For Whom the Bell Tolls : Refining Risk Assessment for Sudden Cardiac Death.

Sudden cardiac death is one of the most important causes of death worldwide. Advancements in medical treatment, percutaneous interventions, and device therapy (ICD and CRTD) showed consistent reduction in mortality, mainly in survivors of SCD and in patients with ischemic cardiomyopathy and depressed left ventricular function. Patients with non-ischemic cardiomyopathies, mildly reduced LV function, and channelopathies have increased risk for SCD. Identifying the subgroup of these patients before they experience life-threatening or fatal events is essential to further improve outcomes. In this review, we aimed to summarize the current knowledge for risk stratification and primary prevention, to describe the gaps in evidence, and to discuss future directions for screening and treating patients at risk for SCD. PURPOSE OF REVIEW: The purpose of this review is to provide a comprehensive description of the etiologies of sudden cardiac death, risk stratification strategies, and to describe the current medical and interventional therapies. We aimed to discuss the current gaps in our knowledge of primary prevention of SCD and to review novel approaches and interventions. RECENT FINDINGS: The incidence of SCD has decreased in the last two decades due to improved pharmacological treatment and ICD implantation in SCD survivors and in patients with reduced left ventricular function and ischemic cardiomyopathy. The efficacy of ICD in patients with non-ischemic cardiomyopathy is challenged by new findings from the DANISH trial. Catheter ablation is new emerging strategy to prevent SCD in patients with scar relater or PVC-triggered ventricular arrhythmias. Despite the new treatments, SCD is still a major burden. ICD remains the cornerstone for patients with ischemic cardiomyopathy, whereas appropriate risk stratification of the patients with non-ischemic cardiomyopathy and channelopathies is needed to further improve outcomes. The future of ablation as the treatment and prevention of SCD remains to be studied.

Emergency Department Visits for Atrial Fibrillation in the United States: Trends in Admission Rates and Economic Burden From 2007 to 2014.

BACKGROUND: Atrial fibrillation (AF) is an increasingly prevalent public health problem and one of the most common causes of emergency department (ED) visits. We aimed to investigate the trends in ED visits and hospital admissions for AF. METHODS AND RESULTS: This is a repeated cross-sectional analysis of ED visit-level data from the Nationwide Emergency Department Sample for 2007 to 2014. We identified adults who visited EDs in the United States, with a principal diagnosis of AF. A sample of 864 759 ED visits for AF, representing a weighted total of 3 886 520 ED visits, were analyzed. The annual ED visits for AF increased by 30.7% from 411 406 in 2007 (95% confidence interval, 389 819-432 993) to 537 801 (95% confidence interval, 506 747-568 855) in 2014. Patient demographics remained consistent, with an average age of 69 to 70 years and slight female predominance (51%-53%) throughout the study period. Hospital admission rates were stable at ≈70% between 2007 and 2010, after which they gradually declined to 62% in 2014 (Ptrend=0.017). Despite the decline in hospital admission rates, AF hospitalizations increased from 288 225 in 2007 to 333 570 in 2014 because of the increase in total annual ED visits during the study. The adjusted annual charges for admitted AF patients increased by 37% from $7.39 billion in 2007 to $10.1 billion in 2014. CONCLUSIONS: Annual ED visits and hospital admissions for AF increased significantly between 2007 and 2014, despite a reduction in admission rates. These data emphasize the need for widespread implementation of effective strategies aimed at improving the management of patients with AF to reduce hospital admissions and the economic burden of AF.

Sex Differences in Long-Term Outcomes With Cardiac Resynchronization Therapy in Mild Heart Failure Patients With Left Bundle Branch Block.

BACKGROUND: Previous studies have shown conflicting results regarding the benefit of cardiac resynchronization therapy (CRT) by sex and QRS duration. METHODS AND RESULTS: In the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT), we evaluated long-term clinical outcome of heart failure (HF) or death, death, and HF alone by sex and QRS duration (dichotomized at 150 ms) in left bundle-branch block patients with CRT with defibrillator backup (CRT-D) versus implantable cardioverter-defibrillator (ICD) only. There were 394 women (31%) and 887 men with left bundle-branch block. During the median follow-up of 5.6 years, women derived greater clinical benefit from CRT-D compared with implantable cardioverter-defibrillator only, with a significant 71% reduction in HF or death (hazard ratio [HR] 0.29, P<0.001) and a 77% reduction in HF alone (HR 0.23, P<0.001) compared with men, who had a 41% reduction in HF or death (HR 0.59, P<0.001) and a 50% reduction in HF alone (HR 0.50, P<0.001) (all sex-by-treatment interaction P<0.05). Men and women had similar reduction in long-term mortality with CRT-D versus implantable cardioverter-defibrillator only (men: HR 0.70, P=0.03; women: HR 0.59, P=0.04). The incremental benefit of CRT-D in women for HF or death and HF alone was consistent with QRS <150 or >150 ms. CONCLUSIONS: During long-term follow-up of mild HF patients with left ventricular dysfunction and wide QRS, both women and men with left bundle-branch block derived sustained benefit from CRT-D versus implantable cardioverter-defibrillator only, with significant reduction in HF or death, HF alone, and all-cause mortality regardless of QRS duration. There is an incremental benefit with CRT-D in women for the end points of HF or death and HF alone. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/. Unique identifiers: NCT00180271, NCT01294449, and NCT02060110.