Percutaneous repair of moderate-to-severe or severe functional mitral regurgitation in patients with symptomatic heart failure: Baseline characteristics of patients in the RESHAPE-HF2 trial and comparison to COAPT and MITRA-FR trials.

AIM: The RESHAPE-HF2 trial is designed to assess the efficacy and safety of the MitraClip device system for the treatment of clinically important functional mitral regurgitation (FMR) in patients with heart failure (HF). This report describes the baseline characteristics of patients enrolled in the RESHAPE-HF2 trial compared to those enrolled in the COAPT and MITRA-FR trials. METHODS AND RESULTS: The RESHAPE-HF2 study is an investigator-initiated, prospective, randomized, multicentre trial including patients with symptomatic HF, a left ventricular ejection fraction (LVEF) between 20% and 50% with moderate-to-severe or severe FMR, for whom isolated mitral valve surgery was not recommended. Patients were randomized 1:1 to a strategy of delivering or withholding MitraClip. Of 506 patients randomized, the mean age of the patients was 70 ± 10 years, and 99 of them (20%) were women. The median EuroSCORE II was 5.3 (2.8-9.0) and median plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) was 2745 (1407-5385) pg/ml. Most patients were prescribed beta-blockers (96%), diuretics (96%), angiotensin-converting enzyme inhibitors/angiotensin receptor blockers/angiotensin receptor-neprilysin inhibitors (82%) and mineralocorticoid receptor antagonists (82%). The use of sodium-glucose cotransporter 2 inhibitors was rare (7%). Cardiac resynchronization therapy (CRT) devices had been previously implanted in 29% of patients. Mean LVEF, left ventricular end-diastolic volume and effective regurgitant orifice area (EROA) were 31 ± 8%, 211 ± 76 ml and 0.25 ± 0.08 cm2, respectively, whereas 44% of patients had mitral regurgitation severity of grade 4+. Compared to patients enrolled in COAPT and MITRA-FR, those enrolled in RESHAPE-HF2 were less likely to have mitral regurgitation grade 4+ and, on average, HAD lower EROA, and plasma NT-proBNP and higher estimated glomerular filtration rate, but otherwise had similar age, comorbidities, CRT therapy and LVEF. CONCLUSION: Patients enrolled in RESHAPE-HF2 represent a third distinct population where MitraClip was tested in, that is one mainly comprising of patients with moderate-to-severe FMR instead of only severe FMR, as enrolled in the COAPT and MITRA-FR trials. The results of RESHAPE-HF2 will provide crucial insights regarding broader application of the transcatheter edge-to-edge repair procedure in clinical practice.

A nationwide, population-based study on specialized care for acute heart failure throughout the COVID-19 pandemic.

AIMS: The COVID-19 pandemic disrupted the delivery of care for patients with heart failure (HF), leading to fewer HF hospitalizations and increased mortality. However, nationwide data on quality of care and long-term outcomes across the pandemic are scarce. METHODS AND RESULTS: We used data from the National Heart Failure Audit (NHFA) linked to national records for hospitalization and deaths. We compared pre-COVID (2018-2019), COVID (2020), and late/post-COVID (2021-2022) periods. Data for 227 250 patients admitted to hospital with HF were analysed and grouped according to the admission year and the presence of HF with (HFrEF) or without reduced ejection fraction (non-HFrEF). The median age at admission was 81 years (interquartile range 72-88), 55% were men (n = 125 975), 87% were of white ethnicity (n = 102 805), and 51% had HFrEF (n = 116 990). In-hospital management and specialized cardiology care were maintained throughout the pandemic with an increasing percentage of patients discharged on disease-modifying medications over time (p < 0.001). Long-term outcomes improved over time (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.90-0.95, p < 0.001), mainly driven by a reduction in cardiovascular death. Receiving specialized cardiology care was associated with better long-term outcomes both for those who had HFrEF (HR 0.79, 95% CI 0.77-0.82, p < 0.001) and for those who had non-HFrEF (HR 0.87, 95% CI 0.85-0.90, p < 0.001). CONCLUSIONS: Despite the disruption of healthcare systems, the clinical characteristics of patients admitted with HF were similar and the overall standard of care was maintained throughout the pandemic. Long-term survival of patients hospitalized with HF continued to improve after COVID-19, especially for HFrEF.

