Ambulatory ventricular arrhythmias in patients with heart failure do not specifically predict an increased risk of sudden death. PROMISE (Prospective Randomized Milrinone Survival Evaluation) Investigators

Arrhythmias and cardiac MRI associations in patients with established cardiac dystrophinopathy

AIMS

Some patients with cardiac dystrophinopathy die suddenly. Whether such deaths are preventable by specific antiarrhythmic management or simply indicate heart failure overwhelming medical therapies is uncertain. The aim of this prospective, cohort study was to describe the occurrence and nature of cardiac arrhythmias recorded during prolonged continuous ECG rhythm surveillance in patients with established cardiac dystrophinopathy and relate them to abnormalities on cardiac MRI.

METHODS AND RESULTS

A cohort of 10 patients (36.3 years; 3 female) with LVEF<40% due to Duchenne (3) or Becker muscular (4) dystrophy or Duchenne muscular dystrophy-gene carrying effects in females (3) were recruited, had cardiac MRI, ECG signal-averaging and ECG loop-recorder implants. All were on standard of care heart medications and none had prior history of arrhythmias.No deaths or brady arrhythmias occurred during median follow-up 30 months (range 13-35). Self-limiting episodes of asymptomatic tachyarrhythmia (range 1-29) were confirmed in 8 (80%) patients (ventricular only 2; ventricular and atrial 6). Higher ventricular arrhythmia burden correlated with extent of myocardial fibrosis (extracellular volume%, p=0.029; native T1, p=0.49; late gadolinium enhancement, p=0.49), but not with LVEF% (p=1.0) on MRI and atrial arrhythmias with left atrial dilatation. Features of VT episodes suggested various underlying arrhythmia mechanisms.

CONCLUSIONS

The overall prevalence of arrhythmias was low. Even in such a small sample size, higher arrhythmia counts occurred in those with larger scar burden and greater ventricular volume, suggesting key roles for myocardial stretch as well as disease progression in arrhythmogenesis. These features overlap with the stage of left ventricular dysfunction when heart failure also becomes overt. The findings of this pilot study should help inform the design of a definitive study of specific antiarrhythmic management in dystrophinopathy.

TRIAL REGISTRATION NUMBER

ISRCTN15622536.

Focus on malignant ventricular premature contractions

Premature ventricular contractions (PVCs) are common. Although often benign, they can also be associated with increased morbidity and mortality. The aim of this review was to assess the risk evaluation of PVCs in patients with or without structural heart disease and discuss the management of this arrhythmia. Reports published in English were searched in PubMed with the following search terms: premature ventricular contraction, ectopic ventricular beat, ventricular extrasystole, antiarrhythmic drugs, ablation, ventricular arrhythmia, ventricular tachycardia, ventricular fibrillation and torsade de pointe. This analysis suggests that all patients with frequent PVCs should be assessed for PVC burden, symptom status and the presence of structural heart disease. PVCs in patients with structurally normal hearts was once considered a benign phenomenon. Uncommonly, PVCs may provoke life-threatening arrhythmias. Ventricular fibrillation is the initial mode of malignant rapid ventricular arrhythmias (MRVAs). Patients with malignant PVC and PVC burden >10% are at increased risk of MRVA in case of myocardial infarction and heart failure. MRVA is the primary cause of sudden cardiac death in patients with and without structural heart disease. Therapeutic options include medical therapy and catheter ablation, the latter more effective and potentially curable, particularly in patients with left ventricular dysfunction. The timely recognition and effective treatment of malignant PVCs in symptomatic patients with underling cardiomyopathy are mandatory to initiate early therapies before the occurrence of adverse clinical outcomes and to improve the long-term prognosis.

Inter-American Society of Cardiology (CIFACAH-ELECTROSIAC) and Latin-American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of implantable cardiodefibrillator in heart failure with reduced ejection fraction

BACKGROUND

Our main objective was to present a multidisciplinary review on the epidemiology of sudden cardiac death (SCD) and the tools that could be used to identify malignant ventricular arrhythmias (VAs) and to perform risk stratification. In addition, indications and contraindications for the use of implantable cardioverter defibrillator (ICD) in general and in special populations including the elderly and patients with chronic kidney disease (CKD) are also given.

METHODS

An expert group from the Inter American Society of Cardiology (IASC), through their HF Council (CIFACAH) and Electrocardiology Council (ElectroSIAC), together with the Latin American Heart Rhythm Society (LAHRS), reviewed and discussed the literature regarding the appropriate use of an ICD in people with heart failure (HF) with reduced ejection fraction (HFpEF). Indications and contraindications for the use of ICD are presented in this multidisciplinary review.

RESULTS

Numerous clinical studies have demonstrated the usefulness of ICD in both primary and secondary prevention of SCD in HFpEF. There are currently precise indications and contraindications for the use of these devices.

CONCLUSIONS

In some Latin American countries, a low rate of implantation is correlated with low incomes, but this is not the case for all Latin America. Determinants of the low rates of ICD implantation in many Latin American countries are still a matter of research. VA remains one of the most common causes of cardiovascular death associated with HFrEF and different tools are available for stratifying the risk of SCD in this population.

The implantable cardiac monitor in heart failure patient: a possible new indication?

Implantable cardiac monitors (ICMs) have found increasing use in clinical practice over the years, proving, when used in high-risk populations, to facilitate the diagnosis of bradyarrhythmias and tachyarrhythmias requiring treatment. Experience with heart failure patients undergoing pacemaker (PMK) or implantable defibrillator (ICD) implantation, which allow for continuous electrocardiographic monitoring and transthoracic impedance assessment, has made it possible to identify predictors of heart failure flare-ups. In this context, the use of telemonitoring has been shown to ensure better management of patients with heart failure. These benefits cannot be assessed to date in patients with heart failure and left ventricular ejection fraction (LVEF) > 35% who have no indication for PMK or ICD implantation. This population has been shown to have a significant incidence of ventricular arrhythmias and bradyarrhythmias. In addition, a significant number of cerebrovascular events are observed in this population, largely attributable to the high incidence of atrial fibrillation (AF). In this population, the occurrence of AF has also been shown to have a negative impact on patients' prognosis; at the same time, a rhythm control strategy has been shown to be more beneficial in this area than a rate control strategy. Studies also suggest arrhythmias have a negative impact on the cognitive status and quality of life of heart failure patients. These reasons could justify the implantation of ICMs equipped with telemonitoring systems in heart failure patients. The information provided by the monitoring system, if properly managed, could bring benefits in terms of prognosis and quality of life along with a reduction in economic costs. We will try here, by answering a few questions, to assess whether there is an indication for ICM in heart failure, which patients should be candidates and how these patients should be managed.

