Clinical Importance of Left Atrial Infiltration in Cardiac Transthyretin Amyloidosis

Atrial fibrillation in the setting of cardiac amyloidosis - A review of the literature

Cardiac amyloidosis (CA) is related to the aggregation of insoluble fibrous deposits of misfolded proteins within the myocardium. Transthyretin amyloidosis (ATTR) and immunoglobulin light-chain amyloidosis are the main forms of CA. Atrial fibrillation (AF) is a common arrhythmia in CA patients, especially in those with ATTR amyloidosis. Increased atrial preload and afterload, atrial enlargement, enhanced atrial wall stress, and autonomic dysfunction are the main mechanisms of AF in CA patients. CA is associated with the formation of endocardial thrombi and systemic embolism. The promoters of thrombogenesis include endomyocardial damage, blood stasis, and hypercoagulability. The prevalence of thrombi in patients with AF remains elevated despite long-term anticoagulation. Consequently, transesophageal ultrasound examinations before cardioversion should be performed to exclude endocardiac thrombi despite anticoagulation. Furthermore, the CHA2DS2-VASc score should not be used to assess the thromboembolic risk in CA patients with AF. Rate control is challenging in patients with CA, while rhythm control is the preferred treatment option, especially in the early stages of the disease process. Although catheter ablation is an effective treatment option, more data are needed to explore the role of the procedure in CA patients.

Diagnostic and prognostic value of the left atrial myopathy evaluation in cardiac amyloidosis using echocardiography

BACKGROUND

Cardiac amyloidosis (CA) is an under-recognized cause of heart failure. Left atrial (LA) myopathy contributes to a worse prognosis in heart failure and is a feature of transthyretin (ATTR) and light-chain (AL) CA. LA mechanical dispersion (LA-MD) is a novel marker of intra-atrial dyssynchrony implicated in LA myopathy and the future development of atrial fibrillation (AF).

AIMS

This study aimed to determine the characteristics and prognostic value of LA myopathy in ATTR and AL cardiomyopathy through a comprehensive LA echocardiographic evaluation.

METHODS

ATTR (n = 86) and AL (n = 86) CA patients were compared with hypertensive heart disease (HHT) patients (n = 58). Transthoracic echocardiographic measurements including LA strain and LA-MD were obtained with patient follow-up for mortality.

RESULTS

ATTR and AL patients had a median follow-up of 66 months, with 26 mortality events. Left ventricular (LV) mass, diastolic function (average-e' and E/e'), LV global longitudinal strain, and LA volume and function (LA function index and strain) were more impaired in ATTR versus AL; these echocardiographic parameters were more impaired in both amyloid groups compared to HHT patients (P < 0.05). LA-MD was increased in ATTR versus AL [median 72.2 (inter-quartile range 55-88.9) vs. 54 (43.5-64.2), respectively, P < 0.001]. Multivariable logistic regression adjusted for age, presence of AF, LV mass, global and basal strain, and E/e' demonstrated that LA-MD was an independent determinant of ATTR CA (P = 0.014). On multivariable analysis, LA reservoir strain was independently associated with the presence of heart failure in the CA group (P < 0.001). LA minimum volume (cut-off ≥18 mL/m2) was a determinant of mortality in AL CA [Cox proportional hazard ratio (HR) 1.042 (1.003-1.082), P = 0.034 and Kaplan-Meier analysis, P = 0.016].

CONCLUSION

Characterizing LA myopathy has significant diagnostic and prognostic utility in CA. ATTR patients have increased atrial dyssynchrony, which may have implications for AF development. LA reservoir strain was associated with heart failure in CA, whilst LA minimum volume was a predictor of mortality in AL CA.

Importance of fourth heart sound and preserved left atrial function in wild-type transthyretin amyloidosis

AIMS

A fourth heart sound (S4) was reported to be almost never present in patients with amyloid light-chain cardiomyopathy. There have been no reports on S4 in patients with wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM). This study aimed to clarify the clinical implications of S4 in patients with ATTRwt-CM.

METHODS AND RESULTS

Seventy-six patients with ATTRwt-CM (mean age: 80.4 ± 5.4 years, 68 males) who had undergone phonocardiography (PCG) were retrospectively assessed. We measured S4 amplitude on digitally recorded PCG. S4 was considered to be present when its amplitude was 1.0 mm or greater on the PCG. Distinct S4 was defined as S4 with an amplitude of 2.0 mm or greater, which is usually recognizable by auscultation. According to the rhythm and presence or absence of S4, the patients were divided into three groups, namely, sinus rhythm (SR) with S4, SR without S4, and non-SR. Non-SR consisted of atrial fibrillation, atrial flutter, and atrial tachycardia. Thirty-six patients were in SR and the remaining 40 patients were in non-SR. In the 36 patients in SR, S4 was shown by PCG to be present in 17 patients (47%), and distinct S4 was recognized in 7 patients (19%) by auscultation. In patients who were in SR, those with S4 had higher systolic blood pressure (124 ± 15 vs. 99 ± 8 mmHg, P < 0.001), lower level of plasma B-type natriuretic peptide (308 [interquartile range (IQR): 165, 354] vs. 508 [389, 765] pg/mL, P = 0.034) and lower level of high-sensitivity cardiac troponin T (0.068 [0.046, 0.089] vs. 0.109 [0.063, 0.148] ng/mL, P = 0.042) than those without S4. There was no significant difference in left atrium (LA) volume index or LA reservoir strain between patients with S4 and without S4. Patients with S4 had more preserved LA systolic function than those without S4 (peak atrial filling velocity: 53 ± 25 vs. 34 ± 9 cm/s, P = 0.033; LA contractile strain: 4.1 ± 2.1 vs. 1.6 ± 2.0%, P = 0.012). Patients in SR without S4 had worse short-term prognosis compared with the other two groups (generalized Wilcoxon test, P = 0.033).

CONCLUSIONS

S4 was present in 47% of the patients in SR with ATTRwt-CM. Patients in SR without S4 had more impaired LA systolic function than those in SR with S4. The absence of S4 portends a poor short-term prognosis in patients with ATTRwt-CM.

Distinctive Deposition Patterns of Sporadic Transthyretin-Derived Amyloidosis in the Atria: A Forensic Autopsy-Based Study

Left-to-right differences in the histopathologic patterns of transthyretin-derived amyloid (ATTR) deposition in the atria of older adults have not yet been investigated. Hence, this study evaluated heart specimens from 325 serial autopsy subjects. The amount of ATTR deposits in the seven cardiac regions, including both sides of atria and atrial appendages, was evaluated semiquantitatively. Using digital pathology, we quantitatively evaluated the immunohistochemical deposition burden of ATTR in the myocardium. We identified 20 sporadic ATTR cardiac amyloidosis cases (nine males). All patients had ATTR deposition in the left atrial regions of the myocardium. In the semiquantitative analysis, 14 of the 20 cases showed more severe ATTR deposition on the left atrial regions than on the right side, with statistically significant differences in the pathology grading (p < 0.01 for both the atrium and atrial appendage). Quantitative analysis further supported the difference. Moreover, six had ATTR deposition in the epineurium and/or neural fibers of the atria. Cluster analysis revealed that ATTR deposition in the myocardium was significantly more severe in males than in females. The heterogeneous distribution of amyloid deposits between atria revealed in this study may impair the orderly transmission of the cardiac conduction system and induce arrhythmias, which may be further aggravated by additional neuropathy in the advanced phase. This impairment could be more severe among males. These findings emphasize that atrial evaluation is important for individuals with sporadic ATTR cardiac amyloidosis, particularly for early detection.

