Left atrial function in cardiac amyloidosis

Cardiovascular Magnetic Resonance in the Management of Cardiac Amyloidosis: Current and Future Clinical Applications

Cardiac magnetic resonance represents the gold standard imaging technique to assess cardiac volumes, wall thickness, mass, and systolic function but also to provide noninvasive myocardial tissue characterization across almost all cardiac diseases. In patients with cardiac amyloidosis, increased wall thickness of all heart chambers, a mildly reduced ejection fraction and occasionally pleural and pericardial effusion are the characteristic morphologic anomalies. The typical pattern after contrast injection is represented by diffuse areas of late gadolinium enhancement, which can be focal and patchy in very early stages, circumferential, and subendocardial in intermediate stages or even diffuse transmural in more advanced stages.

PET/CT-identified atrial hypermetabolism is an index of atrial inflammation in patients with atrial fibrillation

BACKGROUND

Although atrial inflammation has been implicated in the pathophysiology of atrial fibrillation (AF), the identification of atrial inflammation remains challenging. We aimed to establish a positron emission tomography/computed tomography (PET/CT) protocol with 18Fluor-labeled fluorodeoxyglucose (18F-FDG) for the detection of atrial hypermetabolism as surrogate for inflammation in AF.

METHODS

We included n = 75 AF and n = 75 non-AF patients undergoing three common PET/CT protocols (n = 25 per group) optimized for the detection of (a) inflammation and (b) malignancy in predefined fasting protocols, and (c) cardiac viability allowing for maximized glucose uptake. 18F-FDG-uptake was analyzed in predefined loci.

RESULTS

Differences of visual atrial uptake in AF vs non-AF patients were observed in fasting (inflammation [13/25 vs 0/25] and malignancy [10/25 vs 0/25]) protocols while viability protocols showed non-specific uptake in both the groups. In the inflammation protocol, AF patients showed higher uptake in the right atrium [(SUVmax: 2.5 ± .7 vs 2.0 ± .7, P = .01), atrial appendage (SUVmax: 2.4 ± .7 vs 2.0 ± .6, P = .03), and epicardial adipose tissue (SUVmax: 1.4 ± .5 vs 1.1 ± .4, P = .04)]. Malignancy and viability protocols failed to differentiate between AF and non-AF.

CONCLUSION

Glucose uptake suppression protocols appear suitable in detecting differential atrial 18F-FDG uptake between AF and non-AF patients. Imaging-based assessment of inflammation might help to stratify AF patients offering individualized therapeutic approaches.

Decreased Left Atrial Reservoir Strain Is Associated with Adverse Outcomes in Restrictive Cardiomyopathy

Background: Restrictive cardiomyopathy (RCM) places patients at high risk for adverse events. In this study, we aim to evaluate the association between left atrial function and time to adverse events such as all-cause mortality and cardiovascular hospitalizations related to RCM. Material and Methods: In this single-center study, ninety-eight patients with a clinical diagnosis of RCM were recruited from our registry: 30 women (31%); age (mean ± standard deviation) 61 ± 13 years. These patients underwent cardiac magnetic resonance (CMR) imaging from May 2007 to September 2015. Left atrial (LA) function (reservoir, contractile, and conduit strain), LA diameter and area, and left ventricular function (global longitudinal strain, ejection fraction), and volume were quantified, and the presence of late gadolinium enhancement was visually assessed. The cutoff value of the LA reservoir strain was selected based on tertile. An adjusted Cox proportional regression analysis was used to assess time to adverse outcomes with a median follow up of 49 months. Results: In our cohort, all-cause mortality was 36% (35/98). Composite events (all-cause mortality and cardiovascular hospitalizations) occurred in 56% of patients (55/98). All-cause mortality and composite events were significantly associated with a decreased LA reservoir strain (adjusted hazard ratio (aHR) = 0.957, p = 0.002 and aHR = 0.969, p = 0.008) using a stepwise elimination of imaging variables, demographics, and comorbidities. All-cause mortality and composite events were six and almost four times higher, respectively, in patients with the LA reservoir strain <15% (aHR = 5.971, p = 0.005, and HR = 4.252, p = 0.001) compared to patients with the LA reservoir strain >34%. Survival was significantly reduced in patients with an LA reservoir strain <15% (p = 0.008). Conclusions: The decreased LA reservoir strain is independently associated with time to adverse events in patients with RCM.

