Inhibition of the KCa2 potassium channel in atrial fibrillation: a randomized phase 2 trial.

Existing antiarrhythmic drugs to treat atrial fibrillation (AF) have incomplete efficacy, contraindications and adverse effects, including proarrhythmia. AP30663, an inhibitor of the KCa2 channel, has demonstrated AF efficacy in animals; however, its efficacy in humans with AF is unknown. Here we conducted a phase 2 trial in which patients with a current episode of AF lasting for 7 days or less were randomized to receive an intravenous infusion of 3 or 5 mg kg-1 AP30663 or placebo. The trial was prematurely discontinued because of slow enrollment during the coronavirus disease 2019 pandemic. The primary endpoint of the trial was cardioversion from AF to sinus rhythm within 90 min from the start of the infusion, analyzed with Bayesian statistics. Among 59 patients randomized and included in the efficacy analyses, the primary endpoint occurred in 42% (5 of 12), 55% (12 of 22) and 0% (0 of 25) of patients treated with 3 mg kg-1 AP30663, 5 mg kg-1 AP30663 or placebo, respectively. Both doses demonstrated more than 99.9% probability of superiority over placebo, surpassing the prespecified 95% threshold. The mean time to cardioversion, a secondary endpoint, was 47 (s.d. = 23) and 41 (s.d. = 24) minutes for 3 mg kg-1 and 5 mg kg-1 AP30663, respectively. AP30663 caused a transient increase in the QTcF interval, with a maximum mean effect of 37.7 ms for the 5 mg kg-1 dose. For both dose groups, no ventricular arrhythmias occurred and adverse event rates were comparable to the placebo group. AP30663 demonstrated AF cardioversion efficacy in patients with recent-onset AF episodes. KCa2 channel inhibition may be an attractive mechanism for rhythm control of AF that should be studied further in randomized trials. ClinicalTrials.gov registration: NCT04571385 .

A phase 1 trial of AP30663, a KCa2 channel inhibitor in development for conversion of atrial fibrillation.

AIMS: AP30663 is a novel compound under development for pharmacological conversion of atrial fibrillation by targeting the small conductance Ca2+ activated K+ (KCa2) channel. The aim of this extension phase 1 study was to test AP30663 at higher single doses compared to the first-in-human trial. METHODS: Sixteen healthy male volunteers were randomized into 2 cohorts: 6- and 8-mg/kg intravenous single-dose administration of AP30663 vs. placebo. Safety, pharmacokinetic and pharmacodynamic data were collected. RESULTS: AP30663 was associated with mild and transient infusion site reactions with no clustering of other adverse events but with an estimated maximum mean QTcF interval prolongation of 45.2 ms (95% confidence interval 31.5-58.9) in the 6 mg/kg dose level and 50.4 ms (95% confidence interval 36.7-64.0) with 8 mg/kg. Pharmacokinetics was dose proportional with terminal half-life of around 3 h. CONCLUSION: AP30663 in doses up to 8 mg/kg was associated with mild and transient infusion site reactions and an increase of the QTcF interval. Supporting Information support that the QTc effect may be explained by an off-target inhibition of the IKr channel.

Association between primary care electrocardiogram markers and Alzheimer's disease.

OBJECTIVE: The association between common electrocardiogram (ECG) markers and Alzheimer's disease has been scarcely investigated, and it is unknown if ECG markers can improve risk prediction. Thus, we aimed to examine the association between common ECG markers and Alzheimer's disease in a large population. METHODS: We studied the association between ECG markers and Alzheimer's disease using Cox models with adjustment for age, sex, and comorbidities using a large primary care population of patients aged 60 years or more. RESULTS: We followed 172,236 subjects for a median of 7.5 years. Increased PR interval (hazard ratio for PR > 188 ms: 0.76 [95% confidence interval: 0.69-0.83, p < 0.001) and increased QTc interval (hazard ratio for QTc = [426;439]: 0.90 [0.83-0.98], p = 0.02) were associated with a decreased rate of Alzheimer's disease. A positive Sokolow-Lyon index >35 mm (1.22 [1.13-1.33], p < 0.001) and increased T-wave amplitude >4.1 mm (1.15 [1.04-1.27]) were associated with an increased rate of Alzheimer's disease. Upon addition of ECG markers to a reference model, 10-year prediction area under the receiver-operator characteristics curve (AUC) improved by 0.39 [0.06-0.67] %-points. The 10-year absolute risk of Alzheimer's disease was 6.5% and 5.2% for an 82-year old female and a male, respectively, with a favorable ECG, and 12% and 9.2%, respectively, with an unfavorable ECG, almost twice as high. CONCLUSIONS: We identified several common ECG markers which were associated with Alzheimer's disease, and which improved risk prediction for Alzheimer's disease.

