Atrial amyloidosis: mechanisms and clinical manifestations

Left Atrial Markers in Diagnosing and Prognosticating Non-Ischemic Cardiomyopathies: Ready for Prime Time?

The left atrium (LA) is pivotal in cardiac hemodynamics, serving as a dynamic indicator of left ventricular (LV) compliance and diastolic function. The LA undergoes structural and functional adaptations in response to hemodynamic stress, infiltrative processes, myocardial injury, and arrhythmic triggers. Remodeling of the LA in response to these stressors directly impacts pulmonary circulation, eventually leading to pulmonary capillary involvement, pulmonary artery hypertension, and eventually right ventricular failure. LA dysfunction and fibrosis also contribute to the future risk of atrial arrhythmias and mitral regurgitation. The parameters of LA size and function are being recognized as robust markers for the progression of several cardiac pathologies as well as important tools for prognostication. In this article, we briefly describe the different modalities and markers used to evaluate LA pathology in patients with nonischemic cardiomyopathies (NICM). We then provide an overview of the studies that compared the association of the different LA parameters with disease severity and future prognosis. We also identify the gaps in knowledge before these LA parameters make a case for clinical adoption.

2024 update in heart failure

In the last years, major progress has occurred in heart failure (HF) management. The 2023 ESC focused update of the 2021 HF guidelines introduced new key recommendations based on the results of the last years of science. First, two drugs, sodium-glucose co-transporter-2 (SGLT2) inhibitors and finerenone, a novel nonsteroidal, selective mineralocorticoid receptor antagonist (MRA), are recommended for the prevention of HF in patients with diabetic chronic kidney disease (CKD). Second, SGLT2 inhibitors are now recommended for the treatment of HF across the entire left ventricular ejection fraction spectrum. The benefits of quadruple therapy in patients with HF with reduced ejection fraction (HFrEF) are well established. Its rapid and early up-titration along with a close follow-up with frequent clinical and laboratory re-assessment after an episode of acute HF (the so-called 'high-intensity care' strategy) was associated with better outcomes in the STRONG-HF trial. Patients experiencing an episode of worsening HF might require a fifth drug, vericiguat. In the STEP-HFpEF-DM and STEP-HFpEF trials, semaglutide 2.4 mg once weekly administered for 1 year decreased body weight and significantly improved quality of life and the 6 min walk distance in obese patients with HF with preserved ejection fraction (HFpEF) with or without a history of diabetes. Further data on safety and efficacy, including also hard endpoints, are needed to support the addition of acetazolamide or hydrochlorothiazide to a standard diuretic regimen in patients hospitalized due to acute HF. In the meantime, PUSH-AHF supported the use of natriuresis-guided diuretic therapy. Further options and most recent evidence for the treatment of HF, including specific drugs for cardiomyopathies (i.e., mavacamten in hypertrophic cardiomyopathy and tafamidis in transthyretin cardiac amyloidosis), device therapies, cardiac contractility modulation and percutaneous treatment of valvulopathies, with the recent finding from the TRILUMINATE Pivotal trial, are also reviewed in this article.

Proteostasis Decline and Redox Imbalance in Age-Related Diseases: The Therapeutic Potential of NRF2

Nuclear factor erythroid 2-related factor 2 (NRF2) is a master regulator of cellular homeostasis, overseeing the expression of a wide array of genes involved in cytoprotective processes such as antioxidant and proteostasis control, mitochondrial function, inflammation, and the metabolism of lipids and glucose. The accumulation of misfolded proteins triggers the release, stabilization, and nuclear translocation of NRF2, which in turn enhances the expression of critical components of both the proteasomal and lysosomal degradation pathways. This process facilitates the clearance of toxic protein aggregates, thereby actively maintaining cellular proteostasis. As we age, the efficiency of the NRF2 pathway declines due to several factors including increased activity of its repressors, impaired NRF2-mediated antioxidant and cytoprotective gene expression, and potential epigenetic changes, though the precise mechanisms remain unclear. This leads to diminished antioxidant defenses, increased oxidative damage, and exacerbated metabolic dysregulation and inflammation-key contributors to age-related diseases. Given NRF2's role in mitigating proteotoxic stress, the pharmacological modulation of NRF2 has emerged as a promising therapeutic strategy, even in aged preclinical models. By inducing NRF2, it is possible to mitigate the damaging effects of oxidative stress, metabolic dysfunction, and inflammation, thus reducing protein misfolding. The review highlights NRF2's therapeutic implications for neurodegenerative diseases and cardiovascular conditions, emphasizing its role in improving proteostasis and redox homeostasis Additionally, it summarizes current research into NRF2 as a therapeutic target, offering hope for innovative treatments to counteract the effects of aging and associated diseases.

His108Arg Transthyretin Amyloidosis-Shedding Light on a Distinctively Malignant Variant