Utility of left atrial and ventricular strain for diagnosis of transthyretin amyloid cardiomyopathy in aortic stenosis

Aims

To clarify the usefulness of left atrial (LA) function and left ventricular (LV) function obtained by two‐dimensional (2D) speckle tracking echocardiography to diagnose concomitant transthyretin amyloid cardiomyopathy (ATTR‐CM) in patients with aortic stenosis (AS).

Methods and results

We analysed 72 consecutive patients with moderate to severe AS who underwent ^99mTc‐pyrophosphate (PYP) scintigraphy at Kumamoto University Hospital from January 2012 to September 2020. We divided these 72 patients into 2 groups based on their ^99mTc‐PYP scintigraphy positivity or negativity. Among 72 patients, 16 patients (22%) were positive, and 56 patients (78%) were negative for ^99mTc‐PYP scintigraphy. In clinical baseline characteristics, natural logarithm troponin T was significantly higher in the ^99mTc‐PYP scintigraphy‐positive than scintigraphy‐negative group (−2.9 ± 0.5 vs. −3.5 ± 0.8 ng/mL, P < 0.05). In conventional echocardiography, the severity of AS was not significantly different between these two groups. In 2D speckle tracking echocardiography, the relative apical longitudinal strain (LS) index (RapLSI) [apical LS/ (basal LS + mid LS)] was significantly higher (1.09 ± 0.49 vs. 0.78 ± 0.23, P < 0.05) and the peak longitudinal strain rate (LSR) in LA was significantly lower in the ^99mTc‐PYP scintigraphy‐positive than scintigraphy‐negative group (0.36 ± 0.14 vs. 0.55 ± 0.20 s⁻¹, P < 0.05). Multivariable logistic analysis revealed the peak LSR in LA and RapLSI were significantly associated with ^99mTc‐PYP scintigraphy positivity. Receiver operating characteristic analysis showed that the area under the curve (AUC) of the peak LSR in LA for ^99mTc‐PYP scintigraphy positivity was 0.79 and that the best cut‐off value of the peak LSR in LA was 0.47 s⁻¹ (sensitivity: 78.6% and specificity: 72.3%). The AUC of RapLSI for ^99mTc‐PYP scintigraphy positivity was 0.69, and the cut‐off value of RapLSI was decided as 1.00 (sensitivity: 43.8% and specificity: 87.5%) according to the previous report. The ^99mTc‐PYP scintigraphy positivity in patients with RapLSI ≥ 1.0 and the peak LSR in LA ≤ 0.47 s⁻¹ was 83.3% (5/6), and the ^99mTc‐PYP scintigraphy negativity in patients with RapLSI < 1.0 and the peak LSR in LA > 0.47 s⁻¹ was 96.6% (28/29).

Conclusions

Left atrial and LV strain analysis were significantly associated with ^99mTc‐PYP scintigraphy positivity in ATTR‐CM patients with moderate to severe AS. The combination of the peak LSR in LA and RapLSI might be a useful predictor of the presence of ATTR‐CM in patients with moderate to severe AS.

Prognostic value of left atrial strain in patients with wild-type transthyretin amyloid cardiomyopathy

Aims

This study was performed to investigate whether left atrial (LA) strain by echocardiography provides prognostic information in patients with wild‐type transthyretin amyloid cardiomyopathy (ATTRwt‐CM).

