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Background: Increasing SERCA2 (sarco[endo]-plasmic reticulum Ca 2+ ATPase 2) activity is suggested to be beneficial in chronic heart failure, but no selective SERCA2-activating drugs are available. PDE3A (phosphodiesterase 3A) is proposed to be present in the SERCA2 interactome and limit SERCA2 activity. Disruption of PDE3A from SERCA2 might thus be a strategy to develop SERCA2 activators. Methods: Confocal microscopy, 2-color direct stochastic optical reconstruction microscopy, proximity ligation assays, immunoprecipitations, peptide arrays, and surface plasmon resonance were used to investigate colocalization between SERCA2 and PDE3A in cardiomyocytes, map the SERCA2/PDE3A interaction sites, and optimize disruptor peptides that release PDE3A from SERCA2. Functional experiments assessing the effect of PDE3A-binding to SERCA2 were performed in cardiomyocytes and HEK293 vesicles. The effect of SERCA2/PDE3A disruption by the disruptor peptide OptF (optimized peptide F) on cardiac mortality and function was evaluated during 20 weeks in 2 consecutive randomized, blinded, and controlled preclinical trials in a total of 148 mice injected with recombinant adeno-associated virus 9 (rAAV9)-OptF, rAAV9-control (Ctrl), or PBS, before undergoing aortic banding (AB) or sham surgery and subsequent phenotyping with serial echocardiography, cardiac magnetic resonance imaging, histology, and functional and molecular assays. Results: PDE3A colocalized with SERCA2 in human nonfailing, human failing, and rodent myocardium. Amino acids 277–402 of PDE3A bound directly to amino acids 169–216 within the actuator domain of SERCA2. Disruption of PDE3A from SERCA2 increased SERCA2 activity in normal and failing cardiomyocytes. SERCA2/PDE3A disruptor peptides increased SERCA2 activity also in the presence of protein kinase A inhibitors and in phospholamban-deficient mice, and had no effect in mice with cardiomyocyte-specific inactivation of SERCA2. Cotransfection of PDE3A reduced SERCA2 activity in HEK293 vesicles. Treatment with rAAV9-OptF reduced cardiac mortality compared with rAAV9-Ctrl (hazard ratio, 0.26 [95% CI, 0.11 to 0.63]) and PBS (hazard ratio, 0.28 [95% CI, 0.09 to 0.90]) 20 weeks after AB. Mice injected with rAAV9-OptF had improved contractility and no difference in cardiac remodeling compared with rAAV9-Ctrl after aortic banding. Conclusions: Our results suggest that PDE3A regulates SERCA2 activity through direct binding, independently of the catalytic activity of PDE3A. Targeting the SERCA2/PDE3A interaction prevented cardiac mortality after AB, most likely by improving cardiac contractility.

Background: Organ fibrosis due to excessive production of extracellular matrix by resident fibroblasts is estimated to contribute to >45% of deaths in the Western world, including those due to cardiovascular diseases such as heart failure. Here, we screened for small molecule inhibitors with a common ability to suppress activation of fibroblasts across organ systems. Methods: High-content imaging of cultured cardiac, pulmonary, and renal fibroblasts was used to identify nontoxic compounds that blocked induction of markers of activation in response to the profibrotic stimulus, transforming growth factor-β1. SW033291, which inhibits the eicosanoid-degrading enzyme, 15-hydroxyprostaglandin dehydrogenase, was chosen for follow-up studies with cultured adult rat ventricular fibroblasts and human cardiac fibroblasts (CF), and for evaluation in mouse models of cardiac fibrosis and diastolic dysfunction. Additional mechanistic studies were performed with CFs treated with exogenous eicosanoids. Results: Nine compounds, including SW033291, shared a common ability to suppress transforming growth factor-β1–mediated activation of cardiac, pulmonary, and renal fibroblasts. SW033291 dose-dependently inhibited transforming growth factor-β1–induced expression of activation markers (eg, α-smooth muscle actin and periostin) in adult rat ventricular fibroblasts and normal human CFs, and reduced contractile capacity of the cells. Remarkably, the 15-hydroxyprostaglandin dehydrogenase inhibitor also reversed constitutive activation of fibroblasts obtained from explanted hearts from patients with heart failure. SW033291 blocked cardiac fibrosis induced by angiotensin II infusion and ameliorated diastolic dysfunction in an alternative model of systemic hypertension driven by combined uninephrectomy and deoxycorticosterone acetate administration. Mechanistically, SW033291-mediated stimulation of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase signaling was required for the compound to block CF activation. Of the 12 exogenous eicosanoids that were tested, only 12(S)-hydroxyeicosatetraenoic acid, which signals through the G protein-coupled receptor, GPR31, recapitulated the suppressive effects of SW033291 on CF activation. Conclusions: Inhibition of degradation of eicosanoids, arachidonic acid-derived fatty acids that signal through G protein-coupled receptors, is a potential therapeutic strategy for suppression of pathological organ fibrosis. In the heart, we propose that 15-hydroxyprostaglandin dehydrogenase inhibition triggers CF-derived autocrine/paracrine signaling by eicosanoids, including 12(S)-hydroxyeicosatetraenoic acid, to stimulate extracellular signal-regulated kinase 1/2 and block conversion of fibroblasts into activated cells that secrete excessive amounts of extracellular matrix and contribute to heart failure pathogenesis.

