Survival Following Implantable Cardioverter-Defibrillator Implantation in Patients With Amyloid Cardiomyopathy

Long-Term Clinical Outcomes in Patients With Transthyretin Cardiac Amyloidosis Versus Non-Ischemic Cardiomyopathy

Background

We sought to compare the long-term outcomes in patients with transthyretin cardiac amyloidosis (CA) compared to those with non-ischemic cardiomyopathy (NICM) from a large healthcare system database.

Methods

Patients with CA or NICM were identified from SSM Healthcare System's data warehouse using ICD codes. Inclusion criteria included at least 6 months of follow-up. Outcomes studied were heart failure hospitalization (HFH), ventricular tachyarrhythmias (VTA), implantable cardiac defibrillator (ICD) and pacemaker (PM) placement. Multivariate logistic analysis and Kaplan-Meier survival curves were constructed.

Results

We identified 231 patients with CA and 462 with NICM, matched for age, race, and gender. CA patients had higher incidence of peripheral vascular disease (48.5% vs. 35.5%) and coronary artery disease (10.4% vs. 6.1%). Mean follow-up was 48.1 ± 33.1 months. CA patients had a higher rate of HFH (57.6% vs. 46.1%) and a lower rate of ICD (1.7% vs. 5.9%). In the multivariate model, CA patients had significantly higher odds for HFH (odds ratio: 1.86; 95% confidence interval: 1.29 - 2.68). Kaplan-Meier survival curves showed a trend toward earlier HFH and later PM or ICD implantation in CA patients.

Conclusions

In this retrospective study from a large healthcare system database, compared to NICM, transthyretin CA patients had significantly higher rates of HFH, similar odds of VTA, and a lower likelihood of receiving an intracardiac device.

Prophylactic implantation of cardioverter-defibrillator in patients with advanced light-chain amyloidosis-A pilot study

Background

Ventricular arrhythmias (VAs) and electromechanical dissociation have been observed as the most common causes of sudden cardiac death (SCD) in patients with light chain (AL) amyloidosis. However, an implantable cardioverter-defibrillator (ICD) has rarely been implanted in patients with advanced AL amyloidosis due to very poor prognosis.

Methods

Between July 2021 and December 2022, 10 patients with advanced cardiac AL amyloidosis referred to our institute who received prophylactic ICD implantation were prospectively recruited. The primary endpoint was the prevalence of VAs and appropriate ICD therapies determined by ICD interrogation. The secondary endpoint was all-cause mortality during the follow-up period.

Results

During a mean follow-up of 12.1 ± 4.4 months, sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) occurred in 4 of 10 (40%) patients. One patient had spontaneous termination of VT before the delivery of ICD therapy, and the remaining 3 patients had ICD therapies used, either ATP or shock. Inappropriate shock was not recorded in any patients. Patients with sustained VT/VF had wider QRS duration (143 ± 41 vs. 99 ± 10 ms, p = 0.03) and a higher incidence of bundle branch block (BBB)/interventricular conduction delay (IVCD) (75% vs. 0%, p = 0.01) compared to those without.

Conclusion

VAs are commonly observed among patients with advanced AL amyloidosis, and ICD therapy can be effective in successfully treating sustained VA in these patients. On the basis of our preliminary data, prophylactic ICD implantation may be proposed to the advanced AL amyloidosis to improve the survival rate in selected patients with advanced AL amyloidosis, especially for the patients with wider QRS duration and BBB/IVCD.

Impact of cardiac conduction disease in patients with cardiac amyloidosis: A national retrospective cohort study

BACKGROUND

There is a paucity of data regarding the impact of cardiac conduction disease (CD) on clinical outcomes in patients with cardiac amyloidosis (CA).

METHODS

The National Inpatient Sample (NIS) was queried to identify all CA admissions and those with CD using ICD-10 codes from 2016 to 2019. We explored baseline characteristics and used multivariate logistic regression to assess the association between CD and several clinical outcomes during index admission; a p-value of <0.05 was significant. Propensity score matching (PSM) was performed to validate our results.

