The impact of supraventricular arrhythmias on the outcomes of guideline-compliant implantable cardioverter defibrillator programming.

INTRODUCTION: Several implantable cardioverter defibrillators (ICD) programming strategies are applied to minimize ICD therapy, especially unnecessary therapies from supraventricular arrhythmias (SVA). However, it remains unknown whether these optimal programming recommendations only benefit those with SVAs or have any detrimental effects from delayed therapy on those without SVAs. This study aims to assess the impact of SVA on the outcomes of ICD programming based on 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines. METHODS: Consecutive patients who underwent ICD insertion for primary prevention were classified into four groups based on SVA status and ICD programming: (1) guideline-concordant group (GC) with SVA, (2) GC without SVA, (3) nonguideline concordant group (NGC) with SVA, and (4) NGC without SVA. Cox proportional hazard models were analyzed for freedom from ICD therapies, shock, and mortality. RESULTS: Seven hundred and seventy-two patients (median age, 64 years) were enrolled. ICD therapies were the most frequent in NGC with SVA (24.0%), followed by NGC without SVA (19.9%), GC without SVA (11.6%), and GC with SVA (8.1%). Guideline concordant programming was associated with 68% ICD therapy reduction (HR 0.32, p = .007) and 67% ICD shock reduction (HR 0.33, p = .030) in SVA patients and 44% ICD therapy reduction in those without SVA (HR 0.56, p = .030). CONCLUSION: Programming ICDs in primary prevention patients based on current guidelines reduces therapy burden without increasing mortality in both SVA and non-SVA patients. A greater magnitude of reduced ICD therapy was found in those with supraventricular arrhythmias.

Meteorological Influence on Atrial Fibrillation and Flutter: A Nationwide Observational Study in South Korea (2010-2022).

Background and rationale The impact of meteorological factors, including atmospheric temperature, humidity, and wind speed, on the incidence of atrial fibrillation and flutter (AF) has been the subject of several studies, but the findings have been inconsistent. Given the complex and multifaceted nature of this relationship, a larger-scale study was necessary to provide sufficient statistical power and elucidate potential associations between them. The aim of this study was, thus, to investigate the potential associations between meteorological factors and the incidence of AF. Methods The South Korean government provides open access to national health insurance and weather data for its citizens; the data was available from January 2010 to July 2022. The national health insurance data includes the monthly number of patients diagnosed with a specific condition, reflecting the incidence and prevalence of the condition. Pearson correlation analyses were performed using the statistical analysis software, SAS® OnDemand for Academics (SAS Institute Inc., Cary, North Carolina, United States), to examine the association between each month's national average climate data and the number of patients diagnosed with AF. Results The number of patients diagnosed with AF in the total population showed a statistically significant correlation only with average wind speed (correlation coefficient (r)=-0.42, 95%CI -0.55 to -0.28, p<0.001) and sunshine duration (r=0.27, 95%CI 0.12 to 0.41, p<0.001). Among females aged 20-24 years, there was a statistically significant association with other variables, including average temperature, precipitation, humidity, and atmospheric pressure (p<0.05). Diurnal temperature variation showed inconsistent associations across different age and sex groups. Conclusion The number of patients diagnosed with AF is negatively correlated with average wind speed and positively correlated with sunshine duration in the general population, particularly among the elderly. There was no significant association between the number of patients diagnosed with AF and average temperature, precipitation, or humidity, except for females aged 20-24 years, who exhibited a significant association with these variables. However, it is important to note that these correlations do not establish causality.

Avoiding unnecessary ventricular pacing is associated with reduced incidence of heart failure hospitalizations and persistent atrial fibrillation in pacemaker patients.

AIMS: In bradycardia patients treated with dual-chamber pacing, we aimed to evaluate whether pacing with atrioventricular (AV) delay management [AV hysteresis (AVH)], compared with standard pacing with fixed AV delays, reduces unnecessary ventricular pacing percentage (VPP) and is associated with better clinical outcomes. Main study endpoints were the incidence of heart failure hospitalizations (HFH), persistent atrial fibrillation (AF), and cardiac death. METHODS AND RESULTS: Data from two identical prospective observational studies, BRADYCARE I in the USA and BRADYCARE II in Europe, Africa, and Asia, were pooled. Overall, 2592 patients (75 ± 10 years, 45.1% female, 50% with AVH) had complete clinical and device data at 1-year follow-up and were analysed. Primary pacing indication was sinus node disease (SND) in 1177 (45.4%), AV block (AVB) in 974 (37.6%), and other indications in 441 (17.0%) patients. Pacing with AVH, compared with standard pacing, was associated with a lower 1-year incidence of HFH [1.3% vs. 3.1%, relative risk reduction (RRR) 57.5%, P = 0.002] and of persistent AF (5.3% vs. 7.7%, RRR = 31.1%, P = 0.028). Cardiac mortality was not different between groups (1.0% vs. 1.4%, RRR = 27.8%, P = 0.366). Pacing with AVH, compared with standard pacing, was associated with a lower (P < 0.001) median VPP in all patients (7% vs. 75%), in SND (3% vs. 44%), in AVB (25% vs. 98%), and in patients with other pacing indications (3% vs. 47%). CONCLUSION: Cardiac pacing with AV delay management via AVH is associated with reduced 1-year incidence of HFH and persistent AF, most likely due to a reduction in VPP compared to standard pacing.