Arrhythmic Risk Stratification in Cardiac Amyloidosis: A Review of the Current Literature

Cardiac amyloidosis is the most frequent infiltrative disease caused by the deposition of misfolded proteins in the cardiac tissue, leading to heart failure, brady- and tachyarrhythmia and death. Conduction disorders, atrial fibrillation (AF) and ventricular arrhythmia (VA) significantly impact patient outcomes and demand recognition. However, several issues remain unresolved regarding early diagnosis and optimal management. Extreme bradycardia is the most common cause of arrhythmic death, while fast and sustained VAs can be found even in the early phases of the disease. Risk stratification and the prevention of sudden cardiac death are therefore to be considered in these patients, although the time for defibrillator implantation is still a subject of debate. Moreover, atrial impairment due to amyloid fibrils is associated with an increased risk of AF resistant to antiarrhythmic therapy, as well as recurrent thromboembolic events despite adequate anticoagulation. In the last few years, the aging of the population and progressive improvements in imaging methods have led to increases in the diagnosis of cardiac amyloidosis. Novel therapies have been developed to improve patients' functional status, quality of life and mortality, without data regarding their effect on arrhythmia prevention. In this review, we consider the latest evidence regarding the arrhythmic risk stratification of cardiac amyloidosis, as well as the available therapeutic strategies.

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.

Functional Mitral Regurgitation and Heart Failure With Preserved Ejection Fraction: Clinical Implications and Management

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent and associated with worse cardiovascular outcomes. The pathophysiology of HFpEF mostly relies on the development of elevated left ventricle filling pressure, diastolic dysfunction, and atrial dilatation and impairment. This dynamic process may eventually lead to the development of functional mitral regurgitation (MR), characterized by mitral annular dilatation and consequent leaflet remodeling, in the context of preserved left ventricular ejection fraction. These observations highlight the possible common pathophysiology of MR and HFpEF. However, less is known about the prevalence and the clinical value of MR in the context of HFpEF. This review aims to provide an overview of the association and interplay between functional MR and HFpEF, discuss the underlying mechanisms that are common to these diseases, and summarize potential targeted pharmacological treatments.

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.

Automatic 3D left atrial strain extraction framework on cardiac computed tomography

BACKGROUND AND OBJECTIVE

Strain analysis provides insights into myocardial function and cardiac condition evaluation. However, the anatomical characteristics of left atrium (LA) inherently limit LA strain analysis when using echocardiography. Cardiac computed tomography (CT) with its superior spatial resolution, has become critical for in-depth evaluation of LA function. Recent studies have explored the feasibility of CT-derived strain; however, they relied on manually selected regions of interest (ROIs) and mainly focused on left ventricle (LV). This study aimed to propose a first-of-its-kind fully automatic deep learning (DL)-based framework for three-dimensional (3D) LA strain extraction on cardiac CT.

METHODS

A total of 111 patients undergoing ECG-gated contrast-enhanced CT for evaluating subclinical atrial fibrillation (AF) were enrolled in this study. We developed a 3D strain extraction framework on cardiac CT images, containing a 2.5D GN-U-Net network for LA segmentation, axis-oriented 3D view extraction, and LA strain measure. The segmentation accuracy was evaluated using Dice similarity coefficient (DSC). The model-extracted LA volumes and emptying fraction (EF) were compared with ground-truth measurements using intraclass correlation coefficient (ICC), correlation coefficient (r), and Bland-Altman plot (B-A). The automatically extracted LA strains were evaluated against the LA strains measured from 2D echocardiograms. We utilized this framework to gauge the effect of AF burden on LA strain, employing the atrial high rate episode (AHRE) burden as the measurement parameter.

RESULTS

The GN-U-Net LA segmentation network achieved a DSC score of 0.9603 on the test set. The framework-extracted LA estimates demonstrated excellent ICCs of 0.949 (95 % CI: 0.93-0.97) for minimal LA volume, 0.904 (95 % CI: 0.86-0.93) for maximal LA volume, and 0.902 (95 % CI: 0.86-0.93) for EF, compared with expert measurements. The framework-extracted LA strains demonstrated moderate agreement with the LA strains based on 2D echocardiography (ICCs >0.703). Patients with AHRE > 6 min had significantly lower global strain and LAEF, as extracted by the framework than those with AHRE ≤ 6 min.

CONCLUSION

The promising results highlighted the feasibility and clinical usefulness of automatically extracting 3D LA strain from CT images using a DL-based framework. This tool could provide a 3D-based alternative to echocardiography for assessing LA function.

Left atrial structural and functional remodelling in Fabry disease and cardiac amyloidosis: A comparative analysis

BACKGROUND

Fabry disease (FD) and transthyretin cardiac amyloidosis (TTR CA) are cardiomyopathies with hypertrophic phenotype that share several features, including left atrial (LA) enlargement and dysfunction, but direct comparative data are lacking. Aim of the present study was to perform a comparative analysis of LA remodelling between the two diseases.

METHODS AND RESULTS

In this prospective study, a total of 114 patients (31 FD and 83 TTR CA) were included; all of them had left ventricular hypertrophy (LVH), defined as left ventricular (LV) wall thickness ≥ 12 mm. Despite similar degree of LVH, patients with TTR CA showed worse LV systolic and diastolic function. LA maximal volume index was not significantly different between the two groups (p = 0.084), while patients with TTR CA showed larger LA minimal volume index (p = 0.001). Moreover, all phases of LA mechanics were more impaired in the TTR CA group vs FD (reservoir: 6.9[4.2-15.5] vs 19.0[15.5-29.5], p < 0.001). After excluding patients with atrial fibrillation (AF), these differences remained clearly significant. In multivariable regression analyses, LA reservoir strain showed an independent correlation with TTR CA, controlling for demographic characteristics, AF and LV systolic and diastolic performance (p ≤ 0.001), whereas LV global longitudinal strain did not. Finally, among echocardiographic parameters, LA function demonstrated the highest accuracy in discriminating the two diseases.

CONCLUSIONS

TTR CA is characterized by a more advanced LA structural and functional remodelling in comparison to patients with FD and similar degree of LVH. The association between TTR CA and LA dysfunction remains consistent after adjustment for potential confounders.

