Implantable Cardiac Defibrillator Therapy Research Articles

Abstract 15106: Echocardiography versus Cardiac Magnetic Resonance-Quantification of Right Ventricular Function to Stratify the Risk of Appropriate Defibrillator Therapy

Background: Right ventricular dysfunction is recently referred as an independent predictor of sudden cardiac death. The purpose of this study was to evaluate the efficiency of risk stratification methods for appropriate implantable cardiac defibrillator (ICD) therapy using two different modalities to quantify the right ventricular function. Methods: Consecutive patients undergoing ICD implantations who completed both preprocedural echocardiography and cardiac magnetic resonance (CMR) were retrospectively enrolled. Any channelopathy or arrhythmogenic right ventricular disease were excluded. The right ventricular fractional area change (RVFAC) and estimated pulmonary artery pressure (EPAP) were calculated from echocardiography. The contraction-pressure index (CPI) was defined as the quotient of the RVFAC divided by EPAP. The right ventricular ejection fraction (RVEF) was automatically provided by CMR. Both were evaluated to predict the initial appropriate ICD therapy. Results: In total, 111 patients (59.5±14.9 years, 79 males) including 20 with ischemic cardiomyopathy were retrospectively enrolled. Fifty-six patients received an ICD as secondary prophylaxis. The mean RVFAC, CPI, and RVEF were 36.7±8.9%, 1.4±0.7%, and 39.9±13.8%, respectively. Regarding appropriate ICD therapy events, the best cut-off value of the RVFAC was 34.8 (specificity 0.63, sensitivity 0.65, ROC-AUC 0.64), CPI 1.59 (specificity 0.42, sensitivity 0.94, ROC-AUC 0.61) and RVEF 43.0 (specificity 0.48, sensitivity 0.87, ROC-AUC 0.64). The hazard ratio of a low RVFAC was 3.13 (95%CI: 1.32-7.44, P<0.01, concordance=0.62), that of low CPI was 9.60 (95%CI: 1.27-72.4, P=0.03, c=0.65), and that of reduced RVEF was 5.55 (95%CI: 1.64-18.7, P<0.01, c=0.67). Conclusion: CPI and RVEF were similarly associated with an increased appropriate ICD therapy. The CPI seemed to provide an equivalent stratification for the risk of appropriate ICD therapy as compared to a CMR indicator.

Admission triglyceride-glucose index is predictor of long-term mortality and appropriate implantable cardiacdefibrillator therapy in patients with heart failure.

Background: In this study, the main aim was to evaluate the relation of the triglyceride-glucose (TyG) index to long-term mortality and proper shock therapy in patients with an implantable cardiacdefibrillator (ICD) implanted for heart failure with reduced ejection fraction. Methods: This retrospective study group consisted of 773 patients treated with ICD for heart failure with reduced ejection fraction. The long-term prognostic effect of the TyG index among tertiles was evaluated regarding mortality and appropriate ICD therapy. Results: In the adjusted model, the mortality rates were 14.0% (hazard ratio: 2.24; 95% CI: 1.42-6.88) in tertile 2 and 23.3% (hazard ratio: 3.88; 95% CI: 1.84-14.38) in tertile 3. Conclusion: The TyG index was found to be an independent predictive marker for both long-term mortality and appropriate ICD therapy.