Introduction Patients with ambulatory advanced heart failure (HF) are increasingly considered for durable mechanical circulatory support (MCS) and heart transplantation and their effective triage requires careful assessment of the clinical trajectory. Methods REVIVAL, a prospective, observational study, enrolled 400 ambulatory advanced HF patients from 21 MCS/transplant centers in 2015-2016. Study design included a clinical re-assessment of Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile within 120 days after enrollment. The prognostic impact of a worsening INTERMACS Profile assigned by the treating physician was assessed at 1 year after the Early Relook. Results Early Relook was done in 325 of 400 patients (81%), of whom 24% had a worsened INTERMACS Profile, associated with longer HF history and worse baseline INTERMACS profile, but no difference in baseline LVEF (median 0.20), 6-minute walk, quality of life, or other baseline parameters. Early worsening predicted higher rate of the combined primary endpoint of death, urgent MCS, or urgent transplant by 1 year after Early Relook, (28% vs 15%), with hazard ratio 2.2 (95% CI 1.2- 3.8; p = .006) even after adjusting for baseline INTERMACS Profile and Seattle HF Model score. Deterioration to urgent MCS occurred in 14% vs 5% (p = .006) during the year after Early Relook. Conclusions Early Relook identifies worsening of INTERMACS Profile in a significant population of ambulatory advanced HF, who had worse outcomes over the subsequent year. Early reassessment of ambulatory advanced HF patients should be performed to better define the trajectory of illness and inform triage to advanced therapies.

Background The effects of nonphysiological flow generated by continuous-flow (CF) left ventricular assist devices (LVADs) on the aorta remain poorly understood. Objectives The authors sought to quantify indexes of fibrosis and determine the molecular signature of post–CF-LVAD vascular remodeling. Methods Paired aortic tissue was collected at CF-LVAD implant and subsequently at transplant from 22 patients. Aortic wall morphometry and fibrillar collagen content (a measure of fibrosis) was quantified. In addition, whole-transcriptome profiling by RNA sequencing and follow-up immunohistochemistry were performed to evaluate CF-LVAD–mediated changes in aortic mRNA and protein expression. Results The mean age was 52 ± 12 years, with a mean duration of CF-LVAD of 224 ± 193 days (range 45-798 days). There was a significant increase in the thickness of the collagen-rich adventitial layer from 218 ± 110 μm pre-LVAD to 410 ± 209 μm post-LVAD (P Conclusions There is aortic remodeling and fibrosis after CF-LVAD that correlates with the duration of support. This fibrosis is due, at least in part, to suppression of extracellular matrix–degrading enzyme expression. Further research is needed to examine the contribution of nonphysiological flow patterns on vascular function and whether modulation of pulsatility may improve vascular remodeling and long-term outcomes.

Background Patient-centered care includes matching treatments to patient values and preferences. This assumes clarity and consistency of values and preferences relevant to major medical decisions. We sought to describe stability of patient-reported values regarding aggressiveness of care and preferences for left ventricular assist devices (LVADs) for advanced heart failure. Methods and Results We conducted a secondary analysis of patients undergoing LVAD evaluation at 6 US centers. Surveys at baseline, 1 month, and 6 months included a single 10-point scale on the value of aggressive care (score 1 = “do everything,” 10 = “live with whatever time I have left”) and treatment preference (LVAD, unsure, no LVAD). Data were captured for 232 patients, of whom 196 were ultimately deemed medically eligible for LVAD, and 161 were surgically implanted by 1 month. Values at baseline favored aggressive care (mean [SD], 2.49 [2.63]), trending toward less aggressive over time (1 month, 2.63 [2.05]; 6 months, 3.22 [2.70]). Between baseline and 1 month, values scores changed by ≥2 points in 28% (50/176), as did treatment preferences for 18% (29/161) of patients. Values score changes over time were associated with lower illness acceptance, depression, and eventual LVAD ineligibility. Treatment preference change was associated with values score change. Conclusion Most patients considering LVAD were stable in their values and treatment preferences. This stability, as well as the association between unstable treatment preferences and changes to stated values, highlighted the clinical utility of the values scale of aggressiveness. However, a substantial minority reported significant changes over time that may complicate the process of shared decision making. Improved methods to elicit and clarify values, including support to those with depression and low illness acceptance, is critical for patient-centered care. [Box: see text]

SARS CoV-2 enters host cells via its Spike protein moiety binding to the essential cardiac enzyme angiotensin-converting enzyme (ACE) 2, followed by internalization. COVID-19 mRNA vaccines are RNA sequences that are translated into Spike protein, which follows the same ACE2-binding route as the intact virion. In model systems, isolated Spike protein can produce cell damage and altered gene expression, and myocardial injury or myocarditis can occur during COVID-19 or after mRNA vaccination. We investigated 7 COVID-19 and 6 post-mRNA vaccination patients with myocardial injury and found nearly identical alterations in gene expression that would predispose to inflammation, coagulopathy, and myocardial dysfunction.

Bariatric surgery (BSg) is an effective treatment for morbid obesity, but little is known about the outcomes of BSg patients who undergo orthotopic heart transplantation (OHT). The aim of this study was to determine if BSg alters calcineurin inhibitor (CNI) level variability after OHT. Data were collected from 58 consecutive patients who underwent OHT at a single center from 1/2018 to 4/2019: 4 with BSg prior to OHT (BSg + OHT) and 54 without prior BSg (OHT). CNI level, cardiac biopsy, and left ventricular ejection fraction (LVEF) data were collected during the first 6 months post-OHT. Comparisons were made for 3 measures of CNI variability: coefficient of variation, time in therapeutic range (TTR), and TTR by the Rosendaal method. A Pearson's correlation coefficient was calculated to assess the relationship between CNI TTR, episodes of rejection, and LVEF. The results show TTR was lower in BSg + OHT compared to OHT (12.5% vs 31.3%, P .05). For the entire cohort, greater TTR correlated with fewer episodes of rejection (r = 0.31, P .05). In conclusion, these findings suggest BSg + OHT patients may warrant closer monitoring of CNI levels post-OHT. Furthermore, episodes of rejection and LVEF were similar for BSg + OHT patients, indicating that BSg should not be a contraindication to transplant.

