High recurrence of atrial fibrillation in patients with high tissue atrial natriuretic peptide and amyloid levels after concomitant maze and mitral valve surgery

Effect of tafamidis on left atrial function of patients with transthyretin amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is characterized by the functional and structural effects of amyloid infiltration, predominantly within the ventricles, causing biventricular wall thickening. Amyloid infiltration can be observed in the left atrium in ATTR-CM patients, but the association of left atrial (LA) myocardial function with cardiovascular events and of changes in LA myocardial function with tafamidis administration have not yet been clarified. Our aim was, therefore, to use speckle-tracking strain for investigating LA myocardial function in patients with ATTR-CM treated with tafamidis. We studied 55 patients with biopsy-proven ATTR-CM who had been treated with tafamidis (age: 76 ± 2 years, male: 93%). For speckle-tracking analysis of LA myocardial function, the systolic LA strain (LA reservoir function) was defined for this study as LA myocardial function from the apical 4-chamber view. The primary endpoint was defined as a composite comprising cardiovascular death and/or heart failure hospitalization after tafamidis administration over a median follow-up period of 28 ± 4 months. Patients with baseline LA strain < 8.6% (median value) experienced significantly more cardiovascular events than those without (log-rank P = 0.002). Moreover, LA strain in 26 patients worsened after tafamidis administration, and multivariate logistic regression analysis showed age, global longitudinal strain and relative apical longitudinal strain index were identified as independent determinants of deterioration of LA strain after tafamidis administration. In conclusion, baseline LA reservoir function is closely associated with cardiovascular events after tafamidis administration, and could be an additional parameter for the management of patients with ATTR-CM.

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.

Clinicopathological features of clinically undiagnosed sporadic transthyretin cardiac amyloidosis: a forensic autopsy-based series

OBJECTIVE

To investigate the clinicopathological features of sporadic amyloid transthyretin (ATTR) amyloidosis.

METHODS

We evaluated 1698 serial Japanese forensic autopsy patients. The extent and amount of ATTR deposition in the 16 cardiac regions, including the conduction system, were semiquantitatively evaluated. Ward's hierarchical cluster analysis was applied to classify the cases into subgroups. Also, the relationship between ATTR and amyloid atrial natriuretic factor (AANF) was evaluated.

RESULTS

Forty-four cardiac ATTR amyloidosis patients (mean age 85.4 ± 5.7 years; 22 men) without history of hereditary polyneuropathy were identified (2.6% of all patients, 8.8% of those aged ≥80 years). All the 44 patients were not in the bedridden state and died-out-of-hospital scenarios. Of these, 10 (23%) were sudden death. Cluster analysis classified the patients into three groups (mild, atria-predominant and the severe deposition group). Amyloid deposition had already started simultaneously from each atrium and ventricle; however, the atrial septum and basilar ventricular septum were the sites that revealed the most frequent deposition. Also, a possible association between ATTR and AANF deposits was identified.

CONCLUSIONS

Sporadic ATTR amyloidosis patients might already be susceptible to a risk for sudden death even from an early-phase. Also, ATTR amyloid deposition in such cases might progress with a certain degree of regularity.

Morpho-functional changes of cardiac telocytes in isolated atrial amyloidosis in patients with atrial fibrillation

Telocytes are interstitial cells with long, thin processes by which they contact each other and form a network in the interstitium. Myocardial remodeling of adult patients with different forms of atrial fibrillation (AF) occurs with an increase in fibrosis, age-related isolated atrial amyloidosis (IAA), cardiomyocyte hypertrophy and myolysis. This study aimed to determine the ultrastructural and immunohistochemical features of cardiac telocytes in patients with AF and AF + IAA. IAA associated with accumulation of atrial natriuretic factor was detected in 4.3-25% biopsies of left (LAA) and 21.7-41.7% of right (RAA) atrial appendage myocardium. Telocytes were identified at ultrastructural level more often in AF + IAA, than in AF group and correlated with AF duration and mitral valve regurgitation. Telocytes had ultrastructural signs of synthetic, proliferative, and phagocytic activity. Telocytes corresponded to CD117+, vimentin+, CD34+, CD44+, CD68+, CD16+, S100-, CD105- immunophenotype. No significant differences in telocytes morphology and immunophenotype were found in patients with various forms of AF. CD68-positive cells were detected more often in AF + IAA than AF group. We assume that in aged AF + IAA patients remodeling of atrial myocardium provoked transformation of telocytes into "transitional forms" combining the morphological and immunohistochemical features with signs of fibroblast-, histiocyte- and endotheliocyte-like cells.