Stellate Ganglia and Cardiac Sympathetic Overactivation in Heart Failure

Heart failure (HF) is a major public health problem worldwide, especially coronary heart disease (myocardial infarction)-induced HF with reduced ejection fraction (HFrEF), which accounts for over 50% of all HF cases. An estimated 6 million American adults have HF. As a major feature of HF, cardiac sympathetic overactivation triggers arrhythmias and sudden cardiac death, which accounts for nearly 50–60% of mortality in HF patients. Regulation of cardiac sympathetic activation is highly integrated by the regulatory circuitry at multiple levels, including afferent, central, and efferent components of the sympathetic nervous system. Much evidence, from other investigators and us, has confirmed the afferent and central neural mechanisms causing sympathoexcitation in HF. The stellate ganglion is a peripheral sympathetic ganglion formed by the fusion of the 7th cervical and 1st thoracic sympathetic ganglion. As the efferent component of the sympathetic nervous system, cardiac postganglionic sympathetic neurons located in stellate ganglia provide local neural coordination independent of higher brain centers. Structural and functional impairments of cardiac postganglionic sympathetic neurons can be involved in cardiac sympathetic overactivation in HF because normally, many effects of the cardiac sympathetic nervous system on cardiac function are mediated via neurotransmitters (e.g., norepinephrine) released from cardiac postganglionic sympathetic neurons innervating the heart. This review provides an overview of cardiac sympathetic remodeling in stellate ganglia and potential mechanisms and the role of cardiac sympathetic remodeling in cardiac sympathetic overactivation and arrhythmias in HF. Targeting cardiac sympathetic remodeling in stellate ganglia could be a therapeutic strategy against malignant cardiac arrhythmias in HF.

Clinical electrophysiology of the aging heart

INTRODUCTION

Advancements in medical and consumer-grade technologies have made it easier than ever to monitor a patient's heart rhythm and to diagnose arrhythmias. Octogenarians with symptomatic arrhythmias have unique management challenges due to their frailty, complex drug interactions, cognitive impairment, and competing comorbidities. The management decisions are further complicated by the lack of randomized evidence to guide treatment.

AREAS COVERED

A comprehensive literature review was undertaken to outline various tachyarrhythmias and bradyarrhythmias and their management, the role of cardiac implantable electronic devices, cardiac ablations, and specific geriatric arrhythmia considerations as recommended in international guidelines.

EXPERT OPINION

Atrial fibrillation (AF) is arguably the most important arrhythmia in the elderly and is associated with significant morbidity and mortality. Early diagnosis of AF, potentially with smart devices (wearables), has the potential to reduce the incidence of stroke, systemic emboli, and the risk of dementia. Bradyarrhythmias have a high incidence in the elderly as well, often requiring implantation of a permanent pacemaker. Leadless pacemakers implanted directly into the right ventricle are great options for gaining traction in elderly patients.

The impact of asymptomatic ventricular arrhythmias on the outcome of heart failure patients with reduced ejection fraction

Background

Ventricular arrhythmias cause a significant proportion of sudden deaths. Several studies demonstrate a high prevalence of ventricular arrhythmias in patients with heart failure regardless of the etiology. The aim of this study was to determine the prevalence of silent ventricular arrhythmias in ambulatory heart failure patients with reduced left ventricular ejection fraction (HFrEF) and its correlation to the prognosis.

Results

Four hundred (400) ambulatory HFrEF patients on maximum tolerated doses of heart failure medications were included. Holter monitoring for 7 days was done in all patients searching for silent ventricular arrhythmias. The patients were followed-up for one year to detect the occurrence of major adverse cardiovascular events. We divided the study population into 2 groups based on an LVEF cutoff value of 30% (Group A < 30%, Group B ≥ 30%). Holter monitoring revealed ventricular arrhythmias in 304 patients. Patients with left ventricular ejection fraction (EF) < 30% (Group A) had more complex ventricular arrhythmias in the form of frequent Premature ventricular contractions (PVCs) of ≥ 5% and or non-sustained ventricular tachycardia (NSVT) runs. Furthermore, Among Group A, more major cardiovascular events were observed. Multivariate regression analysis showed that frequent PVCs and severely reduced LVEF were the strongest independent predictors of major cardiovascular events.

Conclusions

ventricular arrhythmias are common in HFrEF patients even in the compensated status. Both, left ventricular systolic function and the PVCs burden were found to be the strongest predictors of major adverse cardiovascular events.

Protective effects of Dapagliflozin on the vulnerability of ventricular arrhythmia in rats with pulmonary artery hypertension induced by monocrotaline

Monocrotaline (MCT)-induced pulmonary artery hypertension (PAH) has been reported to cause right heart failure (RHF). Moreover, Right heart diseases have been determined to cause ventricular arrhythmia (VA). So we can conclude that MCT-induced PAH increases the incidence of VA. In addition, Previous studies have determined the benefits of Dapagliflozin (DA) on the cardiac system, but the responses of MCT-induced RHF to DA are not fully reported. So the present study sought to evaluate the effects of DA on the MCT-induced PAH. A dose intraperitoneal injection of MCT (60 mg/kg) was carried out to induce a rat model with PAH. DA (60 mg/l) was administered for 4 weeks following MCT injection. Echocardiography, body weight, blood pressure, blood glucose, electrophysiological study, and Western blot were performed. Four weeks after the MCT injection, MCT-treated rats decreased body weight, blood glucose and blood pressure. In addition, MCT caused the formation of PAH and RHF. Moreover, MCT-induced PAH rats increased the incidence of VA, prolonged action potential duration (APD), and shortened effective refractory period (ERP). Additionally, PAH rats significantly prevented the activated expressions of Ion channel proteins such as potassium channel (Kv1.5, Kv2.1, Kv4.2, Kv4.3) and L-type Ca channel (Cav1.2). As we expected, these changes above in PAH rats were reversed when DA was administered. Mechanistically, DA significantly reduced the levels of toll-like receptor (TLR4), the nuclear factor kappa B (NF-κB) in MCT-treated rats. In conclusion, these findings determine that DA reduces the vulnerability of VA in PAH rats through the TLR4/NF-κB signaling pathway.

Ventricular Arrhythmias in Seniors with Heart Failure: Present Dilemmas and Therapeutic Considerations: A Systematic Review

BACKGROUND

Heart Failure (HF) is a global public health problem, which affects over 23 million people worldwide. The prevalence of HF is higher among seniors in the USA and other developed countries. Ventricular Arrhythmias (VAs) account for 50% of deaths among patients with HF. We aim to elucidate the factors associated with VAs among seniors with HF, as well as therapies that may improve the outcomes.

METHODS

PubMed, Web of Science, Scopus, Cochrane Library databases, Science Direct, and Google Scholar were searched using specific keywords. The reference lists of relevant articles were searched for additional studies related to HF and VAs among seniors as well as associated outcomes.

RESULTS

The prevalence of VAs increases with worsening HF. A 24-hour Holter electrocardiogram may be useful in risk stratifying patients for device therapy if they do not meet the criterion of low ventricular ejection fraction. Implantable Cardiac Defibrillators (ICDs) are superior to anti-arrhythmic drugs in reducing mortality in patients with HF. Guideline-Directed Medical Therapy (GDMT) together with device therapy may be required to reduce symptoms. In general, the proportion of seniors on GDMT is low. A combination of ICDs and cardiac resynchronization therapy may improve outcomes in selected patients.

CONCLUSION

Seniors with HF and VAs have high mortality even with the use of device therapy and GDMT. The holistic effect of device therapy on outcomes among seniors with HF is equivocal. More studies focused on seniors with advanced HF as well as therapeutic options are, therefore, required.

Effect of sacubitril/valsartan on investigator-reported ventricular arrhythmias in PARADIGM-HF

Aims

Sudden death is a leading cause of mortality in heart failure with reduced ejection fraction (HFrEF). In PARADIGM‐HF, sacubitril/valsartan reduced the incidence of sudden death. The purpose of this post hoc study was to analyse the effect of sacubitril/valsartan, compared to enalapril, on the incidence of ventricular arrhythmias.