Methods and results

Among 129 patients who were diagnosed with ATTRwt‐CM at Kumamoto University Hospital from December 2002 to December 2019, 113 patients who had enough information for two‐dimensional speckle tracking echocardiography were enrolled in this study. During a median follow‐up of 668 days, 28 cardiovascular deaths occurred. Compared with patients in the non‐event group, those in the cardiovascular death group were significantly older (81.5 ± 7.4 vs. 78.1 ± 6.1 years, P < 0.01), had a lower incidence of carpal tunnel syndrome (21% vs. 47%, P < 0.05), and had a higher high‐sensitivity cardiac troponin T [0.085 (0.063–0.105) vs. 0.049 (0.036–0.079) ng/mL, P < 0.01] and B‐type natriuretic peptide concentrations [419 (239–541) vs. 271 (155–462) pg/mL, P < 0.01] and lower estimated glomerular filtration rate (41.8 ± 15.4 vs. 53.4 ± 14.6 mL/min/1.73 m², P < 0.01). Electrocardiography showed higher rate of a V1–V3 QS pattern (52% vs. 24%, P < 0.01) and complete left bundle branch block (27% vs. 6%, P < 0.01), and echocardiography showed a significantly lower peak LA strain rate during the contraction phase (0.16 ± 0.13 vs. 0.28 ± 0.27 S⁻¹, P < 0.05), LA strain during the reservoir phase (LASr) (5.84 ± 2.41 vs. 8.22 ± 4.05%, P < 0.01), and peak LA strain rate during the reservoir phase (0.26 ± 0.09 vs. 0.33 ± 0.15 S⁻¹, P < 0.05) in the cardiovascular death group than in non‐event group. By contrast, conventional echocardiographic findings were not significantly different between these two groups. After adjusting for conventional predictive factors of ATTRwt‐CM (age, high‐sensitivity cardiac troponin T and B‐type natriuretic peptide concentrations, and estimated glomerular filtration rate), multivariable Cox proportional hazard analyses showed that LASr was significantly and independently associated with cardiovascular death in patients with ATTRwt‐CM (odds ratio, 0.84; 95% confidence interval, 0.72–0.98; P < 0.05). After adjusting for age and echocardiographic findings associated with cardiovascular death (LA volume index and peak LA strain rate during the contraction phase), LASr was significantly and independently associated with cardiovascular death in patients with ATTRwt‐CM (odds ratio, 0.83; 95% confidence interval, 0.70–0.98; P < 0.05). Receiver operating characteristic curve analysis showed that the area under the curve of LASr for cardiovascular death was 0.686 and that the best cut‐off value of LASr was 6.69% (sensitivity, 62.4%; specificity, 64.3%). In the Kaplan–Meier analysis, patients with low LASr (<6.69%) had a significantly higher probability of total cardiovascular death (P < 0.05) and heart failure‐related hospitalization (P < 0.05).

Conclusions

Left atrial strain during the reservoir phase provides significant prognostic value in patients with ATTRwt‐CM even after adjusting for conventional predictive factors.

Clinical management of amyloid cardiomyopathy

Clinical heart failure, restrictive cardiomyopathy, and arrhythmias are hallmark features of amyloid cardiomyopathy. In contrast to the advancements in targeted therapies, there is a general lack of evidence-based practice guidelines for clinical management of amyloid cardiomyopathy. In this review, we review the role of routine medical therapy in amyloid cardiomyopathy, from heart failure management to orthostatic hypotension, atrial arrhythmias, thromboembolic complications, and prevention of sudden death. We conclude by discussing approaches to patients with end-stage disease.

The Prevalence of Advanced Interatrial Block and Its Relationship to Left Atrial Function in Patients with Transthyretin Cardiac Amyloidosis

BACKGROUND

Advanced interatrial block (aIAB), which is associated with incident atrial fibrillation and stroke, occurs in the setting of blocked interatrial conduction. Atrial amyloid deposition could be a possible substrate for reduced interatrial conduction, but the prevalence of aIAB in patients with transthyretin cardiac amyloidosis (ATTR-CA) is unknown. We aimed to describe the prevalence of aIAB and its relationship to left atrial function in patients with ATTR-CA in comparison to patients with HF and left ventricular hypertrophy but no CA.

METHODS

The presence of aIAB was investigated among 75 patients (49 patients with ATTR-CA and 26 with HF but no CA). A comprehensive echocardiographic investigation was performed in all patients, including left atrial strain and strain rate measurements.

