conclusions: LAA closure with this next generation LAA closure device was associated with a low incidence of adverse events and a high incidence of anatomic closure. Clinical Trial Registration: URL https://clinicaltrials.gov Unique Identifier NCT02702271

Lead extraction employing laser sheaths is highly successful with a low procedural complication rate. Total mortality is substantially increased with pocket infections or device-related endocarditis, particularly in the setting of diabetes, renal insufficiency, or body mass index <25 kg/m(2). Centers with smaller case volumes tended to have a lower rate of successful extraction.

BB region pacing is safe and effective for attenuating the progression of AF.

Background-Improvements in cardiac mapping are required to advance our understanding and treatment of arrhythmias.This study validated a new noncontact multielectrode array catheter and accompanying analysis system to provide electroanatomic mapping of the entire left ventricular (LV) endocardium during a single beat. Methods and Results-A 9F 64-electrode balloon array catheter with an inflated size of 1.8ϫ4.6 cm was used to simultaneously record electrical potentials generated by the heart and locate a standard electrophysiology (EP) catheter within the same chamber. By use of the recorded location of the EP-catheter tip, LV geometry was determined. Array potentials served as inputs to a high-order boundary-element method to produce 3360 potential points on the endocardial surface translatable into electrograms or color-coded activation maps. Three methods of validation were used: (1) driven electrodes in an in vitro tank were located; (2) waveforms generated from the array catheter were compared with catheter contact waveforms in canine LV; and (3)

The combination of three atrial prevention pacing algorithms did not decrease device classified atrial tachyarrhythmia frequency or burden during a 3-month cross-over period in bradycardic patients and septal or nonseptal atrial pacing leads. Prevention pacing was associated with decreased frequency of premature atrial contractions and with decreased symptomatic atrial tachyarrhythmia frequency in patients with atrial septal leads.

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for the Worldwide Jewel AF Investigators 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 11.4Ϯ8.2 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, Burstϩ, 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 (PϽ0.001). With AT and AF episodes combined, pacing efficacy was 48%. Pacing efficacy was significantly reduced at AT cycle lengths Յ220 ms and AF cycle lengths Յ160 ms (PϽ0.01) The median time from pacing to AT/AF termination was 1.1 minute for the pacing successes and 96 minutes for the failures (PϽ0.001). Conclusions-Atrial