Critical re-evaluation of the identification of iron deficiency states and effective iron repletion strategies in patients with chronic heart failure.

According to current guidelines, iron deficiency is defined by a serum ferritin level <100 ng/ml or a transferrin saturation (TSAT) <20% if the serum ferritin level is 100-299 µg/L. These criteria were developed to encourage the use of intravenous iron as an adjunct to erythropoiesis-stimulating agents in the treatment of renal anaemia. However, in patients with heart failure, these criteria are not supported by any pathophysiological or clinical evidence that they identify an absolute or functional iron deficiency state. A low baseline TSAT-but not serum ferritin level-appears to be a reliable indicator of the effect of intravenous iron to reduce major heart failure events. In randomized controlled trials, intravenous iron decreased the risk of cardiovascular death or total heart failure hospitalization in patients with a TSAT <20% (risk ratio 0.67 [0.49-0.92]) but not in patients with a TSAT ≥20% (risk ratio 0.99 [0.74-1.30]), with the magnitude of the risk reduction being proportional to the severity of hypoferraemia. Patients who were enrolled in clinical trials solely because they had a serum ferritin level <100 µg/L showed no significant benefit on heart failure outcomes, and it is noteworthy that serum ferritin levels of 20-300 µg/L lie entirely within the range of normal values for healthy adults. Current guidelines reflect the eligibility criteria of clinical trials, which inadvertently adopted unvalidated criteria to define iron deficiency. Reliance on these guidelines would lead to the treatment of many patients who are not iron deficient (serum ferritin level <100 µg/L but normal TSAT) and ignores the possibility of iron deficiency in patients with a low TSAT but with serum ferritin level of >300 µg/L. Importantly, analyses of benefit based on trial eligibility-driven guidelines substantially underestimate the magnitude of heart-failure-event risk reduction with intravenous iron in patients who are truly iron deficient. Based on all available data, we recommend a new mechanism-based and trial-tested approach that reflects the totality of evidence more faithfully than the historical process adopted by clinical investigators and by the guidelines. Until additional evidence is forthcoming, an iron deficiency state in patients with heart failure should be defined by a TSAT <20% (as long as the serum ferritin level is <400 µg/L), and furthermore, the use of a serum ferritin level <100 µg/L alone as a diagnostic criterion should be discarded.

Urinary proteomic signature of mineralocorticoid receptor antagonism by spironolactone: evidence from the HOMAGE trial.

OBJECTIVE: Heart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) followed by peptide sequencing identifies parental proteins, for over 70% derived from collagens. This study aimed to refine understanding of the antifibrotic action of spironolactone. METHODS: In this substudy (n=290) to the Heart 'Omics' in Ageing Study trial, patients were randomised to usual therapy combined or not with spironolactone 25-50 mg/day and followed for 9 months. The analysis included 1498 sequenced urinary peptides detectable in ≥30% of patients and carboxyterminal propeptide of procollagen I (PICP) and PICP/carboxyterminal telopeptide of collagen I (CITP) as serum biomarkers of COL1A1 synthesis. After rank normalisation of biomarker distributions, between-group differences in their changes were assessed by multivariable-adjusted mixed model analysis of variance. Correlations between the changes in urinary peptides and in serum PICP and PICP/CITP were compared between groups using Fisher's Z transform. RESULTS: Multivariable-adjusted between-group differences in the urinary peptides with error 1 rate correction were limited to 27 collagen fragments, of which 16 were upregulated (7 COL1A1 fragments) on spironolactone and 11 downregulated (4 COL1A1 fragments). Over 9 months of follow-up, spironolactone decreased serum PICP from 81 (IQR 66-95) to 75 (61-90) µg/L and PICP/CITP from 22 (17-28) to 18 (13-26), whereas no changes occurred in the control group, resulting in a difference (spironolactone minus control) expressed in standardised units of -0.321 (95% CI 0.0007). Spironolactone did not affect the correlations between changes in urinary COL1A1 fragments and in PICP or the PICP/CITP ratio. CONCLUSIONS: Spironolactone decreased serum markers of collagen synthesis and predominantly downregulated urinary collagen-derived peptides, but upregulated others. The interpretation of these opposite UPP trends might be due to shrinking the body-wide pool of collagens, explaining downregulation, while some degree of collagen synthesis must be maintained to sustain vital organ functions, explaining upregulation. Combining urinary and serum fibrosis markers opens new avenues for the understanding of the action of antifibrotic drugs. TRIAL REGISTRATION NUMBER: NCT02556450.

