Optimizing Triage of Ambulatory Patients With Advanced Heart Failure: 2-Year Outcomes From REVIVAL.

BACKGROUND: Left ventricular assist device (LVAD) use remains uncommon in advanced heart failure (HF) patients not dependent on inotropes. OBJECTIVES: Before considering a randomized trial comparing a strategy of earlier use of LVAD to continued medical therapy, a better understanding is needed of the clinical trajectory of ambulatory patients with advanced systolic HF on optimal guideline-directed medical therapy (GDMT). METHODS: REVIVAL enrolled 400 patients with advanced ambulatory systolic HF, ≥1 HF mortality risk marker (≥2 HF hospitalizations past year; or HF hospitalization and high natriuretic peptide; or no HF hospitalizations but low peak oxygen consumption, 6-minute walk, serum sodium, HF survival score or Seattle HF model predicted survival), and no LVAD contraindication at 21 LVAD centers from July 2015 to June 2016. Patients were followed for 2 years or until a primary outcome (death, durable ventricular assist device, or urgent transplant). Clinical outcomes and health-related quality of life were evaluated. RESULTS: Mean baseline left ventricular ejection fraction was 21%, median 6-minute walk was 341 m, and 92% were Interagency Registry for Mechanically Assisted Circulatory Support profiles 5 to 7. Adherence to GDMT and electrical device therapies was robust. Composite primary outcome occurred in 22% and 37% at 1 and 2 years, with death alone in 8% and 16%, respectively. Patients surviving for 2 years maintained GDMT intensity and had no decline in health-related quality of life. CONCLUSION: Structured, serial follow-up at programs with expertise in caring for advanced ambulatory systolic HF patients facilitates triage for advanced therapies. Better strategies are still needed to avoid deaths in a small but significant group of patients who die without advanced therapies. REVIVAL patients not selected for VAD or transplant have robust survival and patient-reported outcomes, which challenges advocacy for earlier VAD implantation. (Registry Evaluation of Vital Information for VADs in Ambulatory Life [REVIVAL]; NCT01369407).

Advancing Transthyretin Amyloidosis Drug Development in an Evolving Treatment Landscape: Amyloidosis Forum Meeting Proceedings.

INTRODUCTION: Hereditary transthyretin amyloidosis (ATTRv, also referred to as hATTR; ORPHA 271861) and wild-type ATTR amyloidosis (ATTRwt; ORPHA 330001) are rare, progressive, systemic protein misfolding disorders with heterogeneous clinical presentations. ATTRv and ATTRwt amyloidosis are characterized by the deposition of amyloid fibrils in multiple organs including the heart, nerves, eyes, and soft tissues. The management of ATTR amyloidosis is complex because of its multisystemic nature and progression despite available treatment options. Morbidity is high and there are many unmet medical needs for patients. While contemporary ATTR amyloidosis cohorts are diagnosed earlier, have lower risk disease and lower mortality compared with the previous era, these advances coupled with the emergence of effective disease-modifying therapies have confounded the design of future prospective clinical trials and interpretation of historical control data. MAIN BODY: The Amyloidosis Forum is a public-private partnership between the US Food and Drug Administration Center for Drug Evaluation and Research and the nonprofit Amyloidosis Research Consortium ( www.arci.org ). This article summarizes proceedings from the 21 June 2023 Amyloidosis Forum on advancing drug development in ATTR amyloidosis in an evolving treatment landscape. The Forum focused on elements of clinical trial design to address these challenges and discussed their strengths and weaknesses from multiple stakeholder perspectives (i.e., patient, sponsor, statistician, clinician, and regulatory authorities). CONCLUSION: Given rapid evolution of natural history in ATTR amyloidosis, the utility of historical control data is limited. Leveraging contemporary real-world data is essential for clinical trial design. Evidence generation from clinical trials should address clinically relevant questions. Key factors in successful trial design must be informed by up-to-date data on natural history, prognostic factors, clinically meaningful thresholds, and sharing available clinical trial data. The Amyloidosis Forum includes the community of patients with ATTR amyloidosis, the physicians who treat them, and the sponsors and regulators who collectively stand ready to support further studies in order to develop novel effective therapies.

