Electrophysiologic abnormalities in AL (primary) amyloidosis with cardiac involvement

Electrocardiographic Patterns and Arrhythmias in Cardiac Amyloidosis: From Diagnosis to Therapeutic Management-A Narrative Review

Electrophysiological aspects of cardiac amyloidosis (CA) are still poorly explored compared to other aspects of the disease. However, electrocardiogram (ECG) abnormalities play an important role in CA diagnosis and prognosis and the management of arrhythmias is a crucial part of CA treatment. Low voltages and a pseudonecrosis pattern with poor R-wave progression in precordial leads are especially common findings. These are useful for CA diagnosis and risk stratification, especially when combined with clinical or echocardiographic findings. Both ventricular and supraventricular arrhythmias are common in CA, especially in transthyretin amyloidosis (ATTR), and their prevalence is related to disease progression. Sustained and non-sustained ventricular tachycardias' prognostic role is still debated, and, to date, there is a lack of specific indications for implantable cardiac defibrillator (ICD). On the other hand, atrial fibrillation (AF) is the most common supraventricular arrhythmia with a prevalence of up to 88% of ATTR patients. Anticoagulation should be considered irrespective of CHADsVA score. Furthermore, even if AF seems to not be an independent prognostic factor in CA, its treatment for symptom control is still crucial. Finally, conduction disturbances and bradyarrhythmias are also common, requiring pacemaker implantation in up to 40% of patients.

Substrate Characterization and Outcomes of Ventricular Tachycardia Ablation in Amyloid Cardiomyopathy: A Multicenter Study

BACKGROUND

Sustained ventricular tachycardia (VT) in cardiac amyloidosis is uncommon, and the substrate and outcomes of catheter ablation are not defined.

METHODS

We included 22 consecutive patients (mean age, 68±10 years; male sex, 91%) with cardiac amyloidosis (ATTR [transthyretin], n=16; light chain, n=6) undergoing catheter ablation for VT/ventricular fibrillation (VF) between 2013 and 2023 in a retrospective, observational, international study. The primary efficacy outcome was recurrent VT/VF during follow-up, while the primary safety end point included major procedure-related adverse events.

RESULTS

The indication for ablation was drug-refractory VT in 17 patients (77%), and premature ventricular complex-initiated polymorphic VT/VF in 5 patients (23%). Catheter ablation was performed using endocardial (n=17.77%) or endo-epicardial approaches (n=5.23%). Complete endocardial electroanatomical voltage maps of the left and right ventricles were obtained in 17 (77%) and 10 (45%) patients, respectively. Each patient had evidence of low-voltage areas, most commonly involving the interventricular septum (n=16); late potentials were recorded in 16 patients (73%). A median of 1 (1-2) VT was inducible per patient; 12 of the 26 mappable VTs (46%) originated from the interventricular septum. Complete procedural success was achieved in 16 patients (73%), with 4 (18%) major procedure-related adverse events. After a median follow-up of 32 (14-42) months, sustained VT/VF recurrence was observed in 9 patients (41%); survival free from VT/VF recurrence was 56% (95% CI, 36%-86%) at 36-month follow-up, and most patients remained on antiarrhythmic drugs. A significant reduction in per patient implantable cardioverter defibrillator therapies was noted in the 6-month period after ablation (before: 6 [4-9] versus after: 0 [0-0]; P<0.001). In multivariable analysis, complete procedural success was associated with reduced risk of recurrent VT/VF (hazard ratio, 0.002; P=0.034).

CONCLUSIONS

Catheter ablation can achieve control of recurrent VT/VF in more than half of patients with cardiac amyloidosis, and the reduction in VT/VF burden post-ablation may be relevant for quality of life. Septal substrate and risk of procedure-related complications challenge successful management of patients with cardiac amyloidosis and VT/VF.

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

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.

Clinical significance and prognostic value of right bundle branch block in permanent pacemaker patients

AIMS

In patients undergoing pacemaker implantation with no prior history of heart failure (HF), the presence of left bundle branch block (LBBB) has been identified as an independent predictor of HF-related death or hospitalization, while the prognostic significance of right bundle branch block (RBBB) remains uncertain. We aimed to assess the long-term risk of all-cause mortality in patients with a standard indication for permanent pacing and normal or moderately depressed left ventricular function when RBBB is detected at the time of implantation.

METHODS

We retrospectively enrolled 1348 consecutive patients who had undergone single- or dual-chamber pacemaker implantation at the study center, from January 1990 to December 2022. Patients with a left ventricular ejection fraction ≤35% or a prior diagnosis of HF were excluded.

RESULTS

The baseline 12-lead electrocardiogram revealed an RBBB in 241 (18%) and an LBBB in 98 (7%) patients. During a median follow-up of 65 [25th-75th percentile: 32-117] months, 704 (52%) patients died. The combined endpoint of cardiovascular death or HF hospitalization was reached by 173 (13%) patients. On multivariate analysis, RBBB was confirmed as an independent predictor of death [hazard ratio, 1.33; 95% confidence interval (CI), 1.09-1.63; P  = 0.005]. However, when considering the combined endpoint of cardiovascular death and HF hospitalization, this endpoint was independently associated with LBBB (hazard ratio, 2.13; 95% CI, 1.38-3.29; P  < 0.001), but not with RBBB.

