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Aims: Patients with HFrEF and worsening HF events (WHFE) are at particularly high risk and urgently need disease‐modifying therapy. CHART‐HF assessed treatment patterns and reasons for medication decisions among HFrEF patients with and without WHFE. Methods and results: CHART‐HF collected retrospective electronic medical records of outpatients with HF and EF < 45% between 2017–2019 from a nationwide panel of 238 cardiologists (458 patients) and the Geisinger Health System (GHS) medical record (1000 patients). The index visit in the WHFE cohort was the first outpatient cardiologist visit ≤6 months following the WHFE, and in the reference cohort was the last visit in a calendar year without WHFE. Demographic characteristics were similar between patients with and without WHFE in both the nationwide panel and GHS. In the nationwide panel, the proportion of patients with versus without WHFE receiving ≥50% of guideline‐recommended dose on index visit was 35% versus 40% for beta blocker, 74% versus 83% for ACEI/ARB/ARNI, and 48% versus 49% for MRA. The proportion of patients receiving ≥50% of guideline‐recommended dose was lower in the GHS: 29% versus 34% for beta‐blocker, 16% versus 31% for ACEI/ARB/ARNI, and 18% versus 22% for MRA. For patients with and without WHFE, triple therapy on index date was 42% and 44% of patients from the nationwide panel, and 14% and 17% in the GHS. Comparing end of index clinic visit with 12‐month follow‐up in the GHS, the proportion of patients on no GDMT increased from 14% to 28% in the WHFE cohort and from 14 to 21% in the non‐WHFE group. Conclusions: Major gaps in use of GDMT, particularly combination therapy, remain among US HFrEF patients. These gaps persist during longitudinal follow‐up and are particularly large among patients with recent WHFE. [ABSTRACT FROM AUTHOR]

Aims: The relationship between accelerometry data and changes in Kansas City Cardiomyopathy Questionnaire‐Physical Limitation Score (KCCQ‐PLS) or 6 min walk test (6MWT) is not well understood. Methods and results: VITALITY‐HFpEF accelerometry substudy (n = 69) data were assessed at baseline and 24 weeks. Ordinal logistic regression models were used to assess the association between accelerometry activity and deterioration, improved, or unchanged KCCQ‐PLS (≥8.33 and ≤ −4.17 points) and 6MWT (≥32 vs. ≤ −32 m). KCCQ‐PLS score deteriorated in 16 patients, improved in 34, and was unchanged in 19. 6MWT deteriorated in 8 patients, improved in 21, and was unchanged in 19. Mean accelerometer wear was 21.4 (±2.1) h/day. Changes in hours active from baseline to 24 weeks were not significantly different among patients who exhibited deterioration, improvement, or no change in KCCQ‐PLS [odds ratio (OR) 0.91, 95% confidence interval (CI) 0.71–1.18; P = 0.48] or 6MWT (OR 1.21, 95% CI 0.91–1.60; P = 0.18). Similar lack of association was observed for other accelerometry metrics and change in KCCQ and 6MWT. These findings were unaffected when KCCQ and 6MWT were examined as continuous variables. Conclusions: Accelerometer‐based activity measures did not correlate with subjective or objective standard measures of health status and functional capacity in heart failure with preserved ejection fraction. Further investigation of their relationships to clinical outcomes is required. [ABSTRACT FROM AUTHOR]

Aims: Whether electrocardiographic (ECG) measurements predict mortality in chronic heart failure with reduced ejection fraction (HFrEF) is unknown. Methods and results: We studied 4880 patients from the Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction (VICTORIA) trial with a baseline 12‐lead ECG. Associations between ECG measurements and mortality were estimated as hazard ratios (HR) and adjusted for the Meta‐Analysis Global Group in Chronic Heart Failure (MAGGIC) risk score, N‐terminal pro‐B‐type natriuretic peptide, and index event. Select interactions between ECG measurements, patient characteristics and mortality were examined. Over a median of 10.8 months, there were 824 cardiovascular (CV) deaths (214 sudden) and 1005 all‐cause deaths. Median age was 68 years (interquartile range [IQR] 60–76), 24% were women, median ejection fraction was 30% (IQR 23–35), 41% had New York Heart Association class III/IV, and median MAGGIC score was 24 (IQR 19–28). After multivariable adjustment, significant associations existed between heart rate (per 5 bpm: HR 1.02), QRS duration (per 10 ms: HR 1.02), absence of left ventricular hypertrophy (HR 0.64) and CV death, and similarly so with all‐cause death (HR 1.02; HR 1.02; HR 0.61, respectively). Contiguous pathologic Q waves were significantly associated with sudden death (HR 1.46), and right ventricular hypertrophy with all‐cause death (HR 1.44). The only sex‐based interaction observed was for pathologic Q waves on CV (men: HR 1.05; women: HR 1.64, pinteraction = 0.024) and all‐cause death (men: HR 0.99; women: HR 1.57; pinteraction = 0.010). Whereas sudden death doubled in females, it did not differ among males (male: HR 1.25, 95% confidence interval [CI] 0.87–1.79; female: HR 2.50, 95% CI 1.23–5.06; pinteraction = 0.141). Conclusion: Routine ECG measurements provide additional prognostication of mortality in high‐risk HFrEF patients, particularly in women with contiguous pathologic Q waves. [ABSTRACT FROM AUTHOR]