PO-05-078 SHOCK REDUCTION THROUGH EARLY DELIVERY OF ANTITACHYCARDIA PACING FOR FAST VENTRICULAR TACHYCARDIAS

Antitachycardia pacing (ATP) is a programmable therapy in implantable cardiac defibrillator (ICD) devices that has been demonstrated to effectively reduce the need for shocks. Limited data, however, exists on the potential benefits of early ATP delivery in the ventricular fibrillation (VF) zone. While ATP is programmed to be delivered as a first line of therapy for ventricular tachycardia (VT) events, it does so only once the episode meets detection criteria by the ICD. Newer generations of BIOTRONIK ICDs have the ability for earlier delivery of ATP, called Early ATP OneShot, to be programmed in the VF therapy zone. Early ATP is delivered when 12 out of 16 events, plus stability criteria, are met to target fast VTs detected in the programmed VF therapy zone. This option is available for patients with longer detection times (VF detection counters of 16 out of 20 or higher) and allows the device to deliver ATP before episode detection counter criteria is met, thus providing therapy earlier than traditional ATP. To compare the success rates of Early ATP OneShot (eATP) for episodes in the VF zone against traditional ATP OneShot (tATP) programming. Using BIOTRONIK’s real-world research database, CERTITUDE, 696 patients with eATP capable ICD devices with VF episodes transmitted via remote monitoring were divided into groups based on tATP (n=584) or eATP (n=112) programming for the VF therapy zone. Each device detected episode was evaluated to determine the therapy (ATP and/or shocks) delivered, whether therapy was successful, or if the episode self-terminated. Patients with detection zone counters lower than 16 out of 20 were excluded. eATP was successful in 69.4% of cases in terminating episodes in the VF zone whereas tATP was successful in 49.1% of cases (p<0.0001). Extrapolation of the eATP success rate to the tATP cohort results in 30.0% less shocks (203 avoided shocks out of 676 total shocks). Cohorts did not differ statistically in mean R-R interval at episode detection, nor in device programming for detection limit zone or counters. Episode duration was shorter in the eATP cohort (p<0.0001). As compared to traditional programming, use of Early ATP OneShot provides increased success rates to terminate fast VTs detected in the VF zone, potentially reducing unnecessary shocks.Tabled 1Table: Comparison of ATP Therapy Groups for Device Detected VF Episodes (PO-05-078)OutcomeEarly ATP OneShotTraditional ATP OneShotp value (difference)Patients with VF Event112584-ATP Therapy Success Rate (Successes/Attempts)69.4% (161/232)49.1% (491/1001)<0.0001Median VF Episode Duration (sec)1217<0.0001Mean R-R interval at VF Episode Detection (ms)2572530.17Mean Programmed Rate of VF Detection Limit (ms)2882910.20Median Programmed Detection Counters for Programmed VF Zone (X/Y criteria)18/2418/240.94 Open table in a new tab

CI-452769-3 INAPPROPRIATE ICD SHOCKS IN PATIENTS WITH LVADS: PREVALENCE, ASSOCIATED FACTORS, AND ETIOLOGIES

Left Ventricular Assist Devices (LVADs) are increasingly used to treat advanced heart failure. While most patients with an LVAD have an implantable cardiac defibrillator (ICD) in situ, there are limited data on the frequency and causes of ICD therapies in patients with LVADs. To define the incidence, programming and patient characteristics associated with appropriate and inappropriate shocks in persons with ICDs and LVADs. We performed a retrospective review at Duke University Hospital of all LVAD recipients implanted with a HeartWare, HeartMate II, and HeartMate III (January 1, 2013 to June 30, 2019) and an ICD in situ. ICD shocks were adjudicated by the treating physician and a 2nd review for the purpose of this study. Among 437 patients with an ICD in situ undergoing LVAD implant, 147 (33.6%) patients had at least one shock episode following LVAD implantation. 12 patients were excluded due to incomplete device history. Among 135 patients, there were a total of 332 shock episodes: 257 (77.4%) appropriate and n=75 (22.6%) inappropriate. Etiologies for inappropriate shocks included SVT (n=66, 19.9%), physiologic oversensing (n=1, 0.3%), and non-physiologic oversensing (n=8, 2.4%). Overall, 92 (68.1%) patients had no inappropriate shock episodes, 43 (31.8%) patients had ≥ 1 inappropriate shock episodes, and 14 (10.4%) patients had ≥ 2 inappropriate shock episodes. Moreover, 26 (19.3%) patients had only inappropriate shock episodes. Among persons with inappropriate shocks, 0 of 47 patients had device programming consistent with consensus AHA recommendations (published after end of follow-up). The rate of inappropriate shocks in LVAD recipients is very high and is most often due to supraventricular arrhythmias. Implementation of current consensus AHA recommendations for LVAD programming may help avoid inappropriate shocks.