CONCLUSION

In patients with standard pacemaker indications and normal or moderately depressed left ventricular function, the presence of basal RBBB was an independent predictor of mortality. However, it was not associated with the combined endpoint of cardiovascular death and HF hospitalization.

Current status and prospect of anti-amyloid fibril therapy in AL amyloidosis

Amyloid light-chain (AL) amyloidosis is a rare hematological disease that produces abnormal monoclonal immunoglobulin light chains to form amyloid fibrils that are deposited in tissues, resulting in organ damage and dysfunction. Advanced AL amyloidosis has a very poor prognosis with a high risk of early mortality. The combination of anti-plasma cell therapy and amyloid fibrils clearance is the optimal treatment strategy, which takes into account both symptoms and root causes. However, research on anti-amyloid fibrils lags far behind research on anti-plasma cells, and there is currently no approved treatment that could clear amyloid fibrils. Nevertheless, anti-amyloid fibril therapies are being actively investigated recently and have shown potential in clinical trials. In this review, we aim to outline the preclinical work and clinical efficacy of fibril-directed therapies for AL amyloidosis.

Amyloidosis and Amyloidogenesis: One Name, Many Diseases

Amyloidosis is a heterogenous group of disorders, caused by the deposition of insoluble fibrils derived from misfolded proteins in the extracellular space of various organs. These proteins have an unstable structure that causes them to misfold, aggregate, and deposit as amyloid fibrils with the pathognomonic histologic property of green birefringence when viewed under cross-polarized light after staining with Congo red. Amyloid fibrils are insoluble and degradation-resistant; resistance to catabolism results in progressive tissue amyloid accumulation. The outcome of this process is organ disfunction independently from the type of deposited protein, however there can be organ that are specifically targeted from certain proteins.

Management of Arrhythmias and Conduction Disorders in Amyloid Cardiomyopathy

Cardiac amyloidosis, a condition characterized by abnormal protein deposition in the heart, leads to restrictive cardiomyopathy and is notably associated with an increased risk of arrhythmias and conduction disorders. This article reviews the current understanding and management strategies for these cardiac complications, with a focus on recent advancements and clinical challenges. The prevalence and impact of atrial arrhythmias, particularly atrial fibrillation, are examined, along with considerations for stroke risk and anticoagulation therapy. The article also addresses the complexities of managing rate and rhythm control, outlining the utility and limitations of pharmacological agents and interventions such as catheter ablation. Furthermore, it reviews the challenges in the treatment of ventricular arrhythmias, including the contentious use of implantable cardioverter-defibrillators for primary and secondary prevention. Individualized approaches, considering the unique characteristics of cardiac amyloidosis, are paramount. Continuous research and clinical exploration are essential to refine treatment strategies and improve outcomes in this challenging patient population.

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.

Prognostic implications of premature ventricular contractions and non-sustained ventricular tachycardia in light-chain cardiac amyloidosis

AIMS

Premature ventricular contractions (PVC) and non-sustained ventricular tachycardia (NSVT) are commonly observed in light chain cardiac amyloidosis (AL-CA), but their association with prognosis is still unclear. We aimed to evaluate the prognostic value of PVCs and NSVT in patients with moderate-to-advanced AL-CA.

METHODS AND RESULTS

We retrospectively included patients with AL-CA at modified 2004 Mayo stages II-IIIb between February 2014 and December 2020. Twenty-four-hour Holter recordings were assessed on admission. The outcomes included (i) new onset of adverse ventricular arrhythmia (VA) or sudden cardiac death (SCD) and (ii) cardiac death during follow-up. Of the 143 patients studied (60.41 ± 11.06 years, male 64.34%), 132 (92.31%) had presence of PVC, and 50 (34.97%) had NSVT on Holter. Twelve (8.4%) patients died in hospital and 131 patients were followed up (median 24.4 months), among whom 71 patients had cardiac death, and 15 underwent adverse VA/SCD. NSVT [hazard ratio (HR): 13.57, 95% confidence interval (CI): 3.06-60.18, P < 0.001], log-transformed PVC counts (HR: 1.46, 95%CI: 1.15-1.86, P = 0.002) and PVC burden (HR: 1.43 95%CI:1.14-1.80, P = 0.002) were predictive of new onset of adverse VA/SCD. The highest tertile of PVC counts (HR: 2.33, 95%CI: 1.27-4.28, P = 0.006) and PVC burden (HR: 2.58, 95%CI: 1.42-4.69, P = 0.002), rather than NSVT (HR: 1.16, 95%CI: 0.67-1.98, P = 0.603), was associated with cardiac death. Higher PVC counts/burden provided incremental value on modified 2004 Mayo stage in predicting cardiac death, with C index increasing from 0.681 to 0.712 and 0.717, respectively (P values <0.05).