Aims: Clinically important thresholds in patient‐reported outcomes measures like the Kansas City Cardiomyopathy Questionnaire (KCCQ) have not been defined for patients with heart failure and preserved ejection fraction (HFpEF). The aim of this study was to estimate meaningful thresholds for improvement or worsening in the KCCQ physical limitation score (PLS) in patients with HFpEF. Methods and results: In this pre‐specified analysis from VITALITY‐HFpEF, anchor‐ and distribution‐based approaches were used to estimate thresholds for improvement or worsening in the KCCQ‐PLS using Patient Global Impression of Change (PGIC) as an anchor. The KCCQ‐PLS contains six elements, with each increment in response resulting in a change of 4.17 points when converted to a 0–100 scale. The mean change in KCCQ‐PLS from baseline to week 12 was calculated for each PGIC group to estimate a meaningful within‐patient change. Of 789 patients enrolled, 698 had complete KCCQ‐PLS and PGIC data at week 12. The mean (± standard deviation) changes in KCCQ‐PLS corresponding to PGIC changes of 'a little better', 'better', and 'much better' were 5.7 ± 18.6, 11.6 ± 19.3, and 18.4 ± 25.3 points, respectively. The scores of patients who responded 'a little better' (n = 177) overlapped substantially with those who reported 'no change' (n = 193; mean change 2.8 ± 18.9). The mean change in KCCQ‐PLS for patients responding 'a little worse' (n = 32) was −2.6 ± 18.0 points. The threshold for meaningful within‐patient change in KCCQ‐PLS based on distribution‐based analyses was 12.3 points. Using area under the curve (AUC) analyses of KCCQ‐PLS, the sensitivity and specificity of a 4.17‐point change were 0.61 and 0.57, for an 8.33‐point change they were 0.49 and 0.64, and for a 12.5‐point change they were 0.44 and 0.72 for being at least a little better on the PGIC (AUC = 0.54). Conclusion: In the VITALITY‐HFpEF trial, a change in KCCQ‐PLS of ≥8.33 points (corresponding to an improvement in ≥2 response categories of KCCQ‐PLS) may represent the minimal clinically important difference for improvement and a change of ≤ −4.17 points (corresponding to a worsening in ≥1 response category of KCCQ‐PLS) may suggest deterioration in patients with HFpEF. [ABSTRACT FROM AUTHOR]

Aims: Coronary artery disease (CAD) portends worse outcomes in heart failure (HF). We aimed to characterize patients with CAD and worsening HF with reduced ejection fraction (HFrEF) and evaluate post hoc whether vericiguat treatment effect varied according to CAD. Methods and results: Cox proportional hazards were generated for the primary endpoint of cardiovascular death or HF hospitalization (CVD/HFH). CAD was defined as previous myocardial infarction, percutaneous coronary intervention, or coronary artery bypass grafting. Of 5048 patients in VICTORIA with available data on CAD status, 2704 had CAD and were older, were more frequently male, diabetic, and had a lower glomerular filtration rate than those without CAD (all p <0.0001). Use of implantable cardioverter defibrillators and cardiac resynchronization therapy (CRT) was higher in patients with versus without CAD (33.5% vs. 21.1%; p <0.0001 and 16.3% vs. 12.8%; p = 0.0006). The primary endpoint of CVD/HFH was higher in those with versus without CAD (40.6 vs. 30.1/100 patient‐years; adjusted hazard ratio [HR] 1.23; p <0.001) as was all‐cause mortality (17.9% vs. 12.7%; adjusted HR 1.32; p <0.001). The primary outcome of CVD/HFH associated with vericiguat in patients with or without CAD was 38.8 versus 27.6 per 100 patient‐years and for placebo was 42.6 versus 32.7 per 100 patient‐years (interaction p = 0.78). Conclusion: In this post hoc study, CAD was associated with more CVD and HFH in patients with HFrEF and worsening HF. Vericiguat was beneficial and safe regardless of concomitant CAD. [ABSTRACT FROM AUTHOR]