Hepatitis B transmission/reactivation associated with Hepatitis B core antibody and Hepatitis C nucleic acid testing positive organs: A report from the Organ Procurement and Transplantation Network Disease Transmission Advisory Committee.

BACKGROUND: Better access to direct-acting antiviral (DAA) therapy has broadened the utilization of hepatitis C virus (HCV) nucleic acid testing (NAT) positive organs with excellent outcomes. However, DAA therapy has been associated with hepatitis B virus (HBV) reactivation. AIM: To determine the risk of HBV transmission or reactivation with utilization of HBV core antibody positive (HBcAb+) and HCV NAT positive (HCV+) organs, which presumably required DAA therapy. METHODS: The number of HBcAb+ donors with delineated HCV NAT status was obtained from the Organ Procurement and Transplantation Network (OPTN) database. The number of unexpected HBV infections from transplanted organs adjudicated as "proven" or "probable" transmission was obtained from the OPTN Ad Hoc Disease Transmission Advisory Committee database. A chart review of the donors of "proven" or "probable" cases was conducted. RESULTS: From January 1, 2016, to December 31, 2021, 7735 organs were procured from 3767 HBcAb+ donors and transplanted into 7469 recipients; 545 (14.5%) donors were also HCV+. HBV transmission or reactivation occurred in seven recipients. The rate is not significantly different between recipients of HCV+ (0.18%, 2/1115) and the HCV NAT negative (HCV-) organs (0.08%, 5/6354) (p = 0.28) or between recipients of HCV+ and HCV- livers as well as non-liver organs. HBV transmission or reactivation occurred within a median of 319 (range, 41-1117) days post-transplant in the setting of missing, inadequate, or truncated prophylaxis. CONCLUSION: HBV reactivation associated with DAA therapy for HBcAb+ HCV+ organs is less frequent than reported in the non-transplant population, possibly due to the common use of HBV prophylaxis in the at-risk transplant population.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines.

AIM: The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy. METHODS: A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate. STRUCTURE: Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Kidney Outcomes Among Medicare Beneficiaries After Hospitalization for Heart Failure.

Importance: Kidney health has received increasing focus as part of comprehensive heart failure (HF) treatment efforts. However, the occurrence of clinically relevant kidney outcomes in contemporary populations with HF has not been well studied. Objective: To examine rates of incident dialysis and acute kidney injury (AKI) among Medicare beneficiaries after HF hospitalization. Design, Setting, and Participants: This retrospective cohort study evaluated adults aged 65 years or older who were hospitalized for HF across 372 sites in the Get With The Guidelines-Heart Failure registry in the US between January 1, 2014, and December 31, 2018. Patients younger than 65 years or requiring dialysis either during or prior to hospitalization were excluded. Data were analyzed from May 4, 2021, to March 8, 2024. Main Outcomes and Measures: The primary outcome was inpatient dialysis initiation in the year after HF hospitalization and was ascertained via linkage with Medicare claims data. Other all-cause and cause-specific hospitalizations were also evaluated. The covariate-adjusted association between discharge estimated glomerular filtration rate (eGFR) and 1-year postdischarge outcomes was examined using Cox proportional hazards regression models. Results: Overall, among 85 298 patients included in the analysis (mean [SD] age, 80 [9] years; 53% women) mean (SD) left ventricular ejection fraction was 47% (16%) and mean (SD) eGFR was 53 (29) mL/min per 1.73 m2; 54 010 (63%) had an eGFR less than 60 mL/min per 1.73 m2. By 1 year after HF hospitalization, 6% had progressed to dialysis, 7% had progressed to dialysis or end-stage kidney disease, and 7% had been readmitted for AKI. Incident dialysis increased steeply with lower discharge eGFR category: compared with patients with an eGFR of 60 mL/min per 1.73 m2 or more, individuals with an eGFR of 45 to less than 60 and of less than 30 mL/min per 1.73 m2 had higher rates of dialysis readmission (45 to <60: adjusted hazard ratio [AHR], 2.16 [95% CI, 1.86-2.51]; <30: AHR, 28.46 [95% CI, 25.25-32.08]). Lower discharge eGFR (per 10 mL/min per 1.73 m2 decrease) was independently associated with a higher rate of readmission for dialysis (AHR, 2.23; 95% CI, 2.14-2.32), dialysis or end-stage kidney disease (AHR, 2.34; 95% CI, 2.24-2.44), and AKI (AHR, 1.25; 95% CI, 1.23-1.27), with similar findings for all-cause mortality, all-cause readmission, and HF readmission. Baseline left ventricular ejection fraction did not modify the covariate-adjusted association between lower discharge eGFR and kidney outcomes. Conclusions and Relevance: In this study, older adults with HF had substantial risk of kidney complications, with an estimated 6% progressing to dialysis in the year after HF hospitalization. These findings emphasize the need for health care approaches prioritizing kidney health in this high-risk population.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines.