CONCLUSION

PVC count, burden, and NSVT significantly correlated with adverse VA/SCD during follow-up in patients with AL-CA. Higher PVC counts/burdens added incremental value for predicting cardiac death.

Predictors and outcomes of pacemaker implantation in patients with cardiac amyloidosis

OBJECTIVE

We sought to investigate prevalence, incidence and prognostic implications of permanent pacemaker (PPM) implantation in patients with cardiac amyloidosis (CA), thereby identifying the predictors of time to PPM implantation.

METHODS

Seven hundred eighty-seven patients with CA (602 men, median age 74 years, 571 transthyretin amyloidosis (ATTR), 216 light-chain amyloidosis (AL)) evaluated at two European referral centres were retrospectively included. Clinical, laboratory and instrumental data were analysed. The associations between PPM implantation and mortality, heart failure (HF) or a composite endpoint of mortality, cardiac transplantation and HF were analysed.

RESULTS

81 (10.3%) patients had a PPM before initial evaluation. Over a median follow-up time of 21.7 months (IQR 9.6-45.2), 81 (10.3%) additional patients (18 with AL (22.2%) and 63 with ATTR (77.8%)) underwent PPM implantation with a median time to implantation of 15.6 months (IQR 4.2-40), complete atrioventricular block was the most common indication (49.4%). Independent predictors of PPM implantation were QRS duration (HR 1.03, 95% CI 1.02 to 1.03, p<0.001) and interventricular septum (IVS) thickness (HR 1.1, 95% CI 1.03 to 1.17, p=0.003). The model to estimate the probability of PPM at 12 months and containing both factors showed a C-statistic of 0.71 and a calibration of slope of 0.98.

CONCLUSIONS

Conduction system disease requiring PPM is a common complication in CA that affects up to 20.6% of patients. QRS duration and IVS thickness are independently associated with PPM implantation. A PPM implantation at 12 months model was devised and validated to identify patients with CA at higher risk of requiring a PPM and who require closer follow-up.

Bradyarrhythmias in Cardiac Amyloidosis and Role of Pacemaker

Cardiac amyloidosis (CA) is an underdiagnosed disease that is caused by deposition of misfolded transthyretin (ATTR) or immunoglobulin light chain (AL) fibrils in the myocardium. Bradyarrhythmias are commonly seen in CA, due to disruption of conducting system by amyloid fibrils. Atrioventricular conduction defect is more common than sinus node dysfunction. Bradyarrhythmias are most prevalent in wtATTR, followed by hATTR and AL. Pacemaker implantation, when indicated, can help provide symptomatic relief but does not confer mortality benefit. Progression of conduction system disease is common and often leads to increased right ventricular pacing burden with time. Therefore, cardiac resynchronizing therapy (biventricular therapy) is often considered as a better and safer option in these patients. Finally, the role of prophylactic pacemaker implantation is controversial, and current guidelines do not recommend prophylactic pacemaker insertion in CA patients.

Arrhythmias in Patients with Cardiac Amyloidosis: A Comprehensive Review on Clinical Management and Devices

Cardiac amyloidosis (CA) is a rare but potentially life-threatening disease in which misfolded proteins accumulate in the cardiac wall tissue. Heart rhythm disorders in CA, including supraventricular arrhythmias, conduction system disturbances, or ventricular arrhythmias, play a major role in CA morbidity and mortality, and thus require supplementary management. Among them, AF is the most frequent arrhythmia during CA hospitalizations and is associated with significantly higher mortality, while ventricular arrhythmias are also common and are usually associated with poor prognosis. Early diagnosis of potential arrythmias could be performed through ECG, Holter monitoring, and/or electrophysiology study. Clinical management of these patients is quite significant, and it usually includes initiation of amiodarone and/or digoxin in patients with AF, potential electrical cardioversion, or ablation in specific patients with indication, as well as initiation of anticoagulants in all patients, independent of AF and CHADS-VASc score, for potential intracardiac thrombus. Moreover, identification of patients with conduction disorders that could benefit from prophylactic pacemaker implantation and/or CRT as well as identification of patients with life-threatening ventricular arrythmias that could benefit from ICD could both increase the survival rates of these patients and improve their quality of life.

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Hepatic Amyloidosis With Multiorgan Involvement

Amyloidosis is a diverse entity that poses both diagnostic and treatment challenges. Whether systemic or local, amyloidosis has varied manifestations including occasional hepatic involvement. Hepatic amyloidosis, although rare, should be on the differential for those with unexplained hepatomegaly, cholestasis, alkaline phosphatase elevations, other associated organomegaly, and those with certain epidemiologic risks. In this study, we report a case of a man with systemic amyloid light chain amyloidosis with multiorgan involvement, acute liver injury, cholestasis, nephrotic syndrome, cardiomegaly, and bleeding diathesis.

