Association Between Air Pollutants and Ventricular Arrhythmias: A Systematic Review and Meta‐Analysis

Implantable Defibrillators for Primary Prevention of Sudden Death in Patients on Dialysis

Rapid effects of air pollution on ventricular arrhythmias

Background: The safety of exercise therapy (ET) in patients with an implantable cardioverter defibrillator (ICD) remains unclear. We sought to explore the current state of evidence and conduct a systematic review on the safety of ICDs during ET. Methods: A systematic review was performed using CINAHL, Cochrane Library, EMBASE, Google Scholar, MEDLINE, PubMed (excluding Medline records), and Web of Science databases searched through April 2015. Studies that quantitively assessed adverse events during ET and after ET in ICD patients compared to one of two control groups (non-ICD ET or non-ET ICD patients) were included. The primary outcome was adverse events during ET. Secondary outcomes were events during ET and follow-up. Results: Meta-analyses were performed on ten eligible studies. During ET, ICD patients experienced an increased risk of adverse events [relative risk (RR)=2.63, 95% confidence interval (CI) (1.71-4.05), P=0.01] compared to non-ICD controls. There was no significant increase risk of adverse events compared to non-ET ICD controls [RR=0.99, 95% CI (0.11-8.95), P=0.99]. ET-ICD patients had fewer adverse events during follow-up compared to non-ET ICD populations [RR=0.90, 95% CI (0.82- 0.99), P=0.02]. A sensitivity analysis including only randomized trials showed similar findings showed no difference in the primary outcome. Conclusions: Our analysis showed increased adverse event during exercise in ICD patients as compared with non-ICD patients. Comparative adverse event rates between exercising and sedentary ICD patients were similar during ET and lower after ET, suggesting that exercise can be safe and potentially protective among ICD patients. More rigorous data from larger randomized trials is needed to further quantify the incremental risk of exercise in high-risk ICD populations.

BackgroundPrevious studies have reported inconsistent results on the relationship between body mass index (BMI) and clinical outcomes in implantable cardioverter defibrillator (ICD) patients. Additionally, research on ICD patients with nonischemic cardiomyopathy (NICM) is lacking.HypothesisThis study aimed to investigate the impact of BMI on mortality and ventricular arrhythmias (VAs) in NICM patients with an ICD.MethodsThis study retrospectively analyzed the data from the Study of Home Monitoring System Safety and Efficacy in Cardiac Implantable Electronic Device‐implanted patients (SUMMIT) in China. Four hundred and eighty NICM patients with an ICD having BMI data were enrolled. Patients were divided into two groups: underweight and normal range group (BMI < 24 kg/m2), overweight and obese group (BMI≥24 kg/m2). The primary endpoint was all‐cause mortality. The secondary endpoint was the first occurrence of VAs requiring appropriate ICD therapy or shock.ResultsDuring a median follow‐up of 61 (1‐95) months, 70 patients (14.6%) died, 173 patients (36%) experienced VAs requiring appropriate ICD therapy, and 112 patients (23.3%) were treated with ICD shock. Multivariate Cox regression modeling indicated a decreased mortality risk in the overweight and obese group compared with the underweight and normal range group (hazard ratio = 0.44, 95% confidence interval 0.26‐0.77, P = .003). However, the risk of VAs was similar in both groups in univariate and multivariate Cox models.ConclusionsCompared with underweight and normal weight, overweight and obesity are protective against mortality but have only a neutral impact on VAs risk in NICM patients with an ICD.