Methods and results

Adverse event reports related to ventricular arrhythmias were examined in PARADIGM‐HF. The effect of randomized treatment on two arrhythmia outcomes was analysed: ventricular arrhythmias and the composite of a ventricular arrhythmia, implantable cardioverter defibrillator (ICD) shock or resuscitated cardiac arrest. The risk of death related to a ventricular arrhythmia was examined in time‐updated models. The interaction between heart failure aetiology, or baseline ICD/cardiac resynchronization therapy‐defibrillator (CRT‐D) use, and the effect of sacubitril/valsartan was analysed. Of the 8399 participants, 333 (4.0%) reported a ventricular arrhythmia and 372 (4.4%) the composite arrhythmia outcome. Ventricular arrhythmias were associated with higher mortality. Compared with enalapril, sacubitril/valsartan reduced the risk of a ventricular arrhythmia (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.62–0.95; p = 0.015) and the composite arrhythmia outcome (HR 0.79, 95% CI 0.65–0.97; p = 0.025). The treatment effect was maintained after adjustment and accounting for the competing risk of death. Baseline ICD/CRT‐D use did not modify the effect of sacubitril/valsartan, but aetiology did: HR in patients with an ischaemic aetiology 0.93 (95% CI 0.71–1.21) versus 0.53 (95% CI 0.37–0.78) in those without an ischaemic aetiology (p for interaction = 0.020).

Conclusions

Sacubitril/valsartan reduced the incidence of investigator‐reported ventricular arrhythmias in patients with HFrEF. This effect may have been greater in patients with a non‐ischaemic aetiology.

Nonsustained ventricular tachycardia during outpatient anesthesia: a case report

During the perioperative period, anesthesiologists frequently observe cardiac tachyarrhythmia. Ventricular tachycardia is very rare in non-cardiac surgeries. However, it can be fatal when it occurs. Therefore, anesthesiologists should be watchful so as to not to miss ventricular tachycardia and take the appropriate steps to manage it promptly. We present a case, with a review of related literature, in which a non-sustained ventricular tachycardia was observed in a patient who visited the hospital for dental treatment.

Optimized implementation of cardiac resynchronization therapy: a call for action for referral and optimization of care

Cardiac resynchronization therapy (CRT) is one of the most effective therapies for heart failure with reduced ejection fraction and leads to improved quality of life, reductions in heart failure hospitalization rates and all-cause mortality. Nevertheless, up to two-thirds of eligible patients are not referred for CRT. Furthermore, post-implantation follow-up is often fragmented and suboptimal, hampering the potential maximal treatment effect. This joint position statement from three European Society of Cardiology Associations, Heart Failure Association (HFA), European Heart Rhythm Association (EHRA) and European Association of Cardiovascular Imaging (EACVI), focuses on optimized implementation of CRT. We offer theoretical and practical strategies to achieve more comprehensive CRT referral and post-procedural care by focusing on four actionable domains: (i) overcoming CRT under-utilization, (ii) better understanding of pre-implant characteristics, (iii) abandoning the term 'non-response' and replacing this by the concept of disease modification, and (iv) implementing a dedicated post-implant CRT care pathway.

Optimized implementation of cardiac resynchronization therapy: a call for action for referral and optimization of care: A joint position statement from the Heart Failure Association (HFA), European Heart Rhythm Association (EHRA), and European Association of Cardiovascular Imaging (EACVI) of the European Society of Cardiology

Cardiac resynchronization therapy (CRT) is one of the most effective therapies for heart failure with reduced ejection fraction and leads to improved quality of life, reductions in heart failure hospitalization rates and all-cause mortality. Nevertheless, up to two-thirds of eligible patients are not referred for CRT. Furthermore, post-implantation follow-up is often fragmented and suboptimal, hampering the potential maximal treatment effect. This joint position statement from three European Society of Cardiology Associations, Heart Failure Association (HFA), European Heart Rhythm Association (EHRA) and European Association of Cardiovascular Imaging (EACVI), focuses on optimized implementation of CRT. We offer theoretical and practical strategies to achieve more comprehensive CRT referral and post-procedural care by focusing on four actionable domains: (i) overcoming CRT under-utilization, (ii) better understanding of pre-implant characteristics, (iii) abandoning the term 'non-response' and replacing this by the concept of disease modification, and (iv) implementing a dedicated post-implant CRT care pathway.

Arrhythmogenic Mechanisms in Hypokalaemia: Insights From Pre-clinical Models

Potassium is the predominant intracellular cation, with its extracellular concentrations maintained between 3. 5 and 5 mM. Among the different potassium disorders, hypokalaemia is a common clinical condition that increases the risk of life-threatening ventricular arrhythmias. This review aims to consolidate pre-clinical findings on the electrophysiological mechanisms underlying hypokalaemia-induced arrhythmogenicity. Both triggers and substrates are required for the induction and maintenance of ventricular arrhythmias. Triggered activity can arise from either early afterdepolarizations (EADs) or delayed afterdepolarizations (DADs). Action potential duration (APD) prolongation can predispose to EADs, whereas intracellular Ca²⁺ overload can cause both EADs and DADs. Substrates on the other hand can either be static or dynamic. Static substrates include action potential triangulation, non-uniform APD prolongation, abnormal transmural repolarization gradients, reduced conduction velocity (CV), shortened effective refractory period (ERP), reduced excitation wavelength (CV × ERP) and increased critical intervals for re-excitation (APD-ERP). In contrast, dynamic substrates comprise increased amplitude of APD alternans, steeper APD restitution gradients, transient reversal of transmural repolarization gradients and impaired depolarization-repolarization coupling. The following review article will summarize the molecular mechanisms that generate these electrophysiological abnormalities and subsequent arrhythmogenesis.

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.

Selective changes in cytosolic β-adrenergic cAMP signals and L-type Calcium Channel regulation by Phosphodiesterases during cardiac hypertrophy

Background In cardiomyocytes, phosphodiesterases (PDEs) type 3 and 4 are the predominant enzymes that degrade cAMP generated by β-adrenergic receptors (β-ARs), impacting notably the regulation of the L-type Ca2+ current (ICa,L). Cardiac hypertrophy (CH) is accompanied by a reduction in PDE3 and PDE4, however, whether this affects the dynamic regulation of cytosolic cAMP and ICa,L is not known. Methods and Results CH was induced in rats by thoracic aortic banding over a time period of five weeks and was confirmed by anatomical measurements. Left ventricular myocytes (LVMs) were isolated from CH and sham-operated (SHAM) rats and transduced with an adenovirus encoding a Förster resonance energy transfer (FRET)-based cAMP biosensor or subjected to the whole-cell configuration of the patch-clamp technique to measure ICa,L. Aortic stenosis resulted in a 46% increase in heart weight to body weight ratio in CH compared to SHAM. In SHAM and CH LVMs, a short isoprenaline stimulation (Iso, 100 nM, 15 s) elicited a similar transient increase in cAMP with a half decay time (t1/2off) of ~50 s. In both groups, PDE4 inhibition with Ro 20-1724 (10 μM) markedly potentiated the amplitude and slowed the decline of the cAMP transient, this latter effect being more pronounced in SHAM (t1/2off ~ 250 s) than in CH (t1/2off ~ 150 s, P < 0.01). In contrast, PDE3 inhibition with cilostamide (1 μM) had no effect on the amplitude of the cAMP transient and a minimal effect on its recovery in SHAM, whereas it potentiated the amplitude and slowed the decay in CH (t1/2off ~ 80 s). Iso pulse stimulation also elicited a similar transient increase in ICa,L in SHAM and CH, although the duration of the rising phase was delayed in CH. Inhibition of PDE3 or PDE4 potentiated ICa,L amplitude in SHAM but not in CH. Besides, while only PDE4 inhibition slowed down the decline of ICa,L in SHAM, both PDE3 and PDE4 contributed in CH. Conclusion These results identify selective alterations in cytosolic cAMP and ICa,L regulation by PDE3 and PDE4 in CH, and show that the balance between PDE3 and PDE4 for the regulation of β-AR responses is shifted toward PDE3 during CH.

