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Lipoprotein a (Lp(a)) is a lipid biomarker that binds cholesterol and bears independent cardiovascular risk. Strategies to lower the level of Lp(a) and mitigate such risk are important both for primary and secondary prevention. Currently there are no approved therapies targeting Lp(a) directly. Lipid lowering therapies prescribed routinely may have no effect on Lp(a) levels. Some agents such as niacin and estrogens can significantly decrease Lp(a), but their use is not recommended due to their adverse safety profile. Statins increase Lp(a) levels by 10–20%, questioning the benefit of such therapy when this biomarker is elevated. The Food and Drug Administration (FDA) endorses new agents to address dyslipidemia such as proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9-i) and Inclisiran, a small interfering RNA. These approaches have been shown to also significantly reduce Lp(a), but more clinical data is needed before implementing their use in clinical practice. Clinical trials are currently ongoing to test the efficacy of newly developed antisense oligonucleotides and small interfering RNAs targeting the gene encoding for Lp(a) in hepatocytes, while other investigations assess small molecules that inhibit Lp(a) assembly. This review summarizes the pathophysiology and clinical implications of Lp(a) elevation, and focuses on proposed Lp(a) therapies and the current state of the clinical trials of such novel agents.

Abstract Mass spectrometry (MS) is a technique widely employed for the identification and characterization of proteins, with personalized medicine, systems biology, and biomedical applications. The application of MS-based proteomics advances our understanding of protein function, cellular signaling, and complex biological systems. MS data analysis is a critical process that includes identifying and quantifying proteins and peptides and then exploring their biological functions in downstream analyses. To address the complexities associated with MS data analysis, we developed ProtPipe to streamline and automate the processing and analysis of high-throughput proteomics and peptidomics datasets with DIA-NN preinstalled. The pipeline facilitates data quality control, sample filtering, and normalization, ensuring robust and reliable downstream analyses. ProtPipe provides downstream analyses, including protein and peptide differential abundance identification, pathway enrichment analysis, protein–protein interaction analysis, and major histocompatibility complex (MHC)–peptide binding affinity analysis. ProtPipe generates annotated tables and visualizations by performing statistical post-processing and calculating fold changes between predefined pairwise conditions in an experimental design. It is an open-source, well-documented tool available at https://github.com/NIH-CARD/ProtPipe, with a user-friendly web interface.

BACKGROUND: In the phase 3 randomized controlled study ATTRibute-CM (Efficacy and Safety of AG10 in Subjects With Transthyretin Amyloid Cardiomyopathy), acoramidis, a transthyretin stabilizer, demonstrated significant efficacy on the primary end point. Participants with transthyretin amyloid cardiomyopathy who completed ATTRibute-CM were invited to enroll in an open-label extension study (OLE). We report the efficacy and safety data of acoramidis in participants who completed ATTRibute-CM and enrolled in the ongoing OLE. METHODS: Participants who previously received acoramidis through month 30 in ATTRibute-CM continued to receive it (continuous acoramidis), and those who received placebo through month 30 were switched to acoramidis (placebo to acoramidis). Participants who received concomitant tafamidis in ATTRibute-CM were required to discontinue it to be eligible to enroll in the OLE. Clinical efficacy outcomes analyzed through month 42 included time to event for all-cause mortality (ACM) or first cardiovascular-related hospitalization (CVH), ACM alone, first CVH alone, ACM or recurrent CVH, change from baseline in NT-proBNP (N-terminal pro-B-type natriuretic peptide), 6-minute walk distance, serum transthyretin, and Kansas City Cardiomyopathy Questionnaire Overall Summary score. Safety outcomes were analyzed through month 42. RESULTS: Overall, 438 of 632 participants in ATTRibute-CM completed treatment, and 389 enrolled in the ongoing OLE (263 continuous acoramidis and 126 placebo to acoramidis). The hazard ratio for ACM or first CVH was 0.57 (95% CI, 0.46–0.72) at month 42 based on a stratified Cox proportional hazards model ( P <0.0001) favoring continuous acoramidis. Similar analyses were performed on ACM alone and first CVH alone, with hazard ratios of 0.64 (95% CI, 0.47–0.88) and 0.53 (95% CI, 0.41–0.69), respectively, at month 42. Treatment effects for NT-proBNP and 6-minute walk distance also favored continuous acoramidis. On initiation of open-label acoramidis in the placebo-to-acoramidis arm, there was a prompt increase in serum transthyretin. Quality of life assessed by Kansas City Cardiomyopathy Questionnaire Overall Summary score was well preserved in continuous-acoramidis participants compared with the placebo-to-acoramidis participants. No new clinically important safety issues were identified in this long-term evaluation. CONCLUSIONS: Early initiation and continuous use of acoramidis in the ATTRibute-CM study through month 42 of the ongoing OLE study were associated with sustained clinical benefits in a contemporary transthyretin amyloid cardiomyopathy cohort, with no clinically important safety issues newly identified. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04988386.