Associations between primary care electrocardiography and non-Alzheimer dementia.

OBJECTIVES: To determine whether electrocardiogram (ECG) markers are associated with incident non-Alzheimer's dementia (non-AD) and whether these markers also improve risk prediction for non-AD. MATERIALS AND METHODS: We retrospectively included 170,605 primary care patients aged 60 years or older referred for an ECG by their general practitioner and followed them for a median of 7.6 years. Using Cox regression, we reported hazard ratios (HRs) for electrocardiogram markers. Subsequently, we evaluated if addition of these electrocardiogram markers to a clinical model improved risk prediction for non-AD using change in area under the receiver-operator characteristics curve (AUC). RESULTS: The 5-year cumulative incidence of non-AD was 3.4 %. Increased heart rate (HR=1.06 pr. 10 bpm [95% confidence interval: 1.04-1.08], p<0.001), shorter QRS duration (HR=1.07 pr. 10 ms [1.05-1.09], p<0.001), elevated J-amplitude (HR=1.16 pr. mm [1.08-1.24], p<0.001), decreased T-peak amplitude (HR=1.02 pr. mm [1.01-1.04], p=0.002), and increased QTc (HR=1.08 pr. 20 ms [1.05-1.10], p<0.001) were associated with an increased rate of non-AD. Atrial fibrillation on the ECG (HR=1.18 [1.08-1.28], p<0.001) Sokolow-Lyon index > 35 mm (HR=1.31 [1.18-1.46], p<0.001) and borderline (HR=1.18 [1.11-1.26], p<0.001) or abnormal (HR=1.40 [1.27-1.55], p<0.001) QRS-T angle were also associated with an increased rate of non-AD. Upon addition of ECG markers to the Cox model, 5-year and 10-year C-statistic (AUC) improved significantly (delta-AUC, 0.36 [0.18-0.50] and 0.20 [0.03-0.35] %-points, respectively). CONCLUSIONS: ECG markers typical of an elevated cardiovascular risk profile were associated with non-AD and improved both 5-year and 10-year risk predictions for non-AD.

Implantable loop recorder detection of atrial fibrillation to prevent stroke (The LOOP Study): a randomised controlled trial.

BACKGROUND: It is unknown whether screening for atrial fibrillation and subsequent treatment with anticoagulants if atrial fibrillation is detected can prevent stroke. Continuous electrocardiographic monitoring using an implantable loop recorder (ILR) can facilitate detection of asymptomatic atrial fibrillation episodes. We aimed to investigate whether atrial fibrillation screening and use of anticoagulants can prevent stroke in individuals at high risk. METHODS: We did a randomised controlled trial in four centres in Denmark. We included individuals without atrial fibrillation, aged 70-90 years, with at least one additional stroke risk factor (ie, hypertension, diabetes, previous stroke, or heart failure). Participants were randomly assigned in a 1:3 ratio to ILR monitoring or usual care (control) via an online system in permuted blocks with block sizes of four or eight participants stratified according to centre. In the ILR group, anticoagulation was recommended if atrial fibrillation episodes lasted 6 min or longer. The primary outcome was time to first stroke or systemic arterial embolism. This study is registered with ClinicalTrials.gov, NCT02036450. FINDINGS: From Jan 31, 2014, to May 17, 2016, 6205 individuals were screened for inclusion, of whom 6004 were included and randomly assigned: 1501 (25·0%) to ILR monitoring and 4503 (75·0%) to usual care. Mean age was 74·7 years (SD 4·1), 2837 (47·3%) were women, and 5444 (90·7%) had hypertension. No participants were lost to follow-up. During a median follow-up of 64·5 months (IQR 59·3-69·8), atrial fibrillation was diagnosed in 1027 participants: 477 (31·8%) of 1501 in the ILR group versus 550 (12·2%) of 4503 in the control group (hazard ratio [HR] 3·17 [95% CI 2·81-3·59]; p<0·0001). Oral anticoagulation was initiated in 1036 participants: 445 (29·7%) in the ILR group versus 591 (13·1%) in the control group (HR 2·72 [95% CI 2·41-3·08]; p<0·0001), and the primary outcome occurred in 318 participants (315 stroke, three systemic arterial embolism): 67 (4·5%) in the ILR group versus 251 (5·6%) in the control group (HR 0·80 [95% CI 0·61-1·05]; p=0·11). Major bleeding occurred in 221 participants: 65 (4·3%) in the ILR group versus 156 (3·5%) in the control group (HR 1·26 [95% CI 0·95-1·69]; p=0·11). INTERPRETATION: In individuals with stroke risk factors, ILR screening resulted in a three-times increase in atrial fibrillation detection and anticoagulation initiation but no significant reduction in the risk of stroke or systemic arterial embolism. These findings might imply that not all atrial fibrillation is worth screening for, and not all screen-detected atrial fibrillation merits anticoagulation. FUNDING: Innovation Fund Denmark, The Research Foundation for the Capital Region of Denmark, The Danish Heart Foundation, Aalborg University Talent Management Program, Arvid Nilssons Fond, Skibsreder Per Henriksen, R og Hustrus Fond, The AFFECT-EU Consortium (EU Horizon 2020), Læge Sophus Carl Emil Friis og hustru Olga Doris Friis' Legat, and Medtronic.

