Clinical use of CRT-D devices with left ventricular sensing: Impact of the desynchronization-detection algorithm.

The use of CRT-D devices with left ventricular (LV) sensing has created controversy about programming various parameters especially the left ventricular T wave protection (LVTP) designed to prevent the delivery of a pacing stimulus into the LV vulnerable period. Such devices are available from two manufacturers. This review focuses only on those provided by Biotronik. As the LVTP controls LV sensing, some investigators have advocated turning off the LVTP to prevent episodic desynchronization known a CRT pacing interrupt. However, LVTP off reduces but does not eliminate this type of desynchronization if triggering of an LV stimulus upon right ventricular sensing (RVs) is programmed on. Deactivation of the LVTP incurs loss of diagnostic data provided by CRT pacing interrupt itself. By choice, the occurrence of CRT pacing interrupt can be totally eliminated by appropriate programming of the LV upper rate interval, LVTP and triggering of an LV pacing event upon RVs. Various programmability options are available according to clinical circumstances. As a rule, clinical judgement must weigh the potential diagnostic benefit of preserving the LVTP capable of recording of episodic CRT pacing interrupt against the loss of diagnostic benefit when LVTP is programmed off (with or without triggering of an LV stimulus upon RVs).

Clinical Impact of Digitalis Therapy in a Large Multicenter Cohort of CRT-Recipients.

(1) Introduction: Digitalis use in patients with severe heart failure is controversial. We assessed the effects of digitalis therapy on mortality in a large, observational study in recipients of cardiac resynchronization therapy (CRT). (2) Methods: Consecutive patients receiving a CRT-defibrillator in three European tertiary referral centers were enrolled and followed-up for a mean 37 months ± 28 months. Digitalis use was assessed at the time of CRT implantation. A multivariate Cox-regression model and propensity score matching were used to determine all-cause mortality as the primary endpoint. CRT-response (defined as improvement of ≥1 NYHA class), echocardiographic improvement (defined as improvement of LVEF of ≥ 5%) and incidence of ICD shocks and rehospitalization were assessed as secondary endpoints in a subgroup of patients. (3) Results: The study comprised 552 CRT-recipients with standard indications, including 219 patients (40%) treated with digitalis. Compared to patients without digitalis, they had more often atrial fibrillation, poorer LVEF and a higher NYHA class (all p ≤ 0.002). Crude analysis of all-cause mortality demonstrated a similar relative risk of death for patients with and without digitalis (HR = 1.14; 95% CI 0.88-1.5; p = 0.40). After adjustment for independent predictors of mortality, digitalis therapy did not alter the risk for death (adjusted HR = 1.04; 95% CI 0.75-1.45; p = 0.82). Furthermore, in comparison to 286 propensity-score-matched patients, mortality was not affected by digitalis intake (propensity-adjusted HR = 1.11; 95% CI 0.72-1.70; p = 0.64). A CRT-response was predominant in digitalis non-users, concerning both improvement of HF symptoms and LVEF (NYHA p < 0.01; LVEF p < 0.01), while patients on digitalis had more often ventricular tachyarrhythmias requiring ICD shock (p = 0.01); although, rehospitalization for cardiac reasons was significantly lower among digitalis users compared to digitalis non-users (HR = 0.58; 95% C. I. 0.40-0.85; p = 0.01). (4) Conclusions: Digitalis therapy had no effect on mortality, but was associated with a reduced response to CRT and increased susceptibility to ventricular arrhythmias requiring ICD shock treatment. Although, digitalis administration positively altered the likelihood for cardiac rehospitalization during follow-up.

Key influences of VDD (DX) ICD selection: Results from a prospective, national survey.