Summary Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a powerful platform for biomedical research. However, they are immature, which is a barrier to modeling adult-onset cardiovascular disease. Here, we sought to develop a simple method that could drive cultured hiPSC-CMs toward maturity across a number of phenotypes, with the aim of utilizing mature hiPSC-CMs to model human cardiovascular disease. hiPSC-CMs were cultured in fatty acid-based medium and plated on micropatterned surfaces. These cells display many characteristics of adult human cardiomyocytes, including elongated cell morphology, sarcomeric maturity, and increased myofibril contractile force. In addition, mature hiPSC-CMs develop pathological hypertrophy, with associated myofibril relaxation defects, in response to either a pro-hypertrophic agent or genetic mutations. The more mature hiPSC-CMs produced by these methods could serve as a useful in vitro platform for characterizing cardiovascular disease., Graphical Abstract, Highlights • Standard (glucose) cultured hiPSC-CMs demonstrate a blunted hypertrophic response • A maturation method induces hiPSC-CM maturation and suppresses HIF1A expression • Mature hiPSC-CMs demonstrate improved sarcomeric morphology and contractility • Mature hiPSC-CMs respond to agonist- or mutation-induced hypertrophy, In this article, Song and colleagues show that a combination of fatty acid medium and micropatterned surfaces induces maturation in human induced pluripotent stem cell-derived cardiomyocytes. Matured cells display improved sarcomere morphology, metabolic maturation, and contractility. These cells also show increased sensitivity to hypertrophic stimuli, including hypertrophic agonist and genetic mutations, representing an ideal system to model cardiovascular disease.

BACKGROUND Patients with continuous-flow left ventricular assist devices (CF-LVADs) experience limitations in functional capacity and frequently, right ventricular (RV) dysfunction. We sought to characterize RV function in the context of global cardiopulmonary performance during exercise in this population. METHODS A total of 26 patients with CF-LVAD (aged 58 ± 11 years, 23 males) completed a hemodynamic assessment with either conductance catheters (Group 1, n = 13) inserted into the right ventricle to generate RV pressure‒volume loops or traditional Swan‒Ganz catheters (Group 2, n = 13) during invasive cardiopulmonary exercise testing. Hemodynamics were collected at rest, 2 sub-maximal levels of exercise, and peak effort. Breath-by-breath gas exchange parameters were collected by indirect calorimetry. Group 1 participants also completed an invasive ramp test during supine rest to determine the impact of varying levels of CF-LVAD support on RV function. RESULTS In Group 1, pump speed modulations minimally influenced RV function. During upright exercise, there were modest increases in RV contractility during sub-maximal exercise, but there were no appreciable increases at peak effort. Ventricular‒arterial coupling was preserved throughout the exercise. In Group 2, there were large increases in pulmonary arterial, left-sided filling, and right-sided filling pressures during sub-maximal and peak exercises. Among all participants, the cardiac output‒oxygen uptake relationship was preserved at 5.8:1. Ventilatory efficiency was severely abnormal at 42.3 ± 11.6. CONCLUSIONS Patients with CF-LVAD suffer from limited RV contractile reserve; marked elevations in pulmonary, left-sided filling, and right-sided filling pressures during exercise; and severe ventilatory inefficiency. These findings explain mechanisms for persistent reductions in functional capacity in this patient population.

Succinylation is a post-translational modification of protein lysine residues with succinyl groups derived from succinyl CoA. Succinylation is considered a significant post-translational modification with the potential to impact protein function which is highly conserved across numerous species. The role of succinylation in the heart, especially in heart failure and myofibril mechanics, remains largely unexplored. Mechanical parameters were measured in myofibrils isolated from failing hearts of ischemic cardiomyopathy patients and non-failing donor controls. We employed mass spectrometry to quantify differential protein expression in myofibrils from failing ischemic cardiomyopathy hearts compared to non-failing hearts. In addition, we combined peptide enrichment by immunoprecipitation with liquid chromatography tandem mass spectrometry to quantitatively analyze succinylated lysine residues in these myofibrils. Several key parameters of sarcomeric mechanical interactions were altered in myofibrils isolated from failing ischemic cardiomyopathy hearts, including lower resting tension and a faster rate of activation. Of the 100 differentially expressed proteins, 46 showed increased expression in ischemic heart failure, while 54 demonstrated decreased expression in ischemic heart failure. Our quantitative succinylome analysis identified a total of 572 unique succinylated lysine sites located on 181 proteins, with 307 significantly changed succinylation events. We found that 297 succinyl-Lys demonstrated decreased succinylation on 104 proteins, while 10 residues demonstrated increased succinylation on 4 proteins. Investigating succinyl CoA generation, enzyme activity assays demonstrated that α-ketoglutarate dehydrogenase and succinate dehydrogenase activities were significantly decreased in ischemic heart failure. An activity assay for succinyl CoA synthetase demonstrated a significant increase in ischemic heart failure. Taken together, our findings support the hypothesis that succinyl CoA production is decreased and succinyl CoA turnover is increased in ischemic heart failure, potentially resulting in an overall decrease in the mitochondrial succinyl CoA pool, which may contribute to decreased myofibril protein succinylation in heart failure.