Electrocardiographic T-wave morphology and risk of mortality.

BACKGROUND: Electrocardiographic T-wave morphology is used in drug safety studies as an adjunct to the QTc interval, but few measurements of T-wave morphology can be interpreted in clinical practice. Morphology combination score (MCS) is a combination of T-wave flatness/peakedness, asymmetry, and notching, enabling easy visual assessment of T-wave morphology. We aimed to test the association between T-wave morphology, quantified by MCS, and mortality. METHODS: We included electrocardiograms recorded in 2001-2011 from 342,294 primary care patients. Using Cox regression, we evaluated the association between MCS, cardiovascular death, and all-cause mortality, adjusting for heart rate, QTc, QT-prolonging drugs, diabetes, ischemic heart disease, hypertension, and congestive heart failure. RESULTS: 270,039 individuals (44% men, median age 55 [inter-quartile range: 42-67 years]) were included and followed for a median of 9.3 years, during which time 13,489 (5.0%) died from cardiovascular causes and 50,481 (18.7%) from any cause. High values of MCS (i.e. asymmetric, flattened, and/or notched T waves) were associated with an adjusted mortality Hazard Ratio of 1.75 (95% CI 1.62-1.89) and 1.61 (1.43-1.92) for women and men, respectively. Low values of MCS (i.e. peaked and symmetric T waves) were associated with a Hazard Ratio of 1.18 (1.08-1.28) and 1.71 (1.48-1.98) for women and men, respectively. CONCLUSIONS: In a large primary care population, we found that T-wave asymmetry, flatness, and notching provided prognostic information on mortality independent of heart rate, QTc, and baseline comorbidities.

Early glycaemic changes after initiation of oral antidiabetic medication and risk of major adverse cardiovascular events: results from a large primary care population of patients with type 2 diabetes.

AIMS: To determine the risk of major adverse cardiovascular events (MACE) and death, associated with an early large and rapid decline in glycated haemoglobin (HbA1C) following first time initiation of an oral antidiabetic drug (OAD). METHODS AND RESULTS: We included 10 518 primary care patients with type 2 diabetes, who initiated an OAD for the first time. For each individual, we measured a decline in HbA1C, as the difference between the pre-treatment HbA1C (within 3 months before OAD initiation) and the post-treatment HbA1C (within 1.5-4.5 months after OAD initiation), divided by the time between the two measurements. The decline was reported in mmol/mol change per 3 months in HbA1C and categorized by the median decline into levels of steep [≥9 mmol/mol (≥0.8%)] and flat decline [<9 mmol/mol per 3 months (<0.8%)]. Pre-treatment HbA1C was categorized by the median, into levels of low (48-62 mmol/mol) and high (>62 mmol/mol). Multiple Cox regression was used to study the effect of decline (steep vs. flat) on the outcome hazard rates separately for patients with low and high pre-treatment HbA1C. Analyses were adjusted for age, sex, traditional cardiovascular risk factors, severe comorbidities, and concomitant medication treatment. During a median follow-up time of 7.7 years, 1625 developed MACE and 2323 died. We found that a steep decline vs. a flat decline was significantly associated with a decreased hazard for MACE, both in individuals with high [hazard ratio (HR) 0.81; 95% confidence interval (CI) 0.69-0.94; P = 0.005] and low pre-treatment HbA1C (HR 0.79; 95% CI 0.66-0.96; P = 0.015). The hazard of MACE was more pronounced on the short-term vs. long-term in individuals with high pre-treatment HbA1C. We found no significant association between combinations of pre-treatment HbA1C and decline categories and hazard of all-cause mortality. However, a combination of a low pre-treatment HbA1C and steep decline was associated with increased 1-year mortality (HR 1.52; 95% CI 1.00-2.29; P = 0.048) and hypoglycaemia (HR 1.82; 95% CI 1.11-2.98; P = 0.017). CONCLUSION: A combination of a high pre-treatment HbA1C and a steep decline in HbA1C was associated with a decreased short-term risk of MACE. A low pre-treatment HbA1C and a steep decline was associated with a long-term reduced risk of MACE, but a short-term increased risk of death and hypoglycaemia.