Identification of three mechanistic pathways for iron-deficient heart failure.

Current understanding of iron-deficient heart failure is based on blood tests that are thought to reflect systemic iron stores, but the available evidence suggests greater complexity. The entry and egress of circulating iron is controlled by erythroblasts, which (in severe iron deficiency) will sacrifice erythropoiesis to supply iron to other organs, e.g. the heart. Marked hypoferraemia (typically with anaemia) can drive the depletion of cardiomyocyte iron, impairing contractile performance and explaining why a transferrin saturation < ≈15%-16% predicts the ability of intravenous iron to reduce the risk of major heart failure events in long-term trials (Type 1 iron-deficient heart failure). However, heart failure may be accompanied by intracellular iron depletion within skeletal muscle and cardiomyocytes, which is disproportionate to the findings of systemic iron biomarkers. Inflammation- and deconditioning-mediated skeletal muscle dysfunction-a primary cause of dyspnoea and exercise intolerance in patients with heart failure-is accompanied by intracellular skeletal myocyte iron depletion, which can be exacerbated by even mild hypoferraemia, explaining why symptoms and functional capacity improve following intravenous iron, regardless of baseline haemoglobin or changes in haemoglobin (Type 2 iron-deficient heart failure). Additionally, patients with advanced heart failure show myocardial iron depletion due to both diminished entry into and enhanced egress of iron from the myocardium; the changes in iron proteins in the cardiomyocytes of these patients are opposite to those expected from systemic iron deficiency. Nevertheless, iron supplementation can prevent ventricular remodelling and cardiomyopathy produced by experimental injury in the absence of systemic iron deficiency (Type 3 iron-deficient heart failure). These observations, taken collectively, support the possibility of three different mechanistic pathways for the development of iron-deficient heart failure: one that is driven through systemic iron depletion and impaired erythropoiesis and two that are characterized by disproportionate depletion of intracellular iron in skeletal and cardiac muscle. These mechanisms are not mutually exclusive, and all pathways may be operative at the same time or may occur sequentially in the same patients.

Association of an impaired GH-IGF-I axis with cardiac wasting in patients with advanced cancer.

BACKGROUND: Growth hormone (GH) resistance is characterized by high GH levels but low levels of insulin-like growth factor-I (IGF-I) and growth hormone binding protein (GHBP) and, for patients with chronic disease, is associated with the development of cachexia. OBJECTIVES: We investigated whether GH resistance is associated with changes in left ventricular (LV) mass (cardiac wasting) in patients with cancer. METHODS: We measured plasma IGF-I, GH, and GHBP in 159 women and 148 men with cancer (83% stage III/IV). Patients were grouped by tertile of echocardiographic LVmass/height2 (women, < 50, 50-61, > 61 g/m2; men, < 60, 60-74, > 74 g/m2) and by presence of wasting syndrome with unintentional weight loss (BMI < 24 kg/m2 and weight loss ≥ 5% in the prior 12 months). Repeat echocardiograms were obtained usually within 3-6 months for 85 patients. RESULTS: Patients in the lowest LVmass/height2 tertile had higher plasma GH (median (IQR) for 1st, 2nd, and 3rd tertile women, 1.8 (0.9-4.2), 0.8 (0.2-2.2), 0.5 (0.3-1.6) ng/mL, p = 0.029; men, 2.1 (0.8-3.2), 0.6 (0.1-1.7), 0.7 (0.2-1.9) ng/mL, p = 0.003). Among women, lower LVmass was associated with higher plasma IGF-I (68 (48-116), 72 (48-95), 49 (35-76) ng/mL, p = 0.007), whereas such association did not exist for men. Patients with lower LVmass had lower log IGF-I/GH ratio (women, 1.60 ± 0.09, 2.02 ± 0.09, 1.88 ± 0.09, p = 0.004; men, 1.64 ± 0.09, 2.14 ± 0.11, 2.04 ± 0.11, p = 0.002). GHBP was not associated with LVmass. Patients with wasting syndrome with unintentional weight loss had higher plasma GH and GHBP, lower log IGF-I/GH ratio, and similar IGF-I. Overall, GHBP correlated inversely with log IGF-I/GH ratio (women, r = - 0.591, p < 0.001; men, r = - 0.575, p < 0.001). Additionally, higher baseline IGF-I was associated with a decline in LVmass during follow-up (r = - 0.318, p = 0.003). CONCLUSION: In advanced cancer, reduced LVmass is associated with increased plasma GH and reduced IGF-I/GH ratio, suggesting increasing GH resistance, especially for patients with wasting syndrome with unintentional weight loss. Higher baseline IGF-I was associated with a decrease in relative LVmass during follow-up.