Background: The heart grows in response to pathological and physiological stimuli. The former often precedes cardiomyocyte loss and heart failure; the latter paradoxically protects the heart and enhances cardiomyogenesis. The mechanisms underlying these differences remain incompletely understood. Although long noncoding RNAs (lncRNAs) are important in cardiac development and disease, less is known about their roles in physiological hypertrophy or cardiomyogenesis. Methods: RNA sequencing was applied to hearts from mice after 8 weeks of voluntary exercise-induced physiological hypertrophy and cardiomyogenesis or transverse aortic constriction for 2 or 8 weeks to induce pathological hypertrophy or heart failure. The top lncRNA candidate was overexpressed in hearts with adeno-associated virus vectors and inhibited with antisense locked nucleic acid–GapmeRs to examine its function. Downstream effectors were identified through promoter analyses and binding assays. The functional roles of a novel downstream effector, dachsous cadherin-related 2 (DCHS2), were examined through transgenic overexpression in zebrafish and cardiac-specific deletion in Cas9-knockin mice. Results: We identified exercise-regulated cardiac lncRNAs, called lncExACTs. lncExACT1 was evolutionarily conserved and decreased in exercised hearts but increased in human and experimental heart failure. Cardiac lncExACT1 overexpression caused pathological hypertrophy and heart failure; lncExACT1 inhibition induced physiological hypertrophy and cardiomyogenesis, protecting against cardiac fibrosis and dysfunction. lncExACT1 functioned by regulating microRNA-222, calcineurin signaling, and Hippo/Yap1 signaling through DCHS2. Cardiomyocyte DCHS2 overexpression in zebrafish induced pathological hypertrophy and impaired cardiac regeneration, promoting scarring after injury. In contrast, murine DCHS2 deletion induced physiological hypertrophy and promoted cardiomyogenesis. Conclusions: These studies identify lncExACT1-DCHS2 as a novel pathway regulating cardiac hypertrophy and cardiomyogenesis. lncExACT1-DCHS2 acts as a master switch toggling the heart between physiological and pathological growth to determine functional outcomes, providing a potentially tractable therapeutic target for harnessing the beneficial effects of exercise.

FLNC truncating mutations ( FLNCtv ) are prevalent causes of inherited dilated cardiomyopathy (DCM), with a high risk of developing arrhythmogenic cardiomyopathy. We investigated the molecular mechanisms of mutant FLNC in the pathogenesis of arrhythmogenic DCM (a-DCM) using patient-specific induced pluripotent stem cell–derived cardiomyocytes (iPSC-CMs). We demonstrated that iPSC-CMs from two patients with different FLNCtv mutations displayed arrhythmias and impaired contraction. FLNC ablation induced a similar phenotype, suggesting that FLNCtv are loss-of-function mutations. Coimmunoprecipitation and proteomic analysis identified β-catenin (CTNNB1) as a downstream target. FLNC deficiency induced nuclear translocation of CTNNB1 and subsequently activated the platelet-derived growth factor receptor alpha (PDGFRA) pathway, which were also observed in human hearts with a-DCM and FLNCtv . Treatment with the PDGFRA inhibitor, crenolanib, improved contractile function of patient iPSC-CMs. Collectively, our findings suggest that PDGFRA signaling is implicated in the pathogenesis, and inhibition of this pathway is a potential therapeutic strategy in FLNC-related cardiomyopathies.

BACKGROUND: Young adult heart transplant (HT) recipients transferring to adult care are at risk for poor health outcomes. We conducted a pilot randomized controlled trial to determine feasibility and test a transition intervention for young adults who underwent HT as children and transferred to adult care. METHODS: Participants were randomized to the transition intervention (4 months long, focused on HT knowledge, self-care, self-advocacy, and social support) or usual care. Self-report questionnaires and medical records data were collected at baseline and 3 and 6 months after the initial adult clinic visit. Longitudinal analyses comparing outcomes over time were performed using generalized estimating equations and linear mixed models. RESULTS: Transfer to adult care was successful and feasible (i.e., excellent participation rates). The average patient standard deviation of mean tacrolimus levels was similar over time in both study arms and < 2.5, indicating adequate adherence. There were no between group and within group differences in percent of tacrolimus bioassays within target range (>50%). Average overall adherence to treatment was similarly good for both groups. Rates of appointment keeping through 6 months after transfer declined over time in both groups. CONCLUSIONS: Feasibility of the study was demonstrated. Our transition intervention did not improve outcomes.

Mitochondrial Ca

Visual Abstract, Highlights • Mitochondrial function is impaired in explanted failing pediatric and adult human hearts. • Elamipretide is a novel mitochondria-targeted drug that is targeted to cardiolipin on the inner mitochondrial membrane and improves coupling of the electron transport chain. • Treatment of explanted human hearts with elamipretide improves human cardiac mitochondrial function. • The study provides novel methods to evaluate the influence of compounds on mitochondria in the human heart and provides proof of principle for the use of elamipretide to improve mitochondrial energetics in failing myocardium due to multiple etiologies and irrespective of age., Summary Negative alterations of mitochondria are known to occur in heart failure (HF). This study investigated the novel mitochondrial-targeted therapeutic agent elamipretide on mitochondrial and supercomplex function in failing human hearts ex vivo. Freshly explanted failing and nonfailing ventricular tissue from children and adults was treated with elamipretide. Mitochondrial oxygen flux, complex (C) I and CIV activities, and in-gel activity of supercomplex assembly were measured. Mitochondrial function was impaired in the failing human heart, and mitochondrial oxygen flux, CI and CIV activities, and supercomplex-associated CIV activity significantly improved in response to elamipretide treatment. Elamipretide significantly improved failing human mitochondrial function.