AIM: The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy. METHODS: A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate. STRUCTURE: Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Cause-Specific Health Care Costs Following Hospitalization for Heart Failure and Cost Offset With SGLT2i Therapy.

BACKGROUND: Little is known regarding differences in cause-specific costs between heart failure (HF) with ejection fraction (EF) ≤40% vs >40%, and potential cost implications of sodium glucose co-transporter 2 inhibitor (SGLT2i) therapy. OBJECTIVES: This study sought to compare cause-specific health care costs following hospitalization for HF with EF ≤40% vs >40% and estimate the cost offset with implementation of SGLT2i therapy. METHODS: This study examined Medicare beneficiaries hospitalized for HF in the Get With The Guidelines-Heart Failure registry from 2016 to 2020. Mean per-patient total (excluding drug costs) and cause-specific costs from discharge through 1-year follow-up were calculated and compared between EF ≤40% vs >40%. Next, risk reductions on total all-cause and HF hospitalizations were estimated in a trial-level meta-analysis of 5 pivotal trials of SGLT2is in HF. Finally, these relative treatment effects were applied to Medicare beneficiaries eligible for SGLT2i therapy to estimate the projected cost offset with implementation of SGLT2i, excluding drug costs. RESULTS: Among 146,003 patients, 50,598 (34.7%) had EF ≤40% and 95,405 (65.3%) had EF >40%. Mean total cost through 1 year was $40,557. Total costs were similar between EF groups overall but were higher for EF ≤40% among patients surviving the 1-year follow-up period. Patients with EF >40% had higher costs caused by non-HF and noncardiovascular hospitalizations, and skilled nursing facilities (all P < 0.001). Trial-level meta-analysis of the 5 SGLT2i clinical trials estimated 11% (rate ratio: 0.89; 95% CI: 0.84-0.93; P < 0.001) and 29% (rate ratio: 0.71; 95% CI: 0.66-0.76; P < 0.001) relative reductions in rates of total all-cause and HF hospitalizations, respectively, regardless of EF. Reductions in all-cause and HF hospitalizations were projected to reduce annual costs of readmission by $2,451 to $2,668 per patient with EF ≤40% and $1,439 to $2,410 per patient with EF >40%. CONCLUSIONS: In this large cohort of older U.S. adults hospitalized for HF, cause-specific costs of care differed among patients with EF ≤40% vs >40%. SGLT2i significantly reduced the rate of HF and all-cause hospitalizations irrespective of EF in clinical trials, and implementation of SGLT2i therapy in clinical practice is projected to reduce costs by $1,439 to $2,668 per patient over the 1 year post-discharge, excluding drug costs.

Diagnostic Pitfall and Clinical Characteristics of Variant Versus Wild-Type Transthyretin Amyloid Cardiomyopathy in Asian Population: The Korean Nationwide Cohort Study.