Abstract 14931: Frailty Status Modifies the Efficacy of ICD Therapy Among Patients With Chronic Heart Failure With Reduced Ejection Fraction

Introduction: Frailty is common in patients with heart failure with reduced ejection fraction (HFrEF) and is independently associated with mortality. Implantable cardiac defibrillator (ICD) therapy is recommended to reduce mortality risk in patients with HFrEF. Whether baseline frailty modifies the efficacy of ICD therapy in HFrEF is not known. Methods: Stable outpatients with HFrEF randomized to ICD vs. placebo in the SCD-HeFT trial were included. Baseline frailty was estimated using Rockwood’s Frailty Index (FI) by dividing the number of deficits present by the number of variables considered (n=37). Participants were categorized into tertiles of FI. Multivariable adjusted Cox proportional hazard models with multiplicative interaction terms (frailty*treatment arm) were constructed to evaluate whether frailty modified the treatment effect of ICD therapy on the primary outcome all-cause mortality and secondary outcomes of cardiovascular (CV) mortality and sudden cardiac death (SCD). Results: Among 1,673 participants (age: 59±12 y, 23% women), the median [IQR] FI ranged from 0.19 [0.14-0.23] in tertile 1 (lower frailty burden) to 0.51 [0.47-0.56] in tertile 3 (higher frailty burden). Baseline frailty significantly modified the treatment effect of ICD therapy (P-interaction: 0.03) ( Fig. A ). Specifically, ICD therapy was associated with a lower risk of all-cause mortality in tertile 1 [HR (95% CI) = 0.55 (0.37-0.80)] but not in tertile 3 participants [HR (95% CI) = 0.90 (0.67-1.22)] ( Fig. B ). Among secondary outcomes, frailty status modified the association of both CV mortality and SCD (P-interaction = 0.007 and 0.04, respectively). Similar results were observed in landmark analyses at 12 months. Conclusions: Among patients with chronic stable HFrEF, baseline frailty modified the treatment effect of ICD therapy with a greater reduction in the risk of CV mortality and SCD in patients with a lower burden of frailty.

Remote monitoring in patients with heart failure with cardiac implantable electronic devices: a systematic review and meta-analysis

BackgroundRemote monitoring (RM) of cardiac implantable electronic devices (CIEDs) is now the standard of care, but whether the demonstrated benefits of RM translate into improvements in heart failure (HF) management...

PO-707-04 ANALYSIS OF PATIENT PREDICTORS AND OUTCOMES IN ICD SHOCK THERAPY EXPERIENCED DURING HEMODIALYSIS

Implantable cardiac defibrillators (ICDs) are the mainstay for the prevention of sudden cardiac death (SCD) in high-risk patients. Dialysis patients have been excluded from major clinical trials, and thus data in this population are scant. No study has reported on outcomes of ICD therapy during hemodialysis.

PO-672-04 1:1 TACHYCARDIA INITIATED BY A PREMATURE VENTRICULAR CONTRACTION: THE APPEAL OF THE PEEL

Despite advances in implantable cardiac defibrillator (ICD) programming, inappropriate ICD therapy remains common. Inappropriate ICD therapy is associated with increased mortality and psychological distress. Careful analysis of stored electrograms (EGMs) can be used to elucidate the mechanism of the arrhythmia and guide therapy.

Predictors of appropriate implantable cardiac defibrillator therapy in cardiac sarcoidosis.

Cardiac sarcoidosis (CS) is associated with an increased risk for sudden cardiac death. An implantable cardiac defibrillator (ICD) is recommended in a subgroup of CS patients. However, the recommendations for primary prevention differ between guidelines. The purpose of the study was to evaluate the efficacy and safety of ICDs in CS and to identify predictors of appropriate therapy. A retrospective cohort study was performed in CS patients with an ICD implantation between 2010 and 2019. Primary outcome was appropriate ICD therapy. Independent predictors were calculated using Cox proportional hazard analysis. 105 patients were included. An ICD was implanted for primary prevention in 79%. During a median follow-up of 2.8 years, 34 patients (32.4%) received appropriate ICD therapy of whom 24 (22.9%) received an appropriate shock. Three patients (2.9%) received an inappropriate shock due to atrial fibrillation. Independent predictors of appropriate therapy included prior ventricular arrhythmias (hazard ratio [HR]: 10.5 [95% confidence interval (CI): 5.0-21.9]) and right ventricular late gadolinium enhancement (LGE) (HR: 3.6 [95% CI: 1.7-7.6]). Within the primary prevention group, right ventricular LGE (HR: 5.7 [95% CI: 1.6-20.7]) was the only independent predictor of appropriate therapy. Left ventricular ejection fraction did not differ between patients with and without appropriate therapy (44.4% vs. 45.6%, p = .70). In CS patients with an ICD, a high rate of appropriate therapy was observed and a low rate of inappropriate shocks. Prior ventricular arrhythmias and right ventricular LGE were independent predictors of appropriate therapy.