BACKGROUND: To preserve the benefit of atrial sensing without the implantation of an additional lead, a single-lead ICD system with a floating atrial dipole (DX ICD) has been developed. The purpose of this nationwide survey was to provide an overview of the current key influences of device selection focusing on DX ICD and to test the applicability of a previously published decision-making flowchart of ICD-type selection. METHODS: An online questionnaire was sent to all implanting centers in Hungary. Eleven centers reported data from 361 DX ICD and 10 CRT-DX systems implantations between February 2021 and May 2023. RESULTS: The most important influencing clinical factors indicated by the participating doctors were elevated risk of atrial fibrillation (AF)/stroke (56%), risk of sinus/supraventricular tachycardias (SVT) (42%), and a potential need for CRT upgrade in the future (36%). The DX ICD was considered in the majority of cases instead of the VVI system (87%), and only in a small proportion instead of a DDD ICD (13%). 60% of the patients with DX ICDs were also included into remote monitoring-based follow-up. In 83% of the cases, good (>2 mV) or excellent (>5) atrial signal amplitude was recorded within 6 weeks after the implantation. CONCLUSION: In the current national survey, the most important influencing factors indicated by the implanters for selecting a DX ICD were the elevated risk of stroke or sinus/SVT and a potential need for CRT upgrade in the future. These findings support the use of a previously published decision-making flowchart.

Negative effects of COVID-19 on the implantation rate of cardiac resynchronization therapy with defibrillator device.

Introduction: COVID-19 drastically impacted the landscape of the United States' medical system. Limited data is available on the nationwide implantation trends in Cardiac Resynchronization Therapy Defibrillator (CRT-D) devices before and during the pandemic. We aimed to explore the impact of the COVID-19 pandemic on CRT-D insertion rates and adverse outcomes related to delays in care. Methods and Results: We conducted a retrospective cross-sectional analysis using the National Inpatient Sample database between 2017 and 2020. Variables were identified using their ICD-10 codes. Inclusion criteria: age ≥ 18 years, presenting for a nonelective admission, primary diagnosis of hypertensive heart disease, hypertensive heart, chronic kidney disease, or heart failure, and underwent insertion of a CRT-D. Between 2017 and 2020, CRT-D devices were inserted during 23,635 admissions. On average, 6198 devices were implanted yearly from 2017 to 2019, with only 5040 devices being implanted in 2020. Additionally, reduced implantation rates were noted for every cohort of hospital size, location, and teaching status during this year. The year 2020 also had the highest average death rate at 1.39%, but this difference was statistically insignificant (adjusted Wald test p = .767), and COVID-19 was not associated with an increased risk of inpatient mortality (OR 0.22, 95% CI 0.03-1.82, p = .162). Conclusion: The COVID-19 pandemic has affected all facets of the healthcare system, especially surgical volume rates. CRT-D procedures significantly decreased in 2020. This is the first retrospective study highlighting the trend of reduced rates of CRT-D implantation as a response to the COVID-19 pandemic.

Impact of atrial fibrillation on 1-year outcome in patients with implantable cardioverter defibrillator or cardiac resynchronization therapy with defibrillator: results from the German DEVICE Registry.

Background: Atrial fibrillation (AF) is a cardiac arrhythmia frequently documented in patients requiring implantable cardioverter defibrillators (ICDs) and/or cardiac resynchronization therapy with defibrillator (CRT-D). Patients with diagnosed AF at the point of ICD or CRT-D implantation may have an impaired follow-up outcome. Methods: The German DEVICE I-II registry is a nationwide prospective multicentre database of patients implanted with ICD and CRT-D with clinical follow-up data. We analysed a 1-year follow up of implanted patients with AF and with sinus rhythm (SR). Results: A total of 4,929 ICD/CRT patients are included in the present analysis: 946 (19.2%) were in AF and 3,983 (80.8%) were SR at time of device implantation. AF patients had a significantly more comorbid profile including older age {72 [interquartile range (IQR), 66-77] vs. 66 (IQR, 56-73) years; P<0.001}, and higher rate of patients with left ventricular ejection fraction <30% (68.2% vs. 61.0%; P<0.001), peripheral artery disease (4.5% vs. 2.7%; P=0.002), diabetes (33.6% vs. 25.5%; P<0.001), hypertension (58.4% vs. 51.1%; P<0.001) and renal failure (22.6% vs. 15.3%; P<0.001). The intra-hospital complication rate was 4.3% in the AF and 3.6% in the SR group (P=0.38). In 1-year follow-up AF patients experienced a significantly higher rate of defibrillator shocks (25% vs. 15.3%; P<0.001). One-year estimated mortality was 10.8% in the AF and 5.9% in the SR group (P<0.001), while estimated 1-year major adverse cardiac and cerebrovascular events (MACCE) rate was 11.2% vs. 7.0% (P<0.001). The effects of AF on electrical shocks and mortality persisted after adjusting for age, sex, advanced New York Heart Association (NYHA) class, severely impaired left ventricular ejection fraction (LVEF), coronary artery disease (CAD), chronic obstructive pulmonary disease (COPD), diabetes mellitus (DM), chronic renal failure (CRF), QRS duration, and type of indication for electronic device implantation. Conclusions: Our clinical data on an extended cohort of contemporary patients confirm the significant impact of AF, and its associated comorbidities, upon mortality and major adverse events after implantation of ICD/CRT.

