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Hypertrophic cardiomyopathy (HCM) is a genetic disorder caused by pathogenic variants in sarcomeric genes, leading to left ventricular hypertrophy and complex phenotypic heterogeneity. While HCM is the most common inherited cardiomyopathy, pharmacological treatment options have previously been limited and were predominantly directed towards symptom control owing to left ventricular outflow obstruction. These therapies, including beta blockers, calcium channel blockers, and disopyramide, have not been shown to affect the natural history of the disease, which is of particular concern for younger patients who have an increased lifetime risk of experiencing arrhythmias, heart failure, and sudden cardiac death. Increased knowledge of the genetic mechanisms underlying this disease in recent years has led to the development of targeted, potentially disease-modifying therapies for both obstructive and nonobstructive phenotypes that may help to prevent or ameliorate left ventricular hypertrophy. In this review article, we will define the etiology and clinical phenotypes of HCM, summarize the conventional therapies for obstructive HCM, discuss the emerging targeted therapies as well as novel invasive approaches for obstructive HCM, describe the therapeutic advances for nonobstructive HCM, and outline the future directions for the treatment of HCM.

ImportanceClinical guidelines for patients with heart failure with reduced ejection fraction (HFrEF) strongly recommend treatment with a sodium-glucose cotransporter-2 inhibitor (SGLT2i) to reduce cardiovascular mortality or HF hospitalization. Nationwide adoption of SGLT2i for HFrEF in the US is unknown.ObjectiveTo characterize patterns of SGLT2i use among eligible US patients hospitalized for HFrEF.Design, Setting, and ParticipantsThis retrospective cohort study analyzed 49 399 patients hospitalized for HFrEF across 489 sites in the Get With The Guidelines–Heart Failure (GWTG-HF) registry between July 1, 2021, and June 30, 2022. Patients with an estimated glomerular filtration rate less than 20 mL/min/1.73 m2, type 1 diabetes, and previous intolerance to SGLT2i were excluded.Main Outcomes and MeasuresPatient-level and hospital-level prescription of SGLT2i at hospital discharge.ResultsOf 49 399 included patients, 16 548 (33.5%) were female, and the median (IQR) age was 67 (56-78) years. Overall, 9988 patients (20.2%) were prescribed an SGLT2i. SGLT2i prescription was less likely among patients with chronic kidney disease (CKD; 4550 of 24 437 [18.6%] vs 5438 of 24 962 [21.8%]; P P P P Conclusions and RelevanceIn this study, prescription of SGLT2i at hospital discharge among eligible patients with HFrEF was low, including among patients with comorbid CKD and T2D who have multiple indications for therapy, with substantial variation among US hospitals. Further efforts are needed to overcome implementation barriers and improve use of SGLT2i among patients with HFrEF.

Many cardiovascular disorders have underlying genetic causes. Clinical genetic testing for cardiovascular disease has become widely available and can be useful for diagnosis, management, and cascade screening in selected conditions and circumstances. This article gives an overview of the current state of genetic testing in inherited cardiovascular conditions, who can benefit from it, and the associated challenges.

Background. Hypertrophic cardiomyopathy (HCM) in pediatric solid organ transplant recipients has been reported in association with use of calcineurin inhibitors. However, data on the incidence and prevalence of HCM in adult posttransplant patients are limited. We sought to describe the clinical characteristics of solid organ transplant recipients who were diagnosed with HCM from 2011 to 2021 at a single center. Methods. Patients who had undergone solid organ transplant and exhibited left ventricular hypertrophy with left ventricular wall thickness ≥13 mm on transthoracic echocardiography were included. Clinical history, pedigree analysis, clinical genetic testing, transthoracic echocardiography, cardiac magnetic resonance imaging, treatment, and follow-up testing results were collected. Categorical variables were described as n (%). Continuous variables were described with medians and interquartile ranges and compared using the Wilcoxon rank-sum and Kruskal-Wallis tests. A 2-sided P < 0.05 was considered statistically significant. Results. Three lung, 5 kidney, and 4 liver transplant recipients from 12 different families were included. Seven patients (58%) did not carry a preexisting diagnosis of hypertension, and none had a history of aortic or subaortic stenosis. A majority of patients exhibited asymmetric septal hypertrophy (67%; medial septal thickness versus left ventricular posterior wall thickness 17 versus 13 mm; P < 0.001) and dynamic left ventricular outflow tract (LVOT) obstruction (58%). All patients were managed long term with calcineurin inhibitors. Clinical genetic testing in 6 patients identified 2 with disease-causing variants in 2 sarcomere genes, myosin binding protein-C and myosin heavy chain 7. Four patients (33%) underwent successful septal reduction therapy for treatment of symptomatic LVOT obstruction. Conclusions. Symptomatic HCM with dynamic LVOT obstruction can develop in solid organ transplant recipients, and genetic testing can identify individuals with sarcomeric HCM. Medical management and septal reduction therapies are treatment options for severe symptomatic disease.

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiomyopathy characterised by ventricular arrhythmia and an increased risk of sudden cardiac death (SCD). Numerous genetic determinants and phenotypic manifestations have been discovered in ACM, posing a significant clinical challenge. Further to this, wider evaluation of family members has revealed incomplete penetrance and variable expressivity in ACM, suggesting a complex genotype-phenotype relationship. This review details the genetic basis of ACM with specific genotype-phenotype associations, providing the reader with a nuanced perspective of this condition; whilst also proposing a future roadmap to delivering precision medicine-based management in ACM.

Background Digitalis glycosides are known to improve the hemodynamic and neurohormonal perturbations that contribute to heart failure (HF)–induced renal dysfunction (RD). The objective of this study was to determine if randomization to digoxin is associated with improvement in renal function (IRF) and to evaluate if patients with digoxin-induced IRF have improved clinical outcomes. Methods and Results Patients in the Digitalis Investigation Group (DIG) dataset with protocol-driven 1-year serum creatinine levels (performed in a central laboratory; n = 980) were studied. IRF was defined as a postrandomization ≥20% increase in estimated glomerular filtration rate (eGFR). IRF occurred in 15.5% of the population (mean improvement in eGFR 34.5 ± 15.4%) and was more common in patients randomized to digoxin (adjusted odds ratio 1.6; P = .02). In patients without IRF, digoxin was not associated with reduced death or hospitalization (adjusted hazard ratio [HR] 0.96, 95% CI 0.8–1.2; P = .67). However, in the group with IRF, digoxin was associated with substantially improved hospitalization-free survival (adjusted HR 0.49, 95% CI 0.3–0.8; P = .006; P interaction = .026). Conclusions In this subset of the DIG trial, digoxin was associated with long-term improvement in kidney function and, in patients demonstrating this favorable renal response, reduction in death or hospitalization. Additional research is necessary to confirm these hypothesis-generating findings.