BACKGROUND The outlook for ambulatory patients with advanced heart failure (HF) and the appropriate timing for left ventricular assist device (LVAD) or transplant remain uncertain. The aim of this study was to better understand disease trajectory and rates of progression to subsequent LVAD therapy and transplant in ambulatory advanced HF. METHODS See Related Editorial, page XXX Patients with advanced HF who were New York Heart Association (NYHA) Class III or IV and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profiles 4 to 7, despite optimal medical therapy (without inotropic therapy), were enrolled across 11 centers and followed for the end-points of survival, transplantation , LVAD placement, and health-related quality of life. A secondary intention-to-treat survival analysis compared outcomes for MedaMACS patients with a matched group of Profile 4 to 7 patients with LVADs from the INTERMACS registry. RESULTS Between May 2013 and October 2015, 161 patients were enrolled with INTERMACS Profiles 4 (12%), 5 (32%), 6 (49%), and 7 (7%). By 2 years after enrollment, 75 (47%) patients had reached a primary end-point with 39 (24%) deaths, 17 (11%) undergoing LVAD implantation, and 19 (12%) receiving a transplant. Compared with 1,753 patients with Profiles 4 to 7 receiving LVAD therapy, there was no overall difference in intention-to-treat survival between medical and LVAD therapy, but survival with LVAD therapy was superior to medical therapy among Profile 4 and 5 patients (p = 0.0092). Baseline health-related quality of life was lower among patients receiving a LVAD than those enrolled on continuing oral medical therapy, but increased after 1 year for survivors in both cohorts. CONCLUSIONS Ambulatory patients with advanced HF are at high risk for poor outcomes, with only 53% alive on medical therapy after 2 years of follow-up. Survival was similar for medical and LVAD therapy in the overall cohort, which included the lower severity Profiles 6 and 7, but survival was better with LVAD therapy among patients in Profiles 4 and 5. Given the poor outcomes in this group of advanced HF patients, timely consideration of transplant and LVAD is of critical importance.

While advancements in left ventricular assist devices (LVAD) have led to improved survival1–5, complications associated with longterm exposure to continuous-flow (CF) circulatory support, such as gastrointestinal bleeding, pump thrombosis and stroke result in significant morbidity. Strokes affect 10% of patients in the first year of support alone.6 Management algorithms for CF-LVAD patients suffering from stroke have been published previously.7 In this article, we summarize the clinical burden of strokes placed in context of other complications, comorbidities, and medication-effects that work together in an almost synergistic fashion to increase the risk of stroke. Physiologic (mal)adaptations to continuous-flow circulatory support are reviewed with an emphasis on the arterial baroreceptor reflex, neurohumoral axis and implications on blood pressure control. Cerebral perfusion and autoregulatory processes in the setting of heart failure with reduced ejection fraction (HFrEF), hypertension and CF-LVAD support are discussed. Finally, we highlight important areas of future research that will advance our understanding of the physiology of this unique patient population, and pave the way for novel management strategies to prevent strokes in CF-LVAD patients.

IMPORTANCE: Orthotopic heart transplant (OHT) recipients are at increased risk for morbidity and mortality after SARS-CoV-2 infection. Although antibody response to COVID-19 vaccination is lower in solid organ transplant recipients, there has been no study assessing the safety and effectiveness of COVID-19 vaccination in OHT recipients. OBJECTIVE: To assess the safety and effectiveness of COVID-19 vaccination and associations with SARS-CoV-2 infection and clinical outcomes in a large population of adult OHT recipients. DESIGN, SETTING, AND PARTICIPANTS: This case-control study examined data from a US heart transplant program at a single center for all adult recipients of OHT who were followed up from January 15, 2021, through January 31, 2022. MAIN OUTCOMES AND MEASURES: The primary outcome was number of SARS-CoV-2 infections and related hospitalizations, intensive care unit (ICU) admissions, and deaths between vaccinated vs unvaccinated adult recipients of OHT. RESULTS: A total of 436 patients who received OHT were included in the study, of which 106 patients were infected with COVID-19. The mean (SD) age was 54 (17) years; 303 (69.5%) were men and 133 (30.5%) were women. There were 366 patients in the vaccinated cohort with 72 COVID-19 infections (19.7%), 15 hospitalizations (4.1%), 4 ICU admissions (1.1%), and 3 deaths (0.8%). There were 70 patients in the unvaccinated cohort with 34 COVID-19 infections (48.6%), 10 hospitalizations (14.3%), 3 ICU admissions (4.3%), and 3 deaths (4.3%). COVID-19 vaccination was associated with a lower risk of COVID-19 infection (risk ratio [RR], 0.41; 95% CI, 0.30-0.56), hospitalization (RR, 0.29; 95% CI, 0.14-0.61), and death (RR, 0.19; 95% CI, 0.05-0.82). Among the 366 vaccinated OHT recipients, there was no echocardiographic evidence of graft dysfunction, clinically significant rejection, or allosensitization at 6 months after they received the COVID-19 vaccine. CONCLUSIONS AND RELEVANCE: Patients with OHT who are infected with SARS-CoV-2 are at greater risk of severe infection and death compared with immunocompetent individuals. COVID-19 vaccination was associated with fewer COVID-19 infections, hospitalizations, and deaths, with no heart transplant–specific adverse events. COVID-19 vaccination for all OHT recipients is of paramount importance.