Improved outcomes of cardiac resynchronization therapy with a defibrillator in systolic heart failure: Analysis of the Japan cardiac device treatment registry database.

Background: Temporal change in outcomes of heart failure patients receiving cardiac resynchronization therapy with a defibrillator (CRT-D) is unknown. Methods: We assess outcomes and underlying heart diseases of patients receiving CRT-D with analyzing database of the Japan cardiac device treatment registry (JCDTR) at the implantation year 2011-2015 and New JCDTR at the implantation year 2018-2021. Results: Proportion of nonischemic heart diseases was about 70% in both the groups (JCDTR: 69%; New JCDTR: 72%). Cardiac sarcoidosis increased with the rate of 5% in the JCDTR to 9% in the New JCDTR group. During an average follow-up of 21 months, death from any cause occurred in 167 of 906 patients in the JCDTR group (18%) and 79 of 611 patients in the New JCDTR group (13%) (adjusted hazard ratio [aHR] in the New JCDTR group, 0.72; 95% confidence interval [CI]: 0.55-0.94; p = .017). The superiority was mainly driven by reduction in the risk of noncardiac death. With regard to appropriate and inappropriate implantable cardioverter-defibrillator (ICD) therapy, there was a significant reduction in the New JCDTR group versus the JCDTR group (aHR in the New JCDTR group, 0.76; 95% CI: 0.59-0.98; p = .032 for appropriate ICD therapy; aHR in the New JCDTR group, 0.24; 95% CI: 0.12-0.50; p < .0001 for inappropriate ICD therapy). Conclusions: All-cause mortality was reduced in CRT-D patients implanted during 2018-2021 compared to those during 2011-2015, with a significant reduction in noncardiac death.

Cardiac Device Therapy in Patients with Chronic Kidney Disease: An Update.

Cardiovascular diseases (CVDs) and chronic kidney disease (CKD) are frequently interconnected and their association leads to an exponential increase in the risk of both fatal and non-fatal events. In addition, the burden of arrhythmias in CKD patients is increased. On the other hand, the presence of CKD is an important factor that influences the decision to pursue cardiac device therapy. Data on CKD patients with device therapy are scarce and mostly derives from observational studies and case reports. Cardiac resynchronization therapy (CRT) is associated with decreased mortality, reduced heart failure symptoms, and improved renal function in early stages of CKD. Implantable cardioverter defibrillators (ICDs) are associated with a significant reduction in the mortality of CKD patients only for the secondary prevention of sudden cardiac death. Cardiac resynchronization therapy with defibrillator (CRT-D) is preferred in patients who meet the established criteria. The need for cardiac pacing is increased three-fold in dialysis patients. CKD is an independent risk factor for infections associated with cardiac devices.

Outcomes of cardiac resynchronization therapy in congenital heart disease: A meta-analysis and systematic review.