Variant transthyretin amyloidosis cardiomyopathy (ATTRv-CM) is a rare form of cardiac amyloidosis associated with many possible mutations in the transthyretin gene, presenting as various distinct clinical phenotypes. Among these, the His108Arg mutation is the most prevalent TTR variant in Austria. However, data describing its clinical phenotype are lacking. This study aims to describe the characteristics, clinical manifestations, and outcomes of patients with the His108Arg variant focusing on cardiac involvement, disease progression, response to therapy, and imaging findings. Methods: Patients were enrolled from a prospective cardiac amyloidosis registry. The baseline assessment included comprehensive echocardiography, cardiac magnetic resonance imaging, a biomarker analysis, and a clinical evaluation. Patients were followed longitudinally, with outcomes such as arrhythmias, heart failure hospitalizations, and response to disease-targeted therapies recorded. Results: Between March 2012 and June 2024, a total of 20 carriers of the His108Arg variant were identified, with 12 exhibiting clear cardiac involvement and 8 remaining asymptomatic. The median age at diagnosis was 62.3 years with significant heterogeneity in the clinical presentation. Patients with ATTRv-CM had a high prevalence of atrial and ventricular arrhythmias, a reduced left ventricular ejection fraction, and elevated cardiac biomarkers. The majority received specific disease-modifying therapies, with varying tolerance and responses. A longitudinal follow-up indicated frequent arrhythmic events, heart failure exacerbations, and three cases of heart transplantation, underscoring the need for stringent monitoring and individualized management strategies. Conclusions: This study represents a unique, comprehensive analysis of the His108Arg variant in ATTR-CM, highlighting its clinical heterogeneity and significant impact on cardiac function and clinical outcomes.

Atrial Lesion and Diastolic Dysfunction May Be Associated With Atrial Fibrillation in Patients With Cardiac Amyloidosis

Background

Atrial fibrillation (AF) is a common arrhythmia associated with cardiac amyloidosis (CA). Diastolic dysfunction and atrial lesions have been reported in patients with AF fibrillation. We aimed to evaluate the diastolic function and atrial lesions in patients with CA and AF.

Methods and Results

We included 27 patients (mean age 72 years) with biopsy-confirmed CA. We analyzed the average E/e' as diastolic function using echocardiography and atrial late gadolinium enhancement (LGE) as an atrial lesion using cardiac magnetic resonance imaging (CMRI). We compared these parameters among 20 patients with sinus rhythm (SR) and 7 with AF. Echocardiography examination showed that average E/e' were larger in the AF group than in the SR group (average E/e': AF, 21.3 [14.5-30.3]; SR, 14.2 [10.3-16.9]; P=0.0053). CMRI demonstrated that atrial LGE was more severe in the AF group than in the SR group (AF, 7/7 [100%]; SR, 11/21 [52.4%]; P=0.00228). Univariate logistic regression analysis showed that average E/e' demonstrated significant association with AF in all patients (odds ratio 1.24; [95% confidence interval 1.03-1.51]; P=0.0251).

Conclusions

AF may be associated with atrial lesions and diastolic dysfunction in patients with CA.

Amyloids and the Heart: An Update

Amyloids consist of fibrils that can be formed by a large variety of different precursor proteins. In localized amyloidosis, amyloids accumulate at the production site with a single organ being affected, whereas in systemic amyloidosis several organs are affected, with the heart being the most common, followed by the kidneys, liver, and the nervous system. The two most frequent systemic amyloidosis types affecting the heart in the vast majority (>95%) of cases are immunoglobulin light chain (AL) amyloidosis and transthyretin (TTR) amyloidosis (ATTR amyloidosis). Patients with amyloid cardiopathy (CA) often present with non-specific heart failure symptoms as well as other clinical manifestations depending on the organ or systems involved. However, there are some findings associated with amyloidosis called "red flags" (clinical, echocardiographic, magnetic resonance imaging), which may assist in guiding the physician to the correct diagnosis. The present state-of-the-art review summarizes the features of the various cardiac phenotypic expressions of amyloidosis, proposes a simplified pathway for its diagnosis, and highlights the rapidly evolving therapeutic landscape.

Long-term outcomes after catheter ablation for idiopathic atypical atrial flutter

BACKGROUND

Idiopathic atypical (non-cavotricuspid isthmus-dependent) atrial flutter (IAAFL) may be seen in patients without structural heart disease and without previous cardiac surgery or ablation.

OBJECTIVE

This study sought to determine the patient characteristics, electrophysiologic and electroanatomic properties, and clinical outcomes after ablation in patients with IAAFL.

METHODS

We retrospectively compared IAAFL patients with cavotricuspid isthmus-dependent AFL (C-AFL) patients undergoing catheter ablation. The primary outcome was a composite of death from cardiovascular causes, ischemic stroke, and hospitalization for worsening of heart failure.

RESULTS

Of 180 patients who underwent catheter ablation for AFL, 89 were included in this study (22 IAAFL and 67 C-AFL). Electrophysiologic study showed significantly longer intra-atrial conduction time and lower atrial voltage during sinus rhythm in the IAAFL group compared with the C-AFL group. The atrial scar was observed in all 22 IAAFL patients, with the most common sites being the posterior or lateral wall of the right atrium in 10 (45.5%) and the anterior wall of the left atrium in 8 (36.4%). During 3.5 ± 2.8 years of follow-up, the composite primary end point occurred significantly more frequently in the IAAFL group (hazard ratio [HR], 3.45; 95% confidence interval [CI], 1.20-9.89; P = .015). In multivariable analysis, brain natriuretic peptide levels (HR, 1.01; 95% CI, 1.00-1.01, per 1 pg/mL; P = .01) and IAAFL (HR, 4.14; 95% CI, 1.21-14.07; P = .02) were independently associated with the primary outcome.

CONCLUSION

IAAFL in patients had distinct electrophysiologic features suggestive of atrial cardiomyopathy. These patients are at risk for development of cardiovascular adverse events after ablation.

Pulmonary Transit Time Derived from First-Pass Perfusion Cardiac MR Imaging: A Potential New Marker for Cardiac Involvement and Prognosis in Light-Chain Amyloidosis

BACKGROUND

First-pass perfusion cardiac MR imaging could reflect pulmonary hemodynamics. However, the clinical value of pulmonary transit time (PTT) derived from first-pass perfusion MRI in light-chain (AL) amyloidosis requires further evaluation.

PURPOSE

To assess the clinical and prognostic value of PTT in patients with AL amyloidosis.