RESULTS

A total of 12,185 patients with CA were identified. Of these, 920 (7.6 %) had CD. The median age of the sample was 72 years (IQR: 64-80). After multivariate adjustment and PSM, the presence of CD in CA was associated with higher odds of ventricular arrhythmias (VA) (aOR = 2.97, 95 % CI 1.78-4.96, p < 0.001), syncope (aOR = 3.44, 95 % CI 1.51-7.83, p = 0.003), and cardiovascular implantable electronic device (CIED) implantation (aOR = 12.86, 95 % CI 5.50-30.04, p < 0.001) but not with sudden cardiac arrest (p = 0.092), acute heart failure (p = 0.060), all-cause in-hospital mortality (p = 0.384), and non-routine discharge in patients admitted for CA (p = 0.271).

CONCLUSIONS

Although CD was not associated with all-cause in-hospital mortality, there was a significant association with VAs and syncope. Syncope is associated with worse survival in patients with CA. Further studies that prospectively follow patients are needed to determine the true effect of cardiac CD on mortality in patients with CA.

Sustained Ventricular Tachycardia as the first presentation of transthyretin amyloid cardiomyopathy

Transthyretin Amyloid Cardiomyopathy (ATTR-CM) was considered an uncommon disease until a few years ago, but advances in the epidemiology and non-invasive diagnostic tests have increased its timely detection. We report a 71 years-old man with history of hypertension and an incidental carcinoma of the left kidney detected 6 years ago, without heart failure who was performed cardiac magnetic resonance images (MRI) by suspicion of hypertrophic cardiomyopathy. Before his cardiologist be aware of the result, he suffered a severe sustained ventricular tachycardia (SVT) that required emergency cardioversion. Echocardiogram and cardiac MRI were suggestive for cardiac amyloidosis and the diagnosis was confirmed by scintigraphy with PYPTc99m (Perugini +3). Serum levels of light chains kappa and lambda were normal, and serum and urine immunofixation were negative; a genetic test had no variants, so supporting an ATTR-CM wild type. PET-CT did not detect metastasis of the renal tumor, but showed cardiac hypermetabolism and pericardial effusion. An implantable cardioverter defibrillator (ICD) was placed and after nine days a shock was delivered by the ICD due to a new event of SVT; in addition a Holter monitoring registered runs of asymptomatic atrial fibrillation. Etiologic treatment for ATTR-CM with Tafamidis 61 mg was started, amiodarone and rivaroxaban were added for control of arrhythmias and prevention of systemic embolism, respectively. After 14 months of follow-up, he is stable in class I NYHA. ATTR-CM is a complex disease, and the treatments should be indicated by a multidisciplinary team that consider the risks, benefits, and costs of each intervention.

Epidemiology, diagnosis, and management of cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative restrictive cardiomyopathy caused by the deposition of amyloid fibrils in the myocardium. It manifests in two primary subtypes: transthyretin cardiac amyloidosis (ATTR) and immunoglobulin light chain cardiac amyloidosis (AL). ATTR is further classified into wild-type and hereditary based on transthyretin gene mutation. Advances in diagnostics and therapeutics have transformed CA from a rare and untreatable condition to a more prevalent and manageable disease. Noninvasive diagnostic tools such as electrocardiography, echocardiography, and cardiac magnetic resonance can raise suspicion for CA; bone scintigraphy can non-invasively confirm ATTR, while AL necessitates histological confirmation. The severity of ATTR and AL can be assessed through serum biomarker-based staging. Treatment approaches differ, ranging from silencing or stabilizing transthyretin and degrading amyloid fibrils in ATTR to employing anti-plasma cell therapies and autologous stem cell transplantation in AL.

Arrhythmic Stratification of Cardiac Amyloidosis: State of the Art

Cardiac amyloidosis is an infiltrative myocardial disease whose prevalence significantly increased in recent years. Its clinical history is changing due to the advent of novel therapies, and careful risk stratification has become impelling. Arrhythmias, frequently found during the course of the disease, include conduction system disease, atrial fibrillation (AF), and ventricular arrhythmias (VAs). Arrhythmic risk stratification is a key to identify those patients at higher risk to develop advanced atrioventricular blocks, asymptomatic AFs, or major VAs. This carries significant clinical implications concerning the indication and timing of implantable cardiac devices, as well as the initiation of anticoagulation therapy.