Breakthrough advances enhancing care in ATTR amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) has been traditionally considered a rare and inexorably fatal condition. ATTR-CM now is an increasingly recognized cause of heart failure (HF) and mortality worldwide with effective pharmacological treatments. Advances in non-invasive diagnosis, coupled with the development of effective treatments, have transformed the diagnosis of ATTR-CM, which is now possible without recourse to endomyocardial biopsy in ≈70 % of cases. Many patients are now diagnosed at an earlier stage. Echocardiography and cardiac magnetic resonance have enabled identification of patients with possible ATTR-CM and more accurate prognostic stratification. Although radionuclide scintigraphy with 'bone' tracers has an established diagnostic value, the diagnostic performance of the bone tracers validated for non-invasive confirmation of ATTR-CM may not be equal. Characterising the wider clinical phenotype of patients with ATTR-CM has enabled identification of features with potential for earlier diagnosis such as carpal tunnel syndrome. Therapies able to slow or halt ATTR-CM progression and increase survival are now available and there is also evidence that patients may benefit from specific conventional HF medications. Cutting-edge research in the field of antibody-mediated removal of ATTR deposits compellingly suggest that ATTR-CM is a truly reversible disorder, bringing hope for patients even with advanced disease. A wide horizon of possibilities is unfolding and awaits discovery.

Incremental diagnostic and prognostic utility of left atrial deformation in heart failure using speckle tracking echocardiography

Left atrium (LA) is a very important component of cardiovascular performance. The assessment of LA function has gathered the interest with expanding research supporting the utility as a biomarker for outcomes in heart failure (HF). Echocardiography is the main imaging modality which helps in a qualitative and quantitative assessment of the LA size and function. Recent advances in probe technology and software analysis have provided a better understanding of LA anatomy, physiology, pathology, and function. A variety of parameters have been defined as markers of LA function but there is no single parameter that best defines LA function. Speckle tracking echocardiography-derived analysis of LA deformation provides a window on all phases of LA function (reservoir, conduit, and booster pump). There is accumulative published data that supported the diagnostic and prognostic values of LA deformation integration during echo assessment of LA in HF. This review article summarized the clinical utility of LA deformation that may help in prediction, diagnosis, categorization, risk stratification, and guiding the proper selection of therapy in HF patients in daily practice.

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.

Cardiac magnetic resonance feature tracking derived left atrial strain in the diagnosis of patients with constrictive pericarditis and restrictive cardiomyopathy

Objective

To explore the diagnostic value of cardiac magnetic resonance feature tracking (CMR-FT) divided left atrial (LA) strain in differentiating constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM).

Methods

Patients with CP (n = 40) and RCM (n = 40), and another 40 normal control group were retrospectively enrolled over a period of 8 years at a tertiary cardiac centre. Left ventricular (LV) and biatrial strain and strain rate (SR) were measured. Atrial strain was used to differentiate between patients with CP and RCM. Then, patients were grouped according to their left ventricular ejection fraction (LVEF), either ≥50% or < 50%. A deeper analysis was done to evaluate the diagnostic value of atrial strain in these subgroups. Receiver operating characteristic curves (ROC) were used to assess the accuracy of myocardial strain based on CMR FT for the differential diagnosis of CP and RCM.

Results

LV and LA strain and SR were significantly lower in patients with CP and RCM than those in the normal controls (P < 0.05). LA strain and SR were significantly lower in the RCM group than in the CP group (P < 0.05). In patients with either LVEF≥50% or＜50%, LA strain were lower in the RCM group than in the CP group (P < 0.05). ROC analysis showed that LA stored strain (LA-εs) had a good differential diagnostic value for CP and RCM, with an area under the curve (AUC) of 0.811 and an optimal cutoff value of 6.98%, above this value it tends to develop CP. Further, an excellent differential diagnostic value was found in patients with LVEF＜50%, with an AUC of 0.955.

Conclusion

LA strain analysis obtained by CMR-FT provides good differential diagnostic value for distinguishing CP from RCM, especially in patients with LVEF＜50%.

Clinical and Prognostic Implications of Right Ventricular Uptake on Bone Scintigraphy in Transthyretin Amyloid Cardiomyopathy

BACKGROUND

The extent of myocardial bone tracer uptake with technetium pyrophosphate, hydroxymethylene diphosphonate, and 3,3-diphosphono-1,2-propanodicarboxylate in transthyretin amyloid cardiomyopathy (ATTR-CM) might reflect cardiac amyloid burden and be associated with outcome.

METHODS

Consecutive patients with ATTR-CM who underwent diagnostic bone tracer scintigraphy with acquisition of whole-body planar and cardiac single-photon emission computed tomography (SPECT) images from the National Amyloidosis Centre and 4 Italian centers were included. Cardiac uptake was defined according to the Perugini classification: 0=absent cardiac uptake; 1=mild uptake less than bone; 2=moderate uptake equal to bone; and 3=high uptake greater than bone. Extent of right ventricular (RV) uptake was defined as focal (basal segment of the RV free wall only) or diffuse (extending beyond basal segment) on the basis of SPECT imaging. The primary outcome was all-cause mortality.

RESULTS

Among 1422 patients with ATTR-CM, RV uptake accompanying left ventricular uptake was identified by SPECT imaging in 100% of cases at diagnosis. Median follow-up in the whole cohort was 34 months (interquartile range, 21 to 50 months), and 494 patients died. By Kaplan-Meier analysis, diffuse RV uptake on SPECT imaging (n=936) was associated with higher all-cause mortality compared with focal (n=486) RV uptake (77.9% versus 22.1%; P<0.001), whereas Perugini grade was not associated with survival (P=0.27 in grade 2 versus grade 3). On multivariable analysis, after adjustment for age at diagnosis (hazard ratio [HR], 1.03 [95% CI, 1.02-1.04]; P<0.001), presence of the p.(V142I) TTR variant (HR, 1.42 [95% CI, 1.20-1.81]; P=0.004), National Amyloidosis Centre stage (each category, P<0.001), stroke volume index (HR, 0.99 [95% CI, 0.97-0.99]; P=0.043), E/e' (HR, 1.02 [95% CI, 1.007-1.03]; P=0.004), right atrial area index (HR, 1.05 [95% CI, 1.02-1.08]; P=0.001), and left ventricular global longitudinal strain (HR, 1.06 [95% CI, 1.03-1.09]; P<0.001), diffuse RV uptake on SPECT imaging (HR, 1.60 [95% CI, 1.26-2.04]; P<0.001) remained an independent predictor of all-cause mortality. The prognostic value of diffuse RV uptake was maintained across each National Amyloidosis Centre stage and in both wild-type and hereditary ATTR-CM (P<0.001 and P=0.02, respectively).

CONCLUSIONS

Diffuse RV uptake of bone tracer on SPECT imaging is associated with poor outcomes in patients with ATTR-CM and is an independent prognostic marker at diagnosis.

Characterization of Transthyretin Mutation G47V Associated with Hereditary Cardiac Amyloidosis

INTRODUCTION

Amyloidosis caused by TTR mutations (ATTRv) is a rare inherited and autosomal dominant disease. More than 150 mutants of TTR have been reported, whereas some of them remain to be investigated.

METHODS

A 52-year-old male presented with heart failure and clinically diagnosed ATTR cardiac amyloidosis (ATTR-CA) was recruited. Whole-exome sequencing (WES) was performed. Biochemical and biophysical experiments characterized protein stability using urea-mediated tryptophan fluorescence. Drug response was analyzed by fibril formation assay. Finally, tetramer TTR concentration in patient's serum sample was measured by ultra-performance liquid chromatography (UPLC).

