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.

Clinical classification of rare cardiac arrhythmogenic and conduction disorders, and rare arrhythmias.

INTRODUCTION Rare cardiovascular diseases and disorders (RCDDs) constitute an important clinical problem, and their proper classification is crucial for expanding knowledge in the field of RCDDs. OBJECTIVES The aim of this paper is to provide an updated classification of rare arrhythmogenic and conduction disorders, and rare arrhythmias (RACDRAs). METHODS We performed a search for RACDRAs using the Orphanet inventory of rare diseases, which includes diseases with a prevalence of no more than 5 per 10 000 in the general population. We supplemented this with a search of PubMed and Scopus databases according to a wider definition proposed by the European Parliament and the Council of the European Union. RESULTS RACDRAs are categorized into 2 groups, primary electrical disorders of the heart and arrhythmias in specific clinical settings. The first group is further divided into subgroups of major clinical presentation: disorders predisposing to supraventricular tachyarrhythmias, ventricular tachyarrhythmias, bradyarrhythmias, and others. The second group includes iatrogenic arrhythmias or heart rhythm disturbances related to medical treatment, arrhythmias associated with metabolic disorders, and others. We provide a classification of RACDRAs and supplement them with respective RCDDs codes. CONCLUSION The clinical classification of RACDRAs may form a basis to facilitate research and progress in clinical practice, both in diagnostic and therapeutic approaches.

Feasibility of complex transfemoral electrophysiology procedures in patients with inferior vena cava filters.

BACKGROUND: The presence of inferior vena cava filters (IVCFs) has been considered a relative contraindication to electrophysiology (EP) procedures that require transfemoral venous placement of multiple catheters and/or long sheaths. There are inadequate data related to complex EP procedures in this population. OBJECTIVE: The purpose of this study was to describe the experience of a single high-volume center with respect to complex EP procedures in patients with IVCFs. METHODS: Patients with IVCFs undergoing complex EP procedures between 2004 and 2018 were identified. Clinical characteristics, IVCF type, procedural findings, and complications were analyzed. RESULTS: Fifty complex ablation procedures were performed in 40 patients (mean age 63.8 ± 10.9 years; 68% men). The mean IVCF dwell time was 69.1 ± 19.1 months, and 48 patients (96%) were on chronic oral anticoagulation. Procedures included ablation of atrial fibrillation (n = 21), ventricular tachycardia (n = 20), supraventricular tachycardia (n = 3), cavotricuspid isthmus flutter (n = 3), supraventricular tachycardia and cavotricuspid isthmus flutter (n = 1), and transvenous lead extraction (n = 3). Twenty procedures included quadripolar catheters (mean 1.4 ± 0.75), and 33 procedures involved deflectable decapolar catheters (mean 1.7 ± 0.47). Long sheaths were used in 35 cases (mean 1.63 ± 0.49) and intracardiac echocardiography in 38. In 4 cases (involving 3 patients), the IVCF was occluded and could not be crossed. There were no procedural complications related to the IVCF. CONCLUSION: The substantial majority of IVCFs in patients presenting for complex EP procedures were patent and easily crossed under fluoroscopic guidance. The presence of an IVCF should not discourage operators from performing procedures that require transfemoral deployment of multiple catheters and/or sheaths.

[Severe cardiac arrhythmias]. / Les troubles du rythme cardiaque sévères.

Cardiac arrhythmias are a common cause of admission in the emergency department. Among these, atrio-ventricular conductive disorders and malignant ventricular arrhythmias are among the most severe, requiring prompt and appropriate management to ensure the best prognosis. Knowledge of the pathophysiology and etiology causing these arrhythmias is mandatory in order to understand its management, acute and chronic, and to facilitate the dialogue between emergency physicians and cardiologists.

