Cardioverter-defibrillator Therapy Research Articles

Stereotactic Arrhythmia Radioablation Treatment of Ventricular Tachycardia: Current Technology and Evolving Indications

Ventricular tachycardia in patients with structural heart disease is a significant cause of morbidity and mortality. According to current guidelines, cardioverter defibrillator implantation, antiarrhythmic drugs, and catheter ablation are established therapies in the management of ventricular arrhythmias but their efficacy is limited in some cases. Sustained ventricular tachycardia can be terminated by cardioverter-defibrillator therapies although shocks in particular have been demonstrated to increase mortality and worsen patients' quality of life. Antiarrhythmic drugs have important side effects and relatively low efficacy, while catheter ablation, even if it is actually an established treatment, is an invasive procedure with intrinsic procedural risks and is frequently affected by patients' hemodynamic instability. Stereotactic arrhythmia radioablation for ventricular arrhythmias was developed as bail-out therapy in patients unresponsive to traditional treatments. Radiotherapy has been mainly applied in the oncological field, but new current perspectives have developed in the field of ventricular arrhythmias. Stereotactic arrhythmia radioablation provides an alternative non-invasive and painless therapeutic strategy for the treatment of previously detected cardiac arrhythmic substrate by three-dimensional intracardiac mapping or different tools. Since preliminary experiences have been reported, several retrospective studies, registries, and case reports have been published in the literature. Although, for now, stereotactic arrhythmia radioablation is considered an alternative palliative treatment for patients with refractory ventricular tachycardia and no other therapeutic options, this research field is currently extremely promising.

Long-term impact of activation circuit-based ventricular tachycardia ablation on ventricular arrhythmia burden

Abstract Funding Acknowledgements Type of funding sources: None. Background Ventricular arrhythmias (VA) are a major cause of morbidity and mortality in heart failure patients. Ventricular tachycardia (VT) ablation is an established treatment for the reduction of recurrent implantable cardioverter-defibrillator (ICD) therapies in this population. In patients with substrate-related VT, mapping of the entire tachycardia circuit, when feasible, may allow for more accurate targeting of the clinical VT. Purpose To assess the long-term impact of catheter ablation based on activation mapping of substrate-related VT on VA burden. Methods Consecutive patients submitted to VT ablation between January 2013 and October 2021 were included. A comprehensive review of clinical records and device monitoring was performed to assess VA burden, defined as all ICD therapies and clinically documented VTs, before and after ablation. The primary outcome was reduction in the overall burden of VA after ablation. The impact of ablation on VA burden was assessed by fixed-effects Poisson regression; comparison at fixed time intervals was performed with a paired-sample Wilcoxon signed-rank test (STATA 12, JASP). Results A total of 134 VT ablation procedures were performed during the study period. Of these, there were 21 procedures where complete mapping of the VT activation circuit was achieved, corresponding to 18 patients. Mean age was 56.7 years, 88% male sex, mean left ventricular ejection fraction 39 ± 13%, BNP 540 ± 627 pg/mL. Etiology was ischemic in 44%, non-ischemic dilated cardiomyopathy in 39%, arrhythmogenic right ventricular dysplasia in 11% and hypertrophic cardiomyopathy in 6%. Mechanical support was in situ in 3 patients (two with temporary VA ECMO and one with LVAD as destination therapy); all but one patient had an ICD. Procedural duration was 209 ± 61 minutes. One patient developed complete AV block; no other peri-procedural complications were observed. During follow-up two patients died due to heart failure, one patient died from refractory cardiogenic shock with refractory incessant VT and one patient underwent orthotopic heart transplant. The mean follow-up time after ablation was 2.2 ± 1.9 years. A significant reduction in VA burden was observed (Figure 1) at 3 months (92.5% reduction, p=0.002) and 6 months after ablation (83.3% reduction, p=0.041). After fixed-effects Poisson regression, there was an estimated long-term reduction of 75% (CI 12-93%, p=0.031) of VA burden after VT circuit ablation. Conclusion Targeted circuit ablation is feasible in a subset of patients referred to VT ablation and leads to a significant sustained decrease in VA burden and device therapies.

Association of QTc Interval and V4-S Wave With Appropriate ICD Therapy in Hypertrophic Cardiomyopathy.