Intravenous iron for heart failure, iron deficiency definitions, and clinical response: the IRONMAN trial.

BACKGROUND AND AIMS: What is the relationship between blood tests for iron deficiency, including anaemia, and the response to intravenous iron in patients with heart failure? METHODS: In the IRONMAN trial, 1137 patients with heart failure, ejection fraction ≤ 45%, and either serum ferritin < 100 µg/L or transferrin saturation (TSAT) < 20% were randomized to intravenous ferric derisomaltose (FDI) or usual care. Relationships were investigated between baseline anaemia severity, ferritin and TSAT, to changes in haemoglobin from baseline to 4 months, Minnesota Living with Heart Failure (MLwHF) score and 6-minute walk distance achieved at 4 months, and clinical events, including heart failure hospitalization (recurrent) or cardiovascular death. RESULTS: The rise in haemoglobin after administering FDI, adjusted for usual care, was greater for lower baseline TSAT (Pinteraction < .0001) and ferritin (Pinteraction = .028) and more severe anaemia (Pinteraction = .014). MLwHF scores at 4 months were somewhat lower (better) with FDI for more anaemic patients (overall Pinteraction = .14; physical Pinteraction = .085; emotional Pinteraction = .043) but were not related to baseline TSAT or ferritin. Blood tests did not predict difference in achieved walking distance for those randomized to FDI compared to control. The absence of anaemia or a TSAT ≥ 20% was associated with lower event rates and little evidence of benefit from FDI. More severe anaemia or TSAT < 20%, especially when ferritin was ≥100 µg/L, was associated with higher event rates and greater absolute reductions in events with FDI, albeit not statistically significant. CONCLUSIONS: This hypothesis-generating analysis suggests that anaemia or TSAT < 20% with ferritin > 100 µg/L might identify patients with heart failure who obtain greater benefit from intravenous iron. This interpretation requires confirmation.

Epidemiology and risk factors for hyperkalaemia in heart failure.

Patients with heart failure (HF), particularly those with impaired renal function receiving renin-angiotensin-aldosterone system inhibitors (RAASis), are at risk of hyperkalaemia; when hyperkalaemia is severe, this can have serious clinical consequences. The incidence, prevalence, and risk factors for hyperkalaemia reported in randomized trials of RAASis may not reflect clinical practice due to exclusion of patients with elevated serum potassium (sK+ ) or severe renal impairment: information on patients managed in routine clinical care is important to understanding the actual burden of hyperkalaemia. This paper reviews the available clinical epidemiology data on hyperkalaemia in HF and considers areas requiring further research. Observational studies published since 2017 that focused on hyperkalaemia, included patients with HF, and had ≥1000 participants were considered. Hyperkalaemia occurrence in HF varied widely from 7% to 39% depending on the setting, HF severity, follow-up length, and concomitant medications. Rates were lowest in patients with newly diagnosed HF and highest in patients with greater disease severity; comorbidities, such as chronic kidney disease and diabetes, and RAASi use, reflected commonly identified risk factors for hyperkalaemia in patients with HF. Hyperkalaemia was most often mild; however, from the limited data available, persistence of mild hyperkalaemia was associated with an increased risk of mortality and major adverse cardiovascular events. There were also limited data available on the progression of hyperkalaemia. Recurrence was common, occurring in one-quarter to two-fifths of hyperkalaemia cases. Despite HF guidelines recommending close monitoring of sK+ , 55-93% of patients did not receive appropriate testing before or after initiation of RAASi or in follow-up to moderate/severe hyperkalaemia detection. Many of the observational studies were retrospective and from a single country. There is a need for international, prospective, longitudinal, observational studies, such as the CARE-HK in HF study (NCT04864795), to understand hyperkalaemia's prevalence, incidence, and severity; to identify and characterize cases that persist, progress, and recur; to highlight the importance of sK+ monitoring when using RAASi; and to assess the impact of newer HF therapies and potassium binders in clinical practice. Data from both clinical trials and observational studies with adjustments for confounding variables will be needed to assess the contribution of hyperkalaemia to clinical outcomes.