Electrocardiographic features and rhythm disorders in cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative cardiomyopathy caused by extracellular deposition of amyloid fibrils, mainly derived from transthyretin, either wild-type or hereditary variants, or immunoglobulin light chains misfolding. It is characterized by an increased left ventricular (LV) mass and diastolic dysfunction, which can lead to heart failure with preserved ejection fraction and/or conduction disturbances. The diagnosis is based on invasive pathology demonstration of amyloid deposits, or non-invasive criteria using advanced cardiovascular imaging techniques. Nevertheless, 12-lead electrocardiogram (ECG) remains of crucial importance in the assessment of patients with CA, since they can manifest peculiar features such as low QRS voltages, in discordance with the LV hypertrophy, but also pseudo-infarction patterns, sinus node dysfunction, atrioventricular blocks, premature supraventricular and ventricular beats, which support the presence of a myocardial disease. Great awareness of these common ECG characteristics of CA is needed to increase diagnostic performance and improve patient's outcome. In the present review, we discuss the current role of the ECG in the diagnosis and management of CA, focusing on the most common ECG abnormalities and rhythm disorders.

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

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

Arrhythmias and Device Therapies in Cardiac Amyloidosis

Cardiac amyloidosis is caused by amyloid fibrils that deposit in the myocardial interstitium, causing restrictive cardiomyopathy and eventually death. The electromechanical, inflammatory, and autonomic changes due to amyloid deposition result in arrhythmias. Atrial fibrillation is by far the most common arrhythmia. The rate control strategy is generally poorly tolerated due to restrictive filling physiology and heart rate dependance, favoring adoption of the rhythm control strategy. Anticoagulation for stroke prophylaxis is warranted, irrespective of CHA2DS2-VASc score in patients with a favorable bleeding profile; data on left appendage closure devices are still insufficient. Ventricular arrhythmias are also not uncommon, and the role of implantable cardioverter-defibrillator in cardiac amyloidosis is controversial. There is no evidence of improvement in outcomes when used for primary prevention in these patients. Bradyarrhythmia is most commonly associated with sudden cardiac death in cardiac amyloidosis. Pacemaker implantation can help provide symptomatic relief but does not confer mortality benefit.

Trends in the Prevalence of Infiltrative Cardiomyopathy Among Patients With in-Hospital Cardiac Arrest

Sarcoidosis, amyloidosis, hemochromatosis and scleroderma are the most forms of infiltrative/nonischemic cardiomyopathy (NICM) associated with sudden cardiac death. In patients who undergo in-hospital cardiac arrest, a high index of suspicion is required to rule out NICM as an underlying contributor. We aimed to analyze the prevalence of NICM among patients with in-hospital cardiac arrest and identify factors associated with increased mortality. We analyzed data from the National Inpatient Sample, and identified patients who were hospitalized across 10 years from 2010 to 2019 with a diagnosis of cardiac arrest and NICM. The total number of patients with in-hospital cardiac arrest was 19,34,260. The total number with NICM was 14,803 (0.77%). Mean age was 63 years. Overall prevalence of NICM across the years ranged between 0.75% to 0.9%, with a significant temporal increase (P < 0.01). Incidence of in-hospital mortality ranged between 61% to 76% for females and 30% to 38% for males. The following comorbidities were more prevalent in patients with NICM than those without: heart failure, chronic obstructive pulmonary disease (COPD), chronic kidney disease, anemia, malignancy, coagulopathy, ventricular tachycardia, acute kidney injury and stroke. The following factors were independent predictors of in-hospital mortality-age, female gender, Hispanic race, history of COPD and presence of malignancy (P = 0.042). The prevalence of infiltrative cardiomyopathy in patients with in-hospital cardiac arrest is increasing. Females, older patients and Hispanic population are at an increased risk of mortality. Sex and race-based disparities in the prevalence of NICM in patients with in-hospital cardiac arrest is an area of further research.