Arrhythmic Manifestations of Cardiac Amyloidosis: Challenges in Risk Stratification and Clinical Management

Amylodiosis is a systemic disease characterized by extracellular deposits of insoluble amyloid in various tissues and organs. Cardiac amyloidosis is a frequent feature of the disease, causing a progressive, restrictive type of cardiomyopathy, and is associated with adverse clinical outcomes and increased mortality. The typical clinical presentation in patients with cardiac amyloidosis is heart failure (HF) with preserved ejection fraction. Most patients present with typical symptoms and signs of HF, such as exertional dyspnea, pretibial edema, pleural effusions and angina pectoris due to microcirculatory dysfunction. However, patients may also frequently encounter various arrhythmias, such as atrioventricular nodal block, atrial fibrillation and ventricular tachyarrhythmias. The management of arrhythmias in cardiac amyloidosis patients with drugs and devices is often a clinical challenge. Moreover, predictors of life-threatening arrhythmic events are not well defined. This review intends to give a deepened insight into the arrhythmic features of cardiac amyloidosis by discussing the pathogenesis of these arrhythmias, addressing the challenges in risk stratification and strategies for management in these patients.

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.

Amyloidosis of the Heart: A Comprehensive Review

Cardiac amyloidosis is a progressive, infiltrative cardiomyopathy, whose types are based on various infiltrating amyloids, namely, light chains in primary amyloidosis, mutated transthyretin proteins in hereditary amyloidosis, and wild-type transthyretin proteins in senile amyloidosis. While cardiac amyloidosis has a non-specific presentation, the type-specific presentations may provide some clues to the diagnosis. While tissue biopsy remains the gold standard, other newer non-invasive methods can aid in the diagnostic approach for suspected cardiac amyloidosis. Various medications used to treat heart failure may lead to adverse outcomes in patients with cardiac amyloidosis. More research is needed to understand the adequate management and treatment of cardiac amyloidosis.

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.

Electrocardiographic features and need for pacemaker in cardiac amyloidosis: Analysis of 58 cases

AIM

Amyloidosis is a disease in which amyloid fibrils can be deposited in different cardiac structures, and several electrocardiographic abnormalities can be produced by this phenomenon. The objective of this study was to describe the most common basal electrocardiographic alterations in patients diagnosed with cardiac amyloidosis (CA) and to determine if these abnormalities have an impact on the need of pacemaker.

METHODS

This retrospective study included patients who had an established diagnosis of CA [light-chain cardiac amyloidosis (LA-CA) or transthyretin cardiac amyloidosis (TTR-CA)] between January 2013 and March 2021. The baseline heart rate, the percentage of patients with a pseudo-infarct pattern, low-voltage pattern or cardiac conductions disturbances, and the impact of these factors on the need of pacemaker were analysed.

RESULTS

Fifty-eight patients with CA (20 with LA-CA and 38 with TTR-CA) were included, and the majority were male (69.0%). Twenty-one patients had atrial fibrillation (AF) at diagnosis. Thirty-five patients had a pseudo-infarct pattern, 35% had a low-voltage pattern, and 22% had criteria for ventricular hypertrophy. Two hirds had a conduction disorder: 18 patients with first degree atrioventricular block, 12 right bundle branch block, 3 left bundle branch block and 25 with a branch hemiblock. There were no differences between LA-CA and TTR-CA. Patients with TTR-CA had a greater need for pacemakers in the folow-up (39±40 meses). Bundle branch block was a predictor of the need for a permanent pacemaker (HR: 23.43; CI 95%: 4.09.134.09; P=.01).

CONCLUSIONS

Electrocardiographic abnormalities in patients diagnosed wich CA are heterogeneus. Most frecuent is the presence of conduction disorders, the pseudoinfarction pattern, followed by the low voltage pattern. Patients with any bundle branch block at the baseline electrocardiogram need more frecuent to require a pacemaker during follow-up, especially in TTR-CA.

Cardiovascular Involvement in Transthyretin Cardiac Amyloidosis

Transthyretin cardiac amyloidosis (ATTR-CA) is a systemic disorder resulting from the extracellular deposition of amyloid fibrils of misfolded transthyretin protein in the heart. ATTR-CA is a life-threatening disease, which can be caused by progressive deposition of wild type transthyretin (wtATTR) or by aggregation of an inherited mutated variant of transthyretin (mATTR). mATTR Is a rare condition transmitted in an autosomal dominant manner with incomplete penetrance, causing heterogenous phenotypes which can range from predominant neuropathic involvement, predominant cardiomyopathy, or mixed. Diagnosis of ATTR-CA is complex and requires integration of different imaging tools (echocardiography, bone scintigraphy, magnetic resonance) with genetics, clinical signs, laboratory tests, and histology. In recent years, new therapeutic agents have shown good efficacy and impact on survival and quality of life in this subset of patients, nevertheless patients affected by ATTR-CA may still carry an unfavorable prognosis, thus highlighting the need for new therapies. This review aims to assess cardiovascular involvement, diagnosis, and management of patients affected by ATTR-CA.

Right Ventricular Endocardial Mapping and a Potential Arrhythmogenic Substrate in Cardiac Amyloidosis-Role of ICD

Patients with cardiac amyloidosis (CA) have an increased risk of sudden cardiac death. (SCD). However, the role of an implantable cardioverter-defibrillator in the primary prevention of SCD in this group of patients is still controversial. We present a case with CA with recurrent syncope and non-sustained ventricular tachycardia. In order to further stratify the risk of SCD, an electrophysiological study with endocardial electroanatomic voltage mapping was performed prior to the ICD placement.