INTRODUCTION: Cardiac resynchronization therapy (CRT) is a standard treatment for patients with heart failure with reduced ejection fraction. However, there is still a gap of evidence in congenital heart disease (CHD) patients regarding resynchronization therapy. METHODS: We performed a meta-analysis and systematic review of CHD patients who received CRT implantation. We comprehensively searched the databases of MEDLINE, EMBASE, and Cochrane database from inception to June 2023. Studies that reported response rate to CRT, total mortality rate, change in QRS duration, change in left ventricular ejection fraction, and change in New York Heart Association functional class were included. RESULTS: A total of 14 studies were included in the study. There were 10 studies that reported response rates after implantation. The overall response rate to CRT in CHD patients was 68% (95% confidence interval [CI] 61%-75%, I2 32%). The response rates in patients with systemic right ventricle (RV), systemic left ventricle (LV), and single ventricle were 58% (95% CI 46%-70%, I2 0%), 80% (95% CI 74%-86% I2 14%), and 67% (95% CI 49%-80% I2 0%). Response to CRT in systemic RV was inferior to systemic LV with an odds ratio of 0.38 (95% CI 0.15-0.95, I2 38%). The total mortality rate from seven studies was 12% (95% CI 8%-18%, I2 55%). The parameters which represented ventricular dyssynchrony improved after CRT implantation. CONCLUSION: The overall response rate to CRT in CHD was 68%. Patients with systemic RV had a lower response rate to CRT when compared to patients with systemic LV. The total mortality rate after CRT implantation was 12%.

Left bundle branch pacing lead for sensing ventricular arrhythmias in implantable cardioverter-defibrillator: A pilot study (LBBP-ICD study).

BACKGROUND: Left bundle branch pacing (LBBP) has been suggested as an alternative modality for biventricular pacing in cardiac resynchronization therapy (CRT)-eligible patients. As it provides stable R-wave sensing, LBBP has been recently used to provide sensing of ventricular arrhythmia in patients receiving implantable cardioverter-defibrillator (ICD) with CRT. OBJECTIVE: The aim of this study was to analyze the long-term safety and efficacy of the LBBP lead for appropriate detection of ventricular arrhythmia and delivery of antitachycardia pacing (ATP) in patients requiring defibrillator therapy with CRT. METHODS: CRT-eligible patients who underwent successful LBBP-optimized ICD and LBBP-optimized CRT with defibrillator were enrolled. The LBBP lead was connected to the right ventricular-P/S port after capping the IS-1 connector plug of the DF-1-ICD lead. LBBP-optimized ICD or LBBP-optimized CRT with defibrillator was decided on the basis of correction of conduction system disease. Documented arrhythmic episodes and therapy delivered were analyzed. RESULTS: Thirty patients were enrolled. The mean age was 59.7 ± 10.5 years. LBBP resulted in an increase in left ventricular ejection fraction from 29.9% ± 4.6% to 43.9% ± 11.2% (P < .0001). During a mean follow-up of 22.9 ± 12.5 months, 254 ventricular arrhythmic events were documented. Appropriate events (n = 225 [89%]) included nonsustained ventricular tachycardia (VT) (n = 212 episodes [94%]), VT (n = 8 [3.5%]), and ventricular fibrillation (n = 5 [2.5%]). ATP efficacy in terminating VT was 75%. Eleven percent of episodes (n = 29) were inappropriately detected because of T-wave oversensing. Inappropriate therapy (ATP) was delivered for 14 episodes (5.5%). Three patients (10%) had worsening of tricuspid regurgitation. CONCLUSION: Sensing from the LBBP lead for arrhythmia detection is safe as ∼90% of the episodes were detected appropriately. Future studies with a dedicated LBBP-defibrillator lead along with algorithms to avoid oversensing can help in combining defibrillation with conduction system pacing.

Cardiac resynchronization therapy with a defibrillator in non-ischemic and ischemic patients for primary and secondary prevention of sudden cardiac death: Analysis of the Japan cardiac device treatment registry database.

Background: Panoramic studies in patients with cardiac resynchronization therapy with a defibrillator (CRT-D) focusing on the etiology and indication are scarce. Besides, a controversy exists regarding requirement of a defibrillator in non-ischemic patients for primary prevention with CRT. Methods: Annual trends of de novo CRT-D implantations from 2011 to 2020 and outcomes of those between January 2011 and August 2015 were analyzed from the Japan cardiac device treatment registry (JCDTR) and New JCDTR database. Results: From 2011 to 2020, 8062 CRT-D recipients were registered, whose dominant indication was primary prevention of sudden cardiac death with a steady rate of about 70%. There was no significant temporal change of the proportion of non-ischemic patients being about 70% and 65% for primary and secondary prevention, respectively. Non-ischemic patients for primary prevention were associated with increased odds of appropriate ICD therapy [adjusted hazard ratio (aHR): 1.66; 95% confidence interval (CI): 1.01-2.75; p = .047] and reduced odds of any death (aHR: 0.66; 95% CI: 0.44-0.99; p = .046) as compared to ischemic patients. Conclusions: Proportion of non-ischemic etiology was much higher than that of ischemic one in the CRT-D cohort. Based on the higher odds of appropriate ICD therapy, non-ischemic patients for primary prevention appear to be prudently selected in Japan.