BackgroundVentricular arrhythmias in patients with hypertrophic cardiomyopathy (HCM) may lead to sudden cardiac death (SCD). We aimed to investigate the relationship between electrocardiogram (ECG) indicators and the risk of appropriate implantable cardioverter-defibrillator (ICD) therapy in HCM.MethodsThe HCM patients receiving ICD implantation were enrolled consecutively. QT interval correction (QTc) was calculated using Bazett's formula. Long or deep S wave in V4 lead was defined as duration time >50 ms and/or voltage amplitude >0.6 mV. The endpoint in our study was at least one ICD appropriate therapy triggered by ventricular tachyarrhythmia (VT) or ventricular fibrillation (VF), including anti-tachyarrhythmia pacing (ATP) and electrical shock.ResultsA total of 149 patients with HCM (mean age 53 ± 14 years, male 69.8%) were studied. Appropriate ICD therapies occurred in 47 patients (31.5%) during a median follow-up of 2.9 years. Cox regression analysis showed that long or deep S wave in V4 lead [hazard ratio (HR) 1.955, 95% confidence interval (CI) 1.017–3.759, P = 0.045] and QTc interval (HR 1.014, 95% CI 1.008–1.021, P < 0.001) were independent risk factors for appropriate ICD therapy. The ROC showed that the optimal cut-off point value for the QTc interval to predict the appropriate ICD therapy was 464 ms, and the AUC was 0.658 (95% CI 0.544–0.762, P = 0.002). The AUC for S wave anomalies in V4 lead was 0.608 (95% CI 0.511–0.706, P = 0.034). We developed a new model that combined the QTc interval and S wave anomalies in V4 lead based on four patient groups. Patients with QTc ≥464 ms and long or deep V4-S wave had the highest risk of developing appropriate ICD therapy (log-rank P < 0.0001). After adding QTc interval and V4-S wave anomalies into the HCM-risk-SCD model, the prediction effect of the new model was significantly improved, and the NRI was 0.302.ConclusionsIn this HCM cohort, QTc and S wave anomalies in V4 lead were found to be significant and strong predictors of the risk of appropriate ICD therapy. Patients with QTc ≥464 ms and long or deep S wave had the highest risk. After QTc interval and V4-S wave anomalies adding to the HCM-risk-SCD model, the prediction effect is significantly improved.

Clinical characterisation of hypertrophic cardiomyopathy caused by MYH7 gene variants in children

Abstract Background Variants in the cardiac Beta Myosin Heavy chain 7 gene (MYH7) are a common cause of hypertrophic cardiomyopathy (HCM) in adults, but their role in paediatric-onset HCM has not been systematically characterised. This study aims to describe the presentation, clinical characteristics and outcomes of childhood HCM secondary to disease-causing MYH7 variants. Methods Retrospective, longitudinal, data from 70 individuals meeting diagnostic criteria for HCM under the age of 18 years with disease-causing MYH7 variants from a single specialist centre (1991–2019) were collected. A Major Adverse Cardiac Event was defined as sudden cardiac death (SCD), heart failure-related death, cardiac transplantation, haemodynamically-compromising sustained ventricular arrhythmia or appropriate implantable cardioverter defibrillator (ICD) therapy. Results Median age at diagnosis was 9.2 years (IQR 4.2–13.3 years); 47 patients (67.1%) were less than 12 years and 7 (10.0%) were under the age of 1 at diagnosis. Twenty-two patients (31.4%) were probands. MYH7 variants were missense (n=67) or truncating (n=1). Reason for presentation were: family screening (n=45, 64.3%); cardiac symptoms (n=12, 17.1%); incidental finding (n=11, 15.7%); and out of hospital cardiac arrest (n=2, 2.9%). At baseline, mean maximum left ventricular wall thickness (MLVWT) z-score was 9.6 (±5.8), 11 patients (15.7%) had resting left ventricular outflow tract obstruction (left ventricular outflow tract gradient ≥30mmHg). Baseline phenotype did not significantly differ between probands and non-probands (MLVWT Z score 11.9 (±4.5) vs 8.5 (±6.1), p-value 0.0675). Over a median follow up of 3.6 years (IQR 1.8–7.9 years), 10 patients (14.3%) underwent a left ventricular septal myectomy at a median age 6.4 years (IQR 3.4–12.1 years) and 27 (38.6%) had an implantable cardioverter defibrillator (ICD) for primary (n=24, 34.3%) or secondary (n=3, 4.3%) prevention. Three patients (4.3%) died (SCD, n=1; heart-failure related, n=1; non-cardiac, n=1) and 3 (4.3%) underwent cardiac transplantation. Ten patients (14.3%) experienced a MACE. Patients who experienced a MACE were more likely to be probands [n= 6 (60.0%) vs n=16 (26.7%); p=0.036] but did not differ in terms of baseline phenotype (p=0.134). Conclusion MYH7 variants can cause infantile and childhood-onset disease, which is associated with significant early cardiac morbidity and mortality. Adverse outcomes were more common in those presenting as probands. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Medical Research Council, Great Ormond Street Hospital charity.

It is possible to predict mortality after ICD implantation?

