Publications by authors named "Thomas D Ryan"

Article Synopsis
  • - Hypertrophic cardiomyopathy (HCM) was traditionally seen as caused by rare, high-risk single-gene changes, but new research indicates common low-risk variants (LowSVs) also play a significant role in the disease.
  • - In a study of over 6000 patients, 12 LowSVs were discovered, which are relatively common in the general population and more prevalent in HCM patients, suggesting they may influence disease severity and risk.
  • - While LowSVs alone are linked to a later onset of HCM and fewer complications, their presence alongside more severe genetic variants increases health risks significantly.
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Duchenne muscular dystrophy is characterised by fibrofatty replacement of muscle, resulting in dilated cardiomyopathy. Hypertrophic cardiomyopathy affects 1:200-1:500 people and is characterised by asymmetric ventricular septal hypertrophy. To date, there have been two separately reported cases describing the combined pathology of these disorders.

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Background: An improved understanding of the natural history in NYHA functional class I patients with obstructive hypertrophic cardiomyopathy (oHCM) is needed.

Objectives: Using a multicenter registry (SHaRe [Sarcomeric Human Cardiomyopathy Registry]), this study described the natural history in patients with oHCM who were classified as NYHA functional class I at the initial visit compared with patients classified as NYHA functional class II and reported baseline characteristics associated with incident clinical events.

Methods: Incident events assessed included a composite of NYHA functional class III to IV symptoms, left ventricular ejection fraction <50%, atrial fibrillation, stroke, ventricular arrhythmias, septal reduction therapy, ventricular assist device or transplantation, or death.

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Article Synopsis
  • Septal reduction therapy (SRT) significantly improves symptoms for patients with obstructive hypertrophic cardiomyopathy (HCM), but its long-term results and predictors of adverse outcomes still need more study.* -
  • An analysis of data from the SHARE registry revealed that among 1,832 patients who underwent SRT, the 30-day mortality rate was low at 0.4%, and after approximately 6.8 years, rates for HCM-related death, heart failure, and ventricular arrhythmias were relatively low.* -
  • Key findings included that older age at SRT increases risks for HCM death and heart failure outcomes, while female patients showed higher susceptibility to heart failure complications post-treatment.*
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The advent of transcatheter aortic valve implantation (TAVI) has caused a paradigm shift in the management of aortic stenosis away from traditional surgical aortic valve replacement (SAVR). However, uncertainty remains about the long-term (>10 year) durability of TAVI valves, especially in younger patients. This viewpoint collates life expectancy data from Australia and Aotearoa New Zealand to propose sex-specific age-based recommendations for choice of SAVR versus TAVI in their respective general populations and among Aboriginal and Torres Strait Islander people in Australia and both Māori and Pacific peoples living in Aotearoa New Zealand.

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As cancer therapies increase in effectiveness and patients' life expectancies improve, balancing oncologic efficacy while reducing acute and long-term cardiovascular toxicities has become of paramount importance. To address this pressing need, the Cardiology Oncology Innovation Network (COIN) was formed to bring together domain experts with the overarching goal of collaboratively investigating, applying, and educating widely on various forms of innovation to improve the quality of life and cardiovascular healthcare of patients undergoing and surviving cancer therapies. The COIN mission pillars of innovation, collaboration, and education have been implemented with cross-collaboration among academic institutions, private and public establishments, and industry and technology companies.

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Introduction/aims: Duchenne muscular dystrophy (DMD) is characterized by fibrofatty replacement of muscle. This has been documented in the ventricular myocardium of DMD patients, but there is limited description of atrial involvement. The purpose of this study is to examine the arrhythmia and ectopy burden in patients with DMD and non-DMD dilated cardiomyopathy (DCM) and to characterize the cardiac histopathologic changes in DMD patients across the disease spectrum.

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The calcium/calmodulin-dependent protein kinase type 2 (CAMK2) family consists of four different isozymes, encoded by four different genes-CAMK2A, CAMK2B, CAMK2G, and CAMK2D-of which the first three have been associated recently with neurodevelopmental disorders. CAMK2D is one of the major CAMK2 proteins expressed in the heart and has been associated with cardiac anomalies. Although this CAMK2 isoform is also known to be one of the major CAMK2 subtypes expressed during early brain development, it has never been linked with neurodevelopmental disorders until now.

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Background: Measurement of trough levels for calcineurin inhibitors by venipuncture sampling is a mainstay of patient management in solid organ transplant recipients but challenging in pediatric patients. Volumetric Absorptive Microsampling (VAMS) is a patient-friendly, minimally invasive sampling technique to accurately collect blood. An assay for measurement of tacrolimus in blood using VAMS, coupled with parallel reaction monitoring (PRM) mass spectrometry, was validated in pediatric heart transplant patients.