RESULTS

For the proband, WES revealed a mutation (c.200G>T; p.Gly67Val and referred to as G47V) in TTR gene. Biochemical and biophysical kinetics study showed that the thermodynamic stability of G47V-TTR (Cm = 2.4 m) was significantly lower than that of WT-TTR (Cm = 3.4 m) and comparable to that of L55P-TTR (Cm = 2.3 m), an early age-of-onset mutation. G47V:WT-TTR heterozygous tetramer kinetic stability (t1/2 = 1.4 h) was further compromised compared to that of the homozygous G47V-TTR (t1/2 = 3.1 h). Among three small molecule stabilizers, AG10 exhibited the best inhibition of the fibrillation of G47V-TTR homozygous protein. Using a UPLC assay, nearly 40% of TTR in this patient was calculated to be non-tetrameric.

CONCLUSION

In this work, we reported a patient presented early onset of clinically typical ATTR-CA due to G47V-TTR mutation. Our work for the first time not only characterized the biochemical properties of G47V-TTR mutation, but also provided hints for the pathogenicity of this mutation.

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.

Deep phenotyping of p.(V142I)-associated variant transthyretin amyloid cardiomyopathy: Distinct from wild-type transthyretin amyloidosis?

AIMS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognized cause of heart failure. A total of 3-4% of individuals of African descent carry a TTR gene mutation encoding the p.(V142I) variant, a powerful risk factor for development of variant ATTR-CM (ATTRv-CM); this equates to 1.6 million carriers in the United States. We undertook deep phenotyping of p.(V142I)-ATTRv-CM and comparison with wild-type ATTR-CM (ATTRwt-CM).

METHODS AND RESULTS

A retrospective study of 413 patients with p.(V142I) ATTRv-CM who attended the UK National Amyloidosis Centre (NAC) was conducted. Patients underwent evaluation at time of diagnosis, including clinical, echocardiography, and biomarker analysis; a subgroup had cardiac magnetic resonance (CMR) imaging. A total of 413 patients with ATTRwt-CM, matched for independent predictors of prognosis (age, NAC Stage, decade of first presentation), were used as a comparator group. At time of diagnosis, patients with ATTRv-CM had significant functional impairment by New York Heart Association classification (NHYA class ≥ III; 38%) and 6-min walk test distance (median 276 m). Median 5-year survival in ATTRv-CM patients was 31 versus 59 months in matched patients with ATTRwt-CM (p < 0.001). Patients with ATTRv-CM had significant impairment of functional parameters by echocardiography including biventricular impairment, high burden of regurgitant valvular disease and low cardiac output. Multivariable analysis revealed the prognostic importance of right ventricular dysfunction. CMR and histological analysis revealed myocyte atrophy and widespread myocardial infiltration in ATTRv-CM.

CONCLUSION

p.(V142I)-ATTRv-CM has an aggressive phenotype characterized by myocyte loss and widespread myocardial infiltration which may account for frequent biventricular failure and poor prognosis in this ATTR-CM genotypic subgroup.

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.

Valvular heart disease in patients with cardiac amyloidosis

Cardiac amyloidosis (CA) is an underdiagnosed condition caused by the deposition of misfolded proteins, namely immunoglobulin light chains and transthyretin, in the extracellular spaces of the heart. Any cardiovascular structure can be affected by amyloid infiltration, including the valves. Amyloid accumulation within the cardiac valves may lead to their structural and functional impairment, with a profound impact on patients' prognosis and quality of life. The most common forms of valvular disease in CA are aortic stenosis (AS), mitral regurgitation (MR), and tricuspid regurgitation (TR). CA and AS share similar risk factors, disease mechanisms, and remodeling patterns, which make their diagnosis particularly challenging. Patients with both CA and AS experience worse outcomes than CA or AS alone, and transcatheter aortic valve replacement may represent a useful therapeutic strategy in this population. Data on MR and TR are quite limited and mainly coming from case reports or small series. This review paper will summarize our current understanding on the epidemiology, disease mechanisms, echocardiographic features, clinical implications, and therapeutic options of AS, MR, and TR in patients with CA.

Hereditary Transthyretin Amyloidosis: How to Differentiate Carriers and Patients Using Speckle-Tracking Echocardiography

BACKGROUND

Hereditary transthyretin amyloidosis is a rare disease caused by transthyretin (TTR) gene mutations. The aim of our study was to identify early signs of cardiac involvement in patients with a TTR gene mutation in order to differentiate carriers from patients with neurological or cardiac disease.

METHODS

A case-control study was carried out on 31 subjects with the TTR mutation. Patients were divided into three groups: 23% with cardiac amyloidosis and polyneuropathy (group A), 42% with only polyneuropathy (group B) and 35% carriers (group C). Speckle-tracking echocardiography (left-ventricular global longitudinal strain-GLS, atrial stiffness) was performed in all patients. The apical/basal longitudinal strain ratio (SAB) and relative apical sparing (RAS) were assessed in all subjects.

RESULTS

Analyzing groups C and B, we only found a significant difference in the SAB (p-value 0.001) and RAS (p-value 0.039). These parameters were significantly more impaired in group A compared to group B (SAB p-value 0.008; RAS p-value 0.002). Also, atrial stiffness was significantly impaired in groups A and B compared to group C.

CONCLUSIONS

Our study suggests the diagnostic role of the SAB and RAS in cardiac amyloidosis. The SAB and RAS showed a gradual increase from carriers to patients with neurological and cardiac diseases. Thus, these parameters, in addition to atrial stiffness, could be used to monitor carriers. More extensive data are needed.

Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023

Central Illustration : Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023 Proposal for including strain in the integrated diastolic function assessment algorithm, adapted from Nagueh et al.67 Am: mitral A-wave duration; Ap: reverse pulmonary A-wave duration; DD: diastolic dysfunction; LA: left atrium; LASr: LA strain reserve; LVGLS: left ventricular global longitudinal strain; TI: tricuspid insufficiency. Confirm concentric remodeling with LVGLS. In LVEF, mitral E wave deceleration time < 160 ms and pulmonary S-wave < D-wave are also parameters of increased filling pressure. This algorithm does not apply to patients with atrial fibrillation (AF), mitral annulus calcification, > mild mitral valve disease, left bundle branch block, paced rhythm, prosthetic valves, or severe primary pulmonary hypertension.