The channel-forming component of anthrax toxin, [([PA.sub.63]).sub.7], is a heptameric water-soluble protein at neutral pH, but under acidic conditions it spontaneously inserts into lipid bilayers to form a 14-stranded [beta]-barrel ion- conducting channel. This channel plays a vital role in anthrax pathogenesis because it serves as a conduit for the membrane translocation of the two enzymatic components of anthrax toxin, lethal factor and edema factor. Anthrax channels open and close in response to changes in transmembrane voltage, a property shared by several other pore-forming toxins. We have discovered an unexpected phenomenon in cysteine-substituted channels that provides a window into this gating process: their normal voltage-dependent gating can be abolished by reaction with methanethiosulfonate (MTS) reagents or exposure to oxidizing conditions. Remarkably, this perturbation is seen with cysteines substituted at sites all along the ~100 [Angstrom] length of the channel's [beta]-barrel. In contrast, reaction with N-ethylmaleimide, a thiol-reactive compound that does not form a mixed disulfide, does not affect gating at any of the sites tested. These findings, coupled with our biochemical detection of dimers, have led us to conclude that MTS reagents are catalyzing the formation of intersubunit disulfide bonds that lock channels in a conducting state, and that voltage gating requires a conformational change that involves the entire [beta]-barrel.

Parasympathetic stimulation of the heart, which provides protection from arrhythmias and sudden death, involves activation of the G protein--coupled inward rectifying [K.sup.+] channel GIRK1/4 and results in an acetylcholine-sensitive [K.sup.+] current, [I.sub.KACh]. We describe a unique relationship between lipid homeostasis, the lipid-sensitive transcription factor SREBP-1, regulation of the cardiac parasympathetic response, and the development of ventricular arrhythmia. In embryonic chick atrial myocytes, lipid lowering by culture in lipoprotein-depleted serum increased SREBP-1 levels, GIRK1 expression, and [I.sub.KACh] activation. Regulation of the GIRK1 promoter by SREBP-1 and lipid lowering was dependent on interaction with 2 tandem sterol response elements and an upstream E-box motif. Expression of dominant negative SREBP-1 (DN--SREBP-1) reversed the effect of lipid lowering on [I.sub.KACh] and GIRK1. In SREBP-1 knockout mice, both the response of the heart to parasympathetic stimulation and the expression of GIRK1 were reduced compared with WT. [I.sub.KACh], attenuated in atrial myocytes from SREBP-1 knockout mice, was stimulated by SREBP-1 expression. Following myocardial infarction, SREBP-1 knockout mice were twice as likely as WT mice to develop ventricular tachycardia in response to programmed ventricular stimulation. These results demonstrate a relationship between lipid metabolism and parasympathetic response that may play a role in arrhythmogenesis., Introduction The balance between the response of the heart to sympathetic and parasympathetic stimuli not only determines the rate and force of contraction but also plays a role in regulating [...]

In nerve and muscle cells, the voltage-gated opening and closing of cation-selective ion channels is accompanied by the translocation of l2-14 elementary charges across the membrane's electric field. Although most of these charges are carried by residues in the S4 helix of the gating module of these channels, the precise nature of their physical movement is currently the topic of spirited debate. Broadly speaking, two classes of models have emerged: those that suggest that small-scale motions can account for the extensive charge displacement, and those that invoke a much larger physical movement. In the most recent incarnation of the latter type of model, which is based on structural and functional data from the archaebacterial [K.sup.+] channel KvAP, a 'voltage-sensor paddle' comprising a helix-turn-helix of S3-S4 translocates ~20 [Angstrom] through the bilayer during the gating cycle (Jiang, Y., A. Lee, J. Chen, V. Ruta, M. Cadene, B.T. Chair, and R. MacKinnon. 2003. Nature. 423:33-41; Jiang, Y., V. Ruta, J. Chen, A. Lee, and R. MacKinnon. 2003. Nature. 423:42-48.; Ruta, V.,J. Chen, and R. MacKinnon. 2005. Cell. 123:463-475). We used two methods to test for analogous motions in the Shaker [K.sup.+] channel, each examining the aqueous exposure of residues near S3. In the first, we employed a pore-blocking maleimide reagent (Blaustein, R.O., P.A. Cole, C. Williams, and C. Miller. 2000. Nat. Struct. Biol. 7:309-311) to probe for state-dependent changes in the chemical reactivity of substituted cysteines; in the second, we tested the state-dependent accessibility of a tethered biotin to external streptavidin (Qiu, X.Q,., K.S. Jakes, A. Finkelstein, and S.L. Slatin. 1994. J. Biol. Chem. 269:7483-7488; Slatin, S.L., X.Q. Qiu, K.S. Jakes, and A. Finkelstein. 1994. Nature. 371:158-161). In both types of experiments, residues predicted to lie near the top of $3 did not exhibit any change in aqueous exposure during the gating cycle. This lack of state dependence argues against large-scale movements, either axially or radially, of Shaker's S3-S4 voltage-sensor paddle.