Optimal Timing of Cardioverter-Defibrillator Implantation in Patients with Left Ventricular Dysfunction after Acute Myocardial Infarction

Background: Prevention of sudden cardiac death (SCD) early after acute myocardial infarction (AMI) is still a challenge, without clear recommendations in spite of the high incidence of life-threatening ventricular arrhythmias, as implantable cardiac defibrillator (ICD) placement is not indicated in the first 40 days after an AMI; this timing is aleatory and it is owed to fact that the two pivotal studies for evaluation of ICDs in primary prevention, MADIT and MADIT II, excluded the patients within three, respectively four weeks after AMI. Methods: We conducted a retrospective, single-center study that included 77 patients with AMI. All patients were monitored by continuous ECG in the first week after the event. Transthoracic echocardiography was performed at discharge and 40 days after the event. Patients with ejection fraction of 35% or less as assessed by 2D echocardiography 40 days after the MI, which received an ICD for the primary prevention of SCD, were included in the study. The subjects were followed for a median of 38 months, by means of device interrogation and echocardiography. Results: We divided our patients into two groups: in the first group, with left ventricular ejection fraction (LVEF) under 30% after MI, all patients remained in the reduced ejection fraction heart failure category, with an increase from an initial mean of 18.93 ± 4.99% to a mean of 22.18 ± 4.53% after a period of 40 days; we obtained a positive and statistically significant correlation (p &lt; 0.001 and r – 0.547), and all patients presented indication of ICD implant 40 day after MI. In the second group with LVEF between 30% and 35% after MI, the mean LVEF increased from an initial mean of 31.73 ± 1.33% to a mean of 32.33 ± 1.49% after a period of 40 days. A statistically significant correlation (p – 0.02 and r – 0.78) was obtained, although 3 patients presented a LVEF over 35% at 40 days post-MI. Most of the ICD therapies (14.54%) appeared in patients with LVEF &lt;30% and these patients also presented a higher percentage of NSVT at initial ECG monitoring (54% vs. 50%) and NSVT at ICD interrogation (80% vs. 66.7%); statistical significance was not reached – p &gt; 0.05. The majority of the ICD therapies (11.9% from 13.4%) appeared in patients with NSVT at initial ECG monitoring; also, these presented an increased number of NSVT at ICD interrogation (77.6% vs. 6%) when compared to patients without VT detection at the initial ECG monitoring. Still, statistical significance was not reached – p &gt; 0.15. Conclusions: The patients could benefit from ICD implant earlier than stated in the actual guidelines, since there are insufficient data in the literature for the waiting time of 40 days. Correlated with the increased risk of SCD in the first months post myocardial infarction, the present study proves the benefit of early ICD implantation considering that all our patients with a low ejection fraction immediately after infarction remained in the same category and the great majority (96.1%) required the implantation of an ICD after 40 days. Thus, we could avoid exposing our patients at risk of SCD for an unnecessary prolonged period, and choose early ICD implantation.

Fragmented QRS is associated with ventricular arrhythmias in heart failure patients: A systematic review and meta-analysis.

IntroductionMany primary prevention heart failure (HF) patients with an implantable cardiac defibrillator (ICD) rarely experience life‐threatening ventricular arrhythmias (VA). New strategies are required to identify patients most at risk of VA and sudden cardiac death who would benefit from an ICD. One potential method is the detection of fragmented QRS (fQRS) on the electrocardiogram. The aim was to assess the predictive capacity of fQRS for VA and mortality in ischemic (ICM) and non‐ischemic cardiomyopathy (NICM) primary prevention HF patients.Methods and ResultsA systematic review and meta‐analysis of studies examining fQRS in HF patients with or without an ICD who met primary prevention indications with reduced ejection fraction ≤40%. Outcome measures were VA (or appropriate ICD therapy) and all‐cause mortality. Ten studies involving 3885 patients were included for analysis. Most patients were male with non‐fQRS patients being significantly younger (−1.5[−2.66, −0.42], p = .03). Diabetes was more likely in fQRS patients (1.12[1.01, 1.25], p = .03) while non‐fQRS patients were 28% more likely to have a history of atrial fibrillation (0.82[0.67,1.00], p = .05). Ventricular arrhythmias were significantly 1.5 times more likely in patients with fQRS (1.51[1.02, 2.25], p = .04). HF patients were 1.7 times more likely to die of any cause if fQRS was present (1.68[1.13, 2.52], p = .01). NICM patients with fQRS have a significant 2.6‐fold increased incidence of death compared with ICM patients (2.55[1.63, 3.98], p < .0001).ConclusionfQRS is associated with VA and all‐cause mortality and may be a novel marker in the risk stratification of primary prevention HF patients indicated for ICD implantation.