Background: Arrhythmogenic cardiomyopathy (ACM) is a genetic heart disease characterized by proclivity for ventricular arrhythmias and systolic dysfunction. Rarely, sudden cardiac arrest (SCA) is the presenting event in ACM. These individuals may have concealed disease with no appreciable structural manifestations on imaging. Aims: To determine the prevalence, clinical features, and outcomes of patients with genotype-positive ACM who presented with a sentinel SCA. Methods: In this retrospective study, 445 genotype-positive ACM patients evaluated from 1/2015-4/2024 were analyzed to identify those whose initial presentation was SCA. Pertinent demographic, clinical, genetic, and outcome data were extracted from the electronic medical record. Structural manifestations were defined by having one of the following on baseline TTE: EF < 50%, LVEDV >56 mL (male) or >51 mL (female), or regional RV akinesia, dyskinesia, or aneurysm. Categorical variables are presented as number (%), and continuous variables as median (IQR). Statistical analysis was done using Fisher’s exact test (categorical), t-test (continuous), and Logrank test (survival). Patients were censored at time of transplant, death, or last followup. Results: Overall, 14/445 (3%) ACM patients presented with sentinel SCA [71% male; median age at SCA 39 (IQR 30-46)]. The most common genetic substrates were DSP -encoded desmoplakin (n=4; 29%), LMNA -encoded lamin A/C (n=3; 21%), and PKP2 -encoded plakophilin-2 (n=3; 21%). During a median followup of 8.4 years, 12 (86%) experienced appropriate ICD shocks, 8 (57%) required catheter ablation for ventricular arrhythmias, 6 (42%) underwent transplant, and 2 (14%) died of cardiac causes. Notably, 5 (35%) patients did not have evidence of structural disease during baseline evaluation. Compared to those with structural disease, this group was younger [median age 28 (IQR 21-29) vs 45 (IQR 41-48), p = 0.002] and less likely to undergo transplant [0 (0%) vs 6 (42%), p = 0.03]. Conclusions: Sentinel SCA is a rare presentation in ACM and may precede overt structural cardiac changes in a subset of younger patients. This population remains at increased risk for recurrent ventricular arrhythmias and often require advanced therapies.