BACKGROUND: Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is an under-recognized cause of heart failure (HF) with clinical phenotypes that vary across regions and genotypes. We sought to characterize the clinical characteristics of ATTR-CM in Asia. METHODS: Data from a nationwide cohort of patients with ATTR-CM from six major tertiary centres in South Korea were analysed between 2010 and 2021. All patients underwent clinical evaluation, biochemical laboratory tests, echocardiography, and transthyretin (TTR) genotyping at the time of diagnosis. The study population comprised 105 Asian ATTR-CM patients (mean age: 69 years; male: 65.7%, wild-type ATTR-CM: 41.9%). RESULTS: Among our cohort, 18% of the patients had a mean left ventricular (LV) wall thickness < 12 mm. The diagnosis of ATTR-CM increased notably during the study period (8 [7.6%] during 2010-2013 vs. 22 [21.0%] during 2014-2017 vs. 75 [71.4%] during 2018-2021). Although the duration between symptom onset and diagnosis did not differ, the proportion of patients with HF presenting mild symptoms increased during the study period (25% NYHA class I/II between 2010-2013 to 77% between 2018-2021). In contrast to other international registry data, male predominance was less prominent in wild-type ATTR-CM (68.2%). The distribution of TTR variants was also different from Western countries and from Japan. Asp38Ala was the most common mutation. CONCLUSION: A nationwide cohort of ATTR-CM exhibited less male predominance, a proportion of patients without increased LV wall thickness, and distinct characteristics of genetic mutations, compared to cohorts in other parts of the world. Our results highlight the ethnic variation in ATTR-CM and may contribute to improving the screening process for ATTR-CM in the Asian population.

The impact of the OPTN policy change on patients with a durable left ventricular assist device and chronic kidney disease: Analysis of the UNOS database.

BACKGROUND: The Organ Procurement and Transplantation Network (OPTN) implemented modifications in 2018 to the adult heart transplant allocation system to better stratify the most medically urgent transplant candidates. We evaluated the impact of these changes on patients supported by a durable left ventricular assist device (LVAD) with chronic kidney disease (CKD). OBJECTIVE: To evaluate the impact of the OPTN policy change on patients supported by durable left ventricular assist devices (LVAD) with chronic kidney disease (CKD). METHODS: We performed an analysis of patients from the United Network of Organ Sharing Database supported by durable LVAD listed for a heart transplant (HT) between October 17, 2016 and September 30, 2021. Patients were divided into two groups: pre- and postpolicy, depending on whether they were listed on or prior to October 17, 2018. Patients who were on dialysis prior to surgery or discharge were excluded from the analysis. Patients with simultaneous heart and kidney transplants were excluded. Patients who were listed for transplant prepolicy change but transplanted postpolicy change were excluded. This cohort was then subdivided into degrees of CKD based on estimated glomerular filtration rate (eGFR), which resulted in 678 patients (23.7%) in Stage 1 (GFR ≥89.499) (Prepolicy: 345, Postpolicy: 333), 1233 (43.1%) in Stage 2 (89.499 > GFR ≥ 59.499) (Prepolicy: 618, Postpolicy: 615), 613 (21.4%) in Stage 3a (59.499 > GFR ≥ 44.499) (Prepolicy: 291, Postpolicy: 322), 294 (10.3%) in Stage 3b (44.499 > GFR ≥ 29.499) (Prepolicy: 143, Postpolicy: 151), 36 (1.3%) in Stage 4 (29.499 > GFR ≥ 15) (Prepolicy: 21, Postpolicy: 15), and 9 (0.3%) in Stage 5 (15 > GFR) (Prepolicy: 4, Postpolicy: 5). The primary outcome was 1-year and 2-year post-HT survival. RESULTS: There were 2863 patients who met the study criteria (1422 prepolicy, 1441 postpolicy). Overall survival, regardless of CKD stage, was lower following the policy change (p < 0.01). There was a similar risk of primary graft failure (PGF) in the pre- and postpolicy period (1.8% vs. 1.2%, p = 0.26). 1-year overall survival was 93% (91, 94) and 89% (87, 91) in the pre- and postpolicy periods, respectively. 2-year overall survival was 89% (88, 91) and 85% (82, 87) in the pre- and postpolicy periods, respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 1 -year survival was 93% (91, 95), 92% (90,93), 89% (86, 91), 89% (86, 93), 80% (68, 94), and 100% (100, 100), respectively. For CKD Stages 1, 2, 3a, 3b, 4, and 5, 2-year survival was 91% (88, 93), 88% (86, 90), 84% (81, 88), 84% (80, 89), 73% (59, 90), and 100% (100, 100), respectively. Patients with CKD 1 and 2 had better survival compared to those with CKD 3 (p < 0.01) and CKD 4 and 5 (p = 0.03) in the pre- and postpolicy periods. Patients with CKD 3 did not have a survival advantage over those with CKD 4 and 5 (p = 0.25). On cox regression analysis, advancing degrees of CKD were associated with an increased risk of mortality. CONCLUSIONS: Patients with LVAD support had decreased overall survival after the OPTN policy change. Patients with more advanced CKD had lower survival than patients without advanced CKD, though they were not impacted by the OPTN policy change.