Programming of implantable cardioverter defibrillators for primary prevention: outcomes at centers with high vs. low concordance with guidelines.

BACKGROUND: While ICD therapy reduction programming strategies are recommended in current multi-society guidelines, concerns remain about a possible trade-off between the benefits of ICD therapy reduction and failure to treat episodes of ventricular arrhythmias. The study is to evaluate the outcomes of primary prevention patients followed in centers with high and low concordance with the 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines. METHODS: Consecutive patients with primary prevention ICD implantation from two centers between 2014 and 2016 were included. One center was classified as high guideline concordance center (HGC) with 47% (146/310) of patients with initial ICD concordant with the guidelines, and the other center was classified as low guideline concordance center (LGC) with only 1% (2/178) of patients with guideline-concordant initial ICD programming. Cox proportional hazard models were used to assess risk of first ICD therapy (ATP or shock), first ICD shock, and mortality. RESULTS: A total of 488 patients were included (mean age, 66 ± 13 years). During a mean follow-up of 1.9 ± 0.9 years, patients followed at HGC were 63% less likely to receive any ICD therapy (adjusted HR [aHR] 0.37, 95% CI 0.42-0.99). There were no significant differences in the rate of first ICD shock (aHR 0.72, 95% CI 0.34-1.52) or mortality (aHR 1.19, 95% CI, 0.47-3.05). CONCLUSIONS: Compared to primary prevention patients followed at LGC, primary prevention ICD patients followed at HGC received a significantly lower rate of ICD therapy, mainly from ATP reduction, without a difference in mortality during follow-up.

Low-dose Amiodarone Is Safe: A Systematic Review and Meta-analysis.

Amiodarone is commonly used for a variety of arrhythmias and, in some parts of the world, is the only available antiarrhythmic drug (AAD). Yet, amiodarone is known to have a wide range of potential side effects, many of which are dose- and duration-dependent. We sought to study the incidence of side effects leading to the discontinuation of low-dose amiodarone, arbitrarily defined as 200 mg/day or less, and very-low-dose amiodarone, defined as 100 mg/day or less. In this study, literature databases were searched through June 2019. Studies that reported the incidence or prevalence of side effects of amiodarone were included. Effect estimates from individual studies were extracted and combined using the random-effects generic inverse variance method of DerSimonian and Laird. A total of 10 observational cohort studies involving 901 patients were included in the analysis. The pooled estimated incidence of overall side effects for low-dose amiodarone was 0.17 [95% confidence interval (CI): 0.12-0.22]. In addition, the pooled estimated incidence of side effects requiring medication discontinuation was 0.06 (95% CI: 0.03-0.11). As compared with 200 mg/day of amiodarone, the pooled estimated incidence of overall side effects was 0.11 (95% CI: 0.04-0.27), while the incidence of side effects requiring medication discontinuation was 0.02 (95% CI: 0.01-0.06) for the dose of 100 mg/day. In conclusion, very-low-dose amiodarone displays a low incidence of significant side effects requiring medication discontinuation.

Programming implantable cardioverter-defibrillator in primary prevention: Guideline concordance and outcomes.

BACKGROUND: Inappropriate therapy is a common adverse effect in patients with an implantable cardioverter-defibrillator (ICD) that may be prevented by appropriate programming. OBJECTIVE: The purpose of this study was to assess the outcomes of device programming based on a 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and a 2019 focused update on optimal ICD programming and testing. METHODS: Consecutive patients who underwent ICD insertion for primary prevention from 2014-2016 at 3 centers were included in the retrospective analysis. Patients were classified into 2 groups based on the tachycardia programming at the time of implant: guideline concordant group (GC) and non-guideline concordant group (NGC). Kaplan-Meier analysis and Cox proportional hazard models were used to estimate freedom from ICD therapy (antitachycardia pacing or shock), ICD shock, and death. RESULTS: A total of 772 patients were included in the study (mean age 63.3 ± 13.8 years). Of this total, 258 patients (33.4%) were in the GC group and 514 patients (66.6%) were in the NGC group. During mean follow-up of 2.02 ± 0.91 years, guideline concordant programming was associated with a 53% reduction in ICD therapy (P <.01) and 50% reduction in ICD shock (P = .02). There were no significant differences in mortality (6% in GC group vs11% in NGC group; P = .22). CONCLUSION: Only one-third of the studied population had an ICD device programmed in concordance with current guidelines. ICD programming based on the current guidelines was associated with a significantly lower rate of ICD therapy and shock without changes in mortality during intermediate-term follow-up.