Prophylactic Implantable Cardioverter-defibrillator Research Articles

Regional disparities and risk factors of mortality among patients at high risk of sudden cardiac death in emerging countries: a nonrandomized controlled trial

BackgroundComprehensive data on patients at high risk of sudden cardiac death (SCD) in emerging countries are lacking. The aim was to deepen our understanding of the SCD phenotype and identify risk factors for death among patients at high risk of SCD in emerging countries.MethodsPatients who met the class I indication for implantable cardioverter-defibrillator (ICD) implantation according to guideline recommendations in 17 countries and regions underrepresented in previous trials were enrolled. Countries were stratified by the WHO regional classification. Patients were or were not implanted with an ICD at their discretion. The outcomes were all-cause mortality and SCD.ResultsWe enrolled 4222 patients, and 3889 patients were included in the analysis. The mean follow-up period was 21.6 ± 10.2 months. There were 433 (11.1%) instances of all-cause mortality and 117 (3.0%) cases of SCD. All-cause mortality was highest in primary prevention (PP) patients from Southeast Asia and secondary prevention (SP) patients from the Middle East and Africa. The SCD rates among PP and SP patients were both highest in South Asia. Multivariate Cox regression modelling demonstrated that in addition to the independent predictors identified in previous studies, both geographic region and ICD use were associated with all-cause mortality in patients with high SCD risk. Primary prophylactic ICD implantation was associated with a 36% (HR = 0.64, 95% CI 0.531–0.802, p < 0.0001) lower all-cause mortality risk and an 80% (HR = 0.20, 95% CI = 0.116–0.343, p < 0.0001) lower SCD risk.ConclusionsThere was significant heterogeneity among patients with high SCD risk in emerging countries. The influences of geographic regions on patient characteristics and outcomes were significant. Improvement in increasing ICD utilization and uptake of guideline-directed medical therapy in emerging countries is urgent.Trial registrationClinicalTrials.gov, NCT02099721.

Long-term prognosis and prognostic factors after primary prophylactic implantable cardioverter-defibrillator therapy

BackgroundLittle is known regarding which patients with ischemic cardiomyopathy (ICM) should be considered for prophylactic therapies, such as an implantable cardioverter-defibrillator (ICD), in the primary percutaneous intervention era. The aim of this study was to investigate the influence of non-sustained ventricular tachycardia (NSVT) on major adverse cardiac events (MACE) in heart failure with reduced ejection fraction (HFrEF) patients. MethodsWe retrospectively analyzed patients of ICM and non-ICM who underwent ICD implantation at our institute from October 2006 to August 2020. MACE were defined as composite outcome of cardiovascular death, heart failure hospitalization, and appropriate ICD therapies. ResultsA total of 167 patients were enrolled [male, 138 (83 %); age, 62.1 ± 11.7 years; left ventricular ejection fraction, 23.5 ± 6.1 %; left ventricular diastolic diameter, 67.4 ± 9.0 mm; atrial fibrillation, 47 (28 %); NSVT, 124 (74 %); use of class III antiarrhythmic drugs, 55 (33 %); ischemic cardiomyopathy, 56 (34 %); cardiac resynchronization therapy, 73 (44 %)]. The median follow-up duration was 61 months. MACE occurred with 71 patients (43 %). When comparing baseline characteristics of the patients, left ventricular ejection fraction (p = 0.02) and atrial fibrillation (p = 0.04) were significantly associated with MACE. The multivariable Cox analysis for the target variable MACE identified atrial fibrillation (hazard ratio 2.00; 95 % confidence index 1.18–3.37; p = 0.01) as an independent predictor for MACE. ConclusionsPrior NSVT before ICD implantation was not an independent predictor of future MACE in patients with HFrEF with primary prophylactic ICD. In contrast, atrial fibrillation was associated with worse prognosis. To predict the prognosis of patients with primary prophylactic ICD, these factors should be assessed as comprehensive risk stratification factors for MACE.

Cardiac Magnetic Resonance as Risk Stratification Tool in Non-Ischemic Dilated Cardiomyopathy Referred for Implantable Cardioverter Defibrillator Therapy-State of Art and Perspectives.