Incidence and Predictors of Ventricular Arrhythmias in Transthyretin Amyloid Cardiomyopathy

BACKGROUND

Wild-type transthyretin amyloid cardiomyopathy (wtATTR-CM) is characterized by heart failure, conduction abnormalities and arrhythmias. The incidence of ventricular arrhythmias, particularly ventricular tachycardias (VTs), in wtATTR-CM is unclear. With the development of targeted therapies and improved overall prognosis, there is an unmet need to identify patients at high risk for VTs who might benefit from ICD therapy.

METHODS

Between 2017 and 2022, 72 patients diagnosed with wtATTR-CM were prospectively evaluated for the presence of ventricular arrhythmias using a Holter ECG. VTs were defined as >3 consecutive beats with a heart rate > 100 beats per minute originating from a ventricle.

RESULTS

The incidence of VTs was 44% (n = 32/72) in unselected wtATTR-CM patients. Patients with VT showed significantly more severe left ventricular (LV) hypertrophy (septum diameter 21 ± 2.6 vs. 19 ± 3.0 mm, p = 0.006), reduced LV ejection fraction (47 ± 8 vs. 52 ± 8%, p = 0.014) and larger left atria (32 ± 7 vs. 28 ± 6 mm², p = 0.020), but no differences in cardiac markers such as NTproBNP and troponin. In a multivariable model, LV hypertrophy (LV mass indexed, OR = 1.02 [1.00-1.03], p = 0.031), LV end-diastolic diameter (OR = 0.85 [0.74-0.98], p = 0.021) and LV end-systolic diameter (OR = 1.19 [1.03-1.349], p = 0.092) were predictive for VT occurrence with an area under the receiver operating characteristic of 0.76 [0.65-0.87].

CONCLUSIONS

The incidence of ventricular arrhythmia in wtATTR-CM is high and is associated with an advanced stage of left ventricular disease. Further studies are needed evaluating the role of VTs in predicting sudden cardiac death and the benefit of ICD therapy in wtATTR-CM.

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.

Prevalence of ventricular arrhythmias and role of implantable cardioverter-defibrillator in cardiac amyloidosis

Cardiac amyloidosis is an underdiagnosed disease that is caused by myocardial deposition of misfolded light chain (AL) or transthyretin (ATTR) amyloid fibrils, leading to restrictive cardiomyopathy and eventually death if untreated. Ventricular arrhythmias are common in cardiac amyloidosis, and the prevalence is higher in AL than ATTR. There are multiple suspected pathogenic mechanisms for ventricular arrhythmia including activation of inflammatory cascade from direct amyloid deposition, and electro-mechanical as well as autonomic dysfunction due to systemic amyloid deposition. Cardiac amyloidosis is associated with an increased risk of sudden cardiac death, and the risk is higher in AL than ATTR. Finally, the role of implantable cardioverter-defibrillators in cardiac amyloidosis is controversial, and while successful termination of life-threatening ventricular arrhythmias has been reported in few studies, there has been no evidence of improvement in outcomes when used for primary prevention in patients with cardiac amyloidosis.

Arrhythmic Burden in Cardiac Amyloidosis: What We Know and What We Do Not

Cardiac amyloidosis (CA), caused by the deposition of insoluble amyloid fibrils, impairs different cardiac structures, altering not only left ventricle (LV) systo-diastolic function but also atrial function and the conduction system. The consequences of the involvement of the cardiac electrical system deserve more attention, as well as the study of the underlying molecular mechanisms. This is an issue of considerable interest, given the conflicting data on the effectiveness of conventional antiarrhythmic strategies. Therefore, this review aims at summarizing the arrhythmic burden related to CA and the available evidence on antiarrhythmic treatment in this population.

A Review of Cardiac amyloidosis: Presentation, Diagnosis, and Treatment

Amyloidosis is a group of disorders that can affect almost any organ due to the misfolding of proteins with their subsequent deposition in various tissues, leading to various disease manifestations based on the location. When the heart is involved, amyloidosis can manifest with a multitude of presentations such as heart failure, arrhythmias, orthostatic hypotension, syncope, and pre-syncope. Diagnosis of cardiac amyloidosis can be difficult due to the non-specific nature of symptoms and the relative rarity of the disease. Amyloidosis can remain undiagnosed for years, leading to its high morbidity and mortality due to this delay in diagnosis. Newer imaging modalities, such as cardiac magnetic resonance imaging, advanced echocardiography, and biomarkers, make a timely cardiac amyloidosis diagnosis more feasible. Many treatment options are available, which have provided new hope for this patient population. This manuscript will review the pathology, diagnosis, and treatment options available for cardiac amyloidosis and provide a comprehensive overview of this complicated disease process.

