Phased, chromosome-scale genome assemblies of tetraploid potato reveal a complex genome, transcriptome, and predicted proteome landscape underpinning genetic diversity.

Cultivated potato is a clonally propagated autotetraploid species with a highly heterogeneous genome. Phased assemblies of six cultivars including two chromosome-scale phased genome assemblies revealed extensive allelic diversity, including altered coding and transcript sequences, preferential allele expression, and structural variation that collectively result in a highly complex transcriptome and predicted proteome, which are distributed across the homologous chromosomes. Wild species contribute to the extensive allelic diversity in tetraploid cultivars, demonstrating ancestral introgressions predating modern breeding efforts. As a clonally propagated autotetraploid that undergoes limited meiosis, dysfunctional and deleterious alleles are not purged in tetraploid potato. Nearly a quarter of the loci bore mutations are predicted to have a high negative impact on protein function, complicating breeder's efforts to reduce genetic load. The StCDF1 locus controls maturity, and analysis of six tetraploid genomes revealed that 12 allelic variants of StCDF1 are correlated with maturity in a dosage-dependent manner. Knowledge of the complexity of the tetraploid potato genome with its rampant structural variation and embedded deleterious and dysfunctional alleles will be key not only to implementing precision breeding of tetraploid cultivars but also to the construction of homozygous, diploid potato germplasm containing favorable alleles to capitalize on heterosis in F1 hybrids.

Characteristics of patients presenting to emergency department for primary atrial fibrillation or flutter at an academic medical center.

OBJECTIVE: In the United States, atrial fibrillation (AF) accounts for over 400,000 hospitalizations annually. Emergency Department (ED) physicians have few resources available to guide AF/AFL (atrial flutter) patient triage, and the majority of these patients are subsequently admitted. Our aim is to describe the characteristics and disposition of AF/AFL patients presenting to the University of North Carolina (UNC) ED with the goal of developing a protocol to prevent unnecessary hospitalizations. METHODS: We performed a retrospective electronic medical chart review of AF/AFL patients presenting to the UNC ED over a 15-month period from January 2015 to March 2016. Demographic and ED visit variables were collected. Additionally, patients were designated as either having primary or secondary AF/AFL where primary AF/AFL patients were those in whom AF/AFL was the primary reason for ED presentation. These primary AF/AFL patients were categorized by AF symptom severity score according to the Canadian Cardiovascular Society Severity of Atrial Fibrillation (CCS-SAF) Scale. RESULTS: A total of 935 patients presented to the ED during the study period with 202 (21.5%) having primary AF/AFL. Of the primary AF/AFL patients, 189 (93.6%) had mild-moderate symptom severity (CCS-SAF ≤ 3). The majority of primary AF/AFL patients were hemodynamically stable, with a mean (SD) SBP of 123.8 (21.3), DBP of 76.6 (14.1), and ventricular rate of 93 (21.9). Patients with secondary AF/AFL were older 76 (13.1), p < 0.001 with a longer mean length of stay 6.1 (7.7), p = 0.31. Despite their mild-moderate symptom severity and hemodynamic stability, nearly 2/3 of primary AF/AFL patients were admitted. CONCLUSION: Developing a protocol to triage and discharge hemodynamically stable AF/AFL patients without severe AF/AFL symptoms to a dedicated AF/AFL clinic may help to conserve healthcare resources and potentially deliver more effective care.

An Atrial Fibrillation Transitions of Care Clinic Improves Atrial Fibrillation Quality Metrics.

OBJECTIVES: This study sought to assess whether an atrial fibrillation (AF)-specific clinic is associated with improved adherence to American College of Cardiology (ACC)/American Heart Association (AHA) clinical performance and quality measures for adults with AF or atrial flutter. BACKGROUND: There are significant gaps in care of patients with AF, including underprescription of anticoagulation and treatment of AF risk factors. An AF specialized clinic was developed to reduce admissions for AF but may also be associated with improved quality of care. METHODS: This retrospective study compared adherence to ACC/AHA measures for patients who presented to the emergency department for AF between those discharged to a typical outpatient appointment and those discharged to a specialized AF transitions clinic run by an advanced practice provider and supervised by a cardiologist. Screening and treatment for common AF risk factors was also assessed. RESULTS: The study enrolled 78 patients into the control group and 160 patients into the intervention group. Patients referred to the specialized clinic were more likely to have stroke risk assessed and documented (99% vs. 26%; p < 0.01); be prescribed appropriate anticoagulation (97% vs. 88%; p = 0.03); and be screened for comorbidities such as tobacco use (100% vs. 14%; p < 0.01), alcohol use (92% vs. 60%; p < 0.01), and obstructive sleep apnea (90% vs. 13%; p < 0.01) and less likely to be prescribed an inappropriate combination of anticoagulant and antiplatelet medications (1% vs. 9%; p < 0.01). CONCLUSIONS: An AF specialized clinic was associated with improved adherence to ACC/AHA clinical performance and quality measures for adult patients with AF.

Likelihood of Spontaneous Cardioversion of Atrial Fibrillation Using a Conservative Management Strategy Among Patients Presenting to the Emergency Department.

Numerous emergency department (ED) atrial fibrillation (AF) protocols have been developed to reduce hospitalizations, focusing on the use of cardioversion in the ED. An alternative strategy of rate control with early specialty follow-up may be more widely applicable. The likelihood of spontaneous cardioversion with such a protocol is unknown. Between 2015 and 2018, 157 patients who presented to the ED with a primary diagnosis of AF and were hemodynamically stable and with low to moderate symptom severity were discharged with early follow-up at an AF specialty clinic. Rhythm at short-term (within 72 hours), within 30-day follow-up, and need for electrical cardioversion was tabulated. Various demographic and co-morbidity variables were assessed to determine their association with likelihood of spontaneous cardioversion. At an average of 2.3 days, 63% and within 30 days, 83% had spontaneous cardioversion. By 90 days, only 6.3% required electrical cardioversion. Diabetes (38% vs 69%, p <0.01), coronary artery disease (39% vs 66%, p = 0.02), reduced ejection fraction (40% vs 72%, p <0.01), dilated right atrium (43% vs 73%, p <0.01) and moderate-to-severely dilated left atrium (38% vs 78%, p <0.01) predicted those who were less likely to convert to sinus rhythm. Most patients who present to the ED with AF will spontaneously convert to sinus rhythm by short-term (2 to 3 days) follow-up with a rate control strategy. In conclusion, aggressive use of electrical cardioversion in the ED may be unnecessary in hemodynamically stable patients without severe symptoms.