Les arythmies cardiaques sont une cause fréquente d'admission aux urgences. Parmi celles-ci, les troubles conductifs atrio-ventriculaires et les arythmies ventriculaires et supraventriculaires malignes sont à classer parmi les plus sévères. Elles nécessitent une prise en charge rapide et appropriée afin de garantir le meilleur pronostic possible aux patients. La connaissance de la physiopathologie et des étiologies engendrant ce type d'arythmie est nécessaire afin d'en comprendre la prise en charge, aiguë et chronique, et de faciliter le dialogue entre urgentistes et cardiologues.

Burden of arrhythmia in recreational marijuana users.

Marijuana or Cannabis is extensively used as a recreational substance globally. Case reports have reported cardiac arrhythmias immediately following recreational marijuana use. However, the burden of arrhythmias in hospitalized marijuana users have not been evaluated through prospective or cross-sectional studies. Therefore, we planned to measure temporal trends of the frequency of arrhythmias in hospitalized marijuana users using National Inpatient Sample (NIS) database in the United States.

[Congenital Cardiac Conduction Abnormalities].

Abnormalities in cardiac conduction can occur due to a variety of factors. So called "idiopathic", conduction system degeneration develops without evident causes and may have hereditary basis. In the majority of cases it has no clinical manifestation, do not require treatment and have overall good prognosis. In this review we focus on congenital complete atrioventricular block and progressive cardiac conduction defect - rare but malignant and potentially lethal conditions that can be caused by genetic mutations and may be isolated or associated with structural heart disease. Cardiac involvement is relatively common in rare hereditary diseases - myodystrophies and mitochondrial cytopathies. Conduction abnormalities are among the most severe manifestations that may determine prognosis in these rare genetic disorders. These conditions deserve special consideration because of rapid progression of conduction defects and high prevalence of sudden cardiac death if no appropriate treatment applied.

A comparison of genetic findings in sudden cardiac death victims and cardiac patients: the importance of phenotypic classification.

Sudden cardiac death (SCD) is responsible for a large proportion of non-traumatic, sudden and unexpected deaths in young individuals. Sudden cardiac death is a known manifestation of several inherited cardiac diseases. In post-mortem examinations, about two-thirds of the SCD cases show structural abnormalities at autopsy. The remaining cases stay unexplained after thorough investigations and are referred to as sudden unexplained deaths. A routine forensic investigation of the SCD victims in combination with genetic testing makes it possible to establish a likely diagnosis in some of the deaths previously characterized as unexplained. Additionally, a genetic diagnose in a SCD victim with a structural disease may not only add to the differential diagnosis, but also be of importance for pre-symptomatic family screening. In the case of SCD, the optimal establishment of the cause of death and management of the family call for standardized post-mortem procedures, genetic screening, and family screening. Studies of genetic testing in patients with primary arrhythmia disorders or cardiomyopathies and of victims of SCD presumed to be due to primary arrhythmia disorders or cardiomyopathies, were systematically identified and reviewed. The frequencies of disease-causing mutation were on average between 16 and 48% in the cardiac patient studies, compared with ∼10% in the post-mortem studies. The frequency of pathogenic mutations in heart genes in cardiac patients is up to four-fold higher than that in SCD victims in a forensic setting. Still, genetic investigation of SCD victims is important for the diagnosis and the possible investigation of relatives at risk.

Abnormal electrocardiographic QRS transition zone and risk of mortality in individuals free of cardiovascular disease.