Background: Continuous-flow (CF) left ventricular assist devices (LVADs) improve outcomes for patients with advanced heart failure (HF). However, the lack of a physiological pulse predisposes to side-effects including uncontrolled blood pressure (BP), and there are little data regarding the impact of CF-LVADs on BP regulation. Methods: Twelve patients (10 males, 60±11 years) with advanced heart failure completed hemodynamic assessment 2.7±4.1 months before, and 4.3±1.3 months following CF-LVAD implantation. Heart rate and systolic BP via arterial catheterization were monitored during Valsalva maneuver, spontaneous breathing, and a 0.05 Hz repetitive squat-stand maneuver to characterize cardiac baroreceptor sensitivity. Plasma norepinephrine levels were assessed during head-up tilt at supine, 30 o and 60 o . Heart rate and BP were monitored during cardiopulmonary exercise testing. Results: Cardiac baroreceptor sensitivity, determined by Valsalva as well as Fourier transformation and transfer function gain of Heart rate and systolic BP during spontaneous breathing and squat-stand maneuver, was impaired before and following LVAD implantation. Norepinephrine levels were markedly elevated pre-LVAD and improved—but remained elevated post-LVAD (supine norepinephrine pre-LVAD versus post-LVAD: 654±437 versus 323±164 pg/mL). BP increased during cardiopulmonary exercise testing post-LVAD, but the magnitude of change was modest and comparable to the changes observed during the pre-LVAD cardiopulmonary exercise testing. Conclusions: Among patients with advanced heart failure with reduced ejection fraction, CF-LVAD implantation is associated with modest improvements in autonomic tone, but persistent reductions in cardiac baroreceptor sensitivity. Exercise-induced increases in BP are blunted. These findings shed new light on mechanisms for adverse events such as stroke, and persistent reductions in functional capacity, among patients supported by CF-LVADs. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03078972.

Rationale: Pathological hypertrophy commonly leads to heart failure (HF) and loss of cardiomyocytes, while physiological hypertrophy protects the heart and enhances cardiomyogenesis. The mechanisms underlying these differences remain unclear. While long noncoding RNAs (lncRNAs) are important in cardiac development and disease, their role in physiological hypertrophy is unknown. Objective: To investigate the role of lncRNAs in physiological hypertrophy. Methods and Results: Mice underwent voluntary wheel running for eight weeks or transverse aortic constriction (TAC) for two or ten weeks. RNAseq identified a novel set of lncRNAs altered in exercised hearts, which we termed l ong n on c oding Ex ercise- A ssociated C ardiac T ranscripts (lncExACTs). lncExACT1 was highly conserved and uniquely downregulated in exercised hearts but upregulated in pathological animal models and hearts from HF patients vs controls (1.8-fold; p p =0.032, N=16) and preserved ejection fraction (3.4-fold; p =0.006, N=18). In mice, AAV9 lncExACT1 overexpression increased cardiac lncExACT1 7-fold at 16 weeks and increased heart (HW) and lung (LW) weight relative to tibial length (TL), reduced fractional shortening (FS) and increased relative wall thickness (RWT) ( p p p Conclusions: lncExACT1 acts as a master switch toggling the heart between physiological and pathological growth and provides a potentially tractable therapeutic target for harnessing the beneficial effects of exercise.

The impact of coronary artery disease (CAD) among liver transplant candidates (LTC) on post-LT clinical outcomes remains unclear. The aim of this study is to determine association of presence and severity of CAD on post-LT major adverse cardiac events (MACE) including cardiac-associated mortality. We conducted a retrospective cohort analysis of 231 patients who underwent diagnostic coronary angiogram (DCA) during their LT evaluation at a tertiary medical center from 2012-2017. Patients were analyzed based on degree of CAD (no CAD, non-obstructive CAD [< 50% stenosis], obstructive CAD [≥50% stenosis]) per DCA results. MACE were noted at 30 days, 1 year, 3 years, and 5 years post-LT, and Kaplan-Meier curves were used to determine post-LT MACE-free probability. LTC with any CAD, including non-obstructive CAD, had lower MACE-free probability at all post-LT time points (0.94 vs 0.65 at 30 days, P = .001; 0.87 vs 0.59 at 1 year, P = .002; 0.87 vs 0.41 at 3 years, P < .001; 0.87 vs 0.37 at 5 years, P < .001). Identification of and medical intervention for non-obstructive CAD should be considered in all LTC, though further studies are necessary to determine optimal medical interventions to mitigate MACE risk in this cohort.

Background Patients with a heart transplant and depression have higher rates of graft failure and noncompliance. Local problem The heart transplant clinic had no standardized approach to assess for depression. Methods The heart transplant clinic implemented routine use of the Patient Health Questionnaire (PHQ). Interventions Team members were educated via an online module about depression. A process for depression screening and follow-up was developed and implemented. Results From July 2018 to February 2019, there were 834 visits; PHQ2 screens were completed during 779 (93%) of those visits with 40 (5%) positive screens. All 40 patients had PHQ9 assessment, with 33 patients (4%) exhibiting moderate or severe depressive symptoms. All 33 patients were provided with mental health resources and received follow-up. Median time to administer PHQ2 was 2 minutes (range 1-3 minutes). Conclusions Implementation of universal depression screening in a heart transplant clinic is feasible, identifies patients with depression, and does not add significant clinical burden.