Abstract Introduction Implantable Cardioverter Defibrillators (ICD) therapy is not recommended in patients who do not have a reasonable expectation of survival for at least 1 year, although specific recommendations regarding clinical or functional status evaluation are lacking. Purpose To identify predictors of all-cause mortality in patients who implanted an ICD. Methods Prospective single-center study of patients who implanted ICD between 2015 and 2019. Clinical characteristics were evaluated at baseline and mortality was assessed using the national registry of citizens. We performed uni and multivariate analysis to compare clinical characteristics of patients who died and who survived using Cox regression and Kaplan-Meier methods. For the predictor creatinine, we assessed the discrimination power and the best cut-off using the area under the ROC curve (AUC) method. Results From 2015–2019, 414 ICDs were implanted (81% male, 62±12 years-old), and 50 (13%) of the patients died after a median follow-up of 23 [11–41] months. Patients who died during the follow-up were older (67±9 vs 61±12, p=0.002), had more diabetes (48% vs 33%, p=0.033) and a higher creatinine (1.23 [0.84–1.86] vs 1.00 [0.84–1.22], p&amp;lt;0.001). The remaining comorbidities were similar between groups (Fig. 1). Patients who died had more frequently an ICD implanted after complication associated with a previous device or as a pacemaker upgrade (6% vs 2%, p=0.030). They also had a higher frequency of ischaemic cardiomyopathy (i-CMP) (82% vs 56%, p=0.002) and of ejection fraction (EF) ≤50% (96% vs 82%, p=0.040). The best cut-off value of creatinine to predict mortality with a sensitivity of 65% and a specificity of 72% was 1.2mg/dl (AUC 0.650; CI95% 0.53–0.77). After adjusting for diabetes, i-CMP, EF ≤50% and upgrade/re-implantation after complication, we found that age (HR 1.033; 95% CI 1.00–1.06, p=0.041) and creatinine ≥1.2mg/dl (HR 2.134; 95% CI 1.09–4.19, p=0.028) were independent predictors of all-cause mortality. Conclusion In our cohort of patients who underwent ICD implantation for primary or secondary sudden cardiac death prevention, the all-cause mortality over a median follow-up period of 23 [11–41] months was 13%. We found that in addition to age, a baseline creatinine level ≥1.2mg/dl increases by 2-fold mortality in patients who undergo ICD implantation. Decisions regarding ICD candidacy should not be based on age alone but should also consider creatinine that predisposes to mortality despite ICD implantation. Funding Acknowledgement Type of funding sources: None. All cause mortality

Previous pacemaker therapy was not associated with the risk of clinical events in patients with atrial fibrillation: the Fushimi AF Registry

Abstract Background Patients with atrial fibrillation (AF) occasionally require pacemaker implantation. Meanwhile, patients with implanted pacemaker are occasionally found to have subclinical AF and develop clinical AF. However, little is known about the clinical outcomes of AF patients with implanted pacemaker. Purpose We aimed to investigate the clinical outcomes in AF patients undergoing previous pacemaker therapy. Methods The Fushimi AF Registry is a community-based prospective survey of the AF patients in a city of Japan. Follow-up data including prescription status were available for 4,447 patients. After exclusion of patients with implantable cardioverter defibrillator and cardiac resynchronization therapy, we investigated 293 AF patients with pacemaker implantation at baseline. We performed propensity score-matching analysis to assess the impact of pacemaker therapy in AF patients. Results Of a total cohort, patients with pacemaker were more often female (51.2% vs. 39.7%; p&amp;lt;0.01) and older (78.0 vs. 73.3 years of age; p&amp;lt;0.01). Patients with pacemaker were more likely to have pre-existing heart failure (33.1% vs. 26.6%; p&amp;lt;0.01), valvular heart disease (22.9% vs. 16.8%; p&amp;lt;0.01), chronic kidney disease (48.8% vs. 34.7%; p&amp;lt;0.01), and history of performing direct current cardioversion (7.2% vs. 3.1%; p&amp;lt;0.01), compared with patients without pacemaker. Mean CHA2DS2-VASc score was higher in patients with pacemaker (3.80 vs. 3.34; p&amp;lt;0.01). Patients with pacemaker were more often prescribed oral anticoagulants (62.1% vs. 55.2%; p=0.02), verapamil (13.3% vs. 9.4%; p=0.03), and loop diuretics (30.7% vs. 21.8%; p&amp;lt;0.01). Using propensity score-matching, 291 patients with pacemaker and 291 without pacemaker were matched and baseline characteristics were comparable. The median follow-up period was 1,819 days. All-cause death occurred in 91 patients with pacemaker (6.0 /100 person-years) and 79 patients without pacemaker (5.9 /100 person-years), with a hazard ratio (HR) for patients with pacemaker of 1.01 (95% confidence interval [CI], 0.75 to 1.37; p=0.93). Furthermore, HR of cardiac death for patients with pacemaker was 1.00 (95% CI, 0.23 to 4.32; p=0.99), that of stroke or systemic embolism was 0.69 (95% CI, 0.44 to 1.07; p=0.10) and that of hospitalization for heart failure was 0.94 (95% CI, 0.65 to 1.37; p=0.76). Conclusion We identified that patients undergoing previous pacemaker therapy were not associated with the incidence of various adverse clinical events in Japanese AF patients. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Boehringer Ingelheim, Bayer Healthcare, Pfizer, Bristol-Myers Squibb, Astellas Pharma, AstraZeneca, Daiichi Sankyo, Novartis Pharma, MSD, Sanofi-Aventis, Takeda Pharmaceutical, and the Practical Research Project for Life-Style related Diseases including Cardiovascular Diseases and Diabetes Mellitus from Japan Agency for Medical Research and Development.