AIMS: We examined the prognostic significance of abnormal electrocardiographic QRS transition zone (clockwise and counterclockwise horizontal rotations) in individuals free of cardiovascular disease (CVD). METHODS AND RESULTS: A total of 5541 adults (age 53 ± 10.4 years, 54% women, 24% non-Hispanic black, 25% Hispanic) without CVD or any major electrocardiogram (ECG) abnormalities from the US Third National Health and Nutrition Examination Survey were included in this analysis. Clockwise and counterclockwise horizontal rotations were defined from standard 12-lead ECG using Minnesota ECG Classification. Mortality and cause of death were assessed through 2006. At baseline, 282 participants had clockwise rotation and 3500 had counterclockwise rotation. During a median follow of 14.6 years, 1229 deaths occurred of which 415 were due to CVD. In multivariable-adjusted Cox proportional hazard analysis and compared with normal rotation, clockwise rotation was significantly associated with increased risk of all-cause mortality {hazard ratio (HR) [95% confidence interval (CI)]: 1.43 (1.15-1.78); P = 0.002} and CVD mortality [HR (95% CI): 1.61 (1.09, 2.37) P = 0.016]. In contrast, counterclockwise rotation was associated with significantly lower risk of all-cause mortality [HR (95% CI): 0.86 (0.76, 0.97); P = 0.017] and non-significant association with CVD mortality [HR (95% CI): 1.07 (0.86, 1.33); P = 0.549]. These results were consistent in subgroup analysis stratified by age, sex, and race. CONCLUSION: In a diverse community-based population free of CVD and compared with normal rotation, clockwise rotation was associated with increased risk of all-cause and CVD mortality while counterclockwise rotation was associated with lower risk of all-cause mortality and non-significant association with CVD mortality. These findings call for attention to these often neglected ECG markers, and probably call for revising the current definition of normal rotation.

Fuzzy rough sets, and a granular neural network for unsupervised feature selection.

A granular neural network for identifying salient features of data, based on the concepts of fuzzy set and a newly defined fuzzy rough set, is proposed. The formation of the network mainly involves an input vector, initial connection weights and a target value. Each feature of the data is normalized between 0 and 1 and used to develop granulation structures by a user defined α-value. The input vector and the target value of the network are defined using granulation structures, based on the concept of fuzzy sets. The same granulation structures are also presented to a decision system. The decision system helps in extracting the domain knowledge about data in the form of dependency factors, using the notion of new fuzzy rough set. These dependency factors are assigned as the initial connection weights of the proposed network. It is then trained using minimization of a novel feature evaluation index in an unsupervised manner. The effectiveness of the proposed network, in evaluating selected features, is demonstrated on several real-life datasets. The results of FRGNN are found to be statistically more significant than related methods in 28 instances of 40 instances, i.e., 70% of instances, using the paired t-test.

Long-term follow-up of arrhythmia characteristics and clinical outcomes in heart transplant patients.

INTRODUCTION: Arrhythmias occur frequently after heart transplantation (HT), but knowledge of their impact on long-term outcomes is limited. This study sought to investigate the characteristics of the arrhythmias among biatrial orthotopic HT patients during long-term follow-up. METHODS: This study included 217 patients who received biatrial orthotopic HT. Patients were classified into 5 groups according to the arrhythmia episodes that occurred >1 month after HT: no arrhythmias (group 1; n = 149); atrial tachyarrhythmias only (group 2; n = 34); ventricular tachyarrhythmias only (group 3; n = 9); bradyarrhythmias only (group 4; n = 7); or double/triple arrhythmias (group 5; n = 18). We analyzed their long-term outcomes respectively. RESULTS: During 83 ± 51 months of follow-up, all-cause mortality rates were higher in groups 3 (88.9%) and 5 (72.2%) compared with the other groups (groups 1, 2, and 4: 21.5%, 41.2%, and 57.1%, respectively; P < .001). Cardiovascular mortality rates were higher in groups 4 (42.9%) and 5 (61.1%) compared with the other groups (groups 1, 2, and 3: 8.1%, 20.6%, and 0% respectively; P < .001). Noncardiovascular mortality rate was greater in group 3 (88.9%) compared with the other groups (groups 1, 2, 4, and 5: 13.4%, 20.6%, 14.3%, and 11.1%, respectively; P < .001). Sudden death rates were higher in groups 4 (42.9%) and 5 (44.4%) compared with the other groups (groups 1, 2, and 3: 7.4%, 8.8%, and 0%, respectively; P < .001). CONCLUSION: Patients with posttransplantation arrhythmias experienced significantly worse clinical outcomes.

Arrhythmia type after persistent atrial fibrillation ablation predicts success of the repeat procedure.