Evaluation and treatment of premature ventricular contractions in heart failure with reduced ejection fraction

Premature ventricular complexes (PVCs) are often observed in patients presenting with heart failure with a reduced ejection fraction (HFrEF). PVCs may in some patients be considered to be the cause of heart failure, while in others it may be the consequence of heart failure. PVCs are important prognostic markers in HFrEF. The uncertainty whether PVCs are the cause or effect in HFrEF impacts clinical decision making. In this review, we discuss the complexity of the cause-effect relationship between PVCs and HFrEF. We demonstrate a workflow with the use of a trial period of amiodarone that may discover whether the reduced LVEF is reversible, the symptoms are due to PVCs and whether biventricular pacing can be increased by the reduction of PVCs. The use of non-invasive and invasive (high-density) mapping techniques may help to improve accuracy and efficacy in the treatment of PVC, which will be demonstrated. With these results in mind, we conclude this review highlighting the future directions for PVC research and treatment.

Ventricular tachyarrhythmia detection by implantable loop recording in patients with heart failure and preserved ejection fraction: the VIP-HF study

AIMS

The primary aim of the VIP-HF study was to examine the incidence of sustained ventricular tachyarrhythmias (VTs) in heart failure (HF) with mid-range (HFmrEF) or preserved ejection fraction (HFpEF). Secondary aims were to examine the incidence of non-sustained VTs, bradyarrhythmias, HF hospitalizations and mortality.

METHODS AND RESULTS

This was an investigator-initiated, prospective, multicentre, observational study of patients with HF and left ventricular ejection fraction (LVEF) >40%. Patients underwent extensive phenotyping, after which an implantable loop recorder was implanted. We enrolled 113 of the planned 250 patients [mean age 73 ± 8 years, 51% women, New York Heart Association class II/III 54%/46%, median N-terminal pro B-type natriuretic peptide 1367 (710-2452) pg/mL and mean LVEF 54 ± 6%; 75% had LVEF >50%]. Eighteen percent had non-sustained VTs and 37% had atrial fibrillation on Holter monitoring. During a median follow-up of 657 (219-748) days, the primary endpoint of sustained VT was observed in one patient. The incidence of the primary endpoint was 0.6 (95% confidence interval 0.2-3.5) per 100 person-years. The incidence of the secondary endpoint of non-sustained VT was 11.5 (7.1-18.7) per 100 person-years. Five patients developed bradyarrhythmias [3.2 (1.4-7.5) per 100 person-years], three were implanted with a pacemaker. In total, 23 patients (20%) were hospitalized for HF [16.3 (10.9-24.4) per 100 person-years]. Fourteen patients (12%) died [8.7 (5.2-14.7) per 100 person-years]; 10 due to cardiovascular causes, and four sudden deaths, one with implantable loop recorder-confirmed bradyarrhythmias as terminal event, three others undetermined.

CONCLUSION

Despite the lower than expected number of included patients, the incidence of sustained VTs in HFmrEF/HFpEF was low. Clinically relevant bradyarrhythmias were more often observed than expected.

Sudden Cardiac Death Prediction in Non-ischemic Dilated Cardiomyopathy: a Multiparametric and Dynamic Approach

PURPOSE OF REVIEW

Sudden cardiac death is recognised as a devastating consequence of non-ischaemic dilated cardiomyopathy. Although implantable cardiac defibrillators offer protection against some forms of sudden death, the identification of patients in this population most likely to benefit from this therapy remains challenging and controversial. In this review, we evaluate current guidelines and explore established and novel predictors of sudden cardiac death in patients with non-ischaemic dilated cardiomyopathy.

RECENT FINDINGS

Current international guidelines for primary prevention implantable defibrillator therapy do not result in improved longevity for many patients with non-ischemic cardiomyopathy and severe left ventricular dysfunction. More precise methods for identifying higher-risk patients that derive true prognostic benefit from this therapy are required. Dynamic and multi-parametric characterization of myocardial, electrical, serological and genetic substrate offers novel strategies for predicting major arrhythmic risk. Balancing the risk of non-sudden death offers an opportunity to personalize therapy and avoid unnecessary device implantation for those less likely to derive benefit.

Heart Failure with Preserved Ejection Fraction and Sudden Death: How to Identify High Risk Patients?

Background: Cardiac failure with preserved ejection fraction corresponds to half of the cardiac failure cases, having a similar prognosis to patients with reduced ejection fraction. Cardiac sudden death is responsible to about one quarter of the death on these patients. Despite some trials were intended to identify patients with a higher risk to these outcome, it is not already know: how we should proceed to stratify the risk of sudden death in this patients. Methods: To assess the profile of patients with cardiac sudden death and cardiac failure with preserved ejection fraction, we did a literature review, searching for the newer articles about the theme. Outcome: Several trials were published involving patients with divers characteristics that can help us to identify patients with a higher risk of sudden death. The publication of risk score demonstrated that would be possible to identify patients with a >10% risk of sudden death in 5 years, what would be equivalent to the risk of reduced ejection fraction patients eligible to implantable cardioverter-defibrillator (ICD) therapy. Trials with electrophysiological study and programmed ventricular stimulation showed a good strategy to identify low risk patients for future arrhythmic events. Conclusion: Sudden death must be a target of the therapy in the patients with preserved heart failure. Efforts should be done with the objective to identify higher risk patients and search for the better risk stratification strategy, and after that, the definition of the benefit or not, of the invasive therapy as ICD.

Ventricular arrhythmias not meeting criteria for terminating cardiopulmonary exercise testing stratify prognosis and disease severity in heart failure of preserved, midrange, and reduced ejection fraction

Background

Continued high mortality in heart failure patients indicates the need for additional methods of risk stratification and phenotyping.

Hypothesis

We hypothesized that ventricular arrhythmias that do not meet test‐termination criteria (non‐terminating ventricular arrhythmias [NTVA]) during cardiopulmonary exercise testing (CPET) may help in phenotyping disease severity and prognosis in heart failure with reduced (HFrEF) and midrange (HFmrEF)/preserved (HFpEF) left ventricular ejection fraction (LVEF).

Methods

About 319 patients with heart failure (199 HFrEF; 80 HFmrEF; 41 HFpEF) underwent CPET. Tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP) were measured by echocardiography. B‐type natriuretic peptide (BNP) at rest and peak exercise was also determined. The patients were tracked for primary (cardiac death) and secondary composite outcomes (all‐cause death, heart transplantation/left ventricular assist device implantation, hospitalization for cardiac reasons).