Supportive Care and Symptom Management for Patients With Immunoglobulin Light Chain (AL) Amyloidosis

Immunoglobulin light chain (AL) amyloidosis is a disorder of clonal plasma cells characterized by deposition of amyloid fibrils in a variety of tissues, leading to end-organ injury. Renal or cardiac involvement is most common, though any organ outside the central nervous system can develop amyloid deposition, and symptomatic presentations may consequently vary. The variability and subtlety of initial clinical presentations may contribute to delayed diagnoses, and organ involvement is often quite advanced and symptomatic by the time a diagnosis is established. Additionally, while organ function can improve with plasma-cell-directed therapy, such improvement lags behind hematologic response. Consequently, highly effective supportive care, including symptom management, is essential to improve quality of life and to maximize both tolerance of therapy and likelihood of survival. Considering the systemic nature of the disease, close collaboration between clinicians is essential for effective management.

Defibrillators in heart transplant patients: Not always a shockingly good choice

We know that cardiac implantable cardioverter-defibrillators (ICD)s save lives. The pivotal studies done around 20 years ago confirmed the value of these devices for both primary and secondary prevention of sudden cardiac death (SCD)^1-3 and have led to guideline recommendations for their use in patients with prior episodes of life-threatening sustained ventricular arrhythmias (Class I) or heart failure and a left ventricular ejection fraction (LVEF) of < 35% (Class I) This article is protected by copyright. All rights reserved.

Syncope in patients with transthyretin amyloid cardiomyopathy: clinical features and outcomes

BACKGROUND

We aimed to describe the clinical characteristics, underlying causes and outcomes of syncope in patients with transthyretin amyloid cardiomyopathy (ATTR-CM).

METHODS

The clinical profile and underlying causes of syncopal episodes were reviewed in a cohort of 128 patients with ATTR-CM enrolled from January-2018 to June-2020 in a prospective multicentre registry in 7 hospitals of Galicia (Spain). After enrollment, patients were followed during a median period of 520 days. The effect of syncope on all-cause mortality was assessed by means of multivariate Cox´s regression.

RESULTS

: Thirty (23.4%) patients had a history of previous syncope as a clinical antecedent before being enrolled in the prospective phase of the registry, and 4 (3.1%) experienced a first episode of syncope thereafter. The estimated incidence density rate of syncope during the prospective follow-up period after registry enrolment was 71.9 episodes per 1000 patients-year (95% Confidence Interval (CI) 32.8-111.1). The estimated overall prevalence of syncope was 26.6% (95% CI 18.9%-34.2%). Cardiac arrhythmias (n=11, 32.3%), structural diseases of the heart or great vessels (n=5, 14.7%), a neurally mediated reflex (n=6, 17.6%), and orthostatic hypotension (n=4, 11.8%) were identified as probable underlying causes of syncope; in 8 (23.6%) patients, syncope remained unexplained. Patients with syncope had increased non-adjusted all-cause mortality than patients without it (univariate hazard-ratio 3.37; 95% CI 1.43-7.94). When other independent predictors of survival were added to the survival model, this association was no longer statistically significant (multivariate hazard-ratio 1.81, 95% CI 0.67-4.84).

CONCLUSIONS

Syncope is frequent in patients with ATTR-CM. This study could not demonstrate an independent association between syncope and mortality in those individuals.

Mode of death and outcomes of implantable cardioverter defibrillators in transthyretin amyloid cardiomyopathy

INTRODUCTION

Transthyretin cardiac amyloidosis (ATTR-CM) may associate with sudden cardiac death. We report on the mode of death and outcomes with implantable cardioverter defibrillators (ICDs) in a cohort with ATTR-CM.