Association between cardiac autonomic function and physical activity in patients at high risk of sudden cardiac death: a cohort study

BackgroundHigh levels of physical activity (PA) and heart rate variability (HRV) are associated with cardiovascular benefits in patients with cardiovascular diseases. HRV, representing cardiac autonomic function, is positively associated with PA. However, the impacts of PA and cardiac autonomic function on cardiovascular outcomes were not analysed in the same study population. This lack of evidence supported our hypothesis that PA might contribute to cardiovascular benefits via enhanced cardiac autonomic function.MethodsPatients with implantable cardioverter defibrillator (ICD) or cardiac resynchronisation therapy defibrillator (CRT-D) implantation were included from the SUMMIT registry. HRV and PA values were assessed during the first 30–60 days post device implantation using a continuous home monitoring system. Causal mediation analysis was conducted to explore the possible mediation function of HRV in the association of PA with long-term cardiac death and all-cause mortality in patients at a high risk of sudden cardiac death.ResultsOver a mean follow-up period of 47.7 months, 63 cardiac deaths (18.9%) and 85 all-cause death events (25.5%) were observed among 342 patients with ICD/CRT-D implantation. A positive linear association between HRV and PA was demonstrated and the β value of HRV was 0.842 (95% confidence interval [CI]: 0.261–1.425, P = 0.005) in the multiple linear regression analysis. Multivariable Cox proportional hazards analysis revealed that high levels of PA (≥11.0%) and HRV (≥75.9 ms) were independent protective factors against cardiac death (PA: hazard ratio [HR] = 0.273; 95% CI, 0.142–0.526, P < 0.001; HRV: HR = 0.224; 95% CI, 0.103–0.489, P < 0.001) and all-cause mortality (PA: HR = 0.299; 95% CI, 0.177–0.505, P < 0.001; HRV: HR = 0.394; 95% CI, 0.231–0.674, P = 0.001). Causal mediation analysis demonstrated partial mediation effects of PA that were mediated through HRV on cardiac death (mediation proportion = 12.9, 95%CI: 2.2–32.0%, P = 0.006) and all-cause mortality (mediation proportion = 8.2, 95%CI: 1.6–20.0%, P = 0.006).ConclusionsHRV might be a modest mediator in the association between high levels of PA and the reduced risks of cardiac death and all-cause mortality in ICD/CRT-D recipients. This finding supports that enhanced cardiac autonomic function might be one of the underlying mechanisms by which regular PA contributes to cardiovascular benefits.

Association Between Changes in Physical Activity and New-Onset Atrial Fibrillation After ICD/CRT-D Implantation.

Background: Changes in physical activity (PA) after implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillators (CRT-D) implantation were unknown. The association of PA changes with new-onset atrial fibrillation (AF), cardiac death and all-cause mortality was unclear in patients at high risk of sudden cardiac death.Methods: Patients receiving ICD/CRT-D implantation from SUMMIT registry were retrospectively analyzed. Changes in PA were considered from baseline status to 1 year after implantation. New-onset AF was defined as the first atrial high-rate episode ≥1% of the daily AF burden detected after implantation.Results: Over a mean follow-up of 50.3 months, 124 new-onset AF events (36.2%), 61 cardiac deaths (17.8%), and 87 all-cause deaths (25.4%) were observed in 343 patients with ICD/CRT-D implantation. PA at 1 year after implantation was increased compared with PA at baseline (11.97 ± 5.83% vs. 10.82 ± 5.43%, P = 0.008), and PA at 1 year was improved in 210 patients (61.2%). Per 1% decrease in PA was associated with 12.4, 18.3, and 14.3% higher risks of new-onset AF, cardiac death and all-cause mortality, regardless of different baseline characteristics. Patients with decreased PA had 2-fold risks of new-onset AF (hazard ratio [HR] = 1.972, 95% confidence interval [CI]: 1.352–2.877, P < 0.001) as high as those with unchanged/increased PA. Decreased PA was an independent risk factor for cardiac death (HR = 3.358, 95% CI: 1.880–5.996, P < 0.001) and all-cause mortality (HR = 2.803, 95% CI:1.732–4.535, P < 0.001).Conclusion: PA decrease after ICD/CRT-D implantation is associated with a higher incidence of new-onset AF, resulting in worsened outcomes in cardiac death and all-cause mortality.

Temporal trends in outcome and patient characteristics in dilated cardiomyopathy, data from the Swedish Heart Failure Registry 2003\u20132015

BackgroundTemporal trends in clinical composition and outcome in dilated cardiomyopathy (DCM) are largely unknown, despite considerable advances in heart failure management. We set out to study clinical characteristics and prognosis over time in DCM in Sweden during 2003–2015.MethodsDCM patients (n = 7873) from the Swedish Heart Failure Registry were divided into three calendar periods of inclusion, 2003–2007 (Period 1, n = 2029), 2008–2011 (Period 2, n = 3363), 2012–2015 (Period 3, n = 2481). The primary outcome was the composite of all-cause death, transplantation and hospitalization during 1 year after inclusion into the registry.ResultsOver the three calendar periods patients were older (p = 0.022), the proportion of females increased (mean 22.5%, 26.4%, 27.6%, p = 0.0001), left ventricular ejection fraction was higher (p = 0.0014), and symptoms by New York Heart Association less severe (p < 0.0001). Device (implantable cardioverter defibrillator and/or cardiac resynchronization) therapy increased by 30% over time (mean 11.6%, 12.3%, 15.1%, p < 0.0001). The event rates for mortality, and hospitalization were consistently decreasing over calendar periods (p < 0.0001 for all), whereas transplantation rate was stable. More advanced physical symptoms correlated with an increased risk of a composite outcome over time (p = 0.0043).ConclusionsFrom 2003 until 2015, we observed declining mortality and hospitalizations in DCM, paralleled by a continuous change in both demographic profile and therapy in the DCM population in Sweden, towards a less affected phenotype.