Results

Forty‐seven (15%) of the patients demonstrated NTVA during CPET, regardless of coronary artery disease prevalence. Patients without arrhythmias had a significantly higher LVEF (P < .05), TAPSE/PASP ratio (P < .001), peak oxygen consumption (P < .01), lower resting and peak BNP (P < .001), and the minute ventilation/carbon dioxide production slope (P < .001) compared to those with NTVA. Seventy‐one patients died during the tracking period, 54 for cardiac reasons. NTVA during CPET was a significant predictor of primary and secondary outcomes in the total heart failure cohort (HR: 5.3, 3.7; 95% CI: 3.1‐9.1, 2.4‐5.5; P < .001, respectively), as well as in subgroups categorized according to reduced and middle‐range/preserved LVEF (P < .001).

Conclusion

Exercise‐induced ventricular arrhythmias that do not reach test‐termination criteria are nonetheless indicative of an advanced disease severity phenotype and worse prognosis.

Pharmacological interventions for heart failure in people with chronic kidney disease

BACKGROUND

Approximately half of people with heart failure have chronic kidney disease (CKD). Pharmacological interventions for heart failure in people with CKD have the potential to reduce death (any cause) or hospitalisations for decompensated heart failure. However, these interventions are of uncertain benefit and may increase the risk of harm, such as hypotension and electrolyte abnormalities, in those with CKD.

OBJECTIVES

This review aims to look at the benefits and harms of pharmacological interventions for HF (i.e., antihypertensive agents, inotropes, and agents that may improve the heart performance indirectly) in people with HF and CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies through 12 September 2019 in consultation with an Information Specialist and using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials of any pharmacological intervention for acute or chronic heart failure, among people of any age with chronic kidney disease of at least three months duration.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the records to identify eligible studies and extracted data on the following dichotomous outcomes: death, hospitalisations, worsening heart failure, worsening kidney function, hyperkalaemia, and hypotension. We used random effects meta-analysis to estimate treatment effects, which we expressed as a risk ratio (RR) with 95% confidence intervals (CI). We assessed the risk of bias using the Cochrane tool. We applied the GRADE methodology to rate the certainty of evidence.

MAIN RESULTS

One hundred and twelve studies met our selection criteria: 15 were studies of adults with CKD; 16 studies were conducted in the general population but provided subgroup data for people with CKD; and 81 studies included individuals with CKD, however, data for this subgroup were not provided. The risk of bias in all 112 studies was frequently high or unclear. Of the 31 studies (23,762 participants) with data on CKD patients, follow-up ranged from three months to five years, and study size ranged from 16 to 2916 participants. In total, 26 studies (19,612 participants) reported disaggregated and extractable data on at least one outcome of interest for our review and were included in our meta-analyses. In acute heart failure, the effects of adenosine A1-receptor antagonists, dopamine, nesiritide, or serelaxin on death, hospitalisations, worsening heart failure or kidney function, hyperkalaemia, hypotension or quality of life were uncertain due to sparse data or were not reported. In chronic heart failure, the effects of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) (4 studies, 5003 participants: RR 0.85, 95% CI 0.70 to 1.02; I² = 78%; low certainty evidence), aldosterone antagonists (2 studies, 34 participants: RR 0.61 95% CI 0.06 to 6.59; very low certainty evidence), and vasopressin receptor antagonists (RR 1.26, 95% CI 0.55 to 2.89; 2 studies, 1840 participants; low certainty evidence) on death (any cause) were uncertain. Treatment with beta-blockers may reduce the risk of death (any cause) (4 studies, 3136 participants: RR 0.69, 95% CI 0.60 to 0.79; I² = 0%; moderate certainty evidence). Treatment with ACEi or ARB (2 studies, 1368 participants: RR 0.90, 95% CI 0.43 to 1.90; I² = 97%; very low certainty evidence) had uncertain effects on hospitalisation for heart failure, as treatment estimates were consistent with either benefit or harm. Treatment with beta-blockers may decrease hospitalisation for heart failure (3 studies, 2287 participants: RR 0.67, 95% CI 0.43 to 1.05; I² = 87%; low certainty evidence). Aldosterone antagonists may increase the risk of hyperkalaemia compared to placebo or no treatment (3 studies, 826 participants: RR 2.91, 95% CI 2.03 to 4.17; I² = 0%; low certainty evidence). Renin inhibitors had uncertain risks of hyperkalaemia (2 studies, 142 participants: RR 0.86, 95% CI 0.49 to 1.49; I² = 0%; very low certainty). We were unable to estimate whether treatment with sinus node inhibitors affects the risk of hyperkalaemia, as there were few studies and meta-analysis was not possible. Hyperkalaemia was not reported for the CKD subgroup in studies investigating other therapies. The effects of ACEi or ARB, or aldosterone antagonists on worsening heart failure or kidney function, hypotension, or quality of life were uncertain due to sparse data or were not reported. Effects of anti-arrhythmic agents, digoxin, phosphodiesterase inhibitors, renin inhibitors, sinus node inhibitors, vasodilators, and vasopressin receptor antagonists were very uncertain due to the paucity of studies.

AUTHORS' CONCLUSIONS

The effects of pharmacological interventions for heart failure in people with CKD are uncertain and there is insufficient evidence to inform clinical practice. Study data for treatment outcomes in patients with heart failure and CKD are sparse despite the potential impact of kidney impairment on the benefits and harms of treatment. Future research aimed at analysing existing data in general population HF studies to explore the effect in subgroups of patients with CKD, considering stage of disease, may yield valuable insights for the management of people with HF and CKD.

A PDE3A Promoter Polymorphism Regulates cAMP-Induced Transcriptional Activity in Failing Human Myocardium

BACKGROUND

The phosphodiesterase 3A (PDE3A) gene encodes a PDE that regulates cardiac myocyte cyclic adenosine monophosphate (cAMP) levels and myocardial contractile function. PDE3 inhibitors (PDE3i) are used for short-term treatment of refractory heart failure (HF), but do not produce uniform long-term benefit.

OBJECTIVES

The authors tested the hypothesis that drug target genetic variation could explain clinical response heterogeneity to PDE3i in HF.

METHODS

PDE3A promoter studies were performed in a cloned luciferase construct. In human left ventricular (LV) preparations, mRNA expression was measured by reverse transcription polymerase chain reaction, and PDE3 enzyme activity by cAMP-hydrolysis.

RESULTS

The authors identified a 29-nucleotide (nt) insertion (INS)/deletion (DEL) polymorphism in the human PDE3A gene promoter beginning 2,214 nt upstream from the PDE3A1 translation start site. Transcription factor ATF3 binds to the INS and represses cAMP-dependent promoter activity. In explanted failing LVs that were homozygous for PDE3A DEL and had been treated with PDE3i pre-cardiac transplantation, PDE3A1 mRNA abundance and microsomal PDE3 enzyme activity were increased by 1.7-fold to 1.8-fold (p < 0.05) compared with DEL homozygotes not receiving PDE3i. The basis for the selective up-regulation in PDE3A gene expression in DEL homozygotes treated with PDE3i was a cAMP response element enhancer 61 nt downstream from the INS, which was repressed by INS. The DEL homozygous genotype frequency was also enriched in patients with HF.