We hypothesized that survival in implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) patients is predicted by baseline Heart Rate Score. Heart Rate Score is determined from the atrial paced and sensed histogram of a DDD ICD or CRT-D, and defined as percent of beats in the histogram in the tallest 10 beats/min range bin. It was calculated at initial remote monitoring for patients enrolled in LATITUDE® without persistent atrial fibrillation, and with pulse generators implanted in 2006-2011. Univariate, multivariate, and Kaplan-Meier analyses determined the impact of Heart Rate Score on survival. Of 57,893 ICDs and 67,929 CRT-Ds followed for 2.4 ± 1.5 years, each 10% increase in Heart Rate Score was associated with decreased survival (CRT-D hazard ratio [HR] 1.07 95%, confidence interval 1.06-1.07, P < 0.0001; ICD HR 1.05, 95% confidence interval 1.04-1.06, P < 0.0001). Multivariate analysis showed survival decreased with increasing age, atrial fibrillation, presence of a shock in first-year follow-up, and increasing programmed lower pacing rate in ICD and CRT-D patients. Increased percent right ventricular pacing predicted mortality in ICD patients, while male gender and lower percent left ventricular pacing predicted mortality in CRT patients. Heart Rate Score predicted survival independent of those variables. Heart Rate Score correlates with heart rate variability (standard deviation of average R-R intervals [SDANN]) when both are obtainable, but SDANN was only present in 6% of patients with Heart Rate Score >70%. A simple device histogram measure, Heart Rate Score, predicts survival in ICD and CRT-D patients independent of the available variables, and even when SDANN is unavailable.

POSTER PRESENTATIONS

Ventricular arrhythmia burden during the coronavirus disease 2019 (COVID-19) pandemic.

P2875Comparison between ejection fraction, global longitudinal strain, mechanical dispersion and delta contraction duration in predicting first and subsequent arrhythmic events in ICD patients

Pre-implantation implantable cardioverter defibrillator concerns and Type D personality increase the risk of mortality in patients with an implantable cardioverter defibrillator

Sodium-glucose cotransporter-2 (SGLT2) inhibitors improve outcomes in heart failure (HF), but their effect on arrhythmias is less clear. Patients with implantable cardioverter-defibrillators (ICDs) are a high risk population for ventricular arrhythmias. However, the effects of SGLT2 inhibitors on ventricular arrhythmias remains a source of debate. We systematically searched PubMed, Scopus, and Cochrane databases from inception to August 19, 2025, for studies evaluating SGLT2 inhibitors and arrhythmic/cardiovascular outcomes. Pooled mean differences (MD) and risk ratios (RR) with 95% confidence intervals (CI) were calculated using a random-effects model. A total of 1,605 patients were included in our analysis. SGLT2 inhibitors was associated with a significant reduction in the risk of ventricular arrhythmia (RR: 0.38; 95% CI: 0.17 to 0.81; p = 0.01), ventricular tachycardia (RR: 0.60; 95% CI: 0.41 to 0.88; p = 0.009), and supraventricular tachycardia (RR: 0.67; 95% CI: 0.47 to 0.95; p = 0.02). No significant effect was observed on non-sustained VT (RR: 0.94; 95% CI: 0.52 to 1.67; p = 0.83). However, SGLT2 inhibitors were also associated with a significant reduction in ICD shocks (RR: 0.49; 95% CI: 0.38 to 0.64; p < 0.00001) and cardiovascular mortality (RR: 0.39; 95% CI: 0.22 to 0.70; p = 0.002). In ICD patients, SGLT2 inhibitor therapy significantly reduced ventricular arrhythmias, discrete sustained VT, and SVT, with secondary analyses suggesting fewer ICD shocks and reduction in CV mortality in the patients with ICD.