Incidence, Predictors, and Success of Ventricular Tachycardia Catheter Ablation in Arrhythmogenic Right Ventricular Cardiomyopathy (from the Nordic ARVC Registry).

Catheter ablation may reduce ventricular tachycardia (VT) burden in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients. However, little is known about factors predicting need for ablation. Therefore, we sought to investigate predictors and use of VT ablation and to evaluate the postprocedural outcome in ARVC patients. We studied 435 patients from the Nordic ARVC registry including 220 probands with definite ARVC according to the 2010 task force criteria and 215 mutation-carrying relatives identified through cascade screening. Patients were followed until first-time VT ablation, death, heart transplantation, or January 1st 2018. Additionally, patients undergoing VT ablation were further followed from the time of ablation for recurrent ventricular arrhythmias. The cumulative use of VT ablation was 4% (95% confidence interval [CI] 3% to 6%) and 11% (95% CI 8% to 15%) after 1 and 10 years. All procedures were performed in probands in whom cumulative use was 8% (95% CI 5% to 12%) and 20% (95% CI 15% to 26%). In adjusted analyses among probands, only young age predicted ablation. In patients undergoing ablation, risk of recurrent arrhythmias was 59% (95% CI 44% to 71%) and 74% (95% CI 59% to 84%) 1 and 5 years after the procedure. Despite high recurrence rates, the burden of ventricular arrhythmias was reduced after ablation (p = 0.0042). Young age, use of several antiarrhythmic drugs and inducibility to VT after ablation were associated with an unfavorable outcome. In conclusion, twenty percent of ARVC probands developed a clinical indication for VT ablation within 10 years whereas mutation-carrying relatives were without such need. Although the burden of ventricular arrhythmias decreased after ablation, risk of recurrence was substantial.

Effect of diabetes duration on the relationship between glycaemic control and risk of death in older adults with type 2 diabetes.

AIM: To investigate the effect of diabetes duration on glycaemic control, measured using mean glycated haemoglobin (HbA1c) level, and mortality risk within different age, sex and clinically relevant, comorbidity-defined subgroups in an elderly population with type 2 diabetes (T2D). METHODS: We studied older (≥65 years) primary care patients with T2D, who had three successive annual measurements of HbA1c taken between 2005 and 2013. The primary exposure was the mean of all three HbA1c measurements. Follow-up began on the date of the third measurement. Individual mean HbA1c levels were categorized into clinically relevant groups (<6.5% [<48 mmol/mol]; 6.5%-6.9% [48-52 mmol/mol]; 7%-7.9% [53-63 mmol/mol]; 8%-8.9% [64-74 mmol/mol]; and ≥9% [≥75 mmol/mol]). We used multiple Cox regression to study the effect of glycaemic control on the hazard of all-cause mortality, adjusted for age, sex, use of concomitant medication, and age- and disease-related comorbidities. RESULTS: A total of 9734 individuals were included. During a median (interquartile range) follow-up of 7.3 (4.6-8.7) years, 3320 individuals died. We found that the effect of mean HbA1c on all-cause mortality depended on the duration of diabetes (P for interaction <.001). For individuals with short diabetes duration (<5 years), the risk of death increased with poorer glycaemic control (increasing HbA1c), whereas for individuals with longstanding diabetes (≥5 years), we found a J-shaped association, where a mean HbA1c level between 6.5% and 7.9% [48 and 63 mmol/mol] was associated with the lowest risk of death. For individuals with longstanding diabetes, both low (<6.5% [<48 mmol/mol]; hazard ratio [HR] 1.21, 95% confidence interval [CI] 1.07-1.37, P = .002) and high mean HbA1c levels (≥9.0% [≥75 mmol/mol]; HR 1.60, 95% CI 1.28-1.99, P < .001) were associated with an increased risk of death. We also calculated 5-year absolute risks of all-cause mortality, separately for short and long diabetes duration, and found similar risk patterns across different age groups, sex and comorbidity strata. CONCLUSIONS: In elderly individuals with T2D, the effect of glycaemic control (measured by HbA1c) on all-cause mortality depended on the duration of diabetes. Of particular clinical importance, we found that strict glycaemic control was associated with an increased risk of death among individuals with long (≥ 5 years) diabetes duration. Conversely, for individuals with short diabetes duration, strict glycaemic control was associated with the lowest risk of death. These results indicate that tight glycemic control may be beneficial in people with short duration of diabetes, whereas a less stringent target may be warranted with longer diabetes exposure.