Atrial Strain Assessment for the Early Detection of Cancer Therapy-Related Cardiac Dysfunction in Breast Cancer Women (The STRANO STUDY: Atrial Strain in Cardio-Oncology)

Left ventricular global longitudinal strain (GLS) has an important role in the diagnosis of cancer therapy-related cardiac dysfunction (CTRCD). Little is known about the role of atrial function in diagnosing CTRCD. The aim of our study was to assess the impact of anti-cancer drugs on atrial function measured by speckle-tracking echocardiography in breast cancer women. A prospective multicenter study was conducted enrolling 169 breast cancer women treated with anthracyclines. A cardiological evaluation including an electrocardiogram and echocardiogram with an analysis of GLS, left atrial (LA) strain, and LA stiffness (LASi) was performed at baseline (T0), 3 (T1), and 6 months (T2) after starting chemotherapy. The patients were divided into two groups: patients with asymptomatic mild cardiotoxicity at T1 (with a relative reduction in GLS > 15%; Group 1) and those without (Group 2). We did not find a significant change in left ventricular ejection fraction (LVEF) at T1 and T2; we found a significant change in GLS (p-value < 0.0001) in the peak atrial longitudinal strain (PALS) and in LASi (p-value < 0.0001). Impairment of atrial function was greater in Group 1 compared to Group 2. A PALS variation > 20.8% identified patients who were most likely to develop asymptomatic mild cardiotoxicity [AUC 0.62; CI (0.51-0.73) p = 0.06, sensitivity 45%, specificity 69.5%]. Conclusions: PALS and LASi significantly change during chemotherapy in association with GLS. Atrial strain is an additional parameter that could be measured together with GLS to detect cardiotoxicity early.

Left Atrial Phasic Function via Cardiac Magnetic Resonance Imaging in Patients with Duchenne Muscular Dystrophy

Cardiac dysfunction is a leading cause of morbidity and mortality in Duchenne muscular dystrophy (DMD). Left atrial (LA) function is a poorly understood concept in this patient population, and research suggests underlying structural changes that could affect atrial function. Cardiac magnetic resonance (CMR) imaging may provide an important non-invasive approach to evaluating LA function. This study was a single center retrospective review of consecutive CMR studies over a 1 year period comparing LA phasic function within a cohort of DMD patients, and to those with structurally and functionally normal hearts. LA strain measurements including global reservoir, conduit, boost-pump strain, and LA volumes were obtained retrospectively. Spearman correlation analyses were performed on atrial strain measurements. 107 DMD and 79 normal CMR studies were included. The DMD cohort had worse systolic function (p < 0.001), smaller indexed max LA and left ventricular (LV) volumes (p < 0.001), and greater LA emptying fraction (p < 0.001). In the DMD cohort, emptying fraction decreased with advanced patient age (p < 0.001) and diminishing systolic function (p < 0.001). DMD patients with moderate or severe LV dysfunction demonstrated lower LA emptying fraction (p = 0.002), more impaired 2-chamber LA reservoir (p = 0.003), and LA pump (p = 0.006) and conduit strain (p = 0.018). DMD patients with preserved function have lower indexed LA volumes with higher LA emptying fractions than controls. Progression of disease and age is associated with decreased LA emptying fraction with early manifestations in reservoir and conduit strain. These findings suggest that strain markers of LA compliance and early left ventricular relaxation are associated with worsening cardiomyopathy in the DMD population.

Prognostic Utility of Left Atrial Strain to Predict Thrombotic Events and Mortality in Amyloid Cardiomyopathy

BACKGROUND

There is currently no thromboembolic risk stratification tool for amyloid cardiomyopathy (ACM) and the current survival staging systems for ACM have only modest discriminatory ability.

OBJECTIVES

This study aims to evaluate the prognostic value of left atrial (LA) strain to predict incident thrombotic event (TE) and improve survival staging systems in ACM.

METHODS

The authors identified patients with light chain (AL) or transthyretin (ATTR) ACM and no history of atrial fibrillation (AF) at diagnosis. Three components of LA strain (reservoir, conduit, and contractile) were measured and their predictive value for TE and mortality was determined. In addition, the authors evaluated the incremental utility of adding LA strain to current prognostic staging systems.

RESULTS

The authors included 448 patients (50.2% AL; 49.8% ATTR) with median follow-up of 3.8 years. There were 64 (14.3%) TE cases, 103 (23%) AF cases, and 234 (52.2%) deaths. Notably, 75% of TEs occurred without preceding AF documented. LA strain reservoir and LA contractile strain significantly predicted both events: HRs for TE were 2.22 (95% CI: 1.27-3.85; P = 0.006) and 2.63 (95% CI: 1.25-5.00; P = 0.01) per SD decrease in LA strain reservoir and LA contractile strain, respectively. The respective HRs for mortality were 1.32 (95% CI: 1.09-1.59; P < 0.001) and 1.49 (95% CI: 1.22-1.75; P < 0.001). Also, LA strain reservoir and LA contractile strain significantly improved the C-statistics of the Mayo AL staging from 0.65 to 0.68 and 0.70, respectively (P ≤ 0.02); Mayo ATTR staging (0.73 to 0.79 and 0.80, respectively; P < 0.001); and Gillmore ATTR staging (0.70 to 0.79 and 0.80, respectively; P < 0.001).

CONCLUSIONS

LA strain identifies ACM patients with high thrombotic risk (independent of AF) and improves current ACM-specific survival staging.

Cardiac amyloidosis and aortic stenosis: a state-of-the-art review

Cardiac amyloidosis is caused by the extracellular deposition of amyloid fibrils in the heart, involving not only the myocardium but also any cardiovascular structure. Indeed, this progressive infiltrative disease also involves the cardiac valves and, specifically, shows a high prevalence with aortic stenosis. Misfolded protein infiltration in the aortic valve leads to tissue damage resulting in the onset or worsening of valve stenosis. Transthyretin cardiac amyloidosis and aortic stenosis coexist in patients > 65 years in about 4-16% of cases, especially in those undergoing transcatheter aortic valve replacement. Diagnostic workup for cardiac amyloidosis in patients with aortic stenosis is based on a multi-parametric approach considering clinical assessment, electrocardiogram, haematologic tests, basic and advanced echocardiography, cardiac magnetic resonance, and technetium labelled cardiac scintigraphy like technetium-99 m (99mTc)-pyrophosphate, 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid, and 99mTc-hydroxymethylene diphosphonate. However, a biopsy is the traditional gold standard for diagnosis. The prognosis of patients with coexisting cardiac amyloidosis and aortic stenosis is still under evaluation. The combination of these two pathologies worsens the prognosis. Regarding treatment, mortality is reduced in patients with cardiac amyloidosis and severe aortic stenosis after undergoing transcatheter aortic valve replacement. Further studies are needed to confirm these findings and to understand whether the diagnosis of cardiac amyloidosis could affect therapeutic strategies. The aim of this review is to critically expose the current state-of-art regarding the association of cardiac amyloidosis with aortic stenosis, from pathophysiology to treatment.

Advance of echocardiography in cardiac amyloidosis

Cardiac amyloidosis (CA) occurs when the insoluble fibrils formed by misfolded precursor proteins deposit in cardiac tissues. The early clinical manifestations of CA are not evident, but it is easy to progress to refractory heart failure with an inferior prognosis. Echocardiography is the most commonly adopted non-invasive modality of imaging to visualize cardiac structures and functions, and the preferred modality in the evaluation of patients with cardiac symptoms and suspected CA, which plays a vital role in the diagnosis, prognosis, and long-term management of CA. The present review summarizes the echocardiographic manifestations of CA, new echocardiographic techniques, and the application of multi-parametric echocardiographic models in CA diagnosis.