Background: Patients with normal resting left ventricular ejection fraction (LVEF) without either coronary artery disease (CAD) or a hypertensive response can paradoxically develop reduced LVEF during exercise stress echocardiography (ESE). The clinical phenotype and outcomes of these patients is unknown. Hypothesis: Patients who paradoxically develop reduced LVEF during exercise may represent a sub-phenotype of heart failure with preserved LVEF (HFpEF). Aims: To describe the baseline characteristics and clinical outcomes of this unique patient population. Methods: Among all ESE performed between January 2003 and December 2022, patients without a hypertensive response to exercise and without CAD by angiogram within 90 days of ESE, who had a resting LVEF ≥50% with a ≥5% LVEF decrease during ESE were identified. All-cause mortality, HF hospitalization, and atrial fibrillation (AF) outcomes were assessed. Kaplan-Meier and Cox regression methods were used to analyze time-to-event outcomes. Results: Among 213,643 stress echocardiograms performed, 134 patients met eligibility criteria (Table 1). The mean age of the population was 66±10 years, 76% were women, and 16% had AF at baseline. Mean LVEF was 58±4% at rest and 43±4% at peak stress. Stress electrocardiogram met criteria for ischemia in 14%. The 10-year all-cause mortality risk was 12.9% (95% CI 5.5-20.3) with 10 (37%) of 27 deaths due to cancer (Figure 1, Panel A). The 10-year estimated risk of HF hospitalization was 17.6% (95% CI 9.0-26.2) (Figure 1, Panel B). Among 112 patients without AF at baseline, the 10-year risk of developing AF was 23.4% (95% CI 13.4-33.4). Conclusions: Patients with exercise-induced reduced LVEF in the absence of obstructive CAD have a high incidence of HF hospitalizations and AF. Given the preponderance of women, risk for AF, HF hospitalizations, and cancer-related deaths, the possibility that this condition is an early sub-phenotype of HFpEF should be investigated.

Background: Although exercise stress testing (EST) has shown to unmask latent electrical substrates in PKP2 -mediated arrhythmogenic cardiomyopathy (ACM), the prognostic role of EST-induced ventricular arrhythmia (VA) patterns in PKP2-ACM patients is unclear. Objective: To examine the exercise-induced VA patterns observed during EST in PKP2-ACM patients and explore their correlation with major VA outcomes. Methods: We retrospectively analyzed 621 patients with either genotype-positive ACM or genotype-positive dilated cardiomyopathy evaluated between 01/2015 and 04/2024 to identify those with a disease-causative variant in PKP2 (N = 108). After exclusion of 38 PKP2-ACM patients without EST data, demographic and electrocardiographic data was extracted from the electronic medical record. The arrhythmic burden [premature ventricular contractions (PVCs), PVCs in bigeminy, PVC couplets, non-sustained VT (NSVT), sustained VT, ventricular fibrillation (VF), and PVCs/minute] during each EST phase (baseline, peak, active and passive recovery) were reviewed and correlated with major VA outcomes [sudden cardiac arrest (SCA), sustained VT, and appropriate implantable cardioverter-defibrillator (ICD) shocks]. Results: A total of 186 exercise tests from 70/108 (65%) PKP2-ACM patients (mean age 36 ± 20 years, 40 % male) were analyzed. The presence and burden of PVCs occurring singly, bigeminy, couplets. and NSVT were more prevalent during the recovery phase, specifically the passive recovery phase ( Table ). PKP2-ACM patients with structural disease (64%) were more likely to have an increased VA burden during recovery than those without structural disease [28/45 (62%) vs 4/25 (16%); p<0.001]. Interestingly, the presence of an increased arrhythmic burden (worsening PVCs/min or complex PVCs) during the recovery was associated with major VA over a median follow-up of 47 months (HR 8.576 [1.015-72.449]; p= 0.019). Conclusion: Increased arrhythmic burden during the recovery phase (late > early) is associated with an increased risk of major VAs in PKP2-ACM. Further studies are needed to understand if this observation extends to other ACM genotypes and whether EST-induced VA patterns can be used to assess therapeutic efficacy in PKP2-ACM.