Long-Term Prognostic Value of Less-Stringent Electrocardiographic Q Waves and Fourth Universal Definition of Myocardial Infarction Q Waves.

BACKGROUND: The Fourth Universal Definition of Myocardial Infarction defines electrocardiographic Q waves as duration ≥30 ms and amplitude ≥1 mm or QS complex in 2 contiguous leads. However, current taskforce criteria may be overly restrictive. Therefore, we investigated the association of isolated, lenient, or strict Q waves with long-term outcome. METHODS: From 2001 to 2015, we included Danish primary care patients with digital electrocardiograms (ECGs) that were evaluated for Q waves. If none occurred, patients had no Q waves. If no other contiguous Q wave occurred, patients had isolated Q waves. If another contiguous Q wave occurred meeting only 1 criterion (≥30 ms and <1 mm or <30 ms and ≥1 mm), patients had lenient Q waves. If another contiguous Q wave occurred, patients had strict Q waves. RESULTS: Of 365,206 patients, 87,957 had isolated, lenient, or strict Q waves (24%; median age, 61 years; male, 48%), and 277,249 had no Q waves (76%; median age, 53 years; male, 42%). Mortality risk was increased with isolated (all-cause adjusted hazard ratio [aHR], 1.33; 95% confidence interval [CI], 1.29-1.37; cardiovascular-cause aHR, 1.78; 95% CI, 1.70-1.87), lenient (all-cause aHR, 1.41; 95% CI, 1.33-1.50; cardiovascular-cause aHR, 1.78; 95% CI, 1.63-1.94), or strict (all-cause aHR, 1.64; 95% CI, 1.57-1.72; cardiovascular-cause aHR, 2.70; 95% CI, 2.52-2.89) Q waves compared with no Q waves. Highest mortality risk was associated with lenient or strict Q waves in anteroseptal leads. CONCLUSIONS: This large contemporary analysis suggests that less-stringent Q-wave criteria carry prognostic value in predicting adverse outcome among primary care patients.

Thyroid dysfunction and electrocardiographic changes in subjects without arrhythmias: a cross-sectional study of primary healthcare subjects from Copenhagen.

OBJECTIVE: The objective of the present study was to investigate associations of both overt and subclinical thyroid dysfunction with common ECG parameters in a large primary healthcare population. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: The study population comprised of primary healthcare patients in Copenhagen, Denmark, who had a thyroid function test and an ECG recorded within 7 days of each other between 2001 and 2011. DATA SOURCES: The Danish National Patient Registry was used to collect information regarding baseline characteristics and important comorbidities. OUTCOME MEASURE AND STUDY GROUPS: Common ECG parameters were determined using Marquette 12SL software and were compared between the study groups. The study population was divided into five groups based on their thyroid status. Euthyroid subjects served as the reference group in all analyses. RESULTS: A total of 132 707 patients (age 52±17 years; 50% female) were included. Hyperthyroidism was significantly associated with higher heart rate and prolonged QTc interval with significant interaction with age (p<0.009) and sex (p<0.001). These associations were less pronounced for patients with higher age. Subclinical hyperthyroidism was associated with higher heart rate among females, and a similar trend was observed among males. Hypothyroidism was associated with slower heart rate and shorter QTc but only in women. Moreover, longer P-wave duration, longer PR interval and low voltage were observed in patients with both subclinical and overt hypothyroidism. However, the presence of low voltage was less pronounced with higher age (p=0.001). CONCLUSION: Both overt and subclinical thyroid disorders were associated with significant changes in important ECG parameters. Age and gender have significant impact on the association of thyroid dysfunction particularly on heart rate and QTc interval.