Proteomic profiles of left atrial volume and its influence on response to spironolactone: Findings from the HOMAGE trial and STANISLAS cohort.

AIMS: High left ventricular filling pressure increases left atrial volume and causes myocardial fibrosis, which may decrease with spironolactone. We studied clinical and proteomic characteristics associated with left atrial volume indexed by body surface area (LAVi), and whether LAVi influences the response to spironolactone on biomarker expression and clinical variables. METHODS AND RESULTS: In the HOMAGE trial, where people at risk of heart failure were randomized to spironolactone or control, we analysed 421 participants with available LAVi and 276 proteomic measurements (Olink) at baseline, month 1 and 9 (mean age 73 ± 6 years; women 26%; LAVi 32 ± 9 ml/m2). Circulating proteins associated with LAVi were also assessed in asymptomatic individuals from a population-based cohort (STANISLAS; n = 1640; mean age 49 ± 14 years; women 51%; LAVi 23 ± 7 ml/m2). In both studies, greater LAVi was significantly associated with greater left ventricular masses and volumes. In HOMAGE, after adjustment and correction for multiple testing, greater LAVi was associated with higher concentrations of matrix metallopeptidase-2 (MMP-2), insulin-like growth factor binding protein-2 (IGFBP-2) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) (false discovery rates [FDR] <0.05). These associations were externally replicated in STANISLAS (all FDR <0.05). Among these biomarkers, spironolactone decreased concentrations of MMP-2 and NT-proBNP, regardless of baseline LAVi (pinteraction > 0.10). Spironolactone also significantly reduced LAVi, improved left ventricular ejection fraction, lowered E/e', blood pressure and serum procollagen type I C-terminal propeptide (PICP) concentration, a collagen synthesis marker, regardless of baseline LAVi (pinteraction > 0.10). CONCLUSION: In individuals without heart failure, LAVi was associated with MMP-2, IGFBP-2 and NT-proBNP. Spironolactone reduced these biomarker concentrations as well as LAVi and PICP, irrespective of left atrial size.

Intravenous iron and SGLT2 inhibitors in iron-deficient patients with heart failure and reduced ejection fraction.

AIMS: To explore the potential interaction between use of SGLT2 inhibitors and the increase in haemoglobin in patients randomized to intravenous iron or the control group in the IRONMAN (Effectiveness of Intravenous Iron Treatment versus Standard Care in Patients with Heart Failure and Iron Deficiency) trial. METHODS AND RESULTS: This was a post hoc exploratory analysis of the IRONMAN trial which randomized patients with heart failure, a left ventricular ejection fraction (LVEF) ≤ 45% and iron deficiency (transferrin saturation <20% or ferritin <100 µg/L) to open label intravenous ferric derisomaltose or usual care. Of the 1137 randomized patients, 29 (2.6%) were taking an SGLT2 inhibitor at baseline. The mean (SD) change in haemoglobin from baseline at 4 weeks in those taking an SGLT2 inhibitor at baseline was 1.3 (1.2) g/dL in patients randomized to ferric derisomaltose and 0.1 (0.7) g/dL in the usual care group; between-group difference = 1.0 g/dL (95% CI 0.1, 1.8). The equivalent numbers in the no SGLT2 inhibitor group were 0.6 (0.9) g/dL in those randomized to ferric derisomaltose and 0.1 (0.8) g/dL in the usual care group; between-group difference = 0.4 g/dL (95% CI 0.3, 1.6); interaction P value = 0.10. No patient receiving an SGLT2 inhibitor at baseline developed polycythaemia during follow-up (defined as haemoglobin >16.5 g/dL [men] or >16 g/dL [women]). CONCLUSIONS: In the IRONMAN trial, there was a trend to a greater increase in haemoglobin with ferric derisomaltose in iron-deficient patients taking an SGLT2 inhibitor at baseline, as compared with those not taking one.