Background: Electrocardiography-based artificial intelligence (AI-ECG) validated models that detect cardiac disease are increasingly being applied in clinical practice. The utility of such tools to detect insidious cardiac disease in patients with normal baseline left ventricular ejection fraction (LVEF) who paradoxically develop reduced LVEF during exercise stress echocardiography (ESE), and do not have coronary artery disease (CAD) or hypertension, is unknown. Hypothesis: AI-ECG is useful to diagnose insidious cardiac disease and predict clinical outcomes in patients with exercise-induced cardiomyopathy. Aims: To assess the utility of AI ECG in patients with exercise-induced cardiomyopathy. Methods: Among all ESE performed between January 2003 and December 2022, patients without a hypertensive response to exercise and without CAD (confirmed by coronary angiography within 90 days after ESE), with resting LVEF ≥50% and a paradoxical ≥5% LVEF decrease during ESE were identified. A previously validated AI-ECG algorithm that predicts atrial fibrillation (AF), reduced LVEF, and cardiac amyloidosis (CA) was applied to the baseline ECG closest to the time of ESE. The predicted probability of AF, reduced LVEF, and CA if above the published thresholds, was determined. Results: There were 134 patients with exercise-induced cardiomyopathy who were identified. The mean age of this cohort was 66±10 years, 76% were women and 16% had AF at baseline. Mean LVEF was 58±4% at rest and 43±4% at peak stress. The median follow-up period was 6.8 years (IQR 3.0-12.2). Among patients without a baseline history of AF (n=112), AI-ECG identified 29% with a significant probability of AF, which was associated with a subsequent AF diagnosis at univariable analysis (HR 2.505, 95%CI 1.016-6.177, p=0.046). There were 10 patients with an AI-ECG prediction of reduced LVEF among whom 3 were subsequently hospitalized with HF. AI-ECG was positive for CA in 8 and 3 amongst these had subsequent HF hospitalizations (Table). Conclusions: Baseline AI-ECG may help predict subsequent AF and diagnose preclinical amyloid cardiomyopathy in patients who by resting echocardiography do not seem to have cardiac disease but with exercise develop reduced LVEF.

Background: Disease-causative variants in LMNA -encoded lamin A/C cause a genetic cardiomyopathy characterized by atrioventricular (AV) block, atrial fibrillation (AF) and ventricular arrhythmias (VA). Whether domain/variant-specific late gadolinium enhancement (LGE) patterns exist and carry prognostic significance is unclear. Objective: To determine if specific LGE patterns correlate with LMNA variant type/missense variant localization and clinical outcomes in a large cohort of cardiac laminopathy patients. Methods: Retrospectively, 621 genotype-positive arrhythmogenic/dilated cardiomyopathy patients were analyzed to identify those with a disease-causative variant in LMNA -encoded lamin A/C. After exclusion of patients without cardiac magnetic resonance data, pertinent demographic/clinical data was extracted from the electronic medical record. LGE distribution (subepicardial, midmyocardial, subendocardial, transmural) and location (septal, free wall, apical) patterns were analyzed by variant type (missense vs truncating) and missense variant localization (central rod domain vs tail domain) and correlated with advanced heart failure (AHF), MVA, AV block, AF and thromboembolic (TE) events. Results: 70 out of 116 (60%) LMNA variant-positive (mean age 39±12, 43% male and 94% Caucasian) were included. Missense variants localizing to the C-terminal tail region showed a higher prevalence of transmural and apical LGE (Table). Amongst the 5 (7%) patients with this distinct apical pseudo-infarct LGE pattern, p.Arg471His-LMNA was identified in all cases. Among the 48/70 (69%) of patients with clinically manifest disease, p.Arg471His-LMNA-positive patients (n=6) were noted to have an increased prevalence of TE events [3 (50%) vs 5 (12%), 0=0.050] despite a reduced prevalence of AF [2 (33%) vs 32 (76%), p= 0.031]. No difference in AHF or MVA were observed, but AV block was less prevalent [1 (20%) vs 29 (74%), p= 0.029]. Conclusion: p.Arg471His-LMNA causes a distinct apical pseudo-infarct LGE pattern associated with an increased risk of TE events and a decreased prevalence of AV block and AF. Future studies are needed to better refine the role of domain/variant-specific risk-stratification/anticoagulation in cardiac laminopathy.

