Outcomes following cardioversion for patients with cardiac amyloidosis and atrial fibrillation or atrial flutter

[Arrhythmias and amyloidosis]

Cardiac amyloidosis is an infiltrative cardiomyopathy characterized by the extracellular deposition of amyloid fibrils within the myocardium. Beyond heart failure, patients with cardiac amyloidosis commonly present with arrhythmias and conduction system disorders. Atrial fibrillation is observed in up to 80% of patients at the time of diagnosis, with patients typically maintaining normal heart rates due to concurrent atrioventricular nodal disease. The thromboembolic risk is particularly high in patients with cardiac amyloidosis, and left atrial thrombi have been observed even in the absence of atrial fibrillation. Conduction system diseases are also highly prevalent, often necessitating permanent pacemaker implantation. The use of implantable defibrillators in this population remains controversial. This overview of published data and therapeutic strategies related to arrhythmias and conduction system disorders aims to assist readers in decision-making in complex clinical scenarios.

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.

Perioperative implications of amyloidosis and amyloid cardiomyopathy: A review for anesthesiologists

It is well recognized that amyloid protein can infiltrate many regions of the body. This can include the peripheral nerves, the liver, kidney, spleen, the gastrointestinal tract, and most importantly the myocardium. The amyloid proteins that cause cardiomyopathy may come from genetically altered liver genes (transthyretin amyloid, ATTR) or from the bone marrow with malignant plasma cells (light chain amyloid, AL) generating the aberrant protein. These two types of amyloidosis cause significant damaging effects on both the myocardial cells as well as the conduction system of the heart. The resultant changes can produce dyspnea and exercise intolerance which is thought to be secondary to diastolic dysfunction and reduced stroke volume. This subclinical decompensation poses a significant problem for members of a care team as it often goes unrecognized. In the operating room patients are exposed to dramatic hemodynamic changes and may have difficult airways, autonomic dysfunction, and conduction abnormalities. Although the topic of amyloidosis is well described in cardiology literature, it is underdiagnosed. The purpose of this review is to describe some of the pathophysiology behind the principle proteins that cause cardiac amyloidosis and to comprehensively describe perioperative considerations for anesthesia providers.

Cardiac and renal AL amyloidosis controlled by autologous stem cell transplantation for 17 years accompanying late onset atrial fibrillation and complete atrioventricular block

Amyloid light chain (AL) amyloidosis is a rare hematologic disease that may involve multiple organs. Amongst the organs, cardiac involvement causes the greatest concern as its treatment is challenging. Diastolic dysfunction rapidly progresses to decompensated heart failure, pulseless electrical activity, and atrial standstill due to electro-mechanical dissociation resulting in death. High-dose melphalan plus autologous stem cell transplantation (HDM-ASCT) is the most radical treatment but its risk is very high and thus only less than 20% of patients can receive this therapy under criteria that can suppress treatment-related mortality. In substantial proportion of patients, levels of M protein remain elevated, and organ response cannot be achieved. Moreover, relapse may occur, making prediction of treatment response and judgement of disease eradication very difficult. Herein we report a case of AL amyloidosis who was treated with HDM-ASCT, resulting in preserved cardiac function and resolution of proteinuria for more than 17 years after HDM-ASCT ensuing atrial fibrillation and complete atrioventricular block required management by catheter ablation and pacemaker implantation 10 years and 12 years after transplantation, respectively.

Safety of Catheter Ablation Therapy for Atrial Fibrillation in Cardiac Amyloidosis

Background Despite the high burden of atrial fibrillation in cardiac amyloidosis (CA), the safety of catheter ablation therapy in CA is not well established. We sought to examine short-term safety outcomes following atrial fibrillation ablation in patients with CA compared with matched patients with dilated cardiomyopathy (DCM). Methods and Results Using data from the National Inpatient Sample, we identified all hospitalizations for atrial fibrillation ablation from the fourth quarter of 2015 through 2019. Admissions for CA and DCM were matched in a 1:5 ratio using propensity scores based on the following sociodemographics: age, sex, race or ethnicity, payor, median income, comorbidities, and hospital characteristics. We compared in-hospital outcomes between both cardiomyopathies. We identified 1395 unweighted hospitalizations (representing 6750 national hospitalizations) for atrial fibrillation ablation, out of which 45 (3.2%) were admissions for CA. Compared with DCM, patients with CA were older (72.9 versus 65.1 years), had a higher burden of prior stroke (20.0% versus 8.6%) and chronic kidney disease (53.3% versus 33.6%), and were less likely to have a prior implantable cardioverter-defibrillator (4.4% versus 23.0%). We successfully matched 42 CAs to 210 DCM hospitalizations. After matching, there was no difference in total complications (14.3% versus 10.5%, P=0.60), length-of-stay (3.1 versus 2.1 days, P=0.23), home disposition (97.6% versus 96.2%, P=0.65), and total charges ($137 250 versus $133 910, P=0.24). Conclusions In this nationally representative study of atrial fibrillation catheter ablation in CA, short-term safety outcomes and complication rates were similar to a propensity score-matched cohort of DCM. Further studies exploring long-term safety outcomes are needed.