Infarct-related chronic total coronary occlusion and the risk of ventricular tachyarrhythmic events in out-of-hospital cardiac arrest survivors.

IntroductionChronic total coronary occlusion (CTO) has been identified as a risk factor for ventricular arrhythmias, especially a CTO in an infarct-related artery (IRA). This study aimed to evaluate the effect of an IRA-CTO on the occurrence of ventricular tachyarrhythmic events (VTEs) in out-of-hospital cardiac arrest survivors without ST-segment elevation.MethodsWe conducted a post hoc analysis of the COACT trial, a multicentre randomised controlled trial. Patients were included when they survived index hospitalisation after cardiac arrest and demonstrated coronary artery disease on coronary angiography. The primary endpoint was the occurrence of a VTE, defined as appropriate implantable cardioverter-defibrillator (ICD) therapy, sustained ventricular tachyarrhythmia or sudden cardiac death.ResultsA total of 163 patients from ten centres were included. Unrevascularised IRA-CTO in a main vessel was present in 43 patients (26%). Overall, 61% of the study population received an ICD for secondary prevention. During a follow-up of 1 year, 12 patients (7.4%) experienced at least one VTE. The cumulative incidence rate of VTEs was higher in patients with an IRA-CTO compared to patients without an IRA-CTO (17.4% vs 5.6%, log-rank p = 0.03). However, multivariable analysis only identified left ventricular ejection fraction < 35% as an independent factor associated with VTEs (adjusted hazard ratio 8.7, 95% confidence interval 2.2–35.4). A subanalysis focusing on CTO, with or without an infarct in the CTO territory, did not change the results.ConclusionIn out-of-hospital cardiac arrest survivors with coronary artery disease without ST-segment elevation, an IRA-CTO was not an independent factor associated with VTEs in the 1st year after the index event.Supplementary InformationThe online version of this article (10.1007/s12471-021-01578-3) contains supplementary material, which is available to authorized users.

Grayzone myocardial fibrosis and ventricular arrhythmias in patients with a left ventricular ejection fraction greater than 35%

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Clinical guidelines adopt LVEF cut-offs &amp;lt;30 or &amp;lt;35% as an indication for implantable cardioverter defibrillator (ICD) therapy. Most patients succumbing to sudden cardiac death (SCD), however, have a LVEF≥35%. OBJECTIVES To determine whether myocardial fibrosis (MF) and grayzone fibrosis (GZF) on cardiovascular magnetic resonance (CMR) is associated with ventricular arrhythmias in patients with coronary artery disease (CAD) and a LVEF≥35%. METHODS In this retrospective study of CAD patients, GZF mass using the 3SD method (GZF3SD) and total fibrosis mass using the 2SD method (TF2SD) on CMR were assessed in relation to the primary, combined endpoint of SCD, ventricular tachycardia, ventricular fibrillation or resuscitated cardiac arrest. RESULTS Among 701 patients (age: 65.8 ± 12.3 yrs [mean ± SD]), 28 (3.99%) patients met the primary endpoint over 5.91 years (median; interquartile range 4.42-7.64). In competing risks analysis, a GZF3SD mass ≥ 5.0 g was strongly associated with the primary endpoint (subdistribution hazard ratio [sHR]: 17.4 [95% CI 6.64-45.5]); area under receiver operator characteristic curve [AUC]: 0.85, p &amp;lt; 0.001). A weaker association was observed for TF2SD mass ≥ 23 g (HR: 10.4 [95% CI 4.22-25.8]; AUC: 0.80, p &amp;lt; 0.001). The range of sHRs for GZF3SD mass (1 to 526.6) was wider than for TF2SD mass (1 to 37.6). CONCLUSIONS In CAD patients with a LVEF≥35%, GZF3SD mass was strongly associated with the arrhythmic endpoint. These findings hold promise for its use in identifying patients with CAD and a LVEF≥35% at risk of arrhythmic events. Abstract Figure.

Exercise-optimized programming after S-ICD implantation contributes to a lower risk of inappropriate shocks in the latest generation S-ICDs