Exercise training decreases the load and changes the content of circulating SDS-resistant protein aggregates in patients with heart failure with reduced ejection fraction

BACKGROUND

Heart failure (HF) often disrupts the protein quality control (PQC) system leading to protein aggregate accumulation. Evidence from tissue biopsies showed that exercise restores PQC system in HF; however, little is known about its effects on plasma proteostasis.

AIM

To determine the effects of exercise training on the load and composition of plasma SDS-resistant protein aggregates (SRA) in patients with HF with reduced ejection fraction (HFrEF).

METHODS

Eighteen patients with HFrEF (age: 63.4 ± 6.5 years; LVEF: 33.4 ± 11.6%) participated in a 12-week combined (aerobic plus resistance) exercise program (60 min/session, twice per week). The load and content of circulating SRA were assessed using D2D SDS-PAGE and mass spectrometry. Cardiorespiratory fitness, quality of life, and circulating levels of high-sensitive C-reactive protein, N-terminal pro-B-type natriuretic peptide (NT-proBNP), haptoglobin and ficolin-3, were also evaluated at baseline and after the exercise program.

RESULTS

The exercise program decreased the plasma SRA load (% SRA/total protein: 38.0 ± 8.9 to 36.1 ± 9.7%, p = 0.018; % SRA/soluble fraction: 64.3 ± 27.1 to 59.8 ± 27.7%, p = 0.003). Plasma SRA of HFrEF patients comprised 31 proteins, with α-2-macroglobulin and haptoglobin as the most abundant ones. The exercise training significantly increased haptoglobin plasma levels (1.03 ± 0.40 to 1.11 ± 0.46, p = 0.031), while decreasing its abundance in SRA (1.83 ± 0.54 × 1011 to 1.51 ± 0.59 × 1011, p = 0.049). Cardiorespiratory fitness [16.4(5.9) to 19.0(5.2) ml/kg/min, p = 0.002], quality of life, and circulating NT-proBNP [720.0(850.0) to 587.0(847.3) pg/mL, p = 0.048] levels, also improved after the exercise program.

CONCLUSION

Exercise training reduced the plasma SRA load and enhanced PQC, potentially via haptoglobin-mediated action, while improving cardiorespiratory fitness and quality of life of patients with HFrEF.

Right ventricular to pulmonary artery coupling and outcome in patients with cardiac amyloidosis

AIMS

To investigate the prognostic value of the right ventricle-to-pulmonary artery (RV-PA) coupling in patients with either transthyretin (ATTR) or immunoglobulin light-chain (AL) cardiac amyloidosis (CA).

METHODS AND RESULTS

Overall, 283 patients with CA from 3 Italian high-volume centres were included (median age 76 years; 63% males; 53% with ATTR-CA, 47% with AL-CA). The RV-PA coupling was evaluated by using the tricuspid annular plane systolic excursion/pulmonary artery systolic pressure (TAPSE/PASP) ratio. The median value of TAPSE/PASP was 0.45 (0.33-0.63) mm/mmHg. Patients with a TAPSE/PASP ratio <0.45 were older, had lower systolic blood pressure, more severe symptoms, higher cardiac troponin and N-terminal pro-B-type natriuretic peptide levels, greater left ventricular (LV) thickness, and worse LV systolic and diastolic function. A TAPSE/PASP ratio <0.45 was independently associated with a higher risk of all-cause death or heart failure (HF) hospitalization [hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.32-2.96; P = 0.001] and all-cause death (HR 2.18, 95% CI 1.31-3.62; P = 0.003). The TAPSE/PASP ratio reclassified the risk of both endpoints [net reclassification index 0.46 (95% CI 0.18-0.74) P = 0.001 and 0.49 (0.22-0.77) P < 0.001, respectively], while TAPSE or PASP alone did not (all P > 0.05). The prognostic impact of the TAPSE/PASP ratio was significant both in AL-CA patients (HR for the composite endpoint 2.47, 95% CI 1.58-3.85; P < 0.001) and in ATTR-CA (HR 1.81, 95% CI 1.11-2.95; P = 0.017). The receiver operating characteristic curve showed that the optimal cut-off for predicting prognosis was 0.47 mm/mmHg.

CONCLUSION

In patients with CA, RV-PA coupling predicted the risk of mortality or HF hospitalization. The TAPSE/PASP ratio was more effective than TAPSE or PASP in predicting prognosis.

The correlation of left atrial dysfunction and amyloid load in patients with immunoglobulin light-chain cardiac amyloidosis: a 3T cardiac magnetic resonance study

OBJECTIVE

To investigate the left atrial (LA) changes in immunoglobulin light-chain cardiac amyloidosis (AL-CA) patients with different risk stratifications and to explore the correlation between LA function and the degree of amyloid load using cardiac magnetic resonance (CMR) imaging.

METHODS

Forty-three AL-CA patients were retrospectively enrolled and were divided into low-to-moderate-risk group (n = 16, increased NT-proBNP or troponin I, or both normal) and high-risk group (n = 27, increased NT-proBNP and troponin I). 20 healthy individuals matched for age and gender were included. The function, myocardial deformation of left heart, and left ventricular (LV) tissue characterization among the three groups were compared. The correlation between LA function and LV tissue characterization was investigated.

RESULTS

Compared with the controls, the AL-CA patients had a larger LA volume, lower left atrial emptying fraction (LAEF) and impaired left atrial strain (LAS). The high-risk group exhibited lower reservoir and booster function and increased LV extracellular volume (LV-ECV) than the low-to-moderate-risk group (p < 0.05). LV-ECV was significantly correlated with LAS and LAEF (all p < 0.05) but not LAEFconduit. The LAS and LAEF had a good diagnostic ability for risk stratification of AL-CA patients (area under the curve, 0.70 ~ 0.72).

CONCLUSION

High-risk AL-CA patients showed more severe LA function impairment than low-to-moderate-risk AL-CA patients. LAS and LAEF were closely associated with LV-ECV in AL-CA patients, LAS and LAEF exhibited good capability to differentiate AL-CA patients of different risk stratifications.

ADVANCES IN KNOWLEDGE

CMR-derived LAS and LAEF were correlated with amyloid load, allowing for differentiation of AL-CA patients at different risk stages.