The relatively low incidence of device-treated ventricular arrhythmias in patients with ischemic cardiomyopathy (ICM) who receive implantable cardioverter defibrillators (ICDs) for primary prevention makes improved risk stratification of ICM patients a priority. Although Cornell product (CP) ECG left ventricular hypertrophy (LVH) has been associated with increased mortality in hypertensive patients and population-based studies, whether CP LVH can improve risk stratification of high-risk ICM patients is unclear. The aim of this study is to examine if electrocardiographic LVH predicts mortality and incident ventricular arrhythmia in patients with ICM. All-cause mortality was examined in 317 patients with ICM and a history of non-sustained ventricular tachycardia (VT) who underwent electrophysiology testing. Incident VT and ventricular fibrillation (VF) were assessed in ICD recipients (n = 186). ECG LVH was defined by CP criteria: [(R (aVL) + S (V3)) + 6 mm in women] × QRS duration >2,440 mm ms. During 3 years of follow-up, mortality was 20% (64 of 317) and death or incident VT or VF occurred in 35% of ICD recipients. CP LVH was associated with significantly greater 3-year mortality (28% vs 15%, p = 0.015) and 3-year mortality or incident VT/VF in ICD patients (48% vs 35%, p = 0.011). In Cox multivariate models, CP LVH was an independent predictor of mortality in all patients (hazard ratio (HR) 1.81, 95% confidence interval (CI) 1.11-2.97, p = 0.020) and of the composite endpoint of mortality or incident ventricular arrhythmia in ICD patients (HR 1.82, 95% CI 1.12-3.00, p = 0.016). ECG LVH using CP criteria may enhance risk stratification in high-risk patients with ICM.

In the early development of therapy for acute myocardial infarction, it was thought that once the necrotic process had been completed (usually within 24 hours of coronary artery occlusion), additional therapies could not affect outcome. However, after completion of the necrotic process, the myocardial infarction may thin and stretch (involving lengthwise slippage of myocytes), a phenomenon referred to as myocardial infarct expansion. This process causes local left ventricular cavity dilatation followed by gradual global left ventricular dilatation and lengthwise (eccentric) hypertrophy of the noninfarcted tissue. Apoptosis (programmed cell death) and some attempt of the myocardium to regenerate, especially at the infarct border zone, may also contribute to this remodeling process of the ventricle. If the left ventricle remodels in such a way that it becomes very dilated, then the prognosis is poor, and heart failure is more likely to occur.1 These later processes of myocardial infarct expansion and left ventricular remodeling became the target of therapies such as angiotensin-converting enzyme (ACE) inhibition that could be initiated after 24 hours of coronary occlusion. ACE inhibition, angiotensin receptor blockade, and long-term β-blockade have become standard pharmacological approaches for postinfarction left ventricular dysfunction and heart failure. Response by Pitt and Pitt p 2989 Ventricular arrhythmias can occur in both the acute and chronic phases of acute myocardial infarction and can lead to sudden cardiac death (SCD). Reentrant arrhythmias may arise at the border zone of infarcts, causing monomorphic ventricular tachycardia that may occur years after the index infarction. Recurrent myocardial ischemia resulting in an unstable substrate may contribute to polymorphic ventricular tachycardia or ventricular fibrillation. Agents such as β-blockers that are anti-ischemic may reduce sudden death by quieting this unstable substrate. In the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II, implantable defibrillators were shown to reduce mortality in post–myocardial infarction patients with …

The Implantable Cardioverter Defibrillator (ICD) is an implantable biomedical device that monitors and treats abnormal heartbeats when they occur. The device is attached to the heart with 1 to 3 leads that carry information from the heart to the ICD, allowing it to record heart function, selectively provide pacing if the heart beats too fast or too slowly, and/or administer high-energy shocks if more serious heart rhythms are detected. The primary purpose of the ICD is to prevent premature sudden cardiac death. However, the device can also provide a sense of security, which allows resumption of normal life activities. Current research has suggested that psychological distress can occur in ICD patients and their partners. Anxiety may be more prevalent in ICD partners than in ICD patients.1 ICD partners are particularly worried about ICD shocks, even more so than the patients themselves.2 This Patient Page describes common challenges associated with the psychological adjustment of ICD partners and offers possible strategies to consider in managing these difficulties. A summary is provided in the Table. View this table: Table. Summary of Suggested Strategies for the Partners of Patients With ICDs Once the ICD has been implanted, lifestyle adjustments can be made that promote health and well-being. However, such adjustments may take time and a bit of work; most people take about 3 months to adjust to such major life changes. A patient’s adjustment often mirrors the partner’s adjustment, so effective coping can improve both of your lives. ### Patient Acceptance Patient acceptance refers to how well an individual adapts to the ICD and accepts its pros and cons. Patients and partners may differ on how well they accept the device. The hope for ICD patients is that they reengage with the confidence of having “an emergency room in the chest”; yet some patients experience difficulty and …