BACKGROUND: The aim of the study was to investigate whether the type of arrhythmia recurrence after ablation of persistent atrial fibrillation (AF) has an impact on the maintenance of sinus rhythm after the repeat ablation procedure. METHODS AND RESULTS: Included were 78 consecutive patients (82% men; mean age, 61±10 years; mean left atrial diameter, 47±4 mm) with persistent AF who underwent ≥1 repeat ablation. The initial ablation procedure had consisted of pulmonary vein isolation with additional substrate modification (ablation of complex fractionated atrial electrograms [n=63] or linear lesions [n=15]). Patients presented for reablation either with persistent atrial tachycardia (AT) (group 1, n=36), persistent AF (group 2, n=37), or paroxysmal AF (group 3, n=5). The primary end point was freedom from any arrhythmia off antiarrhythmic drugs 6 and 9 months after the reablation procedure. Estimated proportions of patients reaching the primary end point were 59% for group 1, 28% for group 2, and 100% for group 3 at 6 months and 51%, 23%, and 100%, for groups 1, 2, and 3, respectively, at 9 months (P=0.002). CONCLUSIONS: In patients presenting for a repeat procedure after ablation of persistent AF, the occurrence of AT is associated with a significantly better outcome compared with recurrent persistent AF. These results suggest that AT might be considered as a step toward sinus rhythm.

[Epidemiology, classification and prognosis of palpitations]. / II cardiopalmo: epidemiologia, classificazione e prognosi.

Palpitations can be defined as an unpleasant feeling of heart beat, which is perceived as particularly fast, irregular or intense. This feeling is usually associated with perception of movements and hits in the chest. From the pathophysiological point of view, current knowledge of the neural pathways responsible for the perception of heart beat remains to be clearly elucidated. It has been hypothesized that these pathways include different structures located both at the intracardiac and extracardiac level. Palpitations are a widely diffused complaint in the general population, and particularly in subjects affected by structural heart disease. Clinical presentation makes it possible to divide palpitations into four groups: extrasystolic, tachycardic, anxiety-related, and intense. From the etiological point of view, palpitations may be divided into the following groups: palpitations caused by arrhythmias, by structural heart disease (non-arrhythmic), by psychiatric disease, by systemic noncardiac disease, and by drug or illicit substance assumption. The prompt detection of the causes of palpitations allows to identify clinical conditions potentially at high risk and to choose the most appropriate therapeutic approach.

Introducing a new entity: chemotherapy-induced arrhythmia.

The relationship between chemotherapy and arrhythmias has not been well established. We reviewed the existing literature to better understand this connection. We reviewed published reports on chemotherapy-induced arrhythmias in English using the PubMed/Medline and OVID databases from 1950 onwards as well as lateral references. Arrhythmias were reported as a side effect of many chemotherapeutic drugs. Anthracyclines are associated with atrial fibrillation (AF) at a rate of 2-10%, but rarely with ventricular tachycardia (VT)/fibrillation. Taxol and other antimicrotubular drugs are safe in terms of pro-arrhythmic side effects and do not cause any consistent rhythm abnormalities. Arrhythmias induced by 5-fluorouracil, including VT, are mostly ischaemic in origin and usually occur in the context of coronary spasm produced by this drug. Cisplatin-particularly with intrapericardial use-is associated with a very high rate of AF (12-32%). Melphalan is associated with AF in 7-12% of cases, but it does not appear to cause VT. Interleukin-2 is linked to frequent arrhythmia, mostly AF. We summarized the available data on chemotherapy-induced arrhythmia, particularly AF and VT. Studies with prospective data collection and thorough analyses are needed to establish a causal relationship between certain anticancer drugs and arrhythmia.

[Arrhythmias during pregnancy]. / Herzrhythmusstörungen in der Schwangerschaft.