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Conduction abnormalities and role of cardiac pacing in cardiac amyloidosis: A systematic review

Cardiac amyloidosis (CA) is an increasingly recognized cause of heart failure, characterized by extracellular deposition of insoluble protein fibrils leading to progressive myocardial dysfunction. The most common types of cardiac amyloidosis are immunoglobin light-chain (AL) and transthyretin (ATTR). Conduction abnormalities are commonly encountered among patients with cardiac amyloidosis and are an important cause of morbidity and mortality. Abnormalities range from infra-Hisian intraventricular conduction delay and bundle branch block to complete atrioventricular block. Pacemaker placement in CA patients follows established guidelines, similar to those for patients without CA, with generally good efficacy. The role and appropriate timing of pacemakers for primary prevention of brady-arrhythmias in CA remains uncertain. While biventricular (BiV) pacing has been shown to improve clinical outcomes in patients with systolic heart failure without CA, there are few data examining the utility of BiV pacing in patients with CA. With the advent of effective treatments for AL and ATTR, appropriate application of pacing is important to support patients with CA and conduction disease through therapeutic trials. This systematic review summarizes the current literature examining the utility of pacing in CA.

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.

Electrocardiographic left ventricular strain pattern, ST-segment depression and atrial fibrillation at the time of diagnosis of systemic light chain amyloidosis: Incidence and clinical significance

BACKGROUND

ST/T abnormalities recognized as electrocardiographic (ECG) left ventricular (LV) strain pattern are known as a marker of myocyte death and reduced survival. The purpose of this study was to determine whether ECG LV strain pattern, its components and atrial fibrillation (AF) predict lower survival at the time of diagnosis of systemic light chain (AL) amyloidosis.

METHODS

12‑lead surface electrocardiogram (ECG), standard two-dimensional echocardiography, laboratory analyses were retrospectively evaluated within 2 months of diagnosis in 87 patients with biopsy-proven systemic AL amyloidosis from 2009 to 2017 in a single center. ECG strain pattern was defined as coexistence of ST-segment horizontal or downward sloping depression ≥0.05 mV at its most horizontal section and negative asymmetrical T-wave deeper than 0.1 mV in at least 1 of leads I,aVL,V1-V6. Patients with QRS >120 ms (BBB or major IVCD) were excluded from the analysis.

RESULTS

Kaplan-Meier survival analysis revealed a 1.8-fold shorter overall survival (OS) at 2 years in the ECG strain (21% of participants) group (p = 0.0078), 2.0-fold shorter OS in the ST-segment depression (STd) (isolated and strain related as one group) (34% of participants) group (p < 0.0001), and 3.9-fold shorter OS in AF (23% of participants) group (p < 0.0001) compared with those without. Median survival of patients with STd and AF were and 13.0 (range 1-74) and 9.5 (range 1-74) months respectively. In univariate analysis STd and AF were stronger predictors of inferior OS than relative wall thickness, average E/e' ratio, and LV ejection fraction, but weaker predictors of OS than B-type natriuretic peptide. In multivariate analysis STd and AF lost significance after adjustment for age, gender, number of organs involved and BNP.

CONCLUSIONS

ST-segment depression and AF were not significantly associated with reduced survival in AL amyloidosis at diagnosis.

Left ventricular hypertrophy and sudden cardiac death

Sudden cardiac death (SCD) is among the leading causes of death worldwide, and it remains a public health problem, as it involves young subjects. Current guideline-directed risk stratification for primary prevention is largely based on left ventricular (LV) ejection fraction (LVEF), and preventive strategies such as implantation of a cardiac defibrillator (ICD) are justified only for documented low LVEF (i.e., ≤ 35%). Unfortunately, only a small percentage of primary prevention ICDs, implanted on the basis of a low LVEF, will deliver life-saving therapies on an annual basis. On the other hand, the vast majority of patients that experience SCD have LVEF > 35%, which is clamoring for better understanding of the underlying mechanisms. It is mandatory that additional variables be considered, both independently and in combination with the EF, to improve SCD risk prediction. LV hypertrophy (LVH) is a strong independent risk factor for SCD regardless of the etiology and the severity of symptoms. Concentric and eccentric LV hypertrophy, and even earlier concentric remodeling without hypertrophy, are all associated with increased risk of SCD. In this paper, we summarize the physiology and physiopathology of LVH, review the epidemiological evidence supporting the association between LVH and SCD, briefly discuss the mechanisms linking LVH with SCD, and emphasize the need to evaluate LV geometry as a potential risk stratification tool regardless of the LVEF.