RNA sequencing profiling reveals key mRNAs and long noncoding RNAs in atrial fibrillation

Long noncoding RNAs (lncRNAs) are an emerging class of RNA species that could participate in some critical pathways and disease pathogenesis. However, the underlying molecular mechanism of lncRNAs in atrial fibrillation (AF) is still not fully understood. In the present study, we analyzed RNA-seq data of paired left and right atrial appendages from five patients with AF and other five patients without AF. Based on the gene expression profiles of 20 samples, we found that a majority of genes were aberrantly expressed in both left and right atrial appendages of patients with AF. Similarly, the dysregulated pathways in the left and right atrial appendages of patients with AF also bore a close resemblance. Moreover, we predicted regulatory lncRNAs that regulated the expression of adjacent protein-coding genes (PCGs) or interacted with proteins. We identified that NPPA and its antisense RNA NPPA-AS1 may participate in the pathogenesis of AF by regulating the muscle contraction. We also identified that RP11 - 99E15.2 and RP3 - 523K23.2 could interact with proteins ITGB3 and HSF2, respectively. RP11 - 99E15.2 and RP3 - 523K23.2 may participate in the pathogenesis of AF via regulating the extracellular matrix binding and the transcription of HSF2 target genes, respectively. The close association of the lncRNA-interacting proteins with AF further demonstrated that these two lncRNAs were also associated with AF. In conclusion, we have identified key regulatory lncRNAs implicated in AF, which not only improves our understanding of the lncRNA-related molecular mechanism underlying AF but also provides computationally predicted regulatory lncRNAs for AF researchers.

2019 HRS expert consensus statement on evaluation, risk stratification, and management of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is an arrhythmogenic disorder of the myocardium not secondary to ischemic, hypertensive, or valvular heart disease. ACM incorporates a broad spectrum of genetic, systemic, infectious, and inflammatory disorders. This designation includes, but is not limited to, arrhythmogenic right/left ventricular cardiomyopathy, cardiac amyloidosis, sarcoidosis, Chagas disease, and left ventricular noncompaction. The ACM phenotype overlaps with other cardiomyopathies, particularly dilated cardiomyopathy with arrhythmia presentation that may be associated with ventricular dilatation and/or impaired systolic function. This expert consensus statement provides the clinician with guidance on evaluation and management of ACM and includes clinically relevant information on genetics and disease mechanisms. PICO questions were utilized to evaluate contemporary evidence and provide clinical guidance related to exercise in arrhythmogenic right ventricular cardiomyopathy. Recommendations were developed and approved by an expert writing group, after a systematic literature search with evidence tables, and discussion of their own clinical experience, to present the current knowledge in the field. Each recommendation is presented using the Class of Recommendation and Level of Evidence system formulated by the American College of Cardiology and the American Heart Association and is accompanied by references and explanatory text to provide essential context. The ongoing recognition of the genetic basis of ACM provides the opportunity to examine the diverse triggers and potential common pathway for the development of disease and arrhythmia.

Clinical characteristics and rhythm outcome of catheter ablation of hemodynamically corrected valvular atrial fibrillation

BACKGROUND

Although the hemodynamic burden and structural substrate contribute to valvular atrial fibrillation (VAF) mechanisms, the role of catheter ablation has rarely been reported. We investigated the clinical characteristics, mapping findings, and long-term rhythm outcomes after catheter ablation of hemodynamically corrected VAF.

METHODS

We compared 77 patients with VAF (46.8% male, 52.7±8.8 years old, 46.8% paroxysmal AF, 24.7% with maze procedures) and 2244 patients with non-VAF (NVAF) who underwent catheter ablation. Among the VAF patients, 44 (57.1%) had mechanical valve AF (MV-AF) and 33 (42.9%) underwent a prior mitral valvuloplasty (MVP-AF). We analyzed the catheter ablation rhythm outcomes for MV-AF and MVP-AF.