The bacterial toxin colicin Ia forms voltage-gated channels in planar lipid bilayers. The toxin consists of three domains, with the carboxy-terminal domain (C-domain) responsible for channel formation. The C-domain contributes four membrane-spanning segments and a 68-residue translocated segment to the open channel, whereas the upstream domains and the amino-terminal end of the C-domain stay on the cis side of the membrane. The isolated C-domain, lacking the two upstream domains, also forms channels; however, the amino terminus and one of the normally membrane-spanning segments can move across the membrane. (This can be observed as a drop in single-channel conductance.) In longer carboxy-terminal fragments of colicin Ia that include [less than or equal to] 169 residues upstream from the C-domain, the entire upstream region is translocated. Presumably, a portion of the C-domain creates a pathway for the polar upstream region to move through the membrane. To determine the size of this translocation pathway, we have attached 'molecular stoppers,' small disulfide-bonded polypeptides, to the amino terminus of the C-domain, and determined whether they could be translocated. We have found that the translocation rate is strongly voltage dependent, and that at voltages [greater than or equal to] 90 mV, even a 26-[Angstrom] stopper is translocated. Upon reduction of their disulfide bonds, all of the stoppers are easily translocated, indicating that it is the folded structure, rather than some aspect of the primary sequence, that slows translocation of the stoppers. Thus, the pathway for translocation is [greater than or equal to] 26 [Angstrom] in diameter, or can stretch to this value. This is large enough for an [alpha]-helical hairpin to fit through. KEY WORDS: [alpha]-conotoxin * apamin * charybdotoxin * disulfides * molecular stoppers

Polymeric maleimido-quaternary ammonium (QA) compounds have been shown to function as molecular tape measures when covalently tethered to external cysteine residues of a Shaker K+ channel (Blaustein R.O., P.A. Cole, C. Williams, and C. Miller. 2000. Nat. Struct. Biol. 7:309-311). For sufficiently long compounds, the cysteine-maleimide tethering reaction creates a high concentration, at the channel's pore, of a TEA-like moiety that irreversibly blocks current. This paper investigates a striking feature of the maleimide-cysteine tethering kinetics. Strong blockers--those that induce substantial levels (>80%) of irreversible inhibition of current--react with channel cysteines much more rapidly than weak blockers and, when delivered to channels with four cysteine targets, react with multiexponential kinetics. This behavior is shown to arise from the ability of a strong blocker to concentrate its maleimide end near a channel's cysteine target by exploiting the reversible pore-blocking affinity of its QA headgroup. KEY WORDS: Shaker * tetraethylammonium * block * affinity-label * maleimide