Abstract Funding Acknowledgements Type of funding sources: None. Background Implantable cardioverter-defibrillator (ICD) therapy is associated with the risk of inappropriate shocks (IAS). IAS, defined as any shock on a different rhythm than VT or VF, cause psychological stress, decrease the quality of life and may provoke ventricular arrhythmias. In the subcutaneous ICD (S-ICD) the majority of IAS are caused by T-wave oversensing (TWOS), often during exercise. Exercise-optimized programming during an exercise ECG test (X-ECG) after implantation has shown to be successful in reducing IAS in patients known with TWOS. In recent years, new discrimination algorithms in the latest generation S-ICDs have significantly reduced the risk of TWOS. The benefit of performing an X-ECG in these latest generation S-ICDs to reduce IAS is unclear. Purpose We aim to describe the effect of exercise-optimized programming after S-ICD implantation on inappropriate shock rate in the latest generation S-ICDs. Methods In this retrospective multicenter study, data were collected from two experienced S-ICD hospitals in the Netherlands. All patients underwent an S-ICD implantation of second or third generation between February 2015 and December 2020. Patients younger than 21 years were excluded. Patients with an X-ECG after implantation were compared with patients without X-ECG after implantation. Total number of patients with IAS and cause of the first IAS were evaluated. Results In total, 262 patients were included in the X-ECG group and 61 in the no X-ECG group. The median follow-up time was 22 months in the X-ECG group (IQR 9-33) and 23 months in the no X-ECG group (IQR 12-33, P = 0.9). Mean age was 51 ± 15 years and 61 ± 15 years respectively (P&amp;lt; 0.001). Primary prevention indication was similar in both groups (56% for the X-ECG group versus 49% for the no X-ECG group, P = 0.4). A total of 8 patients (3.1%) experienced IAS in the X-ECG group; 3 first shocks (1.15%) were due to TWOS, 2 (0.8%) were given on a SVT and 3 (1.15%) on other non-cardiac activity. In the no X-ECG group, 6 patients (9.8%) experienced IAS; 1 first shock (1.6%) was due to TWOS, 4 (6.6%) were given on a SVT and 1 (1.6%) on other non-cardiac activity. Patients with an X-ECG had a significantly lower risk of IAS compared to patients in the no X-ECG group (hazard ratio 0.32; 95% CI 0.1 to 0.9; P = 0.027). The Kaplan-Meier estimate of IAS-free survival for the X-ECG group was 61 months (95% CI 59 to 62) and 50 months (95% CI 46 to 55) for the no X-ECG group. Results are shown in the figure. Conclusion This study shows that, in the latest generation S-ICDs, exercise-optimized programming after S-ICD implantation results in a significantly lower risk of IAS in adults. Patients with an X-ECG after S-ICD implantation were younger, which may have affected the outcome. Further prospective data with more equal groups is necessary. Until then, we recommend considering exercise testing after S-ICD implantation in the latest generation S-ICDs. Abstract Figure.

Prognostic role of left atrial enlargement in patients with implantable cardioverter defibrillators for primary prevention

Purpose Left atrial volume index (LAVI) is a predictor of heart failure and adverse events, irrespective of left ventricular systolic function. The role of LAVI in the prediction of appropriate implantable cardioverter-defibrillator (ICD) therapies is currently unclear and was the focus of this study. Methods Consecutive heart failure patients with ischaemic (ICM) or idiopathic (DCM) aetiology receiving ICD for primary prevention were included. The primary endpoint was the occurrence of appropriate ICD therapies (ATs): shocks or antitachycardia pacing (ATP). Inappropriate ICD shocks were also assessed as secondary endpoint. Results Among 198 included patients, severe left atrial dilatation (SLAE = LAVI ≥ 60 ml/m2) was present in 54 (27%). SLAE patients had a higher prevalence of NYHA class ≥ III, severe mitral regurgitation and atrial fibrillation history. During a median follow-up of 45 months (IQR 25–68), ATs occurred more frequently in SLAE group (33% vs. 15%, p = .007) as well as appropriate shocks (24% vs. 10%, p = .014). At multivariate analysis SLAE was an independent predictor of ATs (OR 3.19, 95% CI 1.38–7.38, p = .007). Inappropriate shocks were associated with AF during implantation (p = .03), but not with SLAE (p = .009). Conclusion In DCM or ICM patients candidate to receive an ICD for primary prevention, a severely enlarged left atrium is a predictive factor for ATs (shocks or ATP). The risk of inappropriate shocks was increased in patients with atrial fibrillation, rather than SLAE.

Circulating Soluble ST2 Predicts All-Cause Mortality in Severe Heart Failure Patients with an Implantable Cardioverter Defibrillator

Background Heart failure (HF) is the terminal stage of all cardiovascular events. Although implantable cardioverter defibrillator (ICD) therapies have reduced mortality among the high-risk HF population, it is necessary to determine whether certain factors can predict mortality even after cardiac device implantation. Growth stimulation expressed gene 2 (ST2) is an emerging biomarker for HF patient stratification in different clinical settings. Aims This study aimed to investigate the relationship between baseline soluble ST2 (sST2) levels in serum and the clinical outcomes of high-risk HF patients with device implantation. Methods Between January 2017 and August 2018, we prospectively recruited consecutive patients implanted with an ICD for heart failure, with LVEF ≤35% as recommended, and analyzed the basic characteristics, baseline serum sST2, and NT-proBNP levels, with at least 1-year follow-up. All-cause mortality was the primary endpoint. Results During a 643-day follow-up, all-cause mortality occurred in 16 of 150 patients (10.67%). Incidence of all-cause mortality increased significantly in patients with sST2 levels above 34.98846 ng/ml (16.00% vs. 5.33%, P = 0.034). After adjusting the model (age, gender, device implantation, prevention of sudden death, LVEDD, LVEF, WBC and CLBBB, hsTNT, etiology, and eGFR) and the model combined with NT-proBNP, the risk of all-cause death was increased by 2.5% and 1.9%, respectively, per ng/ml of sST2. The best sST2 cutoff for predicting all-cause death was 43.42671 ng/ml (area under the curve: 0.72, sensitive: 0.69, and specificity: 0.69). Compared to patients with sST2 levels below 43.42671 ng/ml, the risk of all-cause mortality was higher in those with values above the threshold (5.1% vs. 21.2%, P = 0.002). ST2 level ≥43.42671 ng/ml was an independent predictor of all-cause mortality (HR: 3.30 [95% CI 1.02–10.67]). Age (HR: 1.06 [95% CI: 1.01–1.12]) and increased NT-proBNP per 100 (HR: 1.02 [95% CI: 1.01–1.03]) were also associated with all-cause mortality in ICD patients. Conclusions sST2 level was associated with risk of all-cause mortality, and a threshold of 43.43 ng/ml showed good distinguishing performance to predict all-cause mortality in patients with severe heart failure, recommended for ICD implantation. Patients with sST2 levels more than 43.42671 ng/ml even after ICD implantation should therefore be monitored carefully.