Clinical characteristics and natural history of pre-adolescent non-syndromic hypertrophic cardiomyopathy

Abstract Background The clinical presentation and natural history of pre-adolescent sarcomeric hypertrophic cardiomyopathy (HCM) has not been systematically characterised. The aim of this study was to describe the clinical characteristics and outcomes of a large, international, multicentre cohort of children diagnosed with non-syndromic HCM below the age of 12. Methods Data from the International Paediatric Hypertrophic Cardiomyopathy Consortium on 639 children meeting diagnostic criteria for HCM below 12 years of age (pre-adolescent) were collected and compared with 568 diagnosed aged 12–16 years. Patients with syndromic and metabolic HCM were excluded. Results Of 639 (male n=417, 65.3%) children with pre-adolescent HCM, 339 (53.1%) had a family history of HCM and 57 (8.9%) a family history of sudden cardiac death (SCD). At the time of baseline assessment; 132 (20.7%) had heart failure symptoms and 39 (6.1%) reported unexplained syncope. Median maximal left ventricular wall thickness on echocardiogram was 13.6mm (IQR 10–19) with a corresponding median z-score of 8.7 (5.3–14.4). 145 (22.7%) had left ventricular outflow tract obstruction (LVOTO) (maximal LVOT gradient≥30mmHg) and 35 (5.5%) had severe LVOTO (gradient≥90mmHg). Over a median follow up 5.6 years (IQR 2.3–10), 10.5% underwent a myectomy and 23.2% implantable cardiac defibrillator (ICD) implantation for primary (81.8%) or secondary (14.2%) prevention. 42 (6.7%) patients died [SCD 4.9%, heart failure death 0.8%, other 1%] and 21 (3.3%) underwent cardiac transplantation. 69 (10.8%) patients had an arrhythmic event (SCD n=31, resuscitated cardiac arrest n=17, appropriate ICD therapy n=14, sustained VT with haemodynamic compromise n=7). Compared to those presenting after 12 years, those under 12 were less likely to have a family history of SCD (8.9% vs 13%, p:0.047) or report unexplained syncope (6.1% vs 12.3%, p&amp;lt;0.00). The degree of hypertrophy did not differ but a higher proportion of pre-adolescent patients had LVOTO (22.7% vs 14.4%, p&amp;lt;0.00). A higher proportion of pre-adolescent underwent a myectomy (10.5% vs 7.2%, p:0.045) but a lower proportion received a primary prevention ICD (18.9% vs 30.1%, p:0.041). The overall proportion of patients reaching the mortality or arrhythmic end-points did not differ, but SCD and resuscitated cardiac arrest events were more frequent in pre-adolescent patients (4.9% vs 3.9% and 2.7 vs 1.6% respectively). Conclusion Pre-adolescent HCM is associated with a high symptom burden and variable cardiac phenotype, comparable to those presenting later in childhood. Despite baseline similarities and equal overall survival, younger patients were less likely to receive a primary prevention ICD despite being more likely to experience a SCD or resuscitated cardiac arrest. This study suggests that younger patients should not be considered a distinct entity for risk stratification and that similar management strategies to older HCM patients should be employed. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): BHF (British Heart Foudnation) MRC (Medical Research Council)

Implantable Cardiac Device Infections Prevalence: Diagnostic and Therapeutic Implications