RESULTS

Among patients with ATTR-CA, 27% had aIAB and in patients with HF but no CA, this figure was 21%, (p = 0.78). The presence of aIAB was associated with a low strain rate during atrial contraction (<0.91 s-1) (OR: 5.2 (1.4-19.9)), even after adjusting for age and LAVi (OR: 4.5 (1.0-19.19)).

CONCLUSIONS

Advanced interatrial block is common among patients with ATTR-CA, as well as in patients with heart failure and left ventricular hypertrophy but no CA. aIAB is associated with reduced left atrial contractile function.

Very Early Onset of ATTRE89Q Amyloidosis in a Homozygous Patient

Case Presentarion:

Hereditary transthyretin amyloidosis is a progressive, fatal disease that generally involves the peripheral nervous system, the autonomic nervous system, and the heart. It is autosomal dominant with different penetrance depending on the mutation and the genetic background. Many other missense mutations of the TTR gene may cause the disease. Being an overall rare disease is very rare to observe the condition of homozygosity. In particular, cases of homozygosity have been described in patients with ATTRV30M and ATTRV122I amyloidosis. In the former, the phenotype does not seem to be aggravated, having an age of onset and disease course that does not appear to differ from those of heterozygotes, while in the latter, the onset appears to be earlier.

Conclusion:

We report the first case of ATTRE89Q amyloidosis in a patient that was homozygous for the E89Q mutation in the TTR gene. The clinical phenotype resulted in the earlier disease onset reported in this form of amyloidosis, suggesting that the homozygous condition may be prognostically negative.

Use of Drugs for ATTRv Amyloidosis in the Real World: How Therapy Is Changing Survival in a Non-Endemic Area

Background: Over the past decade, three new drugs have been approved for the treatment of hereditary amyloid transthyretin (ATTRv) polyneuropathy. The aim of this work was to analyze whether current therapies prolong survival for patients affected by ATTRv amyloidosis. Methods: The study was conducted retrospectively, analyzing the medical records of 105 patients with genetic diagnoses of familial amyloidotic polyneuropathy followed at the two referral centers for the disease in Sicily, Italy. Of these, 71 received disease-modifying therapy, while 34 received only symptomatic treatment or no therapy. Results: The most used treatment in our patient cohort was tafamidis, followed by liver transplantation, patisiran, inotersen, and diflunisal. The median survival was significantly longer for treated vs. untreated patients (12 years vs. 8 years). In the 71 patients who received disease-modifying treatment, the presence of cardiac involvement, weight loss, or autonomic dysfunction at diagnosis was not related to survival. Conversely, patients diagnosed in the early stage of the disease (PND 1) had significantly longer survival than those diagnosed in the late stage (PND 2–4).

Stroke risk and atrial mechanical dysfunction in cardiac amyloidosis

Amyloidosis is associated with poor prognosis, and patients with cardiac involvement have especially poor outcomes. Cardiac amyloidosis leads to higher rates of atrial arrhythmia and an increased risk of intracardiac thrombus formation. However, atrial mechanical dysfunction due to protein deposition in amyloidosis may lead to thrombus formation in the absence of atrial arrhythmia. We present a 42‐year‐old male patient with familial transthyretin amyloidosis who suffered an embolic stroke that originated from a left atrial appendage thrombus in the absence of any documented atrial fibrillation. This case highlights atrial mechanical dysfunction in patients with cardiac amyloidosis and the need to better stratify thrombotic risk in this population with integration of echocardiographic parameters and transesophageal echocardiography.

Echocardiographic Findings in Cardiac Amyloidosis: Inside Two-Dimensional, Doppler, and Strain Imaging

PURPOSE OF REVIEW

The aim is to provide a description of the most important echocardiographic features in systemic amyloidosis.

RECENT FINDINGS

Amyloidosis is a heterogeneous group of multisystem disorders, characterized by an extracellular deposition of amyloid fibrils. Several imaging tests are available for the diagnosis; however, echocardiography is the cornerstone of the non-invasive imaging modality for cardiac amyloidosis. So far, little is known about the diagnosis of cardiac amyloidosis through imaging modalities. We summarized the most important echocardiographic findings in cardiac amyloidosis. Hence, we offered a systematic report of the diagnostic performance of cardiac amyloidosis using echocardiography.