One-Year Mortality in Patients Undergoing an Implantable Cardioverter Defibrillator or Cardiac Resynchronization Therapy Pulse Generator Replacement: Identifying Patients at Risk.

Implantable cardioverter defibrillators (ICDs) significantly contribute to the prevention of sudden cardiac death in selected patients. However, it is essential to identify those who are likely to not have benefit from an ICD and to defer a pulse generator exchange. Easily implementable guidelines for individual risk stratification and decision making are lacking. This study investigates the 1-year mortality of patients who underwent an ICD or cardiac resynchronization therapy with defibrillator function (CRT-D) pulse generator replacement in a contemporary real-world tertiary hospital setting. The cause of death and patient- and procedure-related factors are stratified, and predictive values for 1-year mortality are evaluated. Patients with a follow-up of ≥365 days (or prior mortality) after an ICD or CRT-D exchange at the Leiden University Medical Center from 1 January 2018 until 31 December 2021 were eligible. In total, 588 patients were included (77% male, 69 [60-76] years old, 59% primary prevention, 46% ischemic cardiomyopathy and 37% mildly reduced left ventricular ejection fraction (LVEF)). Patients undergoing a CRT-D replacement or upgrade had a significantly higher 1-year all-cause mortality (10.7% and 11.9%, respectively) compared to patients undergoing ICD (2.8%) exchange (p = 0.002). LVEF ≤ 30%, New York Heart Association class ≥ 3, estimated glomerular filtration rate ≤ 30 mL/min/m2 and haemoglobin ≤ 7 mmol/L were independently associated with mortality within 1 year after pulse generator replacement. There is a growing need for prospectively validated risk scores to weight individualized risk of mortality with the expected ICD therapy benefit and to support a well-informed, shared decision-making process.

Time-trend treatment effect of cardiac resynchronization therapy with or without defibrillator on mortality: a systematic review and meta-analysis.

AIMS: This study aimed to investigate the impact of cardiac resynchronization therapy with a defibrillator (CRT-D) on mortality, comparing it with CRT with a pacemaker (CRT-P). Additionally, the study sought to identify subgroups, evaluate the time trend in treatment effects, and analyze patient characteristics, considering the changing indications over the past decades. METHODS AND RESULTS: PubMed, CENTRAL, and Embase up to October 2021 were screened for studies comparing CRT-P and CRT-D, focusing on mortality. Altogether 26 observational studies were selected comprising 128 030 CRT patients, including 55 469 with CRT-P and 72 561 with CRT-D device. Cardiac resynchronization therapy with defibrillator was able to reduce all-cause mortality by almost 20% over CRT-P [adjusted hazard ratio (HR): 0.85; 95% confidence interval (CI): 0.76-0.94; P < 0.01] even in propensity-matched studies (HR: 0.83; 95% CI: 0.80-0.87; P < 0.001) but not in those with non-ischaemic aetiology (HR: 0.95; 95% CI: 0.79-1.15; P = 0.19) or over 75 years (HR: 1.08; 95% CI 0.96-1.21; P = 0.17). When treatment effect on mortality was investigated by the median year of inclusion, there was a difference between studies released before 2015 and those thereafter. Time-trend effects could be also observed in patients' characteristics: CRT-P candidates were getting older and the prevalence of ischaemic aetiology was increasing over time. CONCLUSION: The results of this systematic review of observational studies, mostly retrospective with meta-analysis, suggest that patients with CRT-D had a lower risk of mortality compared with CRT-P. However, subgroups could be identified, where CRT-D was not superior such as non-ischaemic and older patients. An improved treatment effect of CRT-D on mortality could be observed between the early and late studies partly related to the changed characteristics of CRT candidates.

Arrhythmic and mortality outcomes in patients with dilated cardiomyopathy receiving cardiac resynchronization therapy without defibrillator.