Cardiovascular emergencies are rare during pregnancy with an incidence of 0,2-4,0%. Emergencies include arrhythmias, acute coronary syndrome, peripartum cardiomyopathy and hypertensive disorders. Electrical DC-cardioversion with 50-100 Joules is indicated in the acute treatment of arrhythmias in all patients in an unstable hemodynamic state. If 100 J fails higher energies (up to 360 J) will be necessary. In stable supraventricular tachycardia intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are frequently present during pregnancy and benign in most patients. However, life-threatening ventricular tachyarrhythmias (sustained ventricular tachycardia [VT], ventricular flutter [VFlt], ventricular fibrillation [VF]) were observed less frequently. Electrical DC-cardioversion is necessary in all pregnant women who are in a hemodynamically unstable state and have a life-threatening ventricular tachyarrhythmias. In hemodynamically stable pregnant women the initial therapy with ajmaline, procainamide or lidocaine is indicated. Implantation of a cardioverter-defibrillator is indicated in patients with syncope caused by VT, VF, VFlt or aborted sudden death.

Manuseio atual das arritmias ventriculares na fase aguda do infarto do miocárdio / Management of ventricular arrhythmias in the setting of acute myocardial infarction

As arritmias ventriculares sustentadas são o principal mecanismo de morte súbita. Frequentemente são a primeira manifestação da doença arterial coronariana, e mesmo quando eficazmente revertidas estão associadas a maior mortalidade intra-hospitalar. Várias anormalidades eletrofisiológicas resultam da isquemia miocárdica. Mecanismos como reentrada, automatismo aumentado e atividade deflagrada estão envolvidos na gênese das arritmias ventriculares na fase aguda do infarto. O conhecimento dos mecanismos e das estratégias de prevenção e tratamento dessas arritmias é essencial no manejo bem-sucedido dos pacientes na fase aguda do infarto do miocárdio.

Sudden cardiac death: epidemiology, mechanisms, and therapy.

Sudden cardiac death is a major public health problem affecting 500,000 patients annually in the United States alone. The major risk factor for sudden cardiac death is the presence of coronary artery disease, usually in the setting of reduced ejection fraction. Globally, the incidence is expected to rise sharply as the prevalence of coronary artery disease and heart failure continue to increase. However, sudden cardiac death is a heterogeneous condition and may be caused by acute ischemia, structural defects, myocardial scar, and/or genetic mutations. Sudden death may occur even in a grossly normal heart. Beta-blockers can reduce the risk of sudden cardiac death, while implantable cardioverter defibrillators are effective at terminating malignant arrhythmias. Ejection fraction remains the major criterion to stratify patients for defibrillator implantation but this strategy alone is insensitive and nonspecific. Novel clinical, electrophysiologic, and genetic markers have been identified that may increase precision in patient selection for primary prevention therapy. This review discusses the epidemiology, mechanisms, etiologies, therapies, treatment guidelines, and future directions in the management of sudden cardiac death.

Changing incidence, type, and natural history of conduction defects after coronary artery bypass grafting.

BACKGROUND: Cardiac conduction defects occur after cardiac surgery. We hypothesized that population aging and increased use of beta-blockers would increase the incidence of new conduction defects after coronary surgery. METHODS: We examined the medical records of 800 coronary artery bypass grafting (CABG) patients (400 from 1991 and 400 from 2001). Exclusion criteria included the following: preexisting conduction defect, permanent pacemaker, and perioperative atrial fibrillation, leaving 303 and 269 patients, respectively, included in the two study years. The incidence, type, and persistence of new conduction defects were determined from the preoperative, postoperative, and the predischarge electrocardiogram. Multivariate analysis identified predictors of new defects. RESULTS: Study populations were well-matched. There was a marked decrease in the incidence of new postoperative conduction defects from 1991 (19%) to 2001 (6%). There was also a change in the most frequently occurring block, from a right-bundle-branch-block in 1991 (10%) to first-degree atrioventricular block (3%) in 2001. Finally, conduction defects in 1991 were more transient. While 19% of 1991 patients showed a conduction defect early postoperatively, only 9% were persistent. In 2001, the incidence of conduction defects at discharge (7%), was equivalent to that early postoperatively (6%). Predictors of new conduction defects included year of operation, age, intraaortic balloon counterpulsation, number of vessels bypassed, and crystalloid cardioplegia. CONCLUSIONS: Our results were the opposite of those predicted. Our report identifies a changing incidence, type, and natural history of conduction defects after CABG. Our comparison demonstrated a decrease in the incidence of new conduction defects, as well as a qualitative change in the defects identified. Multivariate analysis provided predictors of new conduction defects after CABG.