Advanced Non-invasive Imaging Techniques in Chronic Heart Failure and Cardiomyopathies : Focus on Cardiac Magnetic Resonance Imaging and Computed Tomographic

Cardiomyopathies (Cs) are a heterogeneous group of myocardial diseases with structural and/or functional abnormalities.The aetiology is due to genetic-family substrate in most cases, however, the correct and detailed analysis of morphofunctional abnormalities (severity and distribution of hypertrophy, ventricular dilatation, ventricular dysfunction) and tissue characteristics (myocardial fibrosis, myocardial infiltration) are a crucial element for a definite diagnosis.Among the different diagnostic imaging modalities applied in clinical practice (echocardiography, nuclear medicine), cardiac magnetic resonance (CMR) has emerged as a non-invasive diagnostic tool having high ability to quantify systolic function and tissue abnormalities that represent the substrates of many Cs.The main added value of CMR is the ability to identify cardiomyopathies with respect to ischemic heart disease and, above all, to discriminate the major types of cardiomyopathies based on morpho-functional presentation patterns and the presence and location of myocardial fibrosis.Many CMR elements allow increasing diagnostic accuracy but CMR data should be integrated with an appropriate clinical and instrumental context.Computed Tomographic (CT) scan technology has showed a complementary role in patients having Cs and HF.In this chapter, the diagnostic, pathophysiologic and prognostic value of CMR and CT in heart failure due to the most common cardiomyopathies will be discussed.

Reduced left atrial myocardial deformation irrespective of cavity size: a potential cause for atrial arrhythmia in hereditary transthyretin amyloidosis

BACKGROUND

Cardiac amyloidosis (CA) is a myocardial disease and commonly under-diagnosed condition. In CA patients, atrial fibrillation might occur in the absence of left atrial (LA) enlargement.

OBJECTIVES

The aim of this study is to assess LA size and function, and its relationship with atrial arrhythmia in patients with hereditary transthyretin amyloidosis (ATTR).

METHODS

Forty-six patients with confirmed ATTR amyloidosis on abdominal biopsy were studied. Assessment with 2D echocardiography and 2D strain showed 31 patients had increased LV wall thickness (LVWT) (septal thickness >12 mm), and 15 had normal LVWT. In addition to conventional measurements, LV and LA global longitudinal strain (GLS%) and strain rate (SR) were obtained. Western blot analysis was done to assess fibril type. ATTR patients with increased LVWT were compared with 23 patients with hypertrophic cardiomyopathy (HCM) and 31 healthy controls. ATTR amyloidosis patients also underwent 24 hour Holter monitoring to determine the presence of atrial arrhythmia.

RESULTS

Atrial deformation during atrial systole was reduced in ATTR amyloidosis patients with increased LVWT independent of LA size and in contrast to HCM. Twenty of the ATTR amyloidosis patients (54%) had ECG evidence of significant atrial arrhythmic events. LA strain rate, during atrial systole, was the only independent predictor of atrial arrhythmia (β = 3.28, p = .012).

CONCLUSION

In ATTR cardiomyopathy with increased LVWT, LA myocardial function is abnormal, irrespective of atrial cavity size. Reduced LA myocardial SR during atrial systole, irrespective of cavity volume, E/e' and LV deformation, is also a strong predictor for atrial arrhythmic events.

Reference value of left and right atrial size and phasic function by SSFP CMR at 3.0 T in healthy Chinese adults

The size and function of the left atrium (LA) and right atrium (RA) are related closely with the prognosis of cardiovascular diseases. However, their normal reference values, as measured by cardiac magnetic resonance (CMR), are not well established in Chinese populations. Healthy Chinese subjects (n = 135, 66 males, age 23–83 years) without cardiovascular risk factors were recruited. We imaged the LA and RA of all subjects using short axis and long axis slices by steady-state free precession (SSFP) sequences using a 3.0T scanner. The size and functional parameters were measured. Age and gender differences in LA were further explored. The normal reference values of atrial dimensions, volumes, and empty fractions (EFs) were provided by short axis (SAX) and area-length methods. Volumes and EFs derived by the area-length method showed correlated well with those derived by the by SAX method, but significantly underestimated the volumes (all P < 0.001) and overestimated the LA EFs (all P < 0.001). Atrial dimensions and volumes were generally larger in males. Conduit EFs and total EFs showed gender differences. Most atrial parameters correlated with age. In general, our results showed that gender and age have considerable impact on LA and RA size and function.