Non-ischemic dilated cardiomyopathy (DCM) is a disease characterized by left ventricular dilation and systolic dysfunction. Patients with DCM are at higher risk for ventricular arrhythmias and sudden cardiac death (SCD). According to current international guidelines, left ventricular ejection fraction (LVEF) ≤ 35% represents the main indication for prophylactic implantable cardioverter defibrillator (ICD) implantation in patients with DCM. However, LVEF lacks sensitivity and specificity as a risk marker for SCD. It has been seen that the majority of patients with DCM do not actually benefit from the ICD implantation and, on the contrary, that many patients at risk of SCD are not identified as they have preserved or mildly depressed LVEF. Therefore, the use of LVEF as unique decision parameter does not maximize the benefit of ICD therapy. Multiple risk factors used in combination could likely predict SCD risk better than any single risk parameter. Several predictors have been proposed including genetic variants, electric indexes, and volumetric parameters of LV. Cardiac magnetic resonance (CMR) can improve risk stratification thanks to tissue characterization sequences such as LGE sequence, parametric mapping, and feature tracking. This review evaluates the role of CMR as a risk stratification tool in DCM patients referred for ICD.

Benefit of primary and secondary prophylactic implantable cardioverter defibrillator in elderly patients.

The benefit of implantable cardioverter-defibrillator (ICD) in elderly patients has been questioned. In the present study, we aimed to analyse the outcome of patients of different age groups with ICD implantation. We included all patients who received an ICD in our hospital from 2011 to 2020. Primary endpoints were (1) death from any cause and (2) appropriate ICD therapy (antitachycardia pacing/shock). A "benefit of ICD implantation" was defined as appropriate ICD therapy before death from any cause/or survival. "No benefit of ICD implantation" was defined as death from any cause without prior appropriate ICD therapy. A total of 422 patients received an ICD (primary prophylaxis n = 323, secondary prophylaxis n = 99). At the time of implantation, 35 patients (8%) were >80 years and 106 patients were >75 years (25%). During the study period of 4.2 ± 3 years, benefit of ICD occurred in 89 patients (21%) and no benefit in 84 patients (20%). In primary prevention, the proportion of patients who had a benefit from ICD implantation decreased with increasing age, and there were no patients who benefited from ICD therapy in the group of patients >80 years. In secondary prophylaxis, the proportion of patients with a benefit from ICD implantation ranged from 20% to 30% in all age groups. Our study suggests that the indication of primary prophylactic ICD in elderly and very old patients should be critically assessed. On the other hand, no patient should be denied secondary prophylactic ICD implantation because of age.

Prognostic value of cardiac magnetic resonance - LGE distribution in non-ischemic dilated cardiomyopathy for prophylactic implantable-cardioverter defibrillator therapy

Abstract Background/Introduction International guidelines recommend implantable cardioverter-defibrillator (ICD) implantation when patients with nonischemic dilated cardiomyopathy (NICM) have left ventricular ejection fraction (LVEF) of 35% or less. Tissue characterization obtained by cardiac magnetic resonance (CMR) has emerged as a promising tool for better identification of patients at high arrhythmic risk and thus worthy of prophylactic ICD therapy. Purpose Current analysis has the scope to assess the prognostic value of fibrosis as evaluated by late gadolinium enhancement sequences (LGE) specifically regarding its LV wall distribution. The primary endpoint was all-cause mortality. The secondary end-point consisted of major adverse arrhythmic cardiac events (MAACE), defined as combination of SCD, aborted SCD, and sustained ventricular tachycardia. Methods Study population is part of DERIVATE Study, an international, multicenter, prospective, observational registry including consecutive patients from 21 sites across Europe and US referred for heart failure (HF) work-up including transthoracic echocardiography (TTE) and CMR without a history of previous major ventricular arrhythmias. Inclusion criteria were: (i) aged 18 or older, (ii) chronic HF according to the ESC Task force definition, and (iii) LV-EF&amp;lt;50% at initial TTE. All patients underwent TTE and CMR within 3 months. Patients with (i) decompensated within 3 months of enrollment, (ii) recent myocardial infarction (&amp;lt;40 days), (iii) unstable angina, (iv) severe valvular disease, (v) primary or secondary cardiomyopathies other than NICM, (vi) cardiac amyloidosis, and (vii) congenital heart disease were excluded. Results The entire cohort consisted of 1384 subjects [mean age: 56±14 years, male: 948 (68.4%)]. The median follow-up time was 959 days. Mortality and MAACE occurred in 92 (6.6%) and 125 (9%) patients, respectively. SCD, aborted SCD, and sustained VT occurred in 15 (1.1%), 80 (5.8%), and 104 (7.5%), respectively. In the multivariate analyses for all-cause mortality, only the number of segments with LGE at the level of the septum was an independent predictor (p=0.002), while in the analyses for MAACE the only independent predictors were male gender, LVEDVi by CMR, and the number of segments with LGE at the level of septum inferior. Based on the multivariate analysis, the DERIVATE score (including all 1384 patients) ranging from 0 to 8 (Cox regression analysis HR=1.35, 95%CI 1.24-1.46, p&amp;lt; 0.001) was built up. The redistribution of patients according to the CMR composite DERIVATE risk/year MAACE was of 44%, 37% and 32% for the low, intermediate and high risk groups, respectively. Conclusions The arrhythmic risk of patients with NICM is also dependent on the different distribution of fibrosis in the LV. The redistribution of the event rate according to the CMR composite risk score indicates the potential to alter the decision on ICD implantation in a relevant portion of NICM patients.