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Introduction: In children with myocarditis or dilated cardiomyopathy (DCM) on extracorporeal membrane oxygenation (ECMO) for cardiogenic shock, it is often necessary to decompress the left heart to minimize distension and promote myocardial recovery. We compare outcomes in those who underwent balloon atrial septostomy (BAS) versus direct left atrial (LA) drainage for left heart decompression in this population.

Methods: Retrospective study of the Extracorporeal Life Support Organization (ELSO) multicenter registry of patients ≤ 18 years with myocarditis or DCM on ECMO who underwent LA decompression.

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Background: The development of left ventricular systolic dysfunction (LVSD) in hypertrophic cardiomyopathy (HCM) is rare but serious and associated with poor outcomes in adults. Little is known about the prevalence, predictors, and prognosis of LVSD in patients diagnosed with HCM as children.

Methods: Data from patients with HCM in the international, multicenter SHaRe (Sarcomeric Human Cardiomyopathy Registry) were analyzed.

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Requirements for vesicle fusion within the heart remain poorly understood, despite the multitude of processes that necessitate proper intracellular trafficking within cardiomyocytes. Here, we show that Syntaxin 4 (STX4), a target-Soluble -ethylmaleimide sensitive factor attachment receptor (t-SNARE) protein, is required for normal vertebrate cardiac conduction and vesicular transport. Two patients were identified with damaging variants in .

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Patients with Duchenne muscular dystrophy have multiple risk factors for lower extremity oedema. This study sought to define the frequency and predictors of oedema. Patients aged 15 years and older were screened by patient questionnaire, and the presence of oedema was confirmed by subsequent physical exam.

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Transplantation-associated thrombotic microangiopathy (TA-TMA) can range from a self-limiting condition to a lethal transplantation complication. It is important to identify TA-TMA patients at risk for severe multiorgan endothelial injury to implement targeted therapies in a timely manner. Current therapeutic approaches with complement blockade have improved survival markedly in high-risk TA-TMA patients, yet one-third of these patients respond inadequately to eculizumab therapy.

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Objectives: Significant renal insufficiency is identified as a risk factor for post-transplantation mortality in pediatric heart transplant recipients. This study evaluates simultaneous heart-kidney transplantation listing outcomes compared with heart transplant for pediatric candidates with significant renal insufficiency.

Methods: The United Network for Organ Sharing registry was searched for patients (January 1987 to March 2020) who were simultaneously listed for a heart-kidney transplantation or for heart transplant with significant renal insufficiency at the time of listing.

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Left ventricular systolic dysfunction is a known complication of stem cell transplantation (SCT). There has been minimal research to determine whether subclinical cardiac dysfunction exists in SCT patients using tools other than standard echocardiography, such as maximal and submaximal effort cardiopulmonary exercise testing (CPET) and vascular function studies. The objective of this study was to determine the rate of subclinical cardiac dysfunction in patients with normal ejection fraction after SCT, identified by abnormal values by CPET, tissue-Doppler imaging, and arterial stiffness measurements and to further describe submaximal exercise test measures in this population.

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The landscape of pediatric oncology has dramatically changed over the course of the past several decades with five-year survival rates surpassing 80%. Anthracycline therapy has been the cornerstone of many chemotherapy regimens for pediatric patients since its introduction in the 1960s, and recent improved survival has been in large part due to advancements in chemotherapy, refinement of supportive care treatments, and development of novel therapeutics such as small molecule inhibitors, chimeric antigen receptor T-cell therapy, and immune checkpoint inhibitors. Unfortunately, many cancer-targeted therapies can lead to acute and chronic cardiovascular pathologies.

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Background Patients with Duchenne muscular dystrophy (DMD) develop cardiomyopathy because of a dystrophin deficiency causing fibrofatty replacement of the myocardium. Corticosteroid use and mobility limitations place these patients at risk for increased adiposity. We sought to determine the association of adiposity with cardiovascular dysfunction in patients with DMD.

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Objectives: Sepsis-associated myocardial dysfunction is common in pediatric septic shock and negatively impacts outcomes. Early estimation of sepsis-associated myocardial dysfunction risk has the potential to inform clinical care and improve clinical trial design. The Pediatric Sepsis Biomarker Risk Model II is validated as a biomarker-based enrichment algorithm to discriminate children with septic shock with high baseline mortality probability.

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