Transthyretin amyloid cardiomyopathy (ATTR-CM) results in a restrictive cardiomyopathy caused by extracellular deposition of transthyretin, normally involved in the transportation of the hormone thyroxine and retinol-binding protein, in the myocardium. Enthusiasm about ATTR-CM has grown as a result of 3 simultaneous areas of advancement: Imaging techniques allow accurate noninvasive diagnosis of ATTR-CM without the need for confirmatory endomyocardial biopsies; observational studies indicate that the diagnosis of ATTR-CM may be underrecognized in a significant proportion of patients with heart failure; and on the basis of elucidation of the mechanisms of amyloid formation, therapies are now approved for treatment of ATTR-CM. Because therapy for ATTR-CM may be most effective when administered before significant cardiac dysfunction, early identification of affected individuals with readily available noninvasive tests is essential. This scientific statement is intended to guide clinical practice and to facilitate management conformity by covering current diagnostic and treatment strategies, as well as unmet needs and areas of active investigation in ATTR-CM.

The Heart Failure Academic Research Consortium is a partnership between the Heart Failure Collaboratory (HFC) and Academic Research Consortium (ARC), comprised of leading heart failure (HF) academic research investigators, patients, United States (US) Food and Drug Administration representatives, and industry members from the US and Europe. A series of meetings were convened to establish definitions and key concepts for the evaluation of HF therapies including optimal medical and device background therapy, clinical trial design elements and statistical concepts, and study endpoints. This manuscript summarizes the expert panel discussions as consensus recommendations focused on populations and endpoint definitions; it is not exhaustive or restrictive, but designed to stimulate HF clinical trial innovation.

The Heart Failure Academic Research Consortium is a partnership between the Heart Failure Collaboratory (HFC) and Academic Research Consortium (ARC), comprised of leading heart failure (HF) academic research investigators, patients, United States (US) Food and Drug Administration representatives, and industry members from the US and Europe. A series of meetings were convened to establish definitions and key concepts for the evaluation of HF therapies including optimal medical and device background therapy, clinical trial design elements and statistical concepts, and study endpoints. This manuscript summarizes the expert panel discussions as consensus recommendations focused on populations and endpoint definitions; it is not exhaustive or restrictive, but designed to stimulate HF clinical trial innovation.

Background We assessed the relationship between circadian blood pressure (BP) patterns and clinical outcomes in a contemporary cohort of adult heart transplant recipients. Methods This retrospective, cross-sectional study included adult heart transplant recipients at least 6 months post-transplant. Ambulatory BP measurements were recorded over 24 hours. Nondippers were defined as a decline in average nighttime BP ≤ 10% compared with daytime. Primary outcomes were the presence of end organ damage, that is, microalbuminuria, chronic kidney disease, and/or left ventricular hypertrophy. Secondary outcomes were measures of diastolic dysfunction (ie, mitral valve deceleration time, e/e', E/A, and isovolumetric relaxation time), microalbumin/creatinine ratio, eGFR, interventricular septal thickness, and left ventricular posterior wall thickness. Results Of 30 patients, 53.3% (n = 16) were systolic nondippers and 40% (n = 12) were diastolic nondippers. Diastolic nondippers had three times higher urine microalbumin/creatinine ratios than diastolic dippers (P = .03). Systolic nondippers had 16.3% lower mitral valve deceleration time (P = .05) than systolic dippers, while diastolic nondippers had 20.4% higher e/e' (P = .05) than diastolic dippers. There were no significant relationships between BP dipping status and any of the primary outcomes. Conclusions These data suggest that systolic and diastolic nondipping BP patterns are associated with subclinical kidney damage and diastolic dysfunction in heart transplant recipients.

RationaleHuman induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) are a powerful platform for biomedical research. However, they are immature, which is a barrier to modeling adult-onset cardiovascular disease.ObjectiveWe sought to develop a simple method which could drive cultured hiPSC-CMs towards maturity across a number of phenotypes.Methods and resultsCells were cultured in fatty acid-based media and plated on micropatterned surfaces to promote alignment and elongation. These cells display many characteristics of adult human cardiomyocytes, including elongated cell morphology, enhanced maturity of sarcomeric structures, metabolic behavior, and increased myofibril contractile force. Most notably, hiPSC-CMs cultured under optimal maturity-inducing conditions recapitulate the pathological hypertrophy caused by either a pro-hypertrophic agent or genetic mutations.ConclusionsThe more mature hiPSC-CMs produced by the methods described here will serve as a usefulin vitroplatform for characterizing cardiovascular disease.