STUDY TYPE

Prospective observational study.

POPULATION

226 biopsy-proven systemic AL amyloidosis patients (age 58.62 ± 10.10 years, 135 males) and 43 healthy controls (age 42 ± 16.2 years, 20 males).

FIELD STRENGTH/SEQUENCE

SSFP cine and phase sensitive inversion recovery late gadolinium enhancement (LGE) sequences, and multislice first-pass myocardial perfusion imaging with a saturation recovery turbo fast low-angle shot (SR-TurboFLASH) pulse sequence at 3.0T.

ASSESSMENT

PTT was measured as the time interval between the peaks of right and left ventricular cavity arterial input function curves on first-pass perfusion MR images.

STATISTICAL TESTS

Independent-sample t test, Mann-Whitney U test, Chi-square test, Fisher's exact test, analysis of variance, or Kruskal-Wallis test, as appropriate; univariable and multivariable Cox proportional hazards models and Kaplan-Meier curves, area under receiver operating characteristic curve were used to determine statistical significance.

RESULTS

PTT could differentiate AL amyloidosis patients with (N = 188) and without (N = 38) cardiac involvement (area under the curve [AUC] = 0.839). During a median follow-up of 35 months, 160 patients (70.8%) demonstrated all-cause mortality. After adjustments for clinical (Hazard ratio [HR] 1.061, confidence interval [CI]: 1.021-1.102), biochemical (HR 1.055, CI: 1.014-1.097), cardiac MRI-derived (HR 1.077, CI: 1.034-1.123), and therapeutic (HR 1.063, CI: 1.024-1.103) factors, PTT predicted mortality independently in patients with AL amyloidosis. Finally, PTT could identify worse outcomes in patients demonstrating New York Heart Association class III, Mayo 2004 stage III, and transmural LGE pattern.

DATA CONCLUSION

PTT may serve as a new imaging predictor of cardiac involvement and prognosis in AL amyloidosis.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Thromboembolic and bleeding risk in cardiac amyloidosis

Cardiac amyloidosis represents a spectrum of conditions characterized by the accumulation of insoluble fibrils, resulting in progressive deposition and myocardial dysfunction. The exact mechanisms contributing to the heightened risk of thromboembolic events and bleeding tendencies in cardiac amyloidosis remain unclear. Proteins such as transthyretin in transthyretin amyloidosis and light chains in light-chain amyloidosis, along with acute phase proteins in amyloid A (AA) amyloidosis, play complex roles in the coagulation cascade, affecting both coagulation initiation and fibrinolysis regulation. The increased occurrence of atrial fibrillation, systolic and diastolic left ventricular dysfunction, and atrial myopathy in patients with cardiac amyloidosis may predispose them to thrombus formation. This predisposition can occur regardless of sinus rhythm status or even with proper anticoagulant management. Bleeding events are often linked to amyloid deposits around blood vessels, which may increase capillary fragility and cause coagulation disturbances, leading to unstable international normalized ratio levels during anticoagulant therapy. Thus, comprehensive risk assessment for both thrombotic and hemorrhagic complications, especially before commencing anticoagulant therapy, is imperative. This review will explore the essential pathophysiological, epidemiologic, and clinical aspects of thromboembolic and bleeding risk in cardiac amyloidosis, evaluating the existing evidence and uncertainties regarding thrombotic and bleeding risk assessment and antithrombotic treatment.

Epidemiological Changes in Transthyretin Cardiac Amyloidosis: Evidence from In Vivo Data and Autoptic Series

Cardiac amyloidosis is an infiltrative disease that causes progressive myocardial impairment secondary to amyloid fibril deposition in the extracellular space of the myocardium. Many amyloid precursors, including transthyretin protein, are known to determine cardiac damage by aggregating and precipitating in cardiac tissue. Transthyretin cardiac amyloidosis may be either caused by rare genetic mutations of the transthyretin gene in the hereditary variant, or may arise as a consequence of age-related mechanisms in the acquired form. Although it has been labeled as a rare disease, in recent years, transthyretin cardiac amyloidosis has stood out as an emerging cause of aortic stenosis, unexplained left ventricular hypertrophy and heart failure with preserved ejection fraction, particularly in the elderly. Indeed, the integration of data deriving from both in vivo imaging techniques (whose advancement in the last years has allowed to achieve an easier and more accessible non-invasive diagnosis) and forensic studies (showing a prevalence of amyloid deposition in cardiac tissue of elderly patients up to 29%) suggests that cardiac amyloidosis is a more common disease than traditionally considered. Thanks to all the improvements in non-invasive diagnostic techniques, along with the development of efficacious therapies offering improvements in survival rates, transthyretin cardiac amyloidosis has been transformed from an incurable and infrequent condition to a relatively more diffuse and treatable disease, which physicians should take into consideration in the differential diagnostic processes in daily clinical practice.

Myocardial Mechanics and Valvular and Vascular Abnormalities in Cardiac Amyloidosis

Cardiac amyloidosis is an infiltrative disease primarily caused by extracellular tissue deposition of amyloid fibrils in the myocardial interstitium. The aim of the present review was to summarize findings regarding changes in myocardial mechanics, valvular abnormalities, and vascular remodeling detected in patients with cardiac amyloidosis.

