␤1-Adrenergic receptor (␤1AR) stimulation confers cardioprotection via ␤-arrestin-dependent transactivation of epidermal growth factor receptors (EGFRs), however, the precise mechanism for this salutary process is unknown. We tested the hypothesis that the ␤1AR and EGFR form a complex that differentially directs intracellular signaling pathways. ␤1AR stimulation and EGF ligand can each induce equivalent EGFR phosphorylation, internalization, and downstream activation of ERK1/2, but only EGF ligand causes translocation of activated ERK to the nucleus, whereas ␤1AR-stimulated/EGFR-transactivated ERK is restricted to the cytoplasm. ␤1AR and EGFR are shown to interact as a receptor complex both in cell culture and endogenously in human heart, an interaction that is selective and undergoes dynamic regulation by ligand stimulation. Although catecholamine stimulation mediates the retention of ␤1AR-EGFR interaction throughout receptor internalization, direct EGF ligand stimulation initiates the internalization of EGFR alone. Continued interaction of ␤1AR with EGFR following activation is dependent upon C-terminal tail GRK phosphorylation sites of the ␤1AR and recruitment of ␤-arrestin. These data reveal a new signaling paradigm in which ␤-arrestin is required for the maintenance of a ␤1AR-EGFR interaction that can direct cytosolic targeting of ERK in response to catecholamine stimulation.

BackgroundAtrial fibrillation is associated with higher mortality. Identification of causes of death and contemporary risk factors for all‐cause mortality may guide interventions.Methods and ResultsIn the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) study, patients with nonvalvular atrial fibrillation were randomized to rivaroxaban or dose‐adjusted warfarin. Cox proportional hazards regression with backward elimination identified factors at randomization that were independently associated with all‐cause mortality in the 14 171 participants in the intention‐to‐treat population. The median age was 73 years, and the mean CHADS 2 score was 3.5. Over 1.9 years of median follow‐up, 1214 (8.6%) patients died. Kaplan–Meier mortality rates were 4.2% at 1 year and 8.9% at 2 years. The majority of classified deaths (1081) were cardiovascular (72%), whereas only 6% were nonhemorrhagic stroke or systemic embolism. No significant difference in all‐cause mortality was observed between the rivaroxaban and warfarin arms (P=0.15). Heart failure (hazard ratio 1.51, 95% CI 1.33–1.70, P<0.0001) and age ≥75 years (hazard ratio 1.69, 95% CI 1.51–1.90, P<0.0001) were associated with higher all‐cause mortality. Multiple additional characteristics were independently associated with higher mortality, with decreasing creatinine clearance, chronic obstructive pulmonary disease, male sex, peripheral vascular disease, and diabetes being among the most strongly associated (model C‐index 0.677).ConclusionsIn a large population of patients anticoagulated for nonvalvular atrial fibrillation, ≈7 in 10 deaths were cardiovascular, whereas <1 in 10 deaths were caused by nonhemorrhagic stroke or systemic embolism. Optimal prevention and treatment of heart failure, renal impairment, chronic obstructive pulmonary disease, and diabetes may improve survival.Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00403767.

More than 2,400 continuous-flow left ventricular assist devices (LVADs) are implanted each year in the United States alone. Both the number of patients living with LVADs and the life expectancy of these patients are increasing. As a result, patients with LVADs are increasingly encountered by non-LVAD specialists who do not have training in managing advanced heart failure for general medical care, cardiovascular procedures, and other subspecialty care. An understanding of the initial evaluation and management of patients with LVADs is now an essential skill for many health care providers. In this State-of-the-Art Review, we discuss current LVAD technology, summarize our clinical experience with LVADs, and review the current data for the medical management of patients living with LVADs.

Background Novel oral anticoagulants (NOACs) have been shown to be at least as good as warfarin for preventing stroke or transient ischemic attack (TIA) in patients with atrial fibrillation (AF), yet diffusion of these therapies and patterns of use among AF patients with ischemic stroke and TIA have not been well characterized. Methods and Results Using data from Get With The Guidelines®–Stroke, we identified a cohort of 61,655 AF patients with ischemic stroke or TIA hospitalized between 10/2010–09/2012 and discharged on warfarin or NOAC (either dabigatran or rivaroxaban). Multivariable logistic regression was used to identify factors associated with NOAC versus warfarin therapy. In our study population, warfarin was prescribed to 88.9%, dabigatran to 9.6%, and rivaroxaban to 1.5%. NOAC use increased from 0.04% to a 16–17% plateau during the study period, though anticoagulation rates among eligible patients did not change appreciably (93.7% vs. 94.1% from first quarter 2011 to second quarter 2012), suggesting a trend of switching from warfarin to NOACs rather than increased rates of anticoagulation among eligible patients. Several bleeding risk factors and CHA2DS2-VASc scores were lower among those discharged on NOAC versus warfarin therapy (47.9% vs. 40.9% with CHA2DS2-VASc ≤5, p<0.001 for difference in CHA2DS2-VASc). Conclusions NOACs have had modest but growing uptake over time among AF patients hospitalized with stroke or TIA and are prescribed to patients with lower stroke risk compared to warfarin.