Diagnosis and Management of Cardiac Sarcoidosis: A Scientific Statement From the American Heart Association.

Cardiac sarcoidosis is an infiltrative cardiomyopathy that results from granulomatous inflammation of the myocardium and may present with high-grade conduction disease, ventricular arrhythmias, and right or left ventricular dysfunction. Over the past several decades, the prevalence of cardiac sarcoidosis has increased. Definitive histological confirmation is often not possible, so clinicians frequently face uncertainty about the accuracy of diagnosis. Hence, the likelihood of cardiac sarcoidosis should be thought of as a continuum (definite, highly probable, probable, possible, low probability, unlikely) rather than in a binary fashion. Treatment should be initiated in individuals with clinical manifestations and active inflammation in a tiered approach, with corticosteroids as first-line treatment. The lack of randomized clinical trials in cardiac sarcoidosis has led to treatment decisions based on cohort studies and consensus opinions, with substantial variation observed across centers. This scientific statement is intended to guide clinical practice and to facilitate management conformity by providing a framework for the diagnosis and management of cardiac sarcoidosis.

Dobutamine-Induced Myoclonus in a Patient With Advanced Heart Failure and Chronic Kidney Disease.

Dobutamine is a positive inotropic agent often used in treatment of cardiogenic shock. Although there are well-documented adverse effects, dobutamine-induced myoclonus is a rarely reported phenomenon. Our case offers a direct and temporally related description of myoclonus, with onset observed within hours of dobutamine initiation and complete resolution within minutes of discontinuation.

Modern advances in heart transplantation.

Heart transplantation (HTx) is the only definitive therapy for patients with end stage heart disease. With the increasing global prevalence of heart failure, the demand for HTx has continued to grow and outpace supply. In this paper, we will review advances in the field of HTx along the clinical journey of a HTx recipient. Starting with the sensitized patient, we discuss current methods to define sensitization, and assays to help identify clinically relevant anti-HLA antibodies. Desensitization strategies targeting all levels of the adaptive immune system are discussed with emphasis on novel techniques such as anti-CD 38 blockade and use of the Immunoglobulin G-Degrading Enzyme of Streptococcus Pyogenes. We next discuss donor procurement and the resurgence of donation after circulatory death as a viable strategy to significantly and safely increase the donor pool. Post-transplant, we evaluate non-invasive surveillance techniques including gene expression profiling and donor-derived cell-free DNA. Last, we discuss the ground-breaking developments in the field of xenotransplantation.

Usage of older donors is associated with higher mortality after heart transplantation: A UNOS observational study.

BACKGROUND: Utilization of heart from older donors is variable across centers with uncertain outcomes of recipients. We sought to utilize a national registry to examine the usage and outcomes of heart transplant (HT) recipients from older donors. We also explored the impact of current donor heart allocation scheme on the outcomes of hearts from older donors. METHODS: This observational study utilized the United Network for Organ Sharing database between 2015 and 2023 with donors categorized into age <45 years or ≥45 years and evaluated organ disposition and geographical variation. Thirty-day, 1-, and 3-year mortality, and graft failure rates were compared among recipients as per donor age group. We also evaluated annual trends in HT for each group over the follow-up period. RESULTS: A total of 24,966 adult donors were recovered: 3,742 (15.0%) were ≥45 years; 3,349 (15.6%) adults received heart from such donors with significant geographical variation, and a declining utilization in the transplantation rate in current donor allocation system. Donors with age ≥45 years had higher comorbidities and were allotted with a significantly shorter ischemic time to recipients who were significantly less likely to receive temporary mechanical circulatory support and more likely female. Unadjusted and adjusted, 30-day mortality were similar but 1- and 3-year mortality and graft failure rates were significantly higher in recipients of such donors. Spline analysis suggested a higher 1-year mortality risk at older donor age with risk increasing after age 40 years. CONCLUSIONS: Older donor age was associated with worsened 1- and 3-year mortality and graft failure for heart transplant recipients.