Long-term outcomes in carriers of the familial idiopathic ventricular fibrillation linked to the DPP6 locus

Abstract Background Idiopathic ventricular fibrillation (IVF) is a malignant condition with no clinical sequelae except for ventricular fibrillation. The genetic basis is ill-defined but in 2009 a Dutch founder variant - the DPP6 risk haplotype - was linked to a familial form of IVF characterized by a very high incidence of sudden cardiac arrest (SCA) and sudden cardiac death (SCD). Consequently, for more than a decade asymptomatic haplotype-carriers from the ages of 18 (male) and 25 (female) have had an implantable cardioverter-defibrillator (ICD) inserted. However, the associated long-term outcomes in these individuals is unknown. Purpose To assess the long-term outcomes of DPP6 risk haplotype-carriers who presented to our tertiary referral center and qualified for ICD insertion. Methods Clinical follow-up information of DPP6 risk haplotype-carriers, including the occurrence of SCD, SCA, appropriate ICD shocks, and ICD-related complications, was collected through February 2023. ICD-carriers were classified as either asymptomatic (primary prevention), or with previous sudden cardiac arrest (secondary prevention). Survival rates are presented using a survival curve and were compared with the log-rank test. Results A total of 118 haplotype-carriers (62 males) were included. One-hundred nine (92%) carriers had an ICD inserted, for primary (n=85) or secondary prevention (n=24), and 9 patients refused a primary prevention ICD. Among primary prevention ICD-carriers and those who refused implantation (n=94), 9 (10%) patients experienced a total of 28 appropriate shocks, there was 1 SCA and no deaths, during a median follow-up of 11 years (IQR 7-13; Figure). Of these, 9 patients were ever treated with quinidine and 5 still used quinidine at last follow-up. Among secondary prevention ICD carriers, 20 (83%) patients experienced a total of 225 appropriate shocks and one patient died, during a median follow-up of 13 years (IQR 10-16). Of these patients, 11 were ever treated with quinidine, of whom one patient discontinued quinidine due to adverse effects. Overall, 14 (13%) patients experienced inappropriate shocks and 16 (15%) experienced other ICD-related complications. Conclusion Predictive genetic testing of the DPP6 haplotype provides the unique opportunity to identify asymptomatic family members at risk for SCD and insert prophylactic ICDs just on the basis of carrying the risk haplotype. Approximately 10% of DPP6 haplotype-carriers who qualified for ICD insertion for primary prevention, predominantly males, experienced appropriate ICD shocks or SCA during 11 years of follow-up, indicating that our approach to ICD implantation has presumably saved several lives. In those with an ICD for secondary prevention the incidence of appropriate ICD shocks was high, often despite quinidine therapy.Survival until appropriate shock or SCA