Background: It has been demonstrated that the use of cardiac implanted electronic devices (CIED) improve mortality and survivability in a variety of patient populations. Nevertheless, CIED related infection is a serious complication characterized by a high rate of mortality and morbidity.&#x0D; Objectives: To evaluate the prevalence of CIED related infections, risk factors, clinical and demographic characteristics, causative organisms, and the management and outcome of patients presented in the Critical Care Department, Cairo University.&#x0D; Methods: A retrospective analysis was conducted in 1871 individuals who had been implanted with a cardiac device with a total number of devices of 1968 and 2270 procedures performed from January 2007 to December 2017.&#x0D; Results: 59 infectious episodes were identified with an estimated incidence of 2.99% of inserted devices and 2.6% of total procedures. The infection rate was considerably higher in patients with multiple procedures than those who had a single procedure (9.27% vs. 1.18%; P&lt;0.001). The individuals with a dual-chamber implantable cardiac defibrillator (ICD) and cardiac resynchronization therapy devices (CRTD) had the highest infection rate of 6.25% &amp; 6.85%, respectively. The rate of pocket infection (PI) and CIED related endocarditis (CDE) was 1.54% &amp; 1.06% of total devices respectively. Numerous risk factors have been found; the most significant of those are diabetes mellitus, recurrent procedures, the device's complexity, and the existence of more than one lead. Gram-positive cocci were the most isolated organisms in all positive cultures (69.23%). Echocardiography revealed lead vegetations and valvular vegetations in 22 patients and 2 patients respectively. In 53 cases (89.83%), the devices were removed; in 41 cases, the entire system was removed; and in 12 cases, only the generator was removed. The mortality rate was found to be 10.17%, having a considerably higher prevalence in CDE individuals than in pocket infection individuals (20.83% vs. 2.86%; P=0.025).&#x0D; Conclusion: In our center, while the rate of CIED implantation continues to increase, the incidence rate of CIED-related infection continues to decline. Until now, the infection burden associated with secondary intervention is still significantly high. The management strategy of selection is to eliminate the entire system for patients presented with infection especially those with CDE. However, the mortality rate is still high.

Sudden cardiac death risk stratification in patients with a preserved or mildly reduced ejection fraction: role of cardiac magnetic resonance and electrophysiological study

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Patients presenting with syncope of suspected arrhythmogenic origin or symptomatic documented non sustained ventricular tachycardia (NSVT) may represent a population with higher risk for sudden cardiac death (SCD). However today there are still no defined criteria to stratify the risk of SCD in this population. PURPOSE To assess the prognostic value of magnetic resonance (MRI) and electrophysiological study (EPS) in the risk stratification for SCD of patients with a preserved or mildly-reduced ejection fraction (EF) that may benefit from implantable cardiac defibrillator (ICD) therapy. METHODS We selected ischemic and non-ischemic patients with a preserved or mildly-reduced ejection fraction who came to our attention either after a probably arrhythmogenic syncopal event or a documented NSVT between 12/2018 and 09/2020. Patients with other ICD indications following current guideline-criteria were excluded (id est Brugada syndrome, Long QT and hypertrophic cardiomyopathy). All patients underwent an echocardiography, a coronary angiography, and an MRI with gadolinium, those among them with a positive LGE also underwent an induction EPS. Non inducible patients were followed-up clinically or with an implantable event-recorder, while inducible patients received an ICD. RESULTS In our observational study seventeen patients with preserved or only mildly-reduced EF were enrolled (13 males and 5 females; mean age 68 years). Among these patients, nine were identified with an underlying myocardial scar with positive Late-Gadolinium-Enhancement (LGE) in MRI. Based on the clinical orientation and the MRI LGE pattern patients were divided in ischemic group (5 patients) and non-ischemic group (4 patients). All 9 patients underwent an induction EPS. Three of them, 2 with non-ischemic and 1 with an ischemic pattern, demonstrated a reproducible inducibility of a sustained ventricular tachycardia or ventricular fibrillation and were implanted with an ICD. During our follow-up two of the three patients had an adequate shock within a year from the ICD implantation. Among the 6 patients with negative induction EPS there were no clinical events in the follow up, except one death for unknown causes. CONCLUSION Our preliminary results demonstrated that in patients with ischemic or non ischemic cardiopathy with preserved or mildly reduced EF, a positive MRI LGE pattern and the inducibility of ventricular arrhythmias during induction EPS identify a population at higher risk for clinical recurrence of ventricular arryhthmic events. Further investigation is needed to validate this combined diagnostic strategy as new SCD prevention tool.