Interactive teaching of medical 3D cardiac anatomy: atrial anatomy enhanced by ECG and 3D visualization

The most commonly applied way of teaching students to convey the foundations of human anatomy and physiology involves textbooks and lectures. This way of transmitting knowledge causes difficulties for students, especially in the context of three-dimensional imaging of organ structures, and as a consequence translates into difficulties with imagining them. Even despite the rapid uptake of knowledge dissemination provided by online materials, including courses and webinars, there is a clear need for learning programs featuring first-hand immersive experiences tailored to suit individual study paces. In this paper, we present an approach to enhance a classical study program by combining multi-modality data and representing them in a Mixed Reality (MR)-based environment. The advantages of the proposed approach have been proven by the conducted investigation of the relationship between atrial anatomy, its electrophysiological characteristics, and resulting P wave morphology on the electrocardiogram (ECG). Another part of the paper focuses on the role of the sinoatrial node in ECG formation, while the MR-based visualization of combined micro-computed tomography (micro-CT) data with non-invasive CineECG imaging demonstrates the educational application of these advanced technologies for teaching cardiac anatomy and ECG correlations.

Ischemic stroke and the emerging role of left atrial function

INTRODUCTION

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Emerging evidence suggests that left atrial (LA) dysfunction could play a role in the pathophysiology of ischemic stroke, as a possible contributor and as a predictive biomarker.

AREAS COVERED

This narrative review details the intricate relationship between LA function, atrial fibrillation (AF), and ischemic stroke. We discuss imaging techniques used to assess LA function, the mechanisms by which impaired LA function may contribute to stroke, and its potential as a prognostic marker of stroke.

EXPERT OPINION

There is a lack of evidence-based treatments of LA dysfunction in both primary and secondary stroke prevention. This is partly due to the lack of a practical clinical definition and unanswered questions concerning the clinical implications of LA dysfunction in patients without AF. Until such questions are resolved, addressing well-known cardiovascular risk factors, like hypertension and obesity, should be prioritized for preventing AF and ischemic stroke. These risk factors are closely tied to atrial remodeling, emphasizing the importance of targeting primary modifiable factors for preventing future morbidity and mortality.

Assessing left atrial dysfunction in cardiac amyloidosis using LA-LV strain slope

Aims

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an infiltrative disease of the myocardium in which extracellular deposits of amyloid cause progressive cardiac impairment. We aimed to evaluate left atrial (LA) deformation and its association with left ventricular (LV) deformation using LA-LV strain loops in patients with ATTR-CM and patients with LV hypertrophy (LVH). We hypothesized that LA strain in ATTR-CM patients is abnormal and more independent of LV strain, compared to LVH patients.

Methods and results

Retrospective study based on echocardiographic data including 30 patients diagnosed with ATTR-CM based on an end-diastolic interventricular septal (IVSd) thickness of ≥14 mm, and 29 patients with LVH (IVSd ≥ 14 mm and no ATTR-CM diagnosis) together with 30 controls. LV global longitudinal strain (LV-GLS) and LA strain, assessed as peak atrial longitudinal strain (PALS), were acquired and plotted to construct LA-LV strain loops and used regression line to determine a LA-LV strain slope. Significantly lower PALS and LA-LV strain slope values were detected in ATTR-CM patients compared to LVH patients (P = 0.004 and P = 0.014, respectively). A receiver operating characteristic (ROC) curve demonstrated similar area under the curve (AUC) using PALS (AUC 0.72) and LA-LV slope (AUC 0.71), with both resulting in higher values than recorded for LV-GLS (AUC 0.62).

Conclusion

LA deformation demonstrates an independent ability to differentiate ATTR-CM from LVH. Combining LV strain and LA deformation analysis displays the mechanical LA-LV dissociation in ATTR cardiac amyloidosis and potentially unmasks LA amyloid infiltration; this could potentially enable quicker diagnosis and initiation of treatment for ATTR-CM.

Pathophysiology of Cardiac Amyloidosis

Amyloidosis refers to a heterogeneous group of disorders sharing common pathophysiological mechanisms characterized by the extracellular accumulation of fibrillar deposits consisting of the aggregation of misfolded proteins. Cardiac amyloidosis (CA), usually caused by deposition of misfolded transthyretin or immunoglobulin light chains, is an increasingly recognized cause of heart failure burdened by a poor prognosis. CA manifests with a restrictive cardiomyopathy which progressively leads to biventricular thickening, diastolic and then systolic dysfunction, arrhythmias, and valvular disease. The pathophysiology of CA is multifactorial and includes increased oxidative stress, mitochondrial damage, apoptosis, impaired metabolism, and modifications of intracellular calcium balance.

Prevalence and clinical outcomes of isolated or combined moderate to severe mitral and tricuspid regurgitation in patients with cardiac amyloidosis

AIMS

Evidence on the epidemiology and prognostic significance of mitral regurgitation (MR) and tricuspid regurgitation (TR) in patients with cardiac amyloidosis (CA) is scarce.

METHODS AND RESULTS

Overall, 538 patients with either transthyretin (ATTR, n = 359) or immunoglobulin light-chain (AL, n = 179) CA were included at three Italian referral centres. Patients were stratified according to isolated or combined moderate/severe MR and TR. Overall, 240 patients (44.6%) had no significant MR/TR, 112 (20.8%) isolated MR, 66 (12.3%) isolated TR, and 120 (22.3%) combined MR/TR. The most common aetiologies were atrial functional MR, followed by primary infiltrative MR, and secondary TR due to right ventricular (RV) overload followed by atrial functional TR. Patients with isolated or combined MR/TR had a more frequent history of heart failure (HF) hospitalization and atrial fibrillation, worse symptoms, and higher levels of NT-proBNP as compared to those without MR/TR. They also presented more severe atrial enlargement, atrial peak longitudinal strain impairment, left ventricular (LV) and RV systolic dysfunction, and higher pulmonary artery systolic pressures. TR carried the most advanced features. After adjustment for age, sex, CA subtypes, laboratory, and echocardiographic markers of CA severity, isolated TR and combined MR/TR were independently associated with an increased risk of all-cause death or worsening HF events, compared to no significant MR/TR [adjusted HR 2.75 (1.78-4.24) and 2.31 (1.44-3.70), respectively].