Evolutions in Combined Heart-Kidney Transplant.

PURPOSE OF REVIEW: This review describes management practices, outcomes, and allocation policies in candidates for simultaneous heart-kidney transplantation (SHKT). RECENT FINDINGS: In patients with heart failure and concomitant kidney disease, SHKT confers a survival advantage over heart transplantation (HT) alone in patients with dialysis dependence or an estimated glomerular filtration rate (eGFR) < 40 mL/min/1.73 m2. However, when compared to kidney transplantation (KT) alone, SHKT is associated with worse patient and kidney allograft survival. In September 2023, the United Network of Organ Sharing adopted a new organ allocation policy, with strict eligibility criteria for SHKT and a safety net for patients requiring KT after HT alone. While the impact of the policy change on SHKT outcomes remains to be seen, strategies to prevent and slow development of kidney disease in patients with heart failure and to prevent kidney dysfunction after HT and SHKT are necessary.

Moving towards establishing centres of excellence in cardiac amyloidosis: an International Cardio-Oncology Society statement.

The prevalence of amyloidosis has been increasing, driven by a combination of improved awareness, evolution of diagnostic pathways, and effective treatment options for both transthyretin and light chain amyloidosis. Due to the complexity of amyloidosis, centralised expert providers with experience in delineating the nuances of confirmatory diagnosis and management may be beneficial. There are many potential benefits of a centre of excellence designation for the treatment of amyloidosis including recognition of institutions that have been leading the way for the optimal treatment of this condition, establishing the expectations for any centre who is engaging in the treatment of amyloidosis and developing cooperative groups to allow more effective research in this disease space. Standardising the expectations and criteria for these centres is essential for ensuring the highest quality of clinical care and community education. In order to define what components are necessary for an effective centre of excellence for the treatment of amyloidosis, we prepared a survey in cooperation with a multidisciplinary panel of amyloidosis experts representing an international consortium. The purpose of this position statement is to identify the essential elements necessary for highly effective clinical care and to develop a general standard with which practices or institutions could be recognised as a centre of excellence.

Emerging Role of Scintigraphy Using Bone-Seeking Tracers for Diagnosis of Cardiac Amyloidosis: AJR Expert Panel Narrative Review.

Amyloidoses are a complex group of clinical diseases that result from progressive organ dysfunction due to extracellular protein misfolding and deposition. The two most common types of cardiac amyloidosis are transthyretin amyloidosis (ATTR) and light-chain (AL) amyloidosis. Diagnosis of ATTR cardiomyopathy (ATTR-CM) is challenging owing to its phenotypic similarity to other more common cardiac conditions, the perceived rarity of the disease, and unfamiliarity with its diagnostic algorithms; endomyocardial biopsy was historically required for diagnosis. However, myocardial scintigraphy using bone-seeking tracers has shown high accuracy for detection of ATTR-CM and has become a key noninvasive diagnostic test for the condition, receiving support from professional society guidelines and transforming prior diagnostic paradigms. This AJR Expert Panel Narrative Review describes the role of myocardial scintigraphy using bone-seeking tracers in the diagnosis of ATTR-CM. The article summarizes available tracers, acquisition techniques, interpretation and reporting considerations, diagnostic pitfalls, and gaps in the current literature. The critical need for monoclonal testing of patients with positive scintigraphy results to differentiate ATTR-CM from AL cardiac amyloidosis is highlighted. Recent updates in guideline recommendations that emphasize the importance of a qualitative visual assessment are also discussed.