CONCLUSIONS

A 29-nt INS/DEL polymorphism in the PDE3A promoter regulates cAMP-induced PDE3A gene expression in patients treated with PDE3i. This molecular mechanism may explain response heterogeneity to this drug class, and may inform a pharmacogenetic strategy for a more effective use of PDE3i in HF.

Current pharmacotherapeutic strategies for cardiac arrhythmias in heart failure

Introduction: Heart failure (HF) affects over 6 million Americans and is the most common cause of hospital readmissions in the United States. Cardiac arrhythmias are common comorbidities seen in patients with HF and are associated with an increase in morbidity and mortality. Pharmacotherapeutic agents along with device and ablation therapies are the mainstays of treatment for cardiac arrhythmias in HF.Areas covered: An extensive literature review of articles and clinical trials on PUBMED on the topic of pharmacotherapy for cardiac arrhythmias in heart failure was conducted. This review article summarizes the above literature to describe the prevalence of the various types of arrhythmias in HF, the recommended pharmacotherapies for the treatment of these arrhythmias in HF and the evidence that supports these recommendations.Expert opinion: Cardiac arrhythmias are common in HF and are the leading cause of death in this patient population. The management of cardiac arrhythmias in HF is challenging. Pharmacotherapy is the primary though increasingly adjunctive therapy for most cardiac arrhythmias. Further, antiarrhythmic drugs must be used with caution in this patient population due to their potential adverse effects.

Risk Stratification for Sudden Cardiac Death in Non-Ischaemic Dilated Cardiomyopathy

Purpose of Review

Non-ischaemic dilated cardiomyopathy (DCM) occurs in 1 in 2500 individuals in the general population and is associated with considerable morbidity and mortality. Studies involving large numbers of unselected DCM patients have led to consensus guidelines recommending implantable cardioverter-defibrillator (ICD) implantation for protection against sudden cardiac death (SCD) in those with LVEF ≤35%. The purpose of this article is to review the literature for other potential markers including serological, electrocardiographic, echocardiographic, cardiac magnetic resonance, ambulatory ECG and genetic data, to highlight other potential markers that may optimise risk stratification for SCD in this cohort and thereby allow a more personalized approach to ICD-implantation.

Recent Findings

Recent studies including the Danish study to assess the efficacy of ICDs in patients with non-ischemic systolic heart failure on mortality (DANISH) trial have questioned the benefits of ICD implantation in this group of patients with no changes in all-cause mortality. Recent pooled cohorts of patients with genetic DCM and in particular in those with Lamin A/C (LMNA) mutations have identified patients at increased risk of SCD and allowed the creation of algorithms to prognosticate SCD risk in mutation carriers. Furthermore, genetic testing has identified other DCM-causing genes including filamin C (FLNC) and RBM20 which may be associated with higher rates of ventricular arrhythmia.

Summary

To date, risk-stratification for SCD has been hampered by the utilisation of heterogenous subsets of idiopathic DCM patients and by use of static risk models where predictions are based on a single time point with a lack of consideration of disease progression. The current focus of personalised risk-stratification for SCD is shifting towards better characterisation of underlying DCM aetiology and the development of multi-parametric risk-stratification models that incorporate time-dependent disease characteristics and novel biomarkers.

In-hospital ventricular arrhythmia in heart failure patients: 7 year follow-up of the multi-centric HEARTS registry

Aims

The aim of this study was to determine the incidence, predictors, and short‐term and long‐term outcomes associated with in‐hospital sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) collectively termed ventricular arrhythmia (VA) in the heart failure (HF) patients.

Methods and results

The HEart function Assessment Registry Trial in Saudi Arabia (HEARTS registry) is a prospective national registry of patients with chronic HF from18 tertiary care hospitals across Saudi Arabia. Diagnosis of HF was in accordance with American Heart Association/European Society of Cardiology definition criteria. The registry had enrolled 2610 HF patients during the 14 month recruitment period between October 2009 and December 2010. Occurrence of in‐hospital cardiac events, prognosis, and outcome were monitored during the 7 year follow‐up period. The incidence of in‐hospital VA in HF was 4.2%. VA was more common among men, and mean age was lesser than non‐VA patients (58.5 ± 16: 61.5 ± 15 years; P = 0.042). Smoking and family history of cardiomyopathy were significant risk factors of VA. Previous history of arrhythmia, ST elevated myocardial infarction, infections, and hypotension remained significant predictors of in‐hospital VA associated with three to seven times more risk. Patients with VA had higher rates of in‐hospital events like recurrent HF, haemodialysis, shock, sepsis, major bleeding, intra‐aortic balloon pump, and stroke compared with those without VA, all being highly significant (P < 0.001). After adjustment for age, gender, and co‐morbidities, in‐hospital VA increased the risk of cardiogenic shock by 24 times, dialysis and major bleeding by 10 times, and recurrent congestive HF and pacing by five times. Survival analysis showed that all‐cause mortality was significantly higher in the VA patients (P < 0.001). Presence of VA increased in‐hospital and 1 month mortality to 23 and 17 times, respectively.

Conclusions

Lower mean age of VA complicated HF patients is a matter of concern in the Saudi population. HF associated with VA increased in‐hospital events and all‐cause mortality indicating poor prognosis and survival. These findings enable risk stratification and reflect on the importance of early recognition of the clinical markers and predictors of VA prompting immediate management.

Predictive value of rapid-rate non-sustained ventricular tachycardia in the occurrence of appropriate implantable cardioverter-defibrillator therapy

PURPOSE

Rapid-rate non-sustained ventricular tachycardia (RR-NSVT) that meets detection criteria but terminates itself before the delivery of implantable cardioverter-defibrillator (ICD) therapy is not rare in routine ICD interrogation. Whether sustained ventricular tachycardia/fibrillation will occur in a short time after RR-NSVT has not been fully elucidated.

METHODS

Clinical features and follow-up data of 828 ICD patients with home monitoring were retrospectively collected. RR-NSVT characteristics and time interval between the first episode of RR-NSVT and subsequent appropriate ICD therapy were analyzed.

RESULTS

During a mean follow-up of 44.75 ± 20.87 months, 335 episodes of RR-NSVT were documented in 145 patients. A total of 119 patients had both RR-NSVT and appropriate ICD therapy. In multivariate COX regression models, RR-NSVT was an independent predictor of appropriate ICD therapy (HR 7.599, 95%CI 5.926-9.745, P < 0.001), appropriate shock (HR 6.222, 95%CI 4.667-8.294, P < 0.001), and all-cause mortality (HR 2.156, 95%CI 1.499-3.099, P < 0.001). Appropriate ICD therapy was administered after the first RR-NSVT episode in 101 patients, with a median interval of 21 days. Compared to RR-NSVT with appropriate ICD therapy occurring beyond 21 days, RR-NSVT within 21 days prior to appropriate ICD therapy had a longer median duration time (14 s vs. 12 s, P = 0.013), but without significant difference in mean RR interval at initial detection and mean RR interval after episode termination.

CONCLUSIONS

Rapid-rate non-sustained VT was an independent predictor of appropriate ICD therapy and all-cause mortality. The presence of RR-NSVT should be considered a possible herald of more serious cardiac events in ICD patients.

Risk factors for sudden cardiac death to determine high risk patients in specific patient populations that may benefit from a wearable defibrillator

BACKGROUND

There is a high risk for sudden cardiac death (SCD) in certain patient groups that would not meet criteria for implantable cardioverter defibrillator (ICD) therapy. In conditions such as hypertrophic cardiomyopathy (HCM) there are clear risk scores that help define patients who are high risk for SCD and would benefit from ICD therapy. There are however many areas of uncertainty such as certain patients post myocardial infarction (MI). These patients are high risk for SCD but there is no clear tool for risk stratifying such patients.