Cumulative Burden of Myocardial Dysfunction in Cardiac Amyloidosis Assessed Using Four-Chamber Cardiac Strain

BACKGROUND

The aim of this study was to test the hypothesis that prognosis in patients with cardiac amyloidosis is closely coupled with amyloid burden in all four cardiac chambers. The goal was to evaluate longitudinal strain (LS) in each cardiac chamber and to determine whether LS in specific cardiac chambers is preferentially associated with prognosis over conventional two-dimensional echocardiographic parameters in patients with cardiac amyloidosis.

METHODS

Patients with two phenotypes of left ventricular (LV) hypertrophy (cardiac amyloidosis in 55 patients and nonobstructive hypertrophic cardiomyopathy in 40 patients) and 55 healthy subjects were retrospectively enrolled for the simultaneous assessment of LS of all four cardiac chambers in the apical four-chamber view. Patients with cardiac amyloidosis were followed up to record major adverse cardiovascular events, including cardiac death, heart transplantation, nonfatal myocardial infarction, ventricular tachyarrhythmia, and exacerbation of heart failure requiring hospitalization.

RESULTS

LS in each chamber was significantly depressed in patients with both LV hypertrophy phenotypes compared with healthy subjects. Right atrial LS was significantly lower in patients with cardiac amyloidosis than those with nonobstructive hypertrophic cardiomyopathy after adjusting for LV ejection fraction and LV mass index. During a median follow-up period of 10 months, major adverse cardiovascular events developed in 22 patients with cardiac amyloidosis. Four-chamber LS were significantly associated with major adverse cardiovascular events, with incremental value over traditional echocardiographic parameters.

CONCLUSIONS

Cardiac amyloidosis involves all cardiac chambers, and thus, chamber-specific strain analysis may be useful to assess the total cumulative burden of cardiac dysfunction.

Transthyretin-Related Familial Amyloid Polyneuropathy (TTR-FAP): A Single-Center Experience in Sicily, an Italian Endemic Area

Background: Familial amyloid polyneuropathy related to transthyretin gene (TTR-FAP) is a life-threatening disease transmitted as an autosomal dominant trait. Val30Met mutation accounts for the majority of the patients with large endemic foci especially in Portugal, Sweden and Japan. However, more than one hundred other mutations have been described worldwide. A great phenotypic variability among patients with late- and early-onset has been reported.

Objective: To present a detailed report of TTR-FAP patients diagnosed in our tertiary neuromuscular center, in a 20-year period.

Methods: Clinical informations were gathered through the database of our center.

Results: The study involved 76 individuals carrying a TTR-FAP mutation. Three phenotypes were identified, each corresponding to a different TTR variant, homogeneous within and heterogeneous between each other: i) Glu89Gln mutation, characterised by 5th – 6th decade onset, neuropathy as presenting symptoms, early heart dysfunction, cardiomyopathy as major cause of mortality followed by dysautonomia and cachexia; ii) Phe64Leu mutation, marked by familiarity reported in one-half of cases, late onset, severe peripheral neuropathy, moderate dysautonomia and mild cardiomyopathy, death for wasting syndrome; iii) Thr49Ala mutation, distinguished by onset in the 5th decade, autonomic disturbances as inaugural symptoms which may remain isolated for many years, moderate polyneuropathy, cachexia as major cause of mortality followed by cardiomyopathy.

Conclusions: This survey highlighted a prevalence of 8.8/1,000,000 in Sicily Island. Good knowledge of the natural history of the disease according to different TTR mutations allow clinicians to optimise multiprofessional care for patients and to offer carriers a personalized follow-up to reveal first signs of the disease.