Evaluation of MADIT-II Risk Stratification Score Among Nationwide Registry of Heart Failure Patients With Primary Prevention Implantable Cardiac Defibrillators or Resynchronization Therapy Devices

Current guidelines advocate prophylactic Implantable Cardioverter Defibrillator (ICD) for all symptomatic heart failure (HF) patients with low LVEF. Since many patients will never use their device, a score delineating subgroups with differential ICD benefit is crucial. We aimed to Evaluate MADIT II-based Risk Stratification Score (MRSS) feasibility to delineate ICD survival benefit among nationwide registry of HF patients with prophylactic ICDs. Accordingly, all Israeli HF patients with prophylactic ICD/CRTDs were categorized into MRSS-based risk-subgroups. Study endpoints included overall mortality, sustained ventricular arrhythmia (VA), and a competing risk of VA (potential preventable arrhythmic death, where ICD could benefit survival) versus non-arrhythmic death. Potential ICD survival benefit was estimated by the area between these cumulative incidence curves. Among 2,177 HF patients implanted prophylactic device, 189 patients (8.7%) had VA and 316 (14.5%) died during median Follow-up (F/U) of 2.9 years. MRSS risk-subgroups were significantly associated with overall mortality (p < 0.001) and weakly with VA (p 0.3). Competing risk analysis of VA versus non-arrhythmic death revealed significantly shorter duration (p < 0.001) and smaller magnitude of ICD survival benefit with increased risk subgroups, yielding estimated 76, 60, 38, and 0 life-days gained from prophylactic ICD implant during 5-year F/U for the MRSS low, intermediate, high, and very-high risk subgroups, respectively (p for trend< 0.05). In conclusion, MRSS use among nationwide registry of ischemic and non-ischemic cardiomyopathy patients, revealed subgroups with differing ICD survival benefit, suggesting it could help evaluate prophylactic ICD survival benefit.

The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Report 2022

The Pacemaker (PM) and Implantable Cardioverter-Defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the voluntary Italian collaborating centers. For the year 2022 main data about national PM and ICD implantation activity were obtained on the basis of European Cards and subsequently analyzed to create a standard report. PM Registry: data about 17 800 PM implantations were collected (14 191 first implants and 3609 replacements). The number of collaborating centers was 152. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). Main ECG indications included atrioventricular conduction disorders in 46.0% of first PM implants, sick sinus syndrome in 17.7%, atrial fibrillation plus bradycardia in 7.7%, other unspecified ECG and electrophysiological abnormalities in 43.0%. For first PM implants, pacing in DDDR mode was reported in 42.2%, followed by DDD mode (20.6%), VVIR mode (25.1%), VVI mode (11.1%) and finally VDD-VDDR (5.1%). Median value of longevity of explanted PMs was 8.3 years. ICD Registry: data about 5210 ICD implantations were obtained (3656 first implants and 1554 replacements). The number of collaborating centers was 301. Median age of treated patients was 72 years (63 quartile I; 79 quartile III). Primary prevention indication was reported in 72.4% of first implants, secondary prevention in 27.6% (cardiac arrest in 4.6% of records). A single-chamber ICD was used in 30.3% of first implants, dual-chamber ICD in 30.0% and biventricular ICD in 39.7%. Median value of longevity of explanted ICDs was 7.0 years. In the calendar year 2022, the Italian PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The ICD Registry documented a large use of prophylactic and biventricular ICDs, reflecting a favorable adherence in clinical practice to trials and guidelines. The ICD longevity and the number of recalls demonstrated a favorable trend.

QRS complex and T wave planarity for the efficacy prediction of automatic implantable defibrillators

ObjectiveTo test the hypothesis that in recipients of primary prophylactic implantable cardioverter-defibrillators (ICDs), the non-planarity of ECG vector loops predicts (a) deaths despite ICD protection and (b) appropriate ICD shocks.MethodsDigital...

Impact of late gadolinium-enhanced cardiac MRI on arrhythmic and mortality outcomes in nonischemic dilated cardiomyopathy: updated systematic review and meta-analysis

Risk stratification based mainly on the impairment of left ventricular ejection fraction has limited performance in patients with nonischemic dilated cardiomyopathy (NIDCM