CONCLUSION

In a large cohort of patients with CA, MR, and TR were common. Isolated TR and combined MR/TR were associated with worse prognosis regardless of CA aetiology, LV, and RV function, with TR carrying the highest risk.

Coexisting transthyretin and atrial natriuretic peptide amyloid on left atrium in transthyretin amyloid cardiomyopathy

Atrial amyloidosis is primarily caused by atrial natriuretic peptide (ANP) amyloid deposition. The main precursor protein causing cardiac amyloidosis is transthyretin (TTR), also known as TTR amyloid cardiomyopathy (ATTR-CM). A 73-year-old man, who presented with external dyspnea, was diagnosed with decompensated heart failure due to atrial fibrillation and severe mitral regurgitation. Left ventricular hypertrophy and elevated levels of high-sensitivity cardiac troponin T indicated cardiac amyloidosis. 99mtechnetium pyrophosphate scintigraphy findings and cardiac magnetic resonance imaging in the absence of monoclonal proteins were consistent with those of ATTR-CM. The patient underwent mitral valve repair, a maze procedure, and left atrial appendage (LAA) excision. While the histological analysis of the sampled left ventricular tissue led to diagnosis of ATTR-CM, the histological analysis revealed the coexistence of ANP and TTR amyloid deposition in the resected LAA. We report a case of ATTR-CM in which TTR and ANP amyloid deposition coexisted in the surgically resected LAA, indicating that both TTR and ANP amyloid correlate with atrial amyloidosis development in ATTR-CM.

Learning objectives

Atrial natriuretic peptide (ANP) and transthyretin (TTR) amyloids can coexist in the same atrium. Not only TTR amyloids but also ANP amyloids can be correlated with the development of atrial amyloidosis in TTR amyloid cardiomyopathy with subsequent increased risk of atrial fibrillation.

Effects of tafamidis on the left ventricular and left atrial strain in patients with wild-type transthyretin cardiac amyloidosis

AIMS

Although tafamidis is used in patients with wild-type transthyretin cardiac amyloidosis (ATTRwt-CA), its specific effect on cardiac function is unclear. Thus, this study aimed to investigate the effect of tafamidis on left atrial (LA) and left ventricular function using speckle-tracking echocardiography for 1 year of treatment in patients with ATTRwt-CA.

METHODS AND RESULTS

We included 23 patients (mean age, 76 years) with ATTRwt-CA confirmed via biopsy. We analysed the left ventricular and LA strain using 2D speckle-tracking echocardiography and compared these parameters before and 1 year after starting treatment with tafamidis between 16 patients with sinus rhythm (SR) and 7 patients with atrial fibrillation (AF). In ATTRwt-CA patients with SR, LA reservoir strain significantly improved by 1-year tafamidis treatment (10.5 ± 5.0% to 11.9 ± 5.3%, P = 0.0307) although global longitudinal strain (GLS) did not (-10.6 ± 3.1% to -11.3 ± 3.0%, P = 0.0608). In contrast, LA reservoir strain was not significantly changed (5.4 ± 2.9% to 4.9 ± 1.7%, P = 0.4571), and GLS deteriorated (-8.4 ± 2.3% to -6.8 ± 1.4%, P = 0.0267) in ATTRwt-CA patients with AF.

CONCLUSION

LA function improved with tafamidis treatment in ATTRwt-CA patients with SR but not left ventricular function. However, these cardiac functions did not improve with tafamidis treatment in ATTRwt-CA patients with AF.

A Novel Approach to Cardiac Magnetic Resonance Scar Characterization in Patients Affected by Cardiac Amyloidosis: A Pilot Study

Background and Objectives: Cardiac magnetic resonance (CMR) imaging has become an essential instrument in the study of cardiomyopathies; it has recently been integrated into the diagnostic workflow for cardiac amyloidosis (CA) with remarkable results. An additional emerging role is the stratification of the arrhythmogenic risk by scar analysis and the possibility of merging these data with electro-anatomical maps. This is made possible by using a software (ADAS 3D, Galgo Medical, Barcelona, Spain) able to provide 3D heart models by detecting fibrosis along the whole thickness of the myocardial walls. Little is known regarding the applications of this software in the wide spectrum of cardiomyopathies and the potential benefits have yet to be discovered. In this study, we tried to apply the ADAS 3D in the context of CA. Materials and Methods: This study was a retrospectively analysis of consecutive CMR imaging of patients affected by CA that were treated in our center (Marche University Hospital). Wherever possible, the data were processed with the ADAS 3D software and analyzed for a correlation between the morphometric parameters and follow-up events. The outcome was a composite of all-cause mortality, unplanned cardiovascular hospitalizations, sustained ventricular arrhythmias (VAs), permanent reduction in left ventricular ejection fraction, and pacemaker implantation. The secondary outcomes were the need for a pacemaker implantation and sustained VAs. Results: A total of 14 patients were deemed eligible for the software analysis: 8 patients with wild type transthyretin CA, 5 with light chain CA, and 1 with transthyretin hereditary CA. The vast majority of imaging features was not related to the composite outcome, but atrial wall thickening displayed a significant association with both the primary (p = 0.003) and the secondary outcome of pacemaker implantation (p = 0.003). The software was able to differentiate between core zones and border zones of scars, with the latter being the most extensively represented in all patients. Interestingly, in a huge percentage of CMR images, the software identified the highest degree of core zone fibrosis among the epicardial layers and, in those patients, we found a higher incidence of the primary outcome, without reaching statistical significance (p = 0.18). Channels were found in the scar zones in a substantial percentage of patients without a clear correlation with follow-up events. Conclusions: CMR imaging plays a pivotal role in cardiovascular diagnostics. Our analysis shows the feasibility and applicability of such instrument for all types of CA. We could not only differentiate between different layers of scars, but we were also able to identify the presence of fibrosis channels among the different scar zones. None of the data derived from the ADAS 3D software seemed to be related to cardiac events in the follow-up, but this might be imputable to the restricted number of patients enrolled in the study.