Cardiac Amyloidosis for the Primary Care Provider: A Practical Review to Promote Earlier Recognition of Disease

Cardiac amyloidosis is increasingly recognized as an underdiagnosed cause of heart failure. Diagnostic delays of up to 3 years from symptom onset may occur, and patients may be evaluated by more than 5 specialists prior to receiving the correct diagnosis. Newly available therapies improve clinical outcomes by preventing amyloid fibril deposition and are usually more effective in early stages of disease, making early diagnosis essential. Better awareness among primary care providers of the clinical presentation and modern treatment landscape is essential to improve timely diagnosis and early treatment of this disease. In this review, we provide practical guidance on the epidemiology, clinical manifestations, diagnostic evaluation, and treatment of transthyretin and light chain cardiac amyloidosis to promote earlier disease recognition among primary care providers.

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.

A case of AL amyloidosis presenting with refractory ventricular fibrillation

A 66-year-old male with recent diagnosis of heart failure with reduced ejection fraction was referred to our institution for management of cardiogenic/vasodilatory shock. During his evaluation, he suffered a sudden cardiac arrest from refractory ventricular tachycardia/fibrillation (VT/VF) despite normal electrolytes and no evidence of prior ventricular arrhythmias. He was placed on rescue peripheral veno-arterial extracorporeal membrane oxygenation support (VA-ECMO) for 4 days and was decannulated without end-organ damage. Continued workup revealed Mayo stage IV immunoglobulin light chain (AL) amyloidosis. Unfortunately, he developed acute cerebellar hemorrhage several days later. Autopsy findings were consistent with AL amyloidosis, with extensive cardiac fibrosis and amyloid deposition in the myocardium and vasculature. While the most common cause of cardiac death in patients with amyloidosis is severe bradycardia and pulseless electrical activity, sustained ventricular arrhythmias have been reported. The use of implantable cardioverter defibrillators (ICD) is highly debated in this population given the lack of survival benefit. Our patient also developed refractory VT/VF arrest, and ICD shocks would not have rescued him while causing significant distress. Emergent VA-ECMO cannulation allowed us to make a diagnosis, yet this intervention cannot be routinely recommended given the limited survival of patients with AL amyloidosis.

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

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.

Diagnosis and treatment of cardiac amyloidosis: an interdisciplinary consensus statement

The prevalence and significance of cardiac amyloidosis have been considerably underestimated in the past; however, the number of patients diagnosed with cardiac amyloidosis has increased significantly recently due to growing awareness of the disease, improved diagnostic capabilities and demographic trends. Specific therapies that improve patient prognosis have become available for certain types of cardiac amyloidosis. Thus, the earliest possible referral of patients with suspicion of cardiac amyloidosis to an experienced center is crucial to ensure rapid diagnosis, early initiation of treatment, and structured patient care. This requires intensive collaboration across several disciplines, and between resident physicians and specialized centers. The aim of this consensus statement is to provide guidance for the rapid and efficient diagnosis and treatment of light-chain amyloidosis and transthyretin amyloidosis, which are the most common forms of cardiac amyloidosis.

Mortality in Patients With Right Bundle-Branch Block in the Absence of Cardiovascular Disease

Background Right bundle-branch block (RBBB) occurs in 0.2% to 1.3% of people and is considered a benign finding. However, some studies have suggested increased risk of cardiovascular morbidity and mortality. We sought to evaluate risk attributable to incidental RBBB in patients without prior diagnosis of cardiovascular disease (CVD). Methods and Results We reviewed the Mayo Clinic Integrated Stress Center database for exercise stress tests performed from 1993 to 2010. Patients with no known CVD-defined as absence of coronary disease, structural heart disease, heart failure, or cerebrovascular disease-were selected. Only Minnesota residents were included, all of whom had full mortality and outcomes data. There were 22 806 patients without CVD identified; 220 of whom (0.96%) had RBBB, followed for 6 to 23 years (mean 12.4±5.1). There were 8256 women (36.2%), mean age was 52±11 years; and 1837 deaths (8.05%), including 645 cardiovascular-related deaths (2.83%), occurred over follow-up. RBBB was predictive of all-cause (hazard ratio [HR], 1.5; 95% CI, 1.1-2.0; P=0.0058) and cardiovascular-related mortality (HR,1.7; 95% CI, 1.1-2.8; P=0.0178) after adjusting for age, sex, diabetes mellitus, hypertension, obesity, current and past history of smoking, and use of a heart rate-lowering drug. Patients with RBBB exhibited more hypertension (34.1% versus 23.7%, P<0.0003), decreased functional aerobic capacity (82±25% versus 90±24%; P<0.0001), slower heart rate recovery (13.5±11.5 versus 17.1±9.4 bpm; P<0.0001), and more dyspnea (28.2% versus 22.4%; P<0.0399) on exercise testing. Conclusions Patients with RBBB without CVD have increased risk of all-cause mortality, cardiovascular-related mortality, and lower exercise tolerance. These data suggest RBBB may be a marker of early CVD and merit further prospective evaluation.