AIM

To assess risk factors for sudden cardiac death in major cardiac disorders and to help select patients who might benefit from Wearable cardiac defibrillators (WCD).

METHODS

A literature search was performed looking for risk factors for SCD in patients post-MI, patients with left ventricular systolic dysfunction (LVSD), HCM, long QT syndrome (LQTS). There were 41 studies included and risk factors and the relative risks for SCD were compiled in table form.

RESULTS

We extracted data on relative risk for SCD of specific variables such as age, gender, ejection fraction. The greatest risk factors for SCD in post MI patients was the presence of diabetes [Hazard ratio (HR) 1.90-3.80], in patient with LVSD was ventricular tachycardia (Relative risk 3.50), in LQTS was a prolonged QTc (HR 36.53) and in patients with HCM was LVH greater than 20 mm (HR 3.10). A proportion of patients currently not suitable for ICD might benefit from a WCD

CONCLUSION

There is a very high risk of SCD post MI, in patients with LVSD, HCM and LQTS even in those who do not meet criteria for ICD implantation. These patients may be candidates for a WCD. The development of more sensitive risk calculators to predict SCD is necessary in these patients to help guide treatment.

Hypokalemia-Induced Arrhythmias and Heart Failure: New Insights and Implications for Therapy

Routine use of diuretics and neurohumoral activation make hypokalemia (serum K⁺ < 3. 5 mM) a prevalent electrolyte disorder among heart failure patients, contributing to the increased risk of ventricular arrhythmias and sudden cardiac death in heart failure. Recent experimental studies have suggested that hypokalemia-induced arrhythmias are initiated by the reduced activity of the Na⁺/K⁺-ATPase (NKA), subsequently leading to Ca²⁺ overload, Ca²⁺/Calmodulin-dependent kinase II (CaMKII) activation, and development of afterdepolarizations. In this article, we review the current mechanistic evidence of hypokalemia-induced triggered arrhythmias and discuss how molecular changes in heart failure might lower the threshold for these arrhythmias. Finally, we discuss how recent insights into hypokalemia-induced arrhythmias could have potential implications for future antiarrhythmic treatment strategies.

Developing a risk score to predict mortality in the first year after implantable cardioverter defibrillator implantation: Data from the Israeli ICD Registry

INTRODUCTION

Life expectancy of less than 1 year is usually a contraindication for implantable cardioverter defibrillator (ICD) implantation. The aim was to identify patients at risk of death during the first year after implantation.

METHODS AND RESULTS

Data were derived from a prospective Israeli ICD Registry. Two groups of patients were compared, those who died and those who were alive 1 year after ICD implantation. Factors associated with 1-year mortality were identified on a derivation cohort. A risk score was established and validated. A total of 2617 patients have completed 1 year of follow-up after ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation. Age greater than 75 years (hazard ratio [HR], 2.7; 95% confidence interval [95% CI], 1.6 to 4.4), atrial fibrillation (AF; HR, 1.9; 95% CI, 1.12 to 3.17), chronic lung disease (HR, 2.0; 95% CI, 1.1 to 3.76), anemia (HR, 2.3; 95% CI, 1.3 to 3.93) and chronic renal failure (CRF; HR, 3.4; 95% CI, 1.74 to 6.6) were independent risk factors for 1-year mortality. We propose a simple AAACC ("triple A double C") score for prediction of 1-year mortality after ICD implantation: Age greater than 75 years (3 points(pts)), anemia (2 pts), AF (1 pt), CRF (3 pts) and chronic lung disease (1 pt). Mortality risk increased with rising number of points (from 1% with 0 pts to 12.5% with >4 pts). The risk score was evaluated with receiver operating characteristic curve and the area under the curve of the validation curve is 0.71 (95% CI, 0.66 to 0.76).

CONCLUSIONS

Age greater than 75, AF, chronic lung disease, anemia, and CRF were independent risk factors for 1-year mortality. AAACC risk score identifies patients at high risk of death during 1 year after ICD implantation.

Substrates and potential therapeutics of ventricular arrhythmias in heart failure

Heart failure (HF) is a clinical syndrome characterized by ventricular contractile dysfunction. About 50% of death in patients with HF are due to fetal ventricular arrhythmias including ventricular tachycardia and ventricular fibrillation. Understanding ventricular arrhythmic substrates and discovering effective antiarrhythmic interventions are extremely important for improving the prognosis of patients with HF and reducing its mortality. In this review, we discussed ventricular arrhythmic substrates and current clinical therapeutics for ventricular arrhythmias in HF. Base on the fact that classic antiarrhythmic drugs have the limited efficacy, side effects, and proarrhythmic potentials, we also updated some therapeutic strategies for the development of potential new antiarrhythmic interventions for patients with HF.

Prognostic significance of nonsustained ventricular tachycardia in patients receiving cardiac resynchronization therapy for primary prevention: Analysis of the Japan cardiac device treatment registry database

Background

Whether nonsustained ventricular tachycardia (NSVT) is a marker of increased risk of sustained ventricular tachyarrhythmias (VTAs) remains to be established in patients receiving cardiac resynchronization therapy with a defibrillator (CRT‐D) for primary prevention.

Methods

Among the follow‐up data of the Japan cardiac device treatment registry (JCDTR) with an implantation date between January 2011 and August 2015, information regarding a history of NSVT before the CRT‐D implantation for primary prevention had been registered in 269 patients. Outcomes were compared between two groups with and without NSVT: NSVT group (n = 179) and No NSVT group (n = 90).

Results

There was no significant difference with regard to age, gender, and NYHA class between the two groups. Left ventricular ejection fraction (LVEF) was 25.6% in the NSVT group and 28.0% in the No NSVT group (P = .046). The rate of appropriate therapy at 24 months was 26.0% and 18.4% in the NSVT and No NSVT groups (P = .22), respectively. Survival free from heart failure death was reduced in the NSVT group, as compared with the No NSVT group, with the rate of 90.2% vs 97.2% at 24 months (P = .030). A multivariate analysis identified a history of NSVT, anemia, and no use of angiotensin‐converting enzyme inhibitor (ACEI) or angiotensin‐receptor blocker (ARB) as predictors of heart failure death.

Conclusions

NSVT appears to be a surrogate marker of severe heart failure rather than a substrate for subsequent sustained VTAs in patients with CRT‐D for primary prevention.

Circadian pattern of short-term variability of the QT-interval in primary prevention ICD patients - EU-CERT-ICD methodological pilot study

Objective

Short-term variability of the QT-interval (STV-QT) was shown to be associated with an increased risk of ventricular arrhythmias. We aimed at investigating (a) whether STV-QT exhibits circadian pattern, and (b) whether such pattern differs between patients with high and low arrhythmia risk.

Methods

As part of the ongoing EU-CERT-ICD study, 24h high resolution digital ambulatory 12-lead Holter recordings are collected prior to ICD implantation for primary prophylactic indication. Presently available patients were categorized based on their arrhythmia score (AS), a custom-made weighted score of the number of arrhythmic events on the recording. STV-QT was calculated every hour in 30 patients of which 15 and 15 patients had a high and a low AS, respectively.