Cameroon's slow fertility transition: A gender perspective.

We interrogate the proposition that men's attitudes have constrained the fertility transition in Cameroon, where fertility remains high and contraceptive use low despite much socio-economic progress. We use five Demographic and Health Surveys to compare trends in desired family size among young women and men and analyse matched monogamous couple data from the two most recent surveys to examine wives' and husbands' desires to stop childbearing and their relative influence on current contraceptive use. In 2018, average desired family size was 5.6 and 5.1, for young men and women respectively, and this difference (half a child) has not changed since 1998. Among matched couples, the proportions wanting to stop childbearing were similar in wives and their husbands, but wives perceived husbands to be much more pronatalist than themselves. Surprisingly, men's own reported preferences were more closely associated with contraceptive use than wives' perceptions of husbands' preferences. We discerned little evidence that men's attitudes have impeded reproductive change.

Iron deficiency and supplementation in heart failure.

Non-anaemic iron deficiency (NAID) is a strategic target in cardiovascular medicine because of its association with a range of adverse effects in various conditions. Endeavours to tackle NAID in heart failure have yielded mixed results, exposing knowledge gaps in how best to define 'iron deficiency' and the handling of iron therapies by the body. To address these gaps, we harness the latest understanding of the mechanisms of iron homeostasis outside the erythron and integrate clinical and preclinical lines of evidence. The emerging picture is that current definitions of iron deficiency do not assimilate the multiple influences at play in patients with heart failure and, consequently, fail to identify those with a truly unmet need for iron. Additionally, current iron supplementation therapies benefit only certain patients with heart failure, reflecting differences in the nature of the unmet need for iron and the modifying effects of anaemia and inflammation on the handling of iron therapies by the body. Building on these insights, we identify untapped opportunities in the management of NAID, including the refinement of current approaches and the development of novel strategies. Lessons learned from NAID in cardiovascular disease could ultimately translate into benefits for patients with other chronic conditions such as chronic kidney disease, chronic obstructive pulmonary disease and cancer.

Relationship between sex, body size, and cardiac resynchronization therapy benefit: A patient-level meta-analysis of randomized controlled trials.

BACKGROUND: Women might benefit more than men from cardiac resynchronization therapy (CRT) and do so at shorter QRS durations. OBJECTIVE: This meta-analysis was performed to determine whether sex-based differences in CRT effects are better accounted for by height, body surface area (BSA), or left ventricular end-diastolic dimension (LVEDD). METHODS: We analyzed patient-level data from CRT trials (MIRACLE, MIRACLE ICD, MIRACLE ICD II, REVERSE, RAFT, COMPANION, and MADIT-CRT) using bayesian hierarchical Weibull regression models. Relationships between QRS duration and CRT effects were examined overall and in sex-stratified cohorts; additional analyses indexed QRS duration by height, BSA, or LVEDD. End points were heart failure hospitalization (HFH) or death and all-cause mortality. RESULTS: Compared with men (n = 5628), women (n = 1439) were shorter (1.62 [interquartile range, 1.57-1.65] m vs 1.75 [1.70-1.80] m; P < .001), with smaller BSAs (1.76 [1.62-1.90] m2 vs 2.02 [1.89-2.16] m2; P < .001). In adjusted sex-stratified analyses, the reduction in HFH or death was greater for women (hazard ratio, 0.54; credible interval, 0.42-0.70) than for men (hazard ratio, 0.77; credible interval, 0.66-0.89; Pinteraction = .009); results were similar for all-cause mortality even after adjustment for height, BSA, and LVEDD. Sex-specific differences were observed only in nonischemic cardiomyopathy. The effect of CRT on HFH or death was observed at a shorter QRS duration for women (126 ms) than for men (145 ms). Indexing QRS duration by height, BSA, or LVEDD attenuated sex-specific QRS duration thresholds for the effects of CRT on HFH or death but not on mortality. CONCLUSION: Although body size partially explains sex-specific QRS duration thresholds for CRT benefit, it is not associated with the magnitude of CRT benefit. Indexing QRS duration for body size might improve selection of patients for CRT, particularly with a "borderline" QRS duration.