Prevalence of valvular heart disease in cardiac amyloidosis and impact on survival

BACKGROUND

Limited data exists on the prognostic impact of valvular heart disease in cardiac amyloidosis (CA). We therefore sought to define the prevalence of valvular disease in patients with CA and assess the effects of significant valve disease on survival.

METHODS

This multi-center retrospective cohort study included consecutive patients with confirmed transthyretin (TTR) or light chain (AL) amyloidosis. Echocardiographic data closest to the date of amyloid diagnosis was reviewed, and severity was graded according to ASE guidelines. Kaplan-Meier survival analysis was performed to compare survival between patients with moderate or greater valve disease against those with mild or less disease.

RESULTS

We included 345 patients (median age 76 years; 73 % men; 110 AL, 235TTR). The median survival for the total patient cohort with cardiac amyloidosis was 2.92 years, with 30 % of patients surviving at five years after their diagnosis. Median survival comparing AL vs ATTR was 2.58 years vs 2.82 years (p = 0.67) The most common valvular abnormalities in the total cohort were mitral (62 %) and tricuspid (66 %).regurgitation There was a statistically significant difference in median survival between patients with no or mild MR compared to those with moderate or severe MR (2.92 years vs 3.35 years, p = 0.0047) (Fig. 5). There was a statistically significant difference in median survival in patients with no or mild TR compared to those with moderate or severe TR (3.35 years vs 2.3 years, p = 0.015).

CONCLUSION

Our study demonstrates a significant prevalence of mitral and tricuspid regurgitation in CA, with patients with moderate to severe MR and TR having a poorer prognosis.

Cardiac amyloid deposition and the forensic autopsy - A review and analysis

Although amyloid material in the heart is not infrequently encountered at autopsy it may on occasion be difficult to determine the significance in terms of possible contributions to the terminal mechanisms of death. A review was undertaken of the literature and of autopsy cases at Forensic Science SA over a 20-year-period (2003-2022) for all cases where significant amyloid material had been encountered on microscopy of the heart. Sixteen cases were found consisting of 11 cases where cardiac amyloid was involved in the lethal episode, and five where it was considered an incidental feature. Of the 11 lethal cases, there were three where cardiac amyloidosis was the cause of death, and eight where it was a contributing factor, along with ischaemic heart disease (N = 7) and bronchopneumonia (N = 1). The age range was 47-92 years, average 78.6 years, with a male to female ratio of 10:1. The weights of the hearts ranged from 496 to 1059 g - average 648 g. Of the five cases where it was considered an incidental finding, the causes of death were blunt head trauma (N = 2), small intestinal ischaemia (N = 2) and small intestinal obstruction (N = 1). The weights of the hearts ranged from 299 to 487 g, average 369 g. The most relevant types of amyloidosis in forensic cases tend to be light chain amyloidosis, senile cardiac amyloidosis and familial amyloid cardiomyopathy. Other forms of amyloidosis that affect the heart, which include reactive amyloidosis, haemodialysis-related amyloidosis and isolated atrial amyloidosis, either have minimal or no clinical significance, or are of uncertain significance. While it may be difficult to determine the prognostic significance of amyloid material at autopsy clinicopathological correlation may provide useful supportive information.

Pathophysiology and clinical relevance of atrial myopathy

Atrial myopathy is a condition that consists of electrical, structural, contractile, and autonomic remodeling of the atria and is the substrate for development of atrial fibrillation, the most common arrhythmia. Pathophysiologic mechanisms driving atrial myopathy are inflammation, oxidative stress, atrial stretch, and neurohormonal signals, e.g., angiotensin-II and aldosterone. These mechanisms initiate the structural and functional remodeling of the atrial myocardium. Novel therapeutic strategies are being developed that target the pathophysiologic mechanisms of atrial myopathy. In this review, we will discuss the pathophysiology of atrial myopathy, as well as diagnostic and therapeutic strategies.

Current Perspectives on Atrial Amyloidosis: A Narrative Review

Amyloidosis is a systemic disease caused by low molecular weight protein accumulation in the extracellular space, which can lead to different degrees of damage, depending of the organ or tissue involved. The condition is defined cardiac amyloidosis (CA) when heart is affected, and it is associated with an unfavorable outcome. Different types of CA have been recognized, the most common (98%) are those associated with deposition of light chain (AL-CA), and the form secondary to transthyretin deposit. The latter can be classified into two types, a wild type (transthyretin amyloidosis wild type (ATTRwt)-CA), which mainly affects older adults, and the hereditary or variant type (ATTRh-CA or ATTRv-CA), which instead affects more often young people and is associated with genetic alterations. The atrial involvement can be isolated or linked to CA with a nonspecific clinical presentation represented by new onset atrial fibrillation (AF), diastolic dysfunction and heart failure with preserved ejection fraction, or thromboembolism and stroke. Untreated patients have a median survival rate of 9 years for AL-CA and 7 years for ATTR-CA. By contrast, AL-CA and ATTR-CA treated patients have a median survival rate of 24 and 10 years, respectively. Atrial involvement in CA is a common but poor studied event, and alterations of performance can anticipate the anatomical damage. Recently, numerous advances have been made in the diagnostic field with improvements in the available techniques. An early diagnosis therefore allows a more effective therapeutic strategy with a positive impact on prognosis and mortality rate. A multimodality approach to the diagnosis of atrial involvement from CA is therefore recommended, and standard echocardiography, advanced Doppler-echocardiography (DE) and cardiac magnetic resonance (CMR) can be useful to detect early signs of CA and to estabilish an appropriate treatment.

Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy and Cardiac Amyloidosis: From Clinical Management to Catheter Ablation Indication

Atrial fibrillation (AF) is the most common arrhythmia in patients affected by cardiomyopathies. Reports estimate a prevalence of 27% in patients with hypertrophic cardiomyopathy (HCM) and 40% in patients with cardiac amyloidosis (CA). The presence of AF typically results in progressive functional decline, an increased frequency of hospitalizations for heart failure, and a higher thromboembolic risk. Medical management using mainly beta-blockers or amiodarone has produced variable outcomes and a high rate of recurrence. Catheter ablation reduces symptom burden and complications despite a moderate rate of recurrence. Recent evidence suggests that an early rhythm control strategy may lead to more favorable short- and long-term outcomes. In this review, we summarize contemporary data on the management of AF in patients with cardiomyopathy (HCM and CA) with particular reference to the timing and outcomes of ablation procedures.

Electrocardiographic abnormalities in patients with cardiomyopathies

Abnormalities in impulse generation and transmission are among the first signs of cardiac remodeling in cardiomyopathies. Accordingly, 12-lead electrocardiogram (ECG) of patients with cardiomyopathies may show multiple abnormalities. Some findings are suggestive of specific disorders, such as the discrepancy between QRS voltages and left ventricular (LV) mass for cardiac amyloidosis or the inverted T waves in the right precordial leads for arrhythmogenic cardiomyopathy. Other findings are less sensitive and/or specific, but may orient toward a specific diagnosis in a patient with a specific phenotype, such as an increased LV wall thickness or a dilated LV. A "cardiomyopathy-oriented" mindset to ECG reading is important to detect the possible signs of an underlying cardiomyopathy and to interpret correctly the meaning of these alterations, which differs in patients with cardiomyopathies or other conditions.

Clinical and Cardiovascular Magnetic Resonance Imaging Features of Cardiac Amyloidosis

Amyloidosis is a systemic disease characterized by the accumulation of insoluble aggregates in various organs, leading to parenchymal damage. When these amyloid fibrils are deposited in the extracellular matrix of the cardiac structures, the condition is referred to as cardiac amyloidosis (CA). The extent of organ involvement determines the degree of cardiac impairment, which can significantly impact prognosis. The two most implicated proteins in CA are transthyretin and misfolded monoclonal immunoglobulin light chains. These proteins give rise to two distinct clinical forms of CA: transthyretin amyloidosis (ATTR-CA) and light-chain amyloidosis (AL-CA). ATTR-CA is further classified into two subtypes: ATTRm-CA, which occurs at a younger age and is caused by hereditary misfolded mutated proteins, and ATTRwt-CA, which is an acquired wild-type form more commonly observed in older adults, referred to as senile amyloidosis. While AL-CA was considered the most prevalent form for many years, recent autopsy studies have revealed an increase in cases of ATTRwt-CA. This narrative review aims to describe the clinical and imaging features of CA, with a particular focus on cardiac complications and mortality associated with the AL form. Early identification and differentiation of CA from other disorders are crucial, given the higher risk and severity of cardiac involvement in AL-CA. Furthermore, emphasis is placed on the potential utility of cardiovascular magnetic resonance imaging in detecting early cases of CA.

Imaging findings of right cardiac amyloidosis: impact on prognosis and clinical course

Cardiac involvement from amyloidosis is of growing interest in the overall literature. Despite cardiac amyloidosis (CA) has been considered for a long time a rare disease, the diagnostic awareness is increasing mainly thanks to the improvement of diagnostic softwares and of imaging techniques such as cardiac magnetic resonance  (CMR). Some authors have observed an increase of prevalence rate of CA; moreover it's often underestimated because clinical manifestations are aspecific. The interstitial infiltration of the left ventricle has been extensively studied, while the involvement of the right ventricle (RV) has been less investigated. Involvement of the RV, even in the absence of pulmonary hypertension or clearly left ventricle infiltration, plays an important role as prognostic factor and is useful to achieve an early diagnosis. Therefore, the use of fast and low-cost diagnostic methods such as ultrasound strain of the right ventricle could be used to recognize cardiac amyloidosis early. Herein the importance of evaluating the right ventricular involvement, which can predict the most severe course of the disease also without overt clinical manifestations. The role of imaging, in particular of echocardiography, CMR, and scintigraphy is here reported.

Classification of patients with cardiac amyloidosis using machine learning models on Italian electronic clinical health records

Amyloidosis refers to a range of medical conditions in which misshapen proteins accumulate in various organs and tissues, forming insoluble fibrils. Cardiac amyloidosis is frequently linked to the buildup of misfolded transthyretin (TTR) or immunoglobulin light chains (AL). Delayed diagnosis, due to lack of disease awareness, results in a poor prognosis, especially in patients with AL amyloidosis. Early identification is therefore a key factor to improve patient outcomes. This study investigates the use of supervised machine-learning algorithms to support clinicians in classifying amyloidosis and control subjects. The aim of this work is to foster model interpretability reporting the most important risk factors in predicting the presence of cardiac amyloidosis. We analyzed electronic health records (EHRs) of 418 participants acquired in a time window of 12 years as part of a case-control study conducted in Fondazione Toscana Gabriele Monasterio (Italy) clinical practice. This work paves the way for the creation of digital health solutions that can aid in amyloidosis screening. The effective handling, analysis, and interpretation of these solutions can have a transformative effect on modern healthcare, offering new opportunities for improved patient care.