Progressive increase in activation delay during premature stimulation is related to ventricular fibrillation in Brugada syndrome.

The local conduction delay has been deemed to play an important role in the perpetuation of ventricular fibrillation (VF) in Brugada syndrome (BrS). We evaluated the relationship between the activation delay during programmed stimulation and cardiac events in BrS patients. This study included 47 consecutive BrS patients who underwent an electrophysiological study and received implantable cardiac defibrillator therapy. We divided the patients into two groups based on whether they had developed VF (11 patients) or not (36 patients) during the follow-up period of 89 ± 53 months. The activation delay was assessed using the interval between the stimulus and the QRS onset during programmed stimulation. The mean increase in delay (MID) was used to characterize the conduction curves. The MID at the right ventricular outflow tract (RVOT) was significantly greater in patients with VF (4.5 ± 1.2 ms) than in those without VF (2.2 ± 0.9 ms) (p < .001). A receiver operating characteristics curve analysis indicated that the optimal cut-off point for discriminating VF occurrence was 3.3 with 88.9% sensitivity and 91.3% specificity. Furthermore, patients with an MID at the RVOT ≥ 3.3 ms showed significantly higher rates of VF recurrence than those with an MID at the RVOT < 3.3 ms (p < .001). The clinical characteristics, including the signal-averaged electrocardiogram measurement and VF inducibility were similar between the two groups. A prolonged MID at the RVOT was associated with VF and maybe an additional electrophysiological risk factor for VF in BrS patients.

Cost-Effectiveness Analysis of Implantable Cardioverter Defibrillator Therapy for Primary Prevention Patients with Additional Risk Factors in Brazil

Abstract Background: Implantable cardiac defibrillators (ICDs) therapy for primary prevention (PP) of sudden cardiac arrest (SCA) is well-established but underutilized globally. The Improve SCA study has identified a cohort of patients called 1.5 primary prevention (1.5PP), based on PP patients with the presence of documented risk factors: non-sustained ventricular tachycardia, frequent premature ventricular contractions, left ventricular ejection fraction < 25%, and pre-syncope or syncope. Objective: This study evaluated the cost-effectiveness of ICD therapy compared to no ICD among 1.5PP patients [...]

Ventricular arrhythmias among patients with implantable cardioverter-defibrillator during the COVID-19 pandemic.

BackgroundCoronavirus Disease‐2019 (COVID‐19) has been associated with myocardial injury and higher risk of arrhythmic complications. However, no reports are available about the effect of the ongoing pandemic on arrhythmias in patients at risk.ObjectiveTo describe the effect of COVID‐19 pandemic on arrhythmic burden among high‐risk patients.MethodsThis is a cross‐sectional study on the incidence of ventricular arrhythmia (VA) during the pandemic outbreak (study period), compared to the same timeframe in 2019 (reference period). Inclusion criteria were age (>18 years) and having an implantable cardiac defibrillator (ICD).ResultsAmong 455 patients enrolled (mean age 64.9 ± 15.7 years; 25.1% females and 39.6% with CRTD), in the study period, 45 (9.9%) patients experienced a total of 86 VA; 8 patients (1.7%) required antitachycardia‐pacing (ATP) and 6 (1.3%) at least one shock. In the reference period, a total of 69 events occurred in 36 patients (7.9%). Six patients (1.3%) required ATP and three (0.7%) at least one shock. The number of patients that suffered from any arrhythmic events in the study period (9.9% vs 7.9%) did not significantly differ from the reference period (χ2 = 1.09, P = .29). The main predictor of VA during the COVID‐19 pandemic was the previous history of any ICD therapy (OR = 3.84, P < .001).ConclusionsNo evidence of an increase of arrhythmic burden was found during the COVID‐19 pandemic among patients with an ICD.

Real-world evaluation of followup strategies after ICD therapies in patients with VT (REFINE-VT).