Reductions in Insulin Resistance are Mediated Primarily via Weight Loss in Subjects With Type 2 Diabetes on Semaglutide.

CONTEXT: Semaglutide, a once-weekly glucagon-like peptide-1 analog approved for use in patients with type 2 diabetes (T2D), demonstrated superior body weight (BW) reductions and decreased insulin resistance (IR) vs comparators across the Semaglutide Unabated Sustainability in Treatment of Type 2 Diabetes (SUSTAIN) 1-3 clinical trials. OBJECTIVE: To investigate the relationship between IR and BW across the SUSTAIN 1-3 trials. DESIGN: Post hoc analysis of the SUSTAIN 1-3 trials. SETTING: Three hundred and eleven sites in 30 countries. PATIENTS OR OTHER PARTICIPANTS: 2432 subjects with T2D. INTERVENTIONS: Semaglutide 0.5 or 1.0 mg, placebo or active comparator (sitagliptin 100 mg, exenatide extended release 2.0 mg). MAIN OUTCOME MEASURE: To assess the extent of the effect on IR that is mediated (indirect effect) and not mediated (direct effect) by the effect on BW. RESULTS: Across SUSTAIN 1-3, mean BW was significantly reduced with semaglutide 0.5 mg (3.7 kg to 4.3 kg; P < 0.0001) and semaglutide 1.0 mg (4.5 kg to 6.1 kg; P < 0.0001) vs comparators (1.0 kg to 1.9 kg). There were greater reductions in IR with semaglutide 0.5 mg (27% to 36%) and semaglutide 1.0 mg (32% to 46%) vs comparators (17% to 28%). Greater reductions in BW were generally associated with greater decreases in IR. The effect on IR was primarily mediated by weight loss (70% to 80% and 34% to 94%, for semaglutide 0.5 mg and 1.0 mg, respectively, vs comparator). CONCLUSIONS: Semaglutide consistently reduced BW and IR in subjects with T2D in SUSTAIN 1-3. In this analysis, IR improvement was positively associated with, and primarily mediated by, the effect of semaglutide on BW.

Visit-to-Visit Variability of Hemoglobin A1c in People Without Diabetes and Risk of Major Adverse Cardiovascular Events and All-Cause Mortality.

OBJECTIVE: We aimed to study whether visit-to-visit variability of glycated hemoglobin A1c (HbA1c) is associated with incident major adverse cardiovascular events (MACE), all-cause mortality, and type 2 diabetes in people without diabetes. RESEARCH DESIGN AND METHODS: We included primary care patients with no history of diabetes or cardiovascular disease and with three annual HbA1c measurements within normal range (<6.5% [48 mmol/mol]). For each individual, we measured the HbA1c variability as the SD of the residuals obtained from a linear regression on the three HbA1c measurements. From the linear regression, we also obtained the estimated index HbA1c (intercept) and the trend over time (slope). Follow-up began at the date of the third measurement. Associations between HbA1c variability and outcome were analyzed using Cox regression, adjusted for traditional risk factors, intercept, and trend and reported as hazard ratio per SD increase in variability (HRSD). RESULTS: In total, 6,756 individuals were included. During a median follow-up time of 6.3 years, 996 developed MACE, 856 died, and 1,267 developed type 2 diabetes. We found a significant association between increasing HbA1c variability and incident MACE (HRSD 1.09 [95% CI 1.03-1.15]) and all-cause mortality (HRSD 1.13 [95% CI 1.07-1.20]), whereas there were no associations with type 2 diabetes (HRSD 1.00 [95% CI 0.95-1.05]). We calculated 5-year absolute risks of MACE and all-cause mortality and found clinically relevant differences across several age, sex, comorbidity, and HbA1c variability-defined subgroups. CONCLUSIONS: In a primary care population free of diabetes and cardiovascular disease, high HbA1c variability was associated with increased risks of MACE and all-cause mortality.

Rare truncating variants in the sarcomeric protein titin associate with familial and early-onset atrial fibrillation.