Postbypass arrhythmias: pathophysiology, prevention, and therapy.

PURPOSE OF REVIEW: To review the medical literature on new-onset arrhythmias after cardiac bypass surgery in adults, focusing on the most recent advances on this topic. RECENT FINDINGS: Main attention is focused on possible predictors and prevention of postoperative atrial fibrillation, because this arrhythmia is the most common type encountered with cardiac surgery and is associated with increased morbidity and mortality and longer, more expensive hospital stays. Therapeutic management of atrial fibrillation favors class III antiarrhythmic agents like amiodarone and sotalol. Direct-current cardioversion proved to be an ineffective method for treatment of supraventricular tachyarrhythmias. In patients with persistent atrioventricular block or sinus node dysfunction after cardiac valve surgery, a risk score to predict the need for permanent pacing after cardiac valve surgery was developed. This scoring system may be useful for pre- and perioperative management of patients undergoing cardiac valve surgery. SUMMARY: Recent studies demonstrate a continued effort to improve our knowledge about postbypass arrhythmias. New insights in the pathophysiology of postoperative cardiac arrhythmias and advances in prevention and therapy are rapid and results are heterogeneous, so it is difficult for the clinician to keep abreast with these new findings.

Transvenous cryoablation of cardiac arrhythmias.

This study reports on the acute and long-term results of cryoablation in patients with supraventricular and ventricular tachycardia. One hundred fifty nine patients with cardiac arrhythmias (147 with supraventricular and 12 with ventricular tachycardia) were consecutively enrolled in our institution to undergo trnasvenous cryoablation with a new cryotechnology system (CryoCor trade mark ). This cryoablation system consists of a console, an articulating arm housing a pre-cooler, and a disposable sterile steerable bipolar 10-fr catheter. The N(2)O is used as a main refrigerant. The acute and chronic outcomes (after 15 months for patients with supraventricular tachycardia and 9 months for patients with ventricular tachycardia) were comparable to those using radiofrequency energy. From this study we concluded that transvenous cryoablation is a safe and effective therapy for the treatment of cardiac arrhythmias.

Dysautonomia in chronic fatigue syndrome: facts, hypotheses, implications.

The diagnosis of chronic fatigue syndrome (CFS) is based on patient history and treatment on cognitive behavior therapy and graded exercise. There is increasing evidence that dysautonomia occurs in CFS manifest primarily as disordered regulation of cardiovascular responses to stress. We impart our experience relating to diagnosis, monitoring, and treatment of CFS based on identification and management of dysautonomia. Recently proposed methods for assessment of the cardiovascular reactivity, the 'hemodynamic instability score' (HIS) and the 'Fractal and Recurrence Analysis-based Score' (FRAS), served for this purpose. On HUTT, a particular dysautonomia is revealed in CFS patients that differ from dysautonomia in several other disorders. This distinct abnormality in CFS can be identified by HIS >-0.98 (sensitivity 84.5% and specificity 85.1%) and FRAS > +0.22 (sensitivity 70% and specificity 88%). Therefore, the HIS and FRAS may be used, in the appropriate clinical context, to support the diagnosis of CFS, which until now, could only be subjectively inferred. A pilot study suggested that midodrine treatment, directed at the autonomic nervous system in CFS, results first in correction of dysautonomia followed by improvement of fatigue. This finding implies that dysautonomia is pivotal in the pathophysiology CFS, at least in a large part of the patients, and that manipulating the autonomic nervous system may be effective in the treatment of CFS.