Invasive and Non-Invasive Diagnostic Pathways in the Diagnosis of Cardiac Amyloidosis

The appropriate diagnosis and subtyping of cardiac amyloidosis (CA) is frequently missed or delayed due to its vague presentation, clinical overlapping, and diagnostic pitfalls. Recent developments in both invasive and non-invasive diagnostic techniques have significantly changed the diagnostic approach of CA. With the present review, we aim to summarize the current diagnostic approach of CA and to underline the indications of tissue biopsy, either surrogate site or myocardial. The most important factor for timely diagnosis is increased clinical suspicion, especially in certain clinical scenarios. Appropriate imaging with echocardiography or cardiac magnetic resonance (CMR) can provide significant evidence for the diagnosis of CA. Importantly, all patients should undergo monoclonal proteins assessment, with these results significantly determining the steps to follow. A negative monoclonal protein assessment will lead to a non-invasive algorithm which, in combination with positive cardiac scintigraphy, can establish the diagnosis of ATTR-CA. The latter is the only clinical scenario in which the diagnosis can be established without the need of biopsy. However, if the imaging results are negative but the clinical suspicion remains high, a myocardial biopsy should be performed. In the case of the presence of monoclonal protein, an invasive algorithm follows, first by surrogate site sampling and then by myocardial biopsy if the results are inconclusive or prompt diagnosis is needed. The role of endomyocardial biopsy, even though limited by current advances in other techniques, is highly valuable in selected patients and is the only method to reliably establish a diagnosis in challenging cases.

Transthyretin derived amyloid deposits in the atrium and the aortic valve: insights from multimodality evaluations and mid-term follow up

BACKGROUND

Recent studies have reported atrial involvement and coexistence of aortic stenosis in transthyretin (ATTR) cardiac amyloidosis (CA). However, pathological reports of extraventricular ATTR amyloid deposits in atrial structures or heart valves are limited, and the clinical implications of ATTR amyloid deposits outside the ventricles are not fully elucidated.

CASE PRESENTATION

We report 3 cases of extraventricular ATTR amyloid deposits confirmed in surgically resected aortic valves and left atrial structures, all of which were unlikely to have significant ATTR amyloidosis infiltrating the ventricles as determined by multimodality evaluation including ^99mtechnetium-pyrophosphate scintigraphy, cardiac magnetic resonance, endomyocardial biopsy and their mid-term clinical course up to 5 years. These findings suggested that these were extraventricular ATTR amyloid deposits localized in the aortic valve and the left atrium.

CONCLUSIONS

While long-term observation is required to fully clarify whether these extraventricular ATTR amyloid deposits are truly localized outside the ventricles or are early stages of ATTR-CA infiltrating the ventricles, our 3 cases with multimodality evaluations and mid-term follow up suggest the existence of extraventricular ATTR amyloid deposits localized in the aortic valve and left atrial structures.

Treating amyloid transthyretin cardiomyopathy: lessons learned from clinical trials

An increasing awareness of the disease, new diagnostic tools and novel therapeutic opportunities have dramatically changed the management of patients with amyloid transthyretin cardiomyopathy (ATTR-CM). Supportive therapies have shown limited benefits, mostly related to diuretics for the relief from signs and symptoms of congestion in patients presenting heart failure (HF). On the other hand, huge advances in specific (disease-modifying) treatments occurred in the last years. Therapies targeting the amyloidogenic cascade include several pharmacological agents that inhibit hepatic synthesis of TTR, stabilize the tetramer, or disrupt fibrils. Tafamidis, a TTR stabilizer that demonstrated to prolong survival and improve quality of life in the ATTR-ACT trial, is currently the only approved drug for patients with ATTR-CM. The small interfering RNA (siRNA) patisiran and the antisense oligonucleotide (ASO) inotersen have been approved for the treatment of patients with hereditary ATTR polyneuropathy regardless of the presence of cardiac involvement, with patisiran also showing preliminary benefits on the cardiac phenotype. Ongoing phase III clinical trials are investigating another siRNA, vutrisiran, and a novel ASO formulation, eplontersen, in patients with ATTR-CM. CRISPR-Cas9 represents a promising strategy of genome editing to obtain a highly effective blockade of TTR gene expression.

Epidemiology, Mechanisms, and Management of Atrial Fibrillation in Cardiac Amyloidosis

Cardiac amyloidosis (CA) is a restrictive disease that results from intramyocardial amyloid deposition due to immunoglobulin light chain or transthyretin proteins. Up to two-third of CA patients have atrial fibrillation (AF) due to electromechanical, autonomic, and hemodynamic disturbances. AF in CA carries particularly increased risk of thromboembolism, prompting anticoagulation therapy irrespective of CHA₂DS₂VASc score. However, CA is also associated with enhanced bleeding risk that warrants thorough assessment of bleeding profile before initiation of anticoagulation. Management of AF in CA is challenging because these patients poorly tolerate rate control agents, while cardiomyopathy precludes most antiarrhythmic agents, leaving amiodarone as the preferred antiarrhythmic drug. The effectiveness of direct current cardioversion in restoring sinus rhythm in CA is comparable with that in the general population, although intraprocedural complication rates could be higher. Transesophageal echocardiogram should be performed prior to direct current cardioversion, given high incidence of intracardiac thrombus in these patients. Finally, the data on catheter ablation is limited.