Cardiac Amyloidosis

Amyloid deposits are defined by their tinctorial properties. Under the light microscope amyloid deposits are eosinophilic and amorphous when stained with hematoxylin and eosin. With Congo red staining the deposits are positive and under polarized light will exhibit green birefringence. Sixty years later electron microscopy demonstrated that all deposits were fibrillar. All amyloid deposits are protein derived. The clinical characteristics will be driven by the nature of the protein subunit. In cardiology, the 2 most common subunits accounting for well more than 90% of cardiac amyloidosis are either immunoglobulin light chain, amyloid light-chain (AL) amyloidosis, or transthyretin; transthyretin (TTR) amyloidosis. Although 70% of patients with systemic amyloidosis have cardiac involvement the diagnosis is made by cardiologists only 20% of the time, suggesting significant gaps in knowledge in how to establish a workflow to arrive at a diagnosis in everyday practice.

Electrophysiological Manifestations of Cardiac Amyloidosis: JACC: CardioOncology State-of-the-Art Review

Cardiac amyloidosis (CA) is an infiltrative cardiomyopathy caused by the extracellular deposition of amyloid fibrils in the myocardium. Although cardiac amyloidosis patients primarily present with heart failure symptoms, arrhythmias and conduction system disease are frequently encountered. Atrial fibrillation (AF) is observed in up to 70% of patients at the time of diagnosis, and patients typically have controlled ventricular rates caused by concomitant conduction system disease. Thromboembolic risk is particularly high in patients with CA and AF, and left atrial thrombi have been observed even in the absence of clinically diagnosed AF. Atrioventricular nodal and infra-Hisian disease are common, and permanent pacemakers are frequently required. The use of implantable cardioverter-defibrillators in this population is controversial. This review summarizes the published data and therapeutic strategies surrounding arrhythmias and conduction system disease with the goal of aiding clinicians managing the clinical complexities of CA.

Catheter ablation of atrial fibrillation in cardiac amyloidosis

BACKGROUND

Cardiac amyloidosis is a progressive infiltrative disease involving deposition of amyloid fibrils in the myocardium and cardiac conduction system that frequently manifests with heart failure (HF) and arrhythmias, most frequently atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT).

METHODS

We performed an observational retrospective study of patients with a diagnosis of cardiac amyloid who underwent catheter ablation at our institution between January 1, 2011 and December 1, 2018. Patient demographics, procedural characteristics, and outcomes were determined by manual chart review.

RESULTS

A total of 13 catheter ablations were performed over the study period in patients with cardiac amyloidosis, including 10 AT/AF/AFL ablations and three atrioventricular nodal ablations. Left ventricular ejection fraction was lower at the time of AV node ablation than catheter ablation of AT/AF/AFL (23% vs 40%, P = .003). Cardiac amyloid was diagnosed based on the results of preablation cardiac MRI results in the majority of patients (n = 7, 70%). The HV interval was prolonged at 60 ± 15 ms and did not differ significantly between AV nodal ablation patients and AT/AF/AFL ablation patients (69 ± 18 ms vs 57 ± 14 ms, P = .36). The majority of patients undergoing AT/AF/AFL ablation had persistent AF (n = 7, 70%) and NYHA class II (n = 5, 50%) or III (n = 5, 50%) HF symptoms, whereas patients undergoing AV node ablation were more likely to have class IV HF (n = 2, 66%, P = .014). Arrhythmia-free survival in CA patients after catheter ablation of AT/AF/AFL was 40% at 1 year and 20% at 2 years.

CONCLUSIONS

Catheter ablation of AT/AF/AFL may be a feasible strategy for appropriately selected patients with early to mid-stage CA, whereas AV node ablation may be more appropriate in patients with advanced-stage CA.