INTRODUCTION: The routine implantation of cardiac resynchronization therapy with defibrillators in all patients who are candidates for this treatment is now being negotiated, mainly in patients with dilated cardiomyopathy. OBJECTIVE: We investigated the arrhythmic and mortality outcomes following CRT implantation in DCM, as well as the necessity for defibrillator capabilities in that particular group of patients. METHODS: we included 67- patients with DCM with EF ≤ 35%, QRS duration >130 msec and NYHA class II-IV, or those with EF ≤ 35% with indications of permanent pacing for implantation of CRT-P. Patients were followed to obtain good CRT response. Improved clinical outcomes were defined as improvement in at least one NYHA class, ≥5% increase in LVEF, and ≥15% reduction in left ventricular end-systolic volume versus baseline. Patients were classified into responder and non-responder. Patients were followed for 36 months regarding all-cause morbidity mainly ventricular tachycardia and all-cause mortality. RESULTS: CRT responder patients had better clinical outcomes than CRT non-responder patients (post NYHA, 1.3 ± 0.5 vs. 2.5 ± 0.6, p < 0.0001; post LVEF 30.0 ± 1.6 vs. 20.3 ± 2.2%, p < 0.0001; LVESV, 151.7 ± 7.6 vs. 190.4 ± 9.0 ml, p < 0.0001), with lower ventricular arrhythmia (p < 0.0001), lower mortality (p = 0.015) and lower all-cause morbidity (p < 0.001). This survival advantage may be related to the response to CRT response determined by clinical and echocardiographic parameters over a 36-month period of follow-up. CONCLUSIONS: Our findings suggest that CRT-P implantation without defibrillation backup is an encouraging treatment option for patients with DCM, principally those who responded to it. It may result in cost savings, a decrease in complications, and an improvement in all-cause morbidity, particularly ventricular arrhythmia and survival.

Economic evaluation in cardiac electrophysiology: Determining the value of emerging technologies.

Cardiac electrophysiology is a constantly evolving speciality that has benefited from technological innovation and refinements over the past several decades. Despite the potential of these technologies to reshape patient care, their upfront costs pose a challenge to health policymakers who are responsible for the assessment of the novel technology in the context of increasingly limited resources. In this context, it is critical for new therapies or technologies to demonstrate that the measured improvement in patients' outcomes for the cost of achieving that improvement is within conventional benchmarks for acceptable health care value. The field of Health Economics, specifically economic evaluation methods, facilitates this assessment of value in health care. In this review, we provide an overview of the basic principles of economic evaluation and provide historical applications within the field of cardiac electrophysiology. Specifically, the cost-effectiveness of catheter ablation for both atrial fibrillation (AF) and ventricular tachycardia, novel oral anticoagulants for stroke prevention in AF, left atrial appendage occlusion devices, implantable cardioverter defibrillators, and cardiac resynchronization therapy will be reviewed.

Suitability of the left internal jugular vein for CRT-D placement in the setting of extensive venous occlusion: Case report and review of the literature.

Placement of coronary sinus (CS) leads is predominantly accomplished via the left cephalic-axillary-subclavian venous system. However, vein stenosis or occlusion from long-term chronic hemodialysis (HD) in patients with end-stage renal failure can pose a challenge. Cannulation of the CS via the left internal jugular vein (IJV) is technically difficult but often feasible. We report a case in which a patient with end-stage renal disease (ESRD) had extensive left venous system occlusion from prior in dwelling HD catheters, and an AV fistula contralaterally, who underwent biventricular implantable cardioverter defibrillator placement with lead insertion through the left IJV.

Improve the Prevention of Sudden Cardiac Arrest in Patients With Post-Acute Myocardial Infarction.