Abstract 17488: What Are the Gaps? A Qualitative Study on Patient and Family Decision Making Regarding Implantable Cardioverter Defibrillator and Cardiac Resynchronization Therapy

Background: Implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT-D) reduce mortality and improve functional status in selected patients with heart failure (HF). However, there are potential procedural risks and psychosocial concerns associated with device implant. This qualitative study aims to explore patients’ and families’ understanding of ICD/CRT-D, heart failure and arrhythmia in the process of decision making regarding device implant. Methods: We conducted 14 focus groups or interviews in Salt Lake City UT and Silver Spring MD. This study included 23 patients, who had either an ICD or CRT-D implant for primary prevention, and 14 family members. Grounded theory analysis was performed to reach a conceptual understanding of patients’ and families’ perceptions and needs. Results: Patients and families largely made decision of ICD/CRT implant based on physicians’ recommendations, e.g. “I really try to do what they tell me to do” (icdpt 1). Patients perceived ICD as lifesaving and CRT being helpful to improve functional status. Many patients described ICD as lifesaving by “restarting a heart if it stops”, while did not understand HF or ventricular arrhythmia. Patients perceived an urgency to consider ICD implant from their physicians, but no such urgency was perceived when they discussed about CRT-D implant. Few participants were concerned with costs, or had knowledge of potential lead malfunction, device removal and associated risks. Many emphasized the importance of information about life expectancies, what HF is, options of different devices, complications and precautions, and what to expect regarding lifestyle changes. Conclusion: Patients and families largely relied on the information provided by physicians and followed physicians’ guidance. They had limited understanding of their prognosis, HF and arrhythmia, and they were motivated to learn. Discussion about devices should include prognosis and healthy life style changes.

Abstract 16778: Ventricular Tachycardia Ablation Outcomes Based on Scar Location in Patients With Ischemic Cardiomyopathy

Introduction: Catheter ablation of ventricular tachycardia (VT) reduces implantable cardioverter defibrillator (ICD) therapies, improves hospitalization, and improves survival in patients with ischemic cardiomyopathy (ICM). Hypothesis: The goal of this study is to evaluate outcomes of patients with VT ablation by scar location in patients with ICM. Methods: Consecutive retrospective review of patients with ICM who underwent VT ablation at Minneapolis Veterans Affairs Health Care system between July 2008 and September 2019 were assessed for clinical outcomes. Results: Seventy-five patients with ICM underwent VT ablation during the study period. Average age was 67.6 ± 7 years old and 100% Male. Three patients were lost to follow up. Overall mortality was 53.3% and was highest in the inferior wall scar (IWS) group (Figure 1A, Table). Mean survival after ablation was 2.2 years. Most common cause of death was cardiac which included congestive heart failure, myocardial ischemia, and cardiac arrest (VT and pulseless electrical activity) (Figure 1B). On post-ablation echocardiogram, patients with anterior wall scar (AWS) had a lower mean ejection fraction (23%) compared to IWS group (30%) and this was statistically significant (p &lt; 0.03, two-tailed t-test). The average number of ablations for recurrent VT was 1.4 with no significant difference between the groups. Fifty-five percent of patients were on anti-arrhythmics post ablation. Conclusions: VT ablation patients with IWS mediated VT have a trend towards higher mortality compared to those with AWS. This may be due to neuroregulatory pathway of VTs based on cardiac innervation.

Abstract 13843: Icd Therapy After the First Primary-Prevention Implantable Cardioverter-Defibrillator Battery Change-out

Background: Implantable cardioverter-defibrillator (ICD) therapy prevents sudden cardiac death in selected patients with heart failure. When a primary prevention ICD arrives at elective replacement interval (ERI), conventional management is to replace the device. However, the effectiveness of ICDs in patients with nonischemic and ischemic cardiomyopathy (NICM and ICM, respectively) whose left ventricular ejection fraction (LVEF) improved to ≥50% before replacement is unclear. Hypothesis: The therapeutic benefit of primary prevention ICD for NICM is attenuated by the recovery of LVEF at the time of ERI. Methods: Consecutive patients presenting for first time primary prevention ICD battery change-out at a single quaternary care center between 1/1/2008 and 6/27/2019 were included. The primary endpoint was the rate of ICD therapy (ICD discharge and anti-tachycardia pacing) according to LVEF recovery at ERI. Results: During the study period 6851 ICDs were placed, of which 310 underwent battery change-out, of whom 100 did not receive therapy from the first ICD, of whom 44 had NICM. The demographics of the NICM cohort are in the table. Following ERI, 0 (0%) with NICM and recovered LVEF had received ICD therapy, whereas 13 (30%) with persistently low LVEF had received therapy (p = 0.07). Furthermore, among patients without recovered LVEF, the NICM group had a lower rate of therapy (4, 12%) than the ICM group (12, 32%) (p=0.04). Conclusion: Rates of ICD therapy provided by primary prevention ICD after first battery change out trended towards a significantly lower rate in NICM patients with LVEF that recovered to ≥50% than those without LVEF recovery. No other patient demographic significantly predicted therapy-free survival but the analysis was limited by sample size. A prospective study with a larger cohort would be necessary to better estimate therapy-free survival.