Ventricular Arrhythmias in Cardiac Amyloidosis: A Review of Current Literature

Cardiac Amyloidosis is an infiltrative cardiomyopathy which occurs secondary to deposition of mis-folded protein in the myocardium, with the two most common subtypes being AL amyloidosis and TTR amyloidosis. The pathogenesis of the disease is multifaceted and involves a variety of mechanisms including an inflammatory response cascade, oxidative stress and subsequent separation of myocyte fibrils. Cardiac Amyloidosis frequently results in congestive cardiac failure and arrhythmias, from a disruption in cardiac substrate with subsequent electro-mechanical remodelling. Disease progression is usually demonstrated by development of progressive pump failure, which may be seen with a high arrhythmic burden, usually portending a poor prognosis. There is a paucity of literature on the clinical implications of ventricular arrhythmias in the context of cardiac amyloidosis. The important diagnostic investigations for these patients include transthoracic echocardiography, cardiac magnetic resonance imaging and an electrophysiology study. Whilst there are no robust management guidelines, studies have indicated benefits from contemporary pharmacological therapy and case-by-case catheter ablation. There are novel directed therapies available for TTR amyloidosis that have shown to improve overall survival. The role of ICD therapy in cardiac amyloidosis is controversial, with benefits seen predominantly in early phases of the disease process. The only definitive surgical therapy includes heart transplantation, but is largely indicated for progressive decompensated heart failure (Figure 1). Further large-scale studies are required to better outline management paradigms for treating ventricular arrhythmias in cardiac amyloidosis.

Association of Arrhythmias in Cardiac Amyloidosis and Cardiac Sarcoidosis

Cardiac involvement in amyloidosis and sarcoidosis is poorly understood, and is associated with high morbidity and mortality. Atrial and ventricular arrhythmias, along with conduction defects, are frequent in cardiac amyloidosis and sarcoidosis. Atrial dysfunction in cardiac amyloidosis may result in atrial fibrillation and increases the risk of stroke, making anticoagulation significant and challenging. Ventricular arrhythmia and conduction defects are more common in AL amyloidosis and cardiac sarcoidosis. Premature ventricular contractions (PVCs) from Purkinje fibers trigger ventricular arrhythmias in cardiac amyloidosis, while the inflammation and scarring leading to the reentrant process is the cause in cardiac sarcoidosis. The typical treatment modalities include Class II and III antiarrhythmic drugs and ablation techniques, while corticosteroids and immunosuppressants are indicated in cardiac sarcoidosis to reduce the burden of the disease and arrhythmias. Sudden cardiac death can be a manifestation of both disorders that can be prevented by the Implantable cardioverter-defibrillator (ICD), although the predictive risk factors for primary prevention remain uncertain. In this review, we addressed the current understanding of the pathways involved in inducing arrhythmias in cardiac amyloidosis and sarcoidosis-also, the complications including sudden death and stroke associated with arrhythmia in both diseases. We have discussed other preventive steps needed to minimize arrhythmias to provide symptomatic relief and palliation to patients.

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.

Cardiac Care of Patients with Cardiac Amyloidosis

Cardiac amyloidosis, the majority of cases of which are due to immunoglobulin light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR), affects different aspects of the heart and cardiovascular system. Amyloid-induced cardiomyopathy, clinically manifesting with heart failure and electrophysiological abnormalities, has distinct characteristics compared to non-amyloid cardiomyopathies. Accordingly, specific management strategies are required. This paper will review the cardiovascular manifestations of patients with cardiac amyloidosis and their suggested treatment strategies, emphasizing the importance of multidisciplinary care.

Direct Current Cardioversion of Atrial Arrhythmias in Adults With Cardiac Amyloidosis

BACKGROUND

Arrhythmias, conduction abnormalities, and intracardiac thrombus are common in patients with cardiac amyloidosis (CA). Outcomes of direct-current cardioversion (DCCV) for atrial arrhythmias in patients with CA are unknown.

OBJECTIVES

This study sought to examine DCCV procedural outcomes in patients with CA.

METHODS

Patients with CA scheduled for DCCV for atrial arrhythmias from January 2000 through December 2012 were identified and matched 2:1 with control patients by age, sex, type of atrial arrhythmia, and date of DCCV.

RESULTS

CA patients (n = 58, mean age 69 ± 9 years, 81% male) were included. CA patients had a significantly higher cardioversion cancellation rate (28% vs. 7%; p < 0.001) compared with control patients, mainly due to intracardiac thrombus identified on transesophageal echocardiogram (13 of 16 [81%] vs. 2 of 8 [25%]; p = 0.02); 4 of 13 of the CA patients (31%) with intracardiac thrombus on transesophageal echocardiogram received adequate anticoagulation ≥3 weeks and another 2 of 13 (15%) had arrhythmia duration <48 h. DCCV success rate (90% vs. 94%; p = 0.4) was not different. Procedural complications were more frequent in CA versus control patients (6 of 42 [14%] vs. 2 of 106 [2%]; p = 0.007); complications in CA included ventricular arrhythmias in 2 and severe bradyarrhythmias requiring pacemaker implantation in 2. The only complication in the control group was self-limited bradyarrhythmias.

CONCLUSIONS

Patients with CA undergoing DCCV had a significantly high cancellation rate mainly due to a high incidence of intracardiac thrombus even among patients who received adequate anticoagulation. Although the success rate of restoring sinus rhythm was high, tachyarrhythmias and bradyarrhythmias complicating DCCV were significantly more frequent in CA patients compared with control patients.