Importance: Patients with heart failure and preserved ejection fraction (HFpEF) are at high risk of mortality, hospitalizations, and reduced functional capacity and quality of life.Objective: To assess the efficacy of the oral soluble guanylate cyclase stimulator vericiguat on the physical limitation score (PLS) of the Kansas City Cardiomyopathy Questionnaire (KCCQ).Design, Setting, and Participants: Phase 2b randomized, double-blind, placebo-controlled, multicenter trial of 789 patients with chronic HFpEF and left ventricular ejection fraction 45% or higher with New York Heart Association class II-III symptoms, within 6 months of a recent decompensation (HF hospitalization or intravenous diuretics for HF without hospitalization), and with elevated natriuretic peptides, enrolled at 167 sites in 21 countries from June 15, 2018, through March 27, 2019; follow-up was completed on November 4, 2019.Interventions: Patients were randomized to receive vericiguat, up-titrated to 15-mg (n = 264) or 10-mg (n = 263) daily oral dosages, compared with placebo (n = 262) and randomized 1:1:1.Main Outcomes and Measures: The primary outcome was change in the KCCQ PLS (range, 0-100; higher values indicate better functioning) after 24 weeks of treatment. The secondary outcome was 6-minute walking distance from baseline to 24 weeks.Results: Among 789 randomized patients, the mean age was 72.7 (SD, 9.4) years; 385 (49%) were female; mean EF was 56%; and median N-terminal pro-brain natriuretic peptide level was 1403 pg/mL; 761 (96.5%) completed the trial. The baseline and 24-week KCCQ PLS means for the 15-mg/d vericiguat, 10-mg/d vericiguat, and placebo groups were 60.0 and 68.3, 57.3 and 69.0, and 59.0 and 67.1, respectively, and the least-squares mean changes were 5.5, 6.4, and 6.9, respectively. The least-squares mean difference in scores between the 15-mg/d vericiguat and placebo groups was -1.5 (95% CI, -5.5 to 2.5; P = .47) and between the 10-mg/d vericiguat and placebo groups was -0.5 (95% CI, -4.6 to 3.5; P = .80). The baseline and 24-week 6-minute walking distance mean scores in the 15-mg/d vericiguat, 10-mg/d vericiguat, and placebo groups were 295.0 m and 311.8m , 292.1 m and 318.3 m, and 295.8 m and 311.4 m, and the least-squares mean changes were 5.0 m, 8.7 m, and 10.5 m, respectively. The least-squares mean difference between the 15-mg/d vericiguat and placebo groups was -5.5 m (95% CI, -19.7 m to 8.8 m; P = .45) and between the 10-mg/d vericiguat and placebo groups was -1.8 m (95% CI, -16.2 m to 12.6 m; P = .81), respectively. The proportions of patients who experienced symptomatic hypotension were 6.4% in the 15-mg/d vericiguat group, 4.2% in the 10-mg/d vericiguat group, and 3.4% in the placebo group; those with syncope were 1.5%, 0.8%, and 0.4%, respectively.Conclusions and Relevance: Among patients with HFpEF and recent decompensation, 24-week treatment with vericiguat at either 15-mg/d or 10-mg/d dosages compared with placebo did not improve the physical limitation score of the KCCQ.Trial Registration: ClinicalTrials.gov Identifier: NCT03547583. [ABSTRACT FROM AUTHOR]

Background: Dyslipidemia, particularly high-density lipoprotein cholesterol (HDL-C), has recently been implicated in the pathogenesis of age-related macular degeneration (AMD), the leading cause of vision loss. However, epidemiological studies have yielded conflicting results.Methods: We investigated the causal role of plasma lipid levels in AMD in multiethnic populations comprising 16 144 advanced AMD cases and 17 832 controls of European descent, together with 2219 cases and 5275 controls of Asian descent, using Mendelian randomization in three models. Model 1 is a conventional meta-analysis which does not account for pleiotropy of instrumental variable (IV) effects. Model 2 is a univariate, inverse variance weighted regression analysis that accounts for potential unbalanced pleiotropy using MR-Egger method. Finally, Model 3 is a multivariate regression analysis that addresses pleiotropy by MR-Egger method and by adjusting for effects on other lipid traits.Results: A 1 standard deviation (SD) higher HDL-cholesterol level was associated with an odds ratio (OR) for AMD of 1.17 (95% confidence interval: 1.07-1.29) in Europeans (P = 6.88 × 10-4) and of 1.58 (1.24-2.00) in Asians (P = 2.92 × 10-4) in Model 3. The corresponding OR estimates were 1.30 (1.09-1.55) in Europeans (P = 3.18 × 10-3) and 1.42 (1.11-1.80) in Asians (P = 4.42 × 10-3) in Model 1, and 1.21 (1.11-1.31) in Europeans (P = 3.12 × 10-5) and 1.51 (1.20-1.91) in Asians (P = 7.61 × 10-4) in Model 2. Conversely, neither LDL-C (Europeans: OR = 0.96, P = 0.272; Asians: OR = 1.02, P = 0.874; Model 3) nor triglyceride levels (Europeans: OR = 0.91, P = 0.102; Asians: OR = 1.06, P = 0.613) were associated with AMD. We also assessed the association between lipid levels and polypoidal choroidal vasculopathy (PCV) in Asians, a subtype of AMD, and found a similar trend for association of PCV with HDL-C levels.Conclusions: Our study shows that high levels of plasma HDL-C are causally associated with an increased risk for advanced AMD in European and Asian populations, implying that strategies reducing HDL-C levels may be useful to prevent and treat AMD. [ABSTRACT FROM AUTHOR]