Ellenbogen, Kenneth A.

AbstractCardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing‐induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre‐procedure evaluation and preparation, implant procedure management, follow‐up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Cardiac sarcoidosis is a component of an often multiorgan granulomatous disease of still uncertain cause. It is being recognized with increasing frequency, mainly as the result of heightened awareness and new diagnostic tests, specifically cardiac magnetic resonance imaging and 18 F-fluorodeoxyglucose positron emission tomography scans. The purpose of this case-based review is to highlight the potentially life-saving importance of making the early diagnosis of cardiac sarcoidosis using these new tools and to provide a framework for the optimal care of patients with this disease. We will review disease mechanisms as currently understood, associated arrhythmias including conduction abnormalities, and atrial and ventricular tachyarrhythmias, guideline-directed diagnostic criteria, screening of patients with extracardiac sarcoidosis, and the use of pacemakers and defibrillators in this setting. Treatment options, including those related to heart failure, and those which may help clarify disease mechanisms are included.

Abstract Aims His–Purkinje conduction system pacing (HPCSP) utilizing His (HBP) or left bundle branch pacing (LBBP) in patients with atrial fibrillation (AF) and wide QRS duration has not been well studied. We assessed the benefit of left bundle branch block (LBBB) correction during HPCSP in AF patients undergoing atrioventricular junction (AVJ) ablation with LBBB, compared with those with narrow QRS duration. Methods and results This is an observational study in consecutive patients with typical LBBB or narrow QRS duration in whom we attempted HPCSP after AVJ ablation for refractory AF with a left ventricular ejection fraction (LVEF) ≤ 50%. Echocardiographic responses and clinical outcomes were assessed at baseline and during 1 year of follow-up. A total of 178 patients were enrolled, of which 170 achieved AVJ ablation + permanent HPCSP (age 69.3 ± 10.1 years; LVEF 34.3 ± 7.7%), 133 (78.2%) patients had a narrow QRS duration, and 37 (21.2%) had an LBBB. The QRS duration changed from a baseline of 159.7 ± 16.6 ms to a paced QRS duration of 110.4 ± 12.7 ms in the LBBB cohort and from 95.6 ± 10.4 to 100.8 ± 14.5 ms (both P < 0.001) in the narrow QRS cohort after AVJ ablation and pacing. Compared with the narrow QRS cohort, the LBBB cohort showed a greater absolute increase in LVEF (+22.3% vs. +14.2%, P < 0.001), higher super responder rate (71.4% vs. 49.2%, P = 0.011), and greater New York Heart Association (NYHA) class improvement (−1.9 vs. −1.4, P < 0.001) at 1 year. Conclusion Patients with LBBB have greater improvement in LVEF and NYHA class function than patients with narrow QRS from HPCSP after AVJ ablation.

Background: Efforts to improve prescription of oral anticoagulation (OAC) drugs in patients with atrial fibrillation have had limited success in improving guideline adherence. Methods: We evaluated adherence to the American College of Cardiology/American Heart Association performance measures for OAC in eligible patients with a CHA 2 DS 2 -VASc score ≥2 and trends in prescription over time in the American Heart Association’s Get With The Guidelines–AFIB (atrial fibrillation) registry. Adjusted associations with in-hospital outcomes were also determined. The cohort included 33 235 patients with a CHA 2 DS 2 -VASc score ≥2 who were admitted for atrial fibrillation and were enrolled at 115 sites between January 1, 2013, and September 31, 2017. Results: The median (25th, 75th percentile) age was 73 years (65, 81 years); 51% were female; and the median (25th, 75th percentile) CHA 2 DS 2 -VASc score was 4 (3, 5). At admission, 16 206 (59.5%) of 27 221 patients with a previous diagnosis of atrial fibrillation were taking OAC agents, and OAC drug use at admission was associated with a lower adjusted odds of in-hospital ischemic stroke (odds ratio, 0.38; 95% CI, 0.24–0.59; P <0.0001). At discharge, prescription of OAC in eligible patients (no contraindications) was 93.5% (n=25 499 of 27 270). In a sensitivity analysis, when excluding only strict contraindications (4.6%, n=1497 of 32 806), OAC prescription at discharge was 80.3%. OAC prescription at discharge was higher in those aged ≤75 years, men, those with heart failure, those with previous atrial fibrillation ablation, and those with rhythm control ( P <0.0001 for all). OAC use was lowest in Hispanic patients (90.2%, P <0.0001). Prescription of OAC at discharge in eligible patients improved over time from 79.9% to 96.6% ( P <0.0001). Conclusions: Among hospitals participating in the GWTG-AFIB quality improvement program, OAC prescription at discharge in eligible guideline-indicated patients increased significantly and improved consistently over time. These data confirm that high-level adherence to guideline-recommended stroke prevention is achievable.

Advances in the field of defibrillation have brought to practice different types of devices that include the transvenous implantable cardioverter-defibrillator (ICD) with or without cardiac resynchronization therapy, the subcutaneous ICD (S-ICD), and the wearable cardioverter-defibrillator. To ensure optimal use of these devices and to achieve best patient outcomes, clinicians need to understand how these devices work, learn the characteristics of patients who qualify them for one type of device versus another, and recognize the remaining gaps in knowledge surrounding these devices. The transvenous ICD has been shown in several randomized clinical trials to improve the survival of patients resuscitated from near-fatal ventricular fibrillation and those with sustained ventricular tachycardia with syncope or systolic heart failure as a result of ischemic or nonischemic cardiomyopathy despite receiving guideline-directed medical therapy. Important gaps in knowledge regarding the transvenous ICD involve the role of the ICD in patient subgroups not included, or not well represented, in clinical trials and the need to refine the selection criteria for the ICD in patients who are indicated for it. S-ICDs were recently introduced into the clinical arena as another option for many patients who have an approved indication for a transvenous ICD. The main advantage of the S-ICD is a lower risk of infection and lead-related complications; however, the S-ICD does not offer bradycardia or antitachycardia pacing. The S-ICD may be ideal for patients with limited vascular access, high infection risk, or some congenital heart diseases. However, more data are needed regarding the efficacy and effectiveness of the S-ICD in comparison to transvenous ICDs, the extent of defibrillation testing required, and the use of the S-ICD with other novel technologies, including leadless pacemakers. Cardiac resynchronization therapy-defibrillators are indicated in patients with a left ventricular ejection fraction ≤35%, QRS width ≥130 ms, and New York Heart Association class II, III, or ambulatory IV symptoms despite treatment with guideline-directed medical therapy. Multiple randomized controlled trials have shown that the cardiac resynchronization therapy-defibrillator improves survival, quality of life, and several echocardiographic measures. One main challenge related to cardiac resynchronization therapy-defibrillators is the 30% nonresponse rate. Many initiatives are underway to address this challenge including improved cardiac resynchronization therapy and imaging technologies and enhanced selection of patients and device programming.

© 2016 Heart Rhythm Society, the American College of Cardiology Foundation, and the Society for Cardiovascular Angiography and Interventions