Benefits of transvenous implantable cardioverter-defibrillators (ICDs) in prevention of sudden cardiac death among the general population are proven. However, the benefit of ICDs remains unclear in CKD. A propensity-matched analysis was conducted to examine the survival benefits of ICDs placed for primary prevention in those with CKD not on dialysis (eGFR<60 ml/min per 1.73 m(2)). The Cleveland Clinic CKD registry was utilized to identify individuals who had an echocardiogram at the institution (between 2001 and October 2011). A propensity score of the likelihood of receiving an ICD was developed with the following variables: demographics, comorbid conditions, use of cardioprotective medications, eGFR, left ventricular ejection fraction, and ventricular arrhythmia. One-to-one greedy matching was used with 0.1 caliper width to match patients with and without an ICD. A Cox proportional hazards model was used to examine survival of matched patients with and without an ICD. This study included 1053 ICD patients and 9435 potential controls. Of 1053 ICD patients (60%), 631 were matched to the control group. During a median follow-up of 2.9 years (25th and 75th percentiles, 1.5, 4.7), 578 patients died. After adjusting for covariates, the hazard of mortality among propensity-matched patients was 0.69 (95% confidence interval [95% CI], 0.59 to 0.82) for the ICD group compared with the non-ICD group. A significant interaction was found between ICDs and eGFR (P=0.04). Presence of an ICD was associated with a lower risk of death among those with eGFRs of 45-59 ml/min per 1.73 m(2) (hazard ratio [HR], 0.58; 95% CI, 0.44 to 0.77) and 30-44 ml/min per 1.73 m(2) (HR, 0.65; 95% CI, 0.50 to 0.85), but not among those with eGFRs<30 ml/min per 1.73 m(2) (HR, 0.98; 95% CI, 0.71 to 1.35). Transvenous ICDs placed for primary prevention are associated with a survival benefit in those with stage 3 CKD, but not in those with stage 4 CKD.

Disorders of the cardiac muscle or cardiomyopathies are a broad, yet collectively common, group of conditions. Despite the heterogeneous etiologies, mode of death from these conditions is remarkably similar - progressive decline in cardiac function leading to intractable heart failure (HF) and sustained ventricular arrhythmias resulting in sudden cardiac death (SCD). Nearly 50% of patients die within 5 years of a HF diagnosis.1 Indeed, in the United States, HF alone is thought to cause 55,000 deaths per year2 and further contribute to 1 in 9 deaths overall.1 However, while advanced HF and the risk of SCD were once thought to be untreatable, technological advances has seen the emergence of device therapies as viable treatment options. Specifically, implantable cardioverter-defibrillator (ICD) therapy for treatment of ventricular arrhythmias, cardiac resynchronization therapy (CRT) for restoring cardiac synchrony and mechanical efficiency, and ventricular assist device (VAD) therapy to temporarily or permanently replace the function of the failing heart, have all emerged as highly efficacious therapies. The expanding use of device therapies, however, poses many challenges. First, while the indications for these devices are well summarized in clinical guidelines,3,4 considerable hurdles remain in ensuring eligible patients receive these therapies.5 By the same token, establishing the safety and effectiveness of these therapies in populations that are found in clinical practice, yet commonly excluded from trials, such as the elderly6 and uncommon forms of cardiomyopathies,7 is a high priority. Second, rapid dissemination of technologies frequently results in disparities in care. Indeed, age, gender, and racial disparities, in both receipt of these devices and outcomes following implantation, have been well documented. Whether these disparities have persisted, and the potential causative mechanisms underlying these disparities, however, are uncertain.8,9 Third, these devices are not without significant untoward effects; understanding …