Left Atrial Strain Imaging by Speckle Tracking Echocardiography: The Supportive Diagnostic Value in Cardiac Amyloidosis and Hypertrophic Cardiomyopathy

Background: Left atrial (LA) function is crucial for assessing left ventricular filling in various cardiovascular conditions. Cardiac Amyloidosis (CA) is characterized by atrial myopathy and LA function impairment, with diastolic dysfunction up to restrictive filling pattern, leading to progressive heart failure and arrhythmias. This study evaluates LA function and deformation using speckle tracking echocardiography (STE) in patients with CA compared to a cohort of patients with sarcomeric Hypertrophic Cardiomyopathy (HCM) and a control group. Methods: We conducted a retrospective, observational study (from January 2019 to December 2022) including a total of 100 patients: 33 with ATTR-CA, 34 with HCMs, and 33 controls. Clinical evaluation, electrocardiograms, and transthoracic echocardiography were performed. Echocardiogram images were analyzed in post-processing using EchoPac software for LA strain quantification, including LA-reservoir, LA-conduit, and LA-contraction strain. Results: The CA group exhibited significantly impaired LA function compared to HCMs and control groups, with LA-reservoir median values of -9%, LA-conduit -6.7%, and LA-contraction -3%; this impairment was consistent even in the CA subgroup with preserved ejection fraction. LA strain parameters correlated with LV mass index, LA volume index, E/e', and LV-global longitudinal strain and were found to be associated with atrial fibrillation and exertional dyspnea. Conclusions: LA function assessed by STE is significantly impaired in CA patients compared to HCMs patients and healthy controls. These findings highlight the potential supportive role of STE in the early detection and management of the disease.

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.

Association of Left Atrial Hemodynamics by Magnetic Resonance Imaging With Long-Term Outcomes in Patients With Cardiac Amyloidosis

BACKGROUND

Left atrial (LA) function and strain patterns by magnetic resonance imaging (MRI) have been investigated as markers of several cardiovascular pathologies, including cardiac amyloidosis (CA). However, associations with clinical outcomes have not been investigated.

PURPOSE

To compare LA function and strain by MRI in CA patients to a matched cohort of patients without cardiovascular disease (CVD) and evaluate the association with long-term clinical outcomes in CA patients.

STUDY TYPE

Retrospective case control.

POPULATION

A total of 51 patients with CA and 51 age-, gender-, and race-matched controls without CVD who underwent MRI in sinus rhythm.

FIELD STRENGTH/SEQUENCE

ECG-gated balanced steady-state free precession sequence at 1.5 T.

ASSESSMENT

All measurements were completed by one investigator (M.M.B.). LA function and strain parameters were measured including LA indexed minimum and maximum volumes, LA reservoir (R), contractile (CT), and conduit (CD) strain. We compared groups after adjusting for age, hypertension, New York Heart Association class, modified staging system (troponin-I, BNP, estimated GFR) and left ventricular ejection fraction (LVEF) for an endpoint of all-cause mortality and a composite endpoint of heart failure hospitalization (HFH) or death.

STATISTICAL TESTS

Differences between groups were evaluated with t tests for continuous variables or χ² tests for categorical variables. A multivariable regression model was used to assess the associations of the P values-two-sided tests-<0.05 were considered statistically significant.

RESULTS

CA patients with median follow up of 4.9 (8.5) months had significantly lower LA strain and higher LA volumes in comparison to the matched cohort. In the multivariable analysis, only LVEF was significantly associated with death while ƐCT (OR 0.6, CI: 0.41-0.89), indexed minimum LA volume (OR 1.06, CI: 1.02-1.13) and indexed maximum LA volume (OR 1.08, CI: 1.01-1.15) were significantly associated with the composite outcome of death or HFH.

CONCLUSION

In this retrospective study of CA patients, ƐCT and indexed minimum and maximum LA volumes were significantly associated with the composite outcome of death or HFH.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 3.

Risk stratification in transthyretin-related cardiac amyloidosis

Transthyretin related cardiac amyloidosis (TTR-CA) is an infiltrative cardiomyopathy that cause heart failure with preserved ejection fraction, mainly in aging people. Due to the introduction of a non invasive diagnostic algorithm, this disease, previously considered to be rare, is increasingly recognized. The natural history of TTR-CA includes two different stages: a presymptomatic and a symptomatic stage. Due to the availability of new disease-modifying therapies, the need to reach a diagnosis in the first stage has become impelling. While in variant TTR-CA an early identification of the disease may be obtained with a genetic screening in proband's relatives, in the wild-type form it represents a challenging issue. Once the diagnosis has been made, in order to identifying patients with a higher risk of cardiovascular events and death it is necessary to focus on risk stratification. Two prognostic scores have been proposed both based on biomarkers and laboratory findings. However, a multiparametric approach combining information from electrocardiogram, echocardiogram, cardiopulmonary exercise test and cardiac magnetic resonance may be warranted for a more comprehensive risk prediction. In this review, we aim at evaluating a step by step risk stratification, providing a clinical diagnostic and prognostic approach for the management of patients with TTR-CA.

Estimating the Prevalence of Cardiac Amyloidosis in Old Patients with Heart Failure—Barriers and Opportunities for Improvement: The PREVAMIC Study

Background: Cardiac amyloidosis (CA) could be a common cause of heart failure (HF). The objective of the study was to estimate the prevalence of CA in patients with HF. Methods: Observational, prospective, and multicenter study involving 30 Spanish hospitals. A total of 453 patients ≥ 65 years with HF and an interventricular septum or posterior wall thickness > 12 mm were included. All patients underwent a 99mTc-DPD/PYP/HMDP scintigraphy and monoclonal bands were studied, following the current criteria for non-invasive diagnosis. In inconclusive cases, biopsies were performed. Results: The vast majority of CA were diagnosed non-invasively. The prevalence was 20.1%. Most of the CA were transthyretin (ATTR-CM, 84.6%), with a minority of cardiac light-chain amyloidosis (AL-CM, 2.2%). The remaining (13.2%) was untyped. The prevalence was significantly higher in men (60.1% vs 39.9%, p = 0.019). Of the patients with CA, 26.5% had a left ventricular ejection fraction less than 50%. Conclusions: CA was the cause of HF in one out of five patients and should be screened in the elderly with HF and myocardial thickening, regardless of sex and LVEF. Few transthyretin-gene-sequencing studies were performed in older patients. In many patients, it was not possible to determine the amyloid subtype.

A Review of Current and Evolving Imaging Techniques in Cardiac Amyloidosis

Purpose of review

Establishing an early, efficient diagnosis for cardiac amyloid (CA) is critical to avoiding adverse outcomes. We review current imaging tools that can aid early diagnosis, offer prognostic information, and possibly track treatment response in CA.

Recent findings

There are several current conventional imaging modalities that aid in the diagnosis of CA including electrocardiography, echocardiography, bone scintigraphy, cardiac computed tomography (CT), and cardiac magnetic resonance (CMR) imaging. Advanced imaging techniques including left atrial and right ventricular strain, and CMR T1 and T2 mapping as well as ECV quantification may provide alternative non-invasive means for diagnosis, more granular prognostication, and the ability to track treatment response.

Summary

Leveraging a multimodal imaging toolbox is integral to the early diagnosis of CA; however, it is important to understand the unique role and limitations posed by each modality. Ongoing studies are needed to help identify imaging markers that will lead to an enhanced ability to diagnose, subtype and manage this condition.