Implantable cardiac defibrillators (ICDs) can prevent sudden cardiac death, but the risk of recurrent ventricular arrhythmia (VA) and ICD shocks persist. Strategies to minimise such risks include medication optimisation, device programming and ventricular tachycardia (VT) ablation. Whether the choice of these interventions at follow-up are influenced by factors such as the type of arrhythmia or ICD therapy remains unclear. To investigate this, we evaluated ICD follow-up strategies in a real-world population with primary and secondary prevention ICDs. REFINE-VT (Real-world Evaluation of Follow-up strategies after Implantable cardiac-defibrillator therapies in patients with Ventricular Tachycardia) is an observational study of 514 ICD recipients recruited between 2018 and 2019. We found that 77 patients (15%) suffered significant VA and/or ICD therapies, of whom 26% experienced a second event; 31% received no intervention. We observed an inconsistent approach to the choice of strategies across different types of arrhythmias and ICD therapies. Odds of intervening were significantly higher if ICD shock was detected compared with anti-tachycardia pacing (odds ratio [OR] 8.4, 95% confidence interval [CI] 1.7 to 39.6, p=0.007). Even in patients with two events, the rate of escalation of antiarrhythmics or referral for VT ablation were as low as patients with single events. This is the first contemporary study evaluating how strategies that reduce the risk of recurrent ICD events are executed in a real-world population. Significant inconsistencies in the choice of interventions exist, supporting the need for a multi-disciplinary approach to provide evidence-based care to this population.

Renal Denervation for the Management of Refractory Ventricular Arrhythmias: ASystematicReview.

The authors performed a systematic review and meta-analysis to determine the efficacy of renal denervation (RDN) in patients with refractory ventricular arrhythmias (VA) or electrical storm (ES). Although catheter ablation is efficacious for the treatment of structural heart disease ventricular tachycardia (VT), there are proportion of patients who have refractory VT despite multiple procedures. In this setting, novel adjunctive therapies such as renal denervation have been performed. A systematic review of published data was performed. Studies that evaluated patients undergoing RDN for VA or ES were included. Outcome measures of VA, sudden cardiac death, ES, or device therapy were required. Case reports, editorials, and conference presentations were excluded. Random effects meta-analysis was conducted to explore change or final mean values in the study outcomes. A total of 328 articles were identified by the literature search. Seven studies met the eligibility criteria and were included in the systematic review, with a total of 121 pooled patients. The weighted mean age was 63.8 ± 13.1 years, ejection fraction 30.5 ± 10.3%, 76% were men, 99% were on a beta blocker, 79% were on amiodarone, 46% had previously undergone catheter ablation, and 8.3% had previously undergone cardiac sympathetic denervation. Meta-analysis demonstrated a significant effect of RDN in reducing implantable cardiac defibrillator therapies, with a standardized mean difference (SMD) of-3.11 (p<0.001). RDN also reduced the number of VA episodes (SMD-2.13; p<0.001), antitachycardia pacing episodes (SMD-2.82; p=0.002), and shocks (SMD-2.82; p=0.002). RDN is an effective treatment for refractory VAs and ES, although randomized data are lacking.

J point elevation in high precordial leads associated with risk of ventricular fibrillation.

IntroductionThe significance of high precordial electrocardiograms in idiopathic ventricular fibrillation (IVF) is unknown.MethodThis study included 50 consecutive patients (48 men; age, 42 ± 18 years) who had spontaneous ventricular fibrillation not linked to structural heart disease and received implantable cardiac defibrillator therapy. IVF was diagnosed in 35 patients and Brugada syndrome was diagnosed in other 15 patients. Electrocardiograms in high intercostal space were compared between 35 patients with IVF and 105 age‐ and sex‐matched healthy controls (patient: control ratio, 1:3).ResultsThe frequency of J point elevation ≥ 0.1 mV in the 4th intercostal spaces was similar between patients with IVF (14%) and healthy controls (7%). However, the frequency of J point elevation ≥ 0.1 mV in the 3rd intercostal space was higher in patients with IVF (40%) than controls (11%) (p < .01). J point elevation was present only in the 3rd intercostal space but not in the 4th intercostal space in 30% of patients with IVF but only in 6% of controls (p < .01). During follow‐up, the recurrence of ventricular fibrillation was higher in patients with IVF who had J point elevation in the 3rd intercostal space (36%) and Brugada syndrome(40%) than those with IVF who did not have J point elevation in the 3rd intercostal space(11%) (p < .05 for both).ConclusionJ point elevation in the 3rd intercostal space was associated with IVF and recurrences of ventricular fibrillation. Electrocardiogram recordings in the high intercostal space may be useful to identify risk of sudden death.