RESULTS

The left atrial (LA) diameter was greater (p<0.001), LA voltage lower (p<0.001), and procedure-related complication rate higher (mainly sinus node dysfunction, p=0.004) for VAF than NVAF. During 70.2±1.8 months of follow-up, the rhythm outcome of VAF did not significantly differ from that of NVAF after catheter ablation (log rank p=0.399), even after excluding patients with maze procedures (log rank p=0.629). The clinical recurrence rates did not differ between the MV-AF and MVP-AF groups (log rank p=0.244), or between patients with prior maze procedures and those without (log rank p=0.651). The main conduction recovery sites of previous maze procedures were the perimitral (84.2%) and cavotricuspid isthmus (84.2%) areas, and recurrence mechanisms were macroreentry (63.2%) and focal/microreentry (26.3%) at scar border zones.

CONCLUSIONS

Although hemodynamically corrected VAF was associated with advanced LA remodeling, the rhythm outcome did not significantly differ from that of NVAF after catheter ablation.

Late onset of atrial fibrillation in patients undergoing mitral valve repair for type II dysfunction

BACKGROUND

There are few reports regarding factors related to late-onset of atrial fibrillation (Af) after mitral valve repair, which can compromise long-term outcome. We analyzed the risk factors for late Af after mitral valve repair.

METHODS AND RESULTS

Between 2001 and 2015, 318 patients (214 males; median, 57.7 years) underwent mitral valve repair for degenerative mitral insufficiency (MI) without concomitant aortic valve disease in our institute. Patients with a history of paroxysmal or chronic Af preoperatively were excluded. Serial follow-up echocardiography was used to evaluate cardiac function. The follow-up rate was 99%. The mean follow-up period was 6.0±4.1 years. There was no early death and there were nine late deaths. A total of 29 (9.1%) patients developed late Af. Freedom from late Af was 94.0% at 5 years and 82.9% at 10 years. Small ring annuloplasty, left atrial diameter, and pressure half time, which were measured at follow-up echocardiography, were considered as significant (p<0.05) risk factors for late Af. Patients who had late Af developed recurrent MI more frequently than those who did not (p<0.05).

CONCLUSIONS

Remodeling of the atrium caused by functional mitral stenosis is important for late Af, as well as recurrent MI. To prevent these problems, avoiding selection of a small ring at primary mitral repair for type II dysfunction and durable repair are required.

Left atrial function in patients with light chain amyloidosis: A transthoracic 3D speckle tracking imaging study

BACKGROUND

Systemic light chain amyloidosis (AL) is characterized by the extracellular deposition of amyloid fibrils. Transthoracic echocardiography is the modality of choice to assess cardiac function in patients with AL. Whereas left ventricular (LV) function has been well studied in this patient population, data regarding the value of left atrial (LA) function in AL patients are lacking. In this study, we aim to examine the impact of LA volumes and function on survival in AL patients as assessed by real-time 3D echocardiography.

METHODS

A total of 77 patients (67±10 years, 60% men) with confirmed AL and 39 healthy controls were included. All standard 2D echocardiographic and 3D-LA parameters were obtained.

RESULTS

Fourteen patients (18%) were in Mayo Clinic (MC) stage I, 30 (39%) in stage II, and 33 (43%) in stage III at initial evaluation. There was no significant difference among the MC stages groups in terms of age, gender, or cardiovascular risk factors. As compared to patients in MC II and MC I, those in MC III had significantly larger indexed 3D-LA volumes (MCIII: 46±15mL/m², MC II: 38±12mL/m², and MC I: 23±9mL/m², p<0.0001), lower 3D-LA total emptying fraction (3D-tLAEF) (21±13% vs. 31±15% vs. 43±7%, respectively, p<0.0001), and worse 3D peak atrial longitudinal strain (3D-PALS) (11±9% vs. 18±13% vs. 20±7%, respectively, p=0.007). Two-year survival was significantly lower in patients with 3D-tLAEF <+34% (p=0.003) and in those with 3D-PALS <+14% (p=0.034). Both parameters provided incremental prognostic value over maximal LA volume in multivariate analysis.

CONCLUSION

Functional LA parameters are progressively altered in AL patients according to the MC stage. A decrease in 3D-PALS is associated with worse outcome, independently of LA volume.