Racial Differences in Atrial Fibrillation Management Between White Patients and Black Patients in Transthyretin Cardiac Amyloid

Black patients have higher rates of stroke than White patients. Paradoxically, atrial fibrillation (AF) affects twice as many White patients compared with Black patients. Transthyretin cardiac amyloidosis (ATTR-CA) is associated with both AF and strokes. We hypothesized that although Black patients with ATTR-CA have a lower incidence of AF, when diagnosed with AF, they have increased thromboembolic events. Patients with ATTR-CA (n = 558) at 3 international centers were retrospectively identified. We compared baseline characteristics, presence of AF, outcomes of thromboembolism (stroke, transient ischemic attack, and peripheral embolism), major bleed, and mortality by race. Of all patients, 367 of 488 White patients (75%) were diagnosed with AF compared with 39 of 70 Black patients (56%) (p = 0.001). Black patients with AF had a hazard ratio of 5.78 (95% confidence interval 2.30 to 14.50) for time to first thromboembolic event compared with White patients. There were no racial differences in major bleeding. Black patients with AF more often lacked anticoagulation (p = 0.038) and had higher incidence of labile international normalized ratio (p <0.001). In conclusion, these data suggest that although Black patients with ATTR-CA have lower incidence of AF, they have increased thromboembolic events compared with White patients. These findings may be related to treatment discrepancies, time in therapeutic range for warfarin, and disparities in healthcare.

The loss of left atrial contractile function predicts a worse outcome in HFrEF patients

Background

In chronic heart failure, high intracardiac pressures induce a progressive remodeling of small pulmonary arteries up to pulmonary hypertension. At the end of left atrial conduit function, pulmonary and left heart end-systolic pressures equalization might affect left atrial systole. In this single-center prospective study, we aimed to investigate whether peak atrial contraction strain (PACS), measured by speckle tracking echocardiography, was independently associated with prognosis in heart failure with reduced ejection fraction (HFrEF).

Materials and methods

Outpatients with HFrEF and sinus rhythm referred to our echo-labs were enrolled. After clinical and echocardiographic evaluation, off-line speckle tracking echocardiography analysis was performed. Primary and secondary endpoint were cardiovascular death and heart failure hospitalization, respectively. Spline knotted survival model identified the optimal prognostic cut-off for PACS.

Results

The 152 patients were stratified based on PACS <8% (n = 76) or PACS ≥8% (n = 76). Patients with PACS <8% had lower left ventricle and left atrial reservoir strain and higher New York Heart Association (NYHA) class and left atrial volume index (LAVI). Over a mean follow-up of 3.4 ± 2 years, 117 events (51 cardiovascular death, 66 heart failure hospitalizations) were collected. By univariate and multivariate Cox analysis, PACS emerged as a strong and independent predictor of cardiovascular death and heart failure hospitalization, after adjusting for age, sex, left ventricle strain, and E/e', LAVI (HR 0.6 per 5 unit-decrease in PACS). Kaplan-Meier curves showed a sustained divergence in event-free survival rates for the two groups.

Conclusion

The reduction of PACS significantly and independently affects cardiovascular outcome in HFrEF. Therefore, its assessment, although limited to patients with sinus rhythm, could offer additive prognostic information for HFrEF patients.

Atrial cardiomyopathy: Diagnosis, clinical implications and unresolved issues in anticoagulation therapy

Atrial cardiomyopathy (AC) is an evolving pathophysiological entity that has expanded our understanding regarding the atrium and its role in arrhythmogenesis and cardiac thromboembolism. The pathological myocardium in AC promotes arrhythmogenesis through mechanical dysfunction (hypocontractility, fibrosis), adverse alterations of the endothelium and secretion of prothrombotic factors (IL-6, IL-8, TNF-a). 'Red flags', indicative of AC, can be recognized either non-invasively by electrocardiography, echocardiography and cardiac magnetic resonance imaging or invasively by high-density electroanatomical mapping as low bipolar voltage areas of the affected myocardium. Signs of AC have been strongly associated with an increased risk of ischemic stroke, even embolic strokes of undetermined source, regardless of the coexistence of atrial fibrillation (AF). The underlying existence of AC has been negatively correlated with the success rate of catheter ablation of AF. The clinical value of AC is the provision of a novel pathway regarding the potential mechanisms of cerebrovascular events of cardiac thromboembolic origin. In addition, AC may serve as a risk stratification tool to predict the long-term responders of AF catheter ablation.

Influence of temporal resolution on computed tomography feature-tracking strain measurements

PURPOSE

Temporal resolution significantly affects strain values demonstrated by Magnetic resonance feature-tracking and speckle-tracking echocardiography. We investigated the influence of R-R interval reconstruction increments on left ventricular (LV) and left atrial (LA) strain measurements of Computed tomography feature-tracking (CT-FT).

METHODS

Subjects who underwent retrospective electrocardiogram-gated coronary CT angiography (CCTA) were retrospectively included, and CCTA images were reconstructed in 5% and 10% steps throughout the entire cardiac cycle (0-100% R-R interval). LV global longitudinal strain (GLS), circumferential strain (GCS), radial strain (GRS), LA GLS, ejection fraction (EF), and left atrioventricular coupling indices were computed. We evaluated the consistency and variability of continuous variables between the two reconstruction increment groups, the demarcation between the LA conduit and contraction phases, and observer reproducibility in 20 randomly selected participants.

RESULTS

Eighty-one participants with or without cardiac disease were included. The reconstruction increment of the R-R interval significantly affected the CT-FT-derived strain values. The 5% R-R increment resulted in significantly larger absolute strain values. LV GRS had the greatest difference between the two groups. In the subgroups with heart rates greater than 80 beats per minute or impaired cardiac function, group differences were attenuated, especially for LV GLS, LV GRS, and LA GLS. The prevalence of definite demarcation between the LA conduit and contraction phases was significantly higher in the 5% R-R reconstruction increment group than in the 10% R-R reconstruction increment group. The average heart rate during CCTA scanning was a strong risk factor for indefinite demarcation, which is independent of LVEF. As average heart rate increased, so did the incidence of indefinite demarcation between the LA conduit and contraction phases. The observer reproducibility of LV and LA strain values was independent of the R-R reconstruction increment.

CONCLUSION

Reconstruction increment of the R-R interval is an important source of variation in LV and LA CT-FT strain values, especially with low heart rate and preserved cardiac function. It is essential to control the heart rate and apply a narrow R-R reconstruction increment to quantify phasic LA strain.

Left Atrial Strain for Assessment of Left Ventricular Diastolic Function: Focus on Populations with Normal LVEF

Left atrial (LA) strain has emerged as a useful parameter for the assessment of left ventricular (LV) diastolic function and the estimation of LV filling pressures. Some have advocated using LA strain by itself, mainly reservoir strain, as a single stand-alone measurement for this objective. Recent data indicate several challenges for this application in patients with normal left ventricular ejection fraction (LVEF) because of the wide range for normal values and the load dependency of LA strain. Both findings can result in reduced left atrial reservoir strain (LARS) values in normal subjects that overlap those seen in patients with diastolic dysfunction. LARS for the estimation of LV filling pressures is most accurate in patients with depressed LVEF. It is less accurate in patients with normal ejection fraction. In this group of patients, LARS <18% has high specificity for increased LV filling pressures. There are promising data showing the association of LARS with outcome events in patients with normal ejection fraction, and additional data are needed to confirm that it provides incremental information over clinical and other echocardiographic measurements.