A family history of atrial fibrillation constitutes a substantial risk of developing the disease, however, the pathogenesis of this complex disease is poorly understood. We perform whole-exome sequencing on 24 families with at least three family members diagnosed with atrial fibrillation (AF) and find that titin-truncating variants (TTNtv) are significantly enriched in these patients (P = 1.76 × 10-6). This finding is replicated in an independent cohort of early-onset lone AF patients (n = 399; odds ratio = 36.8; P = 4.13 × 10-6). A CRISPR/Cas9 modified zebrafish carrying a truncating variant of titin is used to investigate TTNtv effect in atrial development. We observe compromised assembly of the sarcomere in both atria and ventricle, longer PR interval, and heterozygous adult zebrafish have a higher degree of fibrosis in the atria, indicating that TTNtv are important risk factors for AF. This aligns with the early onset of the disease and adds an important dimension to the understanding of the molecular predisposition for AF.

Biobank-driven genomic discovery yields new insight into atrial fibrillation biology.

To identify genetic variation underlying atrial fibrillation, the most common cardiac arrhythmia, we performed a genome-wide association study of >1,000,000 people, including 60,620 atrial fibrillation cases and 970,216 controls. We identified 142 independent risk variants at 111 loci and prioritized 151 functional candidate genes likely to be involved in atrial fibrillation. Many of the identified risk variants fall near genes where more deleterious mutations have been reported to cause serious heart defects in humans (GATA4, MYH6, NKX2-5, PITX2, TBX5)1, or near genes important for striated muscle function and integrity (for example, CFL2, MYH7, PKP2, RBM20, SGCG, SSPN). Pathway and functional enrichment analyses also suggested that many of the putative atrial fibrillation genes act via cardiac structural remodeling, potentially in the form of an 'atrial cardiomyopathy'2, either during fetal heart development or as a response to stress in the adult heart.

Effect of once-weekly semaglutide on the counterregulatory response to hypoglycaemia in people with type 2 diabetes: A randomized, placebo-controlled, double-blind, crossover trial.

AIMS: To investigate the effects of semaglutide vs placebo on glucagon and other counterregulatory hormones during hypoglycaemia in type 2 diabetes (T2D). METHODS: In this double-blind, placebo-controlled, single-centre trial, we randomized 38 men and women (treated only with metformin) 1:1 to 2 12-week crossover periods of once-weekly subcutaneous semaglutide or placebo, each followed by a hypoglycaemic clamp procedure. The primary endpoint was change in glucagon concentration from target plasma glucose (PG) level 5.5 mmol/L to nadir (target 2.5 mmol/L). RESULTS: The mean (range) participant age was 54.2 (41-64) years, body mass index 29.4 (23.3-36.1) kg/m2 , glycated haemoglobin 60.8 (44.3-83.6) mmol/mol (7.7 [6.2-9.8]%), and diabetes duration 4.5 (0.3-13.2) years. A total of 35 participants completed the trial and were included in the analyses. During the hypoglycaemic clamp from 5.5 mmol/L PG to nadir, the absolute change in mean glucagon concentration was similar for semaglutide vs placebo: 88.3 vs 83.1 pg/mL (estimated difference 5.2 pg/mL [95% confidence interval -7.7 to 18.1]). Concentrations of other counterregulatory hormones increased with both treatments, with a statistically significantly lower increase for noradrenaline and cortisol with semaglutide vs placebo. The glucose infusion rate to maintain constant clamp levels was similar for each treatment group, suggesting an overall similar counterregulatory response. The mean hypoglycaemic symptom score and proportion of participants recognizing hypoglycaemia during the study were lower for semaglutide vs placebo treatment at nadir, but cognitive function test results were similar. No new safety issues were observed for semaglutide. CONCLUSIONS: Semaglutide treatment did not compromise the counterregulatory glucagon response during experimental hypoglycaemia in people with T2D.

Risk Prediction of Atrial Fibrillation Based on Electrocardiographic Interatrial Block.

BACKGROUND: The electrocardiographic interatrial block (IAB) has been associated with atrial fibrillation (AF). We aimed to test whether IAB can improve risk prediction of AF for the individual person. METHODS AND RESULTS: Digital ECGs of 152 759 primary care patients aged 50 to 90 years were collected from 2001 to 2011. We identified individuals with P-wave ≥120 ms and the presence of none, 1, 2, or 3 biphasic P-waves in inferior leads. Data on comorbidity, medication, and outcomes were obtained from nationwide registries. We observed a dose-response relationship between the number of biphasic P-waves in inferior leads and the hazard of AF during follow-up. Discrimination of the 10-year outcome of AF, measured by time-dependent area under the curve, was increased by 1.09% (95% confidence interval 0.43-1.74%) for individuals with cardiovascular disease at baseline (CVD) and 1.01% (95% confidence interval 0.40-1.62%) for individuals without CVD, when IAB was added to a conventional risk model for AF. The highest effect of IAB on the absolute risk of AF was observed in individuals aged 60 to 70 years with CVD. In this subgroup, the 10-year risk of AF was 50% in those with advanced IAB compared with 10% in those with a normal P-wave. In general, individuals with advanced IAB and no CVD had a higher risk of AF than patients with CVD and no IAB. CONCLUSIONS: IAB improves risk prediction of AF when added to a conventional risk model. Clinicians may consider monitoring patients with IAB more closely for the occurrence of AF, especially for high-risk subgroups.