METHODS

A single center observational cohort study of patients with ATTR-CM diagnosed between 2005 and 2019. ICD implant was at discretion of treating cardiologists. Medians are expressed with 25th,75th percentiles.

RESULTS

Eighty-four patients with ATTR-CM (age 73.5 ± 9.7 years, 94% male, median follow-up 21.1 months (11.4-38.1). Nineteen patients (23%) underwent ICD implantation - 18 for primary and 1 for secondary prevention. In the primary prevention ICD group, 1 patient had 2 inappropriate shocks, 1 patient had appropriate ATP on 3 occasions. One patient (mixed ischemic cardiomyopathy and ATTR-CM) with secondary prevention ICD had 15 appropriate shocks in 3 episodes of VT storm. In patients without ICD, ambulatory monitoring review (14,764 h) did not reveal sustained ventricular arrhythmia. Excluding the one patient with secondary prevention ICD, 5 (28%) in the primary prevention ICD group and 22 (34%) in the non-ICD group died, p = 0.14. Mode of death did not vary between both groups.

CONCLUSIONS

Patients with ATTR-CM and primary prevention ICD infrequently receive appropriate device therapy without differing in mode of death, which was mainly related to progressive heart failure, compared to those without ICD.

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.

Arrhythmic Sudden Cardiac Death and the Role of Implantable Cardioverter-Defibrillator in Patients with Cardiac Amyloidosis-A Narrative Literature Review

Cardiac amyloidosis (CA) is considered to be associated with an increased risk of sudden cardiac death (SCD) due to ventricular tachyarrhythmias and electromechanical dissociation. However, current arrhythmic risk stratification and the role of an implantable cardioverter-defibrillator (ICD) for primary prevention of SCD remains unclear. This article provides a narrative review of the literature on electrophysiological abnormalities in the context of ventricular arrhythmias in patients with CA and the role of ICD in terms of survival benefit in this group of patients.

Survival Following Implantable Cardioverter-Defibrillator Implantation in Patients With Amyloid Cardiomyopathy

Background Outcomes data in patients with cardiac amyloidosis after implantable cardioverter-defibrillator (ICD) implantation are limited. We compared outcomes of patients with ICDs implanted for cardiac amyloidosis versus nonischemic cardiomyopathies (NICMs) and evaluated factors associated with mortality among patients with cardiac amyloidosis. Methods and Results Using National Cardiovascular Data Registry's ICD Registry data between April 1, 2010 and December 31, 2015, we created a 1:5 propensity-matched cohort of patients implanted with ICDs with cardiac amyloidosis and NICM. We compared mortality between those with cardiac amyloidosis and matched patients with NICM using Kaplan-Meier survival curves and Cox proportional hazards models. We also evaluated risk factors associated with 1-year mortality in patients with cardiac amyloidosis using multivariable Cox proportional hazards regression models. Among 472 patients with cardiac amyloidosis and 2360 patients with propensity-matched NICMs, 1-year mortality was significantly higher in patients with cardiac amyloidosis compared with patients with NICMs (26.9% versus 11.3%, P<0.001). After adjustment for covariates, cardiac amyloidosis was associated with a significantly higher risk of all-cause mortality (hazard ratio [HR], 1.80; 95% CI, 1.56-2.08). In a multivariable analysis of patients with cardiac amyloidosis, several factors were significantly associated with mortality: syncope (HR, 1.78; 95% CI, 1.22-2.59), ventricular tachycardia (HR, 1.65; 95% CI, 1.15-2.38), cerebrovascular disease (HR, 2.03; 95% CI, 1.28-3.23), diabetes mellitus (HR, 1.55; 95% CI, 1.05-2.27), creatinine = 1.6 to 2.5 g/dL (HR, 1.99; 95% CI, 1.32-3.02), and creatinine >2.5 (HR, 4.34; 95% CI, 2.72-6.93). Conclusions Mortality after ICD implantation is significantly higher in patients with cardiac amyloidosis than in patients with propensity-matched NICMs. Factors associated with death among patients with cardiac amyloidosis include prior syncope, ventricular tachycardia, cerebrovascular disease, diabetes mellitus, and impaired renal function.