Results

The overall dynamicity of STV-QT showed high intra- and inter-individual variability with different circadian patterns associated with low and high AS. High AS patients showed a prominent peak both at 08:00 and 18:00. At these times, STV-QT was significantly higher in the high AS patients compared to the low AS patients (1.22ms±0.55ms vs 0.60ms±0.24ms at 08:00 and 1.12ms±0.39ms vs 0.64ms±0.29ms at 18:00, both p < 0.01).

Conclusion

In patients with high AS, STV-QT peaks in the early morning and late afternoon. This potentially reflects increased arrhythmia risk at these times. Prospective STV-QT determination at these times might thus be more sensitive to identify patients at high risk of ventricular arrhythmias.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

Prognostic Significance of Nonsustained Ventricular Tachycardia Episodes Occurring Early After Implantable Cardioverter-Defibrillator Implantation Among Patients With Left Ventricular Dysfunction

Nonsustained ventricular tachycardias (NSVTs) are frequently observed in patients with left ventricular (LV) dysfunction. The prognostic implications of such NSVTs are conflicting. Our objective was to determine the relation between the burden of NSVT occurring early (within the first 6 months after ICD implant) and prognosis among ICD patients with LV dysfunction. We followed 416 ICD patients (age: 65 ± 11 years; LV ejection fraction: 30 ± 8; ischemic origin: 62%; primary prevention: 63%) with LV dysfunction for 41 ± 27 months. ICD programming was standardized. NSVT was defined as any VT of ≥5 beats at ≥150 beats/min which did not meet the detection criteria occurring within the first 6 months after ICD implant. A total of 250 patients (60%) presented at least one NSVT (median = 2; interquartile range 0 to 7). We classified the patients into 3 groups according to the number of NSVTs: no NSVT (n = 166); 1 to 5 NSVTs (n = 130); and >5 NSVTs (n = 120). The incidence of cardiac mortality (7.2% vs 17.7% vs 31.7%; p = 0.003), hospitalizations for heart failure (10.6% vs 24.4% vs 44.7%; p <0.001), and appropriate shock (15.7% vs 24.8% vs 43.8%; p <0.001) increased significantly with the number of NSVTs. By multivariate analysis, >5 NSVTs were found to be an independent predictor of cardiac mortality (hazard ratio [HR] 1.75; p = 0.03), hospitalization due to heart failure (HR 1.72; p = 0.001), and appropriate shock (HR 1.89; p <0.001) but not of inappropriate therapy (HR 0.9; p = 0.6). In conclusion, among ICD patients with LV dysfunction, NSVT episodes occurring in the first 6 months after implant are independently associated with a poor prognosis. Subjects with >5 NSVTs are at the highest risk.

Sudden Cardiac Risk Stratification with Electrocardiographic Indices - A Review on Computational Processing, Technology Transfer, and Scientific Evidence

Great effort has been devoted in recent years to the development of sudden cardiac risk predictors as a function of electric cardiac signals, mainly obtained from the electrocardiogram (ECG) analysis. But these prediction techniques are still seldom used in clinical practice, partly due to its limited diagnostic accuracy and to the lack of consensus about the appropriate computational signal processing implementation. This paper addresses a three-fold approach, based on ECG indices, to structure this review on sudden cardiac risk stratification. First, throughout the computational techniques that had been widely proposed for obtaining these indices in technical literature. Second, over the scientific evidence, that although is supported by observational clinical studies, they are not always representative enough. And third, via the limited technology transfer of academy-accepted algorithms, requiring further meditation for future systems. We focus on three families of ECG derived indices which are tackled from the aforementioned viewpoints, namely, heart rate turbulence (HRT), heart rate variability (HRV), and T-wave alternans. In terms of computational algorithms, we still need clearer scientific evidence, standardizing, and benchmarking, siting on advanced algorithms applied over large and representative datasets. New scenarios like electronic health recordings, big data, long-term monitoring, and cloud databases, will eventually open new frameworks to foresee suitable new paradigms in the near future.

Increased variability of the coupling interval of premature ventricular contractions as a predictor of cardiac mortality in patients with left ventricular dysfunction

BACKGROUND

The characteristics and prognostic value of the variability of premature ventricular contraction (PVC) coupling intervals (CIs) for cardiac mortality are not yet decisive.

METHODS AND RESULTS

In 133 consecutive patients (58±14 years old, 53 women) who had left ventricular dysfunction (LVD: ejection fraction <50%) and frequent PVCs (≥10/h) who underwent 24-h ambulatory electrocardiography (AECG) recording and (123)I-metaiodobenzylguanidine myocardial single-photon emission computed tomography simultaneously, the heart rate turbulence onset, slope, and T-wave alternans were analyzed from the 24-h AECG. The CI of the PVCs (MEANNV), standard deviation of the CI of the PVCs (SDNV) as an index of the variability of the PVC CI, and their ratio to the preceding N-N intervals (SDNV/SDNN) were calculated from constructed Poincaré plots using the annotated 24-h AECG QRS data. The primary endpoint was cardiac mortality. The mean follow-up period was 63 months. Among 133 patients, 114 survived (group 1) and 19 (14%, group 2) died during the follow-up. The MEANNVand SDNVwere higher in group 2 (539±104 vs. 599±114 ms, P=0.021; 64±34 vs. 83±37 ms, P=0.022, respectively). The SDNV, PVC count, and delayed heart/mediastinum ratio remained as significant predictors of cardiac mortality in the binary logistic regression analysis.

CONCLUSIONS

These results suggest that the SDNVcould be another adjunctive parameter for predicting cardiac mortality in LVD.

[Association of sleep-disordered breathing and malignant arrhythmias in patients with ischemic and dilated cardiomyopathy]

Sleep-disordered breathing (SDB) has so far been a neglected comorbidity in patients with cardiac arrhythmias. Recently however, several studies have revealed a correlation between SDB and malignant ventricular arrhythmias. This review article is intended to provide the reader with an update on the pathophysiological association between SDB and ventricular arrhythmias, available clinical data, and therapeutic options.

Low dialysate potassium concentration: an overrated risk factor for cardiac arrhythmia?

Serum potassium concentrations rise with dietary potassium intake between dialysis sessions and are often at hyperkalemic levels by the next session. Conversely, potassium concentrations fall during each hemodialysis, and sometimes reach hypokalemic levels by the end. Low potassium dialysate, which rapidly decreases serum potassium and often brings it to hypokalemic levels, is almost universally considered a risk factor for life-threatening arrhythmias. While there is little doubt about the threat of lethal arrhythmias due to hyperkalemia, convincing evidence for the danger of low potassium dialysate and rapid or excess potassium removal has not been forthcoming. The original report of more frequent ventricular ectopy in early dialysis that was improved by reducing potassium removal has received very little confirmation from subsequent studies. Furthermore, the occurrence of ventricular ectopy during dialysis does not appear to predict mortality. Studies relating sudden deaths to low potassium dialysate are countered by studies with more thorough adjustment for markers of poor health. Dialysate potassium concentrations affect the excursions of serum potassium levels above or below the normal range, and have the potential to influence dialysis safety. Controlled studies of different dialysate potassium concentration and their effect on mortality and cardiac arrests have not been done. Until these results become available, I propose interim guidelines for the setting of dialysate potassium levels that may better balance risks and benefits.