Heart transplantation in arrhythmogenic right ventricular cardiomyopathy - Experience from the Nordic ARVC Registry.

OBJECTIVE: There is a paucity of data on heart transplantation (HTx) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), and specific recommendations on indications for listing ARVC patients for HTx are lacking. In order to delineate features pertinent to HTx assessment, we explored the pre-HTx characteristics and clinical history in a cohort of ARVC patients who received heart transplants. METHODS: Data from 31 ARVC/HTx patients enrolled in the Nordic ARVC Registry, transplanted between 1988 and 2014 at a median age of 46years (14-65), were compared with data from 152 non-transplanted probands with Definite ARVC according to 2010 Task Force Criteria from the same registry. RESULTS: The HTx patients were younger at presentation, median 31 vs. 38years (p=0.001). There was no difference in arrhythmia-related events. The indication for HTx was heart failure in 28 patients (90%) and ventricular arrhythmias in 3 patients (10%). During median follow-up of 4.9years (0.04-28), there was one early death and two late deaths. Survival was 91% at 5years after HTx. Age at first symptoms under 35years independently predicted HTx in our cohort (OR=7.59, 95% CI 2.69-21.39, p<0.001). CONCLUSION: HTx in patients with ARVC is performed predominantly due to heart failure. This suggests that current 2016 International Society for Heart and Lung Transplantation heart transplant listing recommendations for other cardiomyopathies could be applicable in many cases when taking into account the haemodynamic consequences of right ventricular failure in conjunction with ventricular arrhythmia.

Efficacy and Safety of Once-Weekly Semaglutide Versus Exenatide ER in Subjects With Type 2 Diabetes (SUSTAIN 3): A 56-Week, Open-Label, Randomized Clinical Trial.

OBJECTIVE: To compare the efficacy and safety of once-weekly semaglutide 1.0 mg s.c. with exenatide extended release (ER) 2.0 mg s.c. in subjects with type 2 diabetes. RESEARCH DESIGN AND METHODS: In this phase 3a, open-label, parallel-group, randomized controlled trial, 813 subjects with type 2 diabetes taking oral antidiabetic drugs were randomized (1:1) to semaglutide 1.0 mg or exenatide ER 2.0 mg for 56 weeks. The primary end point was change from baseline in HbA1c at week 56. RESULTS: Mean HbA1c (8.3% [67.7 mmol/mol] at baseline) was reduced by 1.5% (16.8 mmol/mol) with semaglutide and 0.9% (10.0 mmol/mol) with exenatide ER (estimated treatment difference vs. exenatide ER [ETD] -0.62% [95% CI -0.80, -0.44] [-6.78 mmol/mol (95% CI -8.70, -4.86)]; P < 0.0001 for noninferiority and superiority). Mean body weight (95.8 kg at baseline) was reduced by 5.6 kg with semaglutide and 1.9 kg with exenatide ER (ETD -3.78 kg [95% CI -4.58, -2.98]; P < 0.0001). Significantly more subjects treated with semaglutide (67%) achieved HbA1c <7.0% (<53 mmol/mol) versus those taking exenatide ER (40%). Both treatments had similar safety profiles, but gastrointestinal adverse events were more common in semaglutide-treated subjects (41.8%) than in exenatide ER-treated subjects (33.3%); injection-site reactions were more frequent with exenatide ER (22.0%) than with semaglutide (1.2%). CONCLUSIONS: Semaglutide 1.0 mg was superior to exenatide ER 2.0 mg in improving glycemic control and reducing body weight after 56 weeks of treatment; the drugs had comparable safety profiles. These results indicate that semaglutide treatment is highly effective for subjects with type 2 diabetes who are inadequately controlled on oral antidiabetic drugs.