Detection of new-onset atrial fibrillation in heart failure patients using daily non-invasive ECG monitoring in the TIM-HF2 telemedicine trial

Abstract Background Heart failure (HF) and atrial fibrillation (AF) impair the prognosis when they occur concomitantly. Recent telemedical studies suggest that HF patients with AF may derive a greater benefit from telemedicine care but the results are inconsistent. The rate of newly detected AF in HF patients by daily non-invasive electrocardiogram (ECG) monitoring is unknown and a possible influence on the outcome of remote patient management (RPM) remains unclear. Purpose We aimed to investigate the detection of new atrial fibrillation in patients assigned to RPM in comparison to patients assigned to usual care (UC) in the TIM-HF2 trial. Methods The prospective, multicentre and controlled TIM-HF2 trial randomised 1538 patients (765 RPM, 773 UC). All patients had a 12-channel ECG at baseline and after one year at the final study visit. Patients who were assigned to RPM additionally transmitted a daily ECG to the telemedical centre (TMC). We excluded all patients with pacemaker including implantable cardioverter defibrillator (ICD) or cardiac resynchronisation therapy (CRT) in the baseline ECG, leaving 879 patients for analysis (RPM: 442 and UC: 437). The patients were stratified into patients with SR and patients with AF according to the rhythm documented at baseline. The primary endpoint of this analysis was newly documented AF within one year after randomisation. We analysed the daily to the telemedical centre transmitted ECGs of patients assigned to RPM with the documented rhythm status of the ECGs performed at the final study visit of patients assigned to UC. Results 569 patients had SR and 310 patients had AF at baseline. The proportion of patients with AF was nearly the same in the RPM (159, 36.0%) and the UC (151, 34.6%) group. 68 patients (24.0%) were detected with new atrial fibrillation in the RPM group compared to 22 patients (7.8%) in the UC trial arm during the one-year follow-up (p&amp;lt;0.001, number needed to screen 6). Conclusion In patients with heart failure and daily ECG transmission, atrial fibrillation was detected three times more frequently in comparison to usual care within one year. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): The TIM-HF2 study was supported by a research grant of the German Federal Ministry of Education and Research (grant numbers 13KQ0904A, 13KQ0904B, 13KQ1104A). The TIM-HF2 study was a part of the research and development project “Gesundheitsregion der Zukunft Nordbrandenburg – Fontane” (Fontane). The Fontane system was developed in private–public partnership (PPP) supported by research and development grants from the German Federal Ministry of Education and Research, the European Regional Development, and the Federal State Brandenburg.

Stellate ganglion blockade for electrical storm: a case report

Introduction The Chronic Chagasic Cardiomyopathy is one important cause of arrhythmias in Brazil. The usual anti-arrhythmic treatment involves the use of medication, placement of implantable cardioverter defibrillator (ICD) and catheter ablation therapy. Some patients with ICD develop electrical storms (ES), 3 or more episodes of ventricular arrhythmia followed by electrical therapy in 24h. Under these circumstances is believed that the sympathetic tone is heightened. There has been a growing evidence showing that the modulation of neural activity with the Stellate Ganglion Blockade (SGB) can be an adjuvant treatment for patients with ES. Methods Case Report: A 50-year-old male patient with medical history of arrhythmogenic chagasic cardiomyopathy with previous ICD presented several episodes of chest pain, dizziness and Sustained Ventricular Tachycardia frequently leading him to the emergency room (ER). After cardioversion from the ICD and drug optimization he presented better control of the arrhythmia. A month later, a new episode of chest pain, dyspnea, abdominal pain, Sustained Ventricular Tachycardia with a heart rate of 130bpm - below the ICD trigger – brought him to the ER again. In addition to the pharmacological therapy, the stellate ganglion blockade was chosen (SGB). It was performed in sterile conditions and ultrasound-guided. From cricoid cartilage, the probe was moved caudad and laterally to visualize C7’s transverse process. We used a Quincke 22G needle to perform the SG . The tip of the needle was placed on the anterior fascia of the longus coli muscle. Through ultrasound imaging the dispersion of the 10ml of anesthetic solution with lidocaine 1% and bupivacaine 0,25% was seen throughout the stellate ganglion pathway. Results Procedure was performed without any complications.On the 24-hour follow up the patient presented a slow ventricular tachycardia, treated with ATP and sent to cardiac ablation, with satisfactory outcome. Discussion Conclusion: The SGB can be a bedside and efficient option as a treatment for ES, it improves cardiac autonomic modulation decreasing the occurrence of ES and can be used as a bridge for cardiac ablation.

First Argentine Registry of Cardioverter-Defibrillator and Resynchronization Therapy: An Opportunity to Analyze the Present to Improve the Future

First Argentine Registry of Cardioverter-Defibrillator and Resynchronization Therapy: An Opportunity to Analyze the Present to Improve the Future