Background: Implantable cardioverter-defibrillator (ICD) implantation to prevent sudden cardiac death (SCD) in post-myocardial infarction (MI) patients varies by geography but remains low in many regions despite guideline recommendations. Objectives: This study aimed to characterize the care pathway of post-MI patients and understand barriers to referral for further SCD risk stratification and management in patients meeting referral criteria. Methods: This prospective, nonrandomized, multi-nation study included patients ≥18 years of age, with an acute MI ≤30 days and left ventricular ejection fraction <50% ≤14 days post-MI. The primary endpoint was defined as the physician's decision to refer a patient for SCD stratification and management. Results: In total, 1,491 post-MI patients were enrolled (60.2 ± 12.0 years of age, 82.4% male). During the study, 26.7% (n = 398) of patients met criteria for further SCD risk stratification; however, only 59.3% of those meeting criteria (n = 236; 95% CI: 54.4%-64.0%) were referred for a visit. Of patients referred for SCD risk stratification and management, 94.9% (n = 224) attended the visit of which 56.7% (n =127; 95% CI: 50.1%-63.0%) met ICD indication criteria. Of patients who met ICD indication criteria, 14.2% (n = 18) were implanted. Conclusions: We found that ∼40% of patients meeting criteria were not referred for further SCD risk stratification and management and ∼85% of patients who met ICD indications did not receive a guideline-directed ICD. Physician and patient reasons for refusing referral to SCD risk stratification and management or ICD implant varied by geography suggesting that improvement will require both physician- and patient-focused approaches. (Improve Sudden Cardiac Arrest [SCA] Bridge Study; NCT03715790).

Guideline-Directed Medical Therapy and the Risk of Death in Primary Prevention Defibrillator Recipients.

BACKGROUND: Contemporary guideline-directed medical therapy (GDMT) confers a significant mortality benefit for patients with heart failure with reduced ejection fraction (HFrEF), as compared to GDMT prevalent at the time of landmark primary prevention implantable cardioverter-defibrillator (ICD) trials. The impact of modern era GDMT on survival in this population is unknown. OBJECTIVES: This study sought to investigate the impact of number of GDMT medications prescribed for HFrEF on all-cause mortality in recipients of primary prevention ICD. METHODS: A cohort of 4,972 recipients with primary prevention ICD (n = 3,210) or cardiac resynchronization therapy-defibrillator (CRT-D) (n = 1,762) was studied. The association of number of GDMT medications prescribed at the time of device implantation and all-cause mortality at 2 years post implantation was examined. RESULTS: In our primary prevention cohort, 5%, 20%, 52%, and 23% of patients were prescribed 0, 1, 2, or 3-4 GDMT medications, respectively. After risk adjustment for age, sex, ejection fraction, body mass index, the Elixhauser comorbidity score, the type of cardiomyopathy, and the year of device implantation, each additional GDMT conferred a reduction in the risk of death of 36% in recipients of ICD (HR: 0.64; P < 0.001) and 30% in recipients of CRT-D (HR: 0.70; P < 0.001). CONCLUSIONS: A higher number of prescribed GDMT medications is associated with an incremental 1-year survival in recipients of primary prevention ICD with or without CRT. Initiation of maximum number of tolerated GDMT medications should therefore be the goal for all patients with HFrEF. In the setting of robust GDMT, the risk versus benefit of a primary prevention ICD warrants re-examination in future studies.

Effects of COVID-19 lockdown on arrhythmias in patients with implantable cardioverter-defibrillators in southern Italy.

Background: The effects of lockdown on non-COVID patients are varied and unexpected. The aim is to evaluate the burden of cardiac arrhythmias during a lockdown period because of COVID-19 pandemics in a population implanted with cardiac defibrillators and followed by remote monitoring. Methods: In this retrospective, multicentre cohort study, we included 574 remotely monitored implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) recipients implanted before January 1, 2019, at seven hospitals in the Campania region, comparing the burden of arrhythmias occurred during the lockdown period because of COVID-19 epidemics (from March 9 to May 1, 2020) with the arrhythmias burden of the corresponding period in 2019 (reference period). Data collection was performed through remote monitoring. Results: During the lockdown period, we observed ventricular tachyarrhythmias (ventricular tachycardia or fibrillation) in 25 (4.8%) patients while in seasonal reference period we documented ventricular tachyarrhythmias in 12 (2.3%) patients; the comparison between the periods is statistically significant (P < .04). Atrial arrhythmias were detected in 38 (8.2%) subjects during the lockdown period and in 24 (5.2%) during the reference period (P < .004). Conclusion: In seven hospitals in the Campania region, during the pandemic lockdown period, we observed a higher burden of arrhythmic events in ICD/CRT-D patients through device remote monitoring.