Use of Implantable Electronic Devices in Patients With Cardiac Amyloidosis

Arrhythmias are a major cause of morbidity and mortality in the course of cardiac amyloidosis (CA). Less commonly, they may be the initial manifestation that lead to the diagnosis. With improved therapeutic interventions for amyloidosis, it is no longer considered to be a terminal untreatable condition, and there is increasing recognition of the role of implantable electronic devices in CA. The frequency and nature of arrhythmias are largely determined by the type of amyloidosis. Bradyarrhythmias are more common in the transthyretin form of amyloidosis, and risk for ventricular arrhythmias is higher in the light-chain form. Pacemaker implantation is often required and effective for alleviation of symptoms. The role of implantable cardioverter-defibrillators (ICDs) remains controversial, especially for primary prevention of sudden death. Traditional risk stratification tools for sudden death do not appear to be applicable to CA, because decline of left ventricular (LV) systolic dysfunction to the point of the usual indication for an ICD implant in other cardiomyopathies, ie, LV ejection fraction ≤ 35%, usually marks end-stage disease in CA when pump failure becomes the predominant cause of death. The challenge remains the identification of markers for sudden death in early stages of the disease. Included in this review is a general overview of available data on the nature of bradycardia and ventricular arrhythmias, including the role of implantable electronic devices for the treatment of these conditions. Published series of ICD use in CA are summarized and the role of newer pacing techniques, including biventricular pacing, is discussed.

Clinical characteristics and prognosis of Chinese patients with hereditary transthyretin amyloid cardiomyopathy

BACKGROUND

Hereditary transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognized progressive cardiomyopathy with heterogenous clinical manifestations that lead to its misdiagnosis and poor prognosis. This study was performed to describe the clinical characteristics and natural history of Chinese patients to improve clinical awareness of this condition.

METHODS

In this study, we retrospectively investigated 23 patients with a confirmed diagnosis of hereditary ATTR-CM in Peking Union Medical College hospital from From January 1, 2000 to December 31, 2018.

RESULTS

In all, 16 patients (69.6%) were males, the median age at disease onset was 45 (33,55) years old. The median duration from symptom onset to diagnosis was 30 (18,46) months. Phenotypes were classified as exclusively cardiac (n = 1, 4.3%) and mixed type (n = 22, 95.6%). The common mutations were Gly47Arg (7 patients [30.4%]) and Val30Ala (3 patients [13%]). Ventricular hypertrophy was observed in 23 (100%) patients, the mean thickness of the ventricular septum was 16.1 ± 3.9 mm, the mean thickness of the left ventricular posterior wall was 15.1 ± 2.8 mm. The mean left ventricle ejection fraction (LVEF) was 57.3 ± 11.9% and only 5 patients (21.7%) had LVEF < 50%. 18 (78.3%) patients had abnormal electrocardiography and the most common feature was pseudoinfarct pattern (56.5%). Overall survival at 12, 24, 36, 48, and 60 months after diagnosis was 77.8, 55.6, 38.9, 27.8, and 11.1%, respectively. Survival was better in patients with EF ≥50% than in those with EF < 50% [log Rank (Mantel-Cox), χ2 = 4.03, P = 0.045].

CONCLUSIONS

The clinical characteristics of ATTR are heterogeneous: men are more likely to be affected and onset symptoms are not obvious in the heart and mainly include peripheral neuropathy and autonomic neuropathy; however, LV hypertrophy, especially a thick ventricular septum and posterior wall with preserved LVEF, are often detected on echocardiography. Abnormal ECG manifestations are common. The prognosis is poor, and patients with EF > 50% have better survival. Clinicians should be more aware of the complex clinical profile of ATTR amyloidosis to avoid misdiagnosis in practice.

Arrhythmias in hematopoietic stem cell transplantation: A systematic review and meta-analysis

BACKGROUND

There are controversial data regarding the relationship between hematopoietic stem cell transplantation and arrhythmias. This meta-analysis was performed to evaluate the incidence of arrhythmias in patients following hematopoietic stem cell transplantation (HSCT).

METHODS

A literature search was conducted utilizing MEDLINE, EMBASE, and Cochrane Databases from inception through April 2019. Pooled incidence with 95% confidence interval (CI) were calculated using random-effects meta-analysis. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42019131833).

RESULTS

Thirteen studies consisting of 10,587 patients undergoing HSCT were enrolled in this systematic review. Overall, the pooled estimated incidence of all types of arrhythmias following HSCT was 7.2% (95% CI: 4.9%-10.5%). With respect to the most common type of arrhythmia, the pooled estimated incidence of atrial fibrillation/atrial flutter (AF/AFL) within 30 days following HSCT was 4.2% (95% CI: 1.7%-9.6%). Egger's regression test demonstrated no significant publication bias in this meta-analysis of post-HSCT arrhythmia incidence.

CONCLUSION

The overall estimated incidence of arrhythmias following HSCT was 7.2%. Future large scale studies are needed to further elucidate the significance and clinical impact of arrhythmias in post-HSCT patients.