Background During myocardial ischemia, hypoxia-inducible factors are stabilized and provide protection from ischemia and reperfusion injury. Recent studies show that myocyte-specific hypoxia-inducible factor 2A promotes myocardial ischemia tolerance through induction of epidermal growth factor, amphiregulin. Here, the authors hypothesized that hypoxia-inducible factor 2A may enhance epidermal growth factor receptor 1 (ERBB1) expression in the myocardium that could interface between growth factors and its effect on providing tolerance to ischemia and reperfusion injury. Methods Human myocardial tissues were obtained from ischemic heart disease patients and normal control patients to compare ERBB1 expression. Myocyte-specific Hif2a or ErbB1 knockout mice were generated to observe the effect of Hif2a knockdown in regulating ERBB1 expression and to examine the role of ERBB1 during myocardial ischemia and reperfusion injury. Results Initial studies of myocardial tissues from patients with ischemic heart disease showed increased ERBB1 protein (1.12 ± 0.24 vs. 13.01 ± 2.20, P < 0.001). In contrast, ERBB1 transcript was unchanged. Studies using short hairpin RNA repression of Hif2A or Hif2aloxP/loxP Myosin Cre+ mice directly implicated hypoxia-inducible factor 2A in ERBB1 protein induction during hypoxia or after myocardial ischemia, respectively. Repression of RNA-binding protein 4 abolished hypoxia-inducible factor 2A–dependent induction of ERBB1 protein. Moreover, ErbB1loxP/loxP Myosin Cre+ mice experienced larger infarct sizes (22.46 ± 4.06 vs. 46.14 ± 1.81, P < 0.001) and could not be rescued via amphiregulin treatment. Conclusions These findings suggest that hypoxia-inducible factor 2A promotes transcription-independent induction of ERBB1 protein and implicates epidermal growth factor signaling in protection from myocardial ischemia and reperfusion injury. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Objectives The purpose of this study was to assess the phenotype of Filamin C (FLNC) truncating variants in dilated cardiomyopathy (DCM) and understand the mechanism leading to an arrhythmogenic phenotype. Background Mutations in FLNC are known to lead to skeletal myopathies, which may have an associated cardiac component. Recently, the clinical spectrum of FLNC mutations has been recognized to include a cardiac-restricted presentation in the absence of skeletal muscle involvement. Methods A population of 319 U.S. and European DCM cardiomyopathy families was evaluated using whole-exome and targeted next-generation sequencing. FLNC truncation probands were identified and evaluated by clinical examination, histology, transmission electron microscopy, and immunohistochemistry. Results A total of 13 individuals in 7 families (2.2%) were found to harbor 6 different FLNC truncation variants (2 stopgain, 1 frameshift, and 3 splicing). Of the 13 FLNC truncation carriers, 11 (85%) had either ventricular arrhythmias or sudden cardiac death, and 5 (38%) presented with evidence of right ventricular dilation. Pathology analysis of 2 explanted hearts from affected FLNC truncation carriers showed interstitial fibrosis in the right ventricle and epicardial fibrofatty infiltration in the left ventricle. Ultrastructural findings included occasional disarray of Z-discs within the sarcomere. Immunohistochemistry showed normal plakoglobin signal at cell–cell junctions, but decreased signals for desmoplakin and synapse-associated protein 97 in the myocardium and buccal mucosa. Conclusions We found FLNC truncating variants, present in 2.2% of DCM families, to be associated with a cardiac-restricted arrhythmogenic DCM phenotype characterized by a high risk of life-threatening ventricular arrhythmias and a pathological cellular phenotype partially overlapping with arrhythmogenic right ventricular cardiomyopathy.

Extended survival with LVADs has generated interest in implantation for ambulatory patients with advanced heart failure (HF) prior to dependence on inotropes, though we remain limited in our ability to define and advance indications in this less sick advanced HF population. The MedaMACS and ROADMAP studies have informed prognosis and decision-making for ambulatory patients with advanced HF. Sicker INTERMACS profiles are consistently associated with high risk of death or rescue LVAD. Appropriately selected patients in profile 4 should be considered for LVADs based on their high mortality and poor quality of life. These studies also shed light on discordant perceptions of HF disease severity between patients and their physicians. For ambulatory patients with HF not at imminent risk of death, shared decision-making about LVAD requires measured and individualized consideration of risk and benefit beyond survival. Future studies, including the ongoing REVIVAL study, should provide additional prognostic information in this patient population and should aid patients, caregivers, and physicians as they contemplate complex decisions regarding LVAD therapy.

The aim of this study was to measure aortic vascular stiffness from orthotopic heart transplant (OHT) patients exposed to varying types of flow as a result of the presence or absence of left ventricular assist device (LVAD) support pre-OHT.The effects of continuous-flow LVADs (CF-LVADs) on vascular properties are unknown, but may contribute to the pathophysiology of CF-LVAD complications such as stroke, hypertension, and bleeding.Echocardiograms were reviewed from 172 OHT patients immediately before LVAD and at 3 time points post-OHT: baseline, 6 months, and 1 year. For each study, pulse pressure and aortic end-systolic and end-diastolic dimensions were used to calculate aortic strain, distensibility, and stiffness index. Patients were categorized into 3 groups based on the presence or absence of a LVAD and a pulse pre-OHT: No LVAD (n = 111), LVAD No Pulse (n = 30), and LVAD With Pulse (n = 31).The aortic stiffness index among LVAD No Pulse patients increased from 2.8 ± 1.1 pre-CF-LVAD to 10.9 ± 4.7 immediately post-OHT (p 0.001). This aortic stiffness index was also significantly higher compared with No LVAD (3.4 ± 1.1; p 0.001) and LVAD With Pulse (3.7 ± 1.4; p 0.001) immediately post-OHT with attenuation of these differences by 1 year post-OHT. Similar findings were noted for the other indices of aortic stiffness.Aortic stiffness is markedly increased immediately post-OHT among patients bridged with CF-LVADs, with attenuation of this increased stiffness over the first year after transplant. These results suggest that aortic vascular properties are dynamic and may be influenced by alterations in flow pulsatility. As more patients are supported with CF-LVADs and as newer pump technology attempts to modulate pulsatility, further research examining the role of alterations in flow patterns on vascular function and the potential resultant systemic sequelae are needed.