Background: Arrhythmogenic cardiomyopathy (ACM) is a genetic heart disease characterized by fibrofatty replacement of ventricular myocardium. Arrhythmogenic left ventricular (LV) cardiomyopathy (ALVC) is a phenotypic variant of ACM predominantly involving the LV. Mutations in genes encoding for desmosome proteins and filamin C have been implicated in ALVC, especially in the setting of a ring-like late gadolinium enhancement (LGE) imaging pattern. Objective: To identify the underlying genetic substrate responsible for genetically elusive ring-like ALVC in a patient with seemingly sporadic/recessive disease. Methods: A 38-year-old male was referred for genetic investigation to determine the underlying genetic substrate responsible for his ALVC phenotype. The patient fulfilled both electrocardiographic (low voltage in the limb leads and anterolateral T-wave inversions) and imaging (>1 segment of subepicardial LGE) criteria for ALVC. Additionally, the patient experienced unexplained episodes of tachycardia, shakiness, sweating, and nausea prompting concern for an underlying neuromuscular disease. Genome sequencing (GS) was performed on DNA isolated from the affected patient and both of his unaffected parents. Variants were filtered assuming either a sporadic de novo occurrence or an autosomal recessive inheritance pattern. Results: GS identified compound heterozygous GNPTAB variants in the affected patient. A previously reported maternally derived p.Leu257Leu (c.771G>A) variant involving the last nucleotide of exon 7 of the GNPTAB gene and a novel paternally inherited Lys834fs*5 frame-shift variant were identified. The p.Leu257Leu variant has been reported to cause aberrant splicing and exon skipping of the GNPTAB mRNA transcript. Pathogenic variants in the GNPTAB encoded N-acetylglucosamine-1 (GlcNAc)-phosphotransferase subunits alpha/beta cause mucolipidosis type III, a rare recessive lysosomal storage disease characterized by coarse facial features, developmental delay, short stature, skeletal deformities, and cardiac involvement including valvular thickening and cardiomyopathy. Conclusions: Here, using a genome sequencing trio analysis we identified a compound heterozygous GNPTAB pathogenic variants as the underlying genetic substrate in a patient with ring-like ALVC and concomitant neuromuscular disease manifestation. Genome sequencing may identify the genetic etiology responsible for an otherwise undifferentiated diagnosis of cardiomyopathy.

Introduction: The prevalence and prognostic significance of PVC and NSVT in cardiac sarcoidosis (CS), especially in patients with normal or mildly decreased LV function, are not well known and were investigated in the current study. Methods: We included 192 patients with definite and probable CS with LVEF>35%, no prior history of VT/VF or sudden cardiac death, who underwent up to 48 hours of Holter monitoring. They were followed retrospectively for the composite endpoint of sustained VT/VF, advanced heart failure therapy, and all-cause mortality. We performed multivariable analysis for the association of PVC burden and NSVT with the composite endpoint. Covariates were considered if they were present in at least 95% of the study sample and were significantly associated with the composite endpoint in univariable analysis. Results: The median PVC burden in the overall population was 0.3% (IQR 0.02-2.5%) and 36 (18.8%) patients had a PVC burden ≥5%. Sixty-two (32.3%) patients had NSVT detected during monitoring. The PVC burden and prevalence of NSVT in patient subgroups are shown in Figures 1 and 2. A total of 33 (17.2%) patients experienced one of the composite endpoints at a median follow-up of 3 years. In the multivariable analysis (Figure 3), PVC burden ≥5% versus <5% (HR 3.96 [1.19, 5.97], p-value <0.01) and presence of NSVT (HR 4.55 [2.09, 9.94], p-value <0.01) were associated with the composite outcome. Conclusion: Our results suggest that a high PVC burden and the presence of NSVT carry isolated prognostic value in CS. In addition, ventricular ectopy does not appear to be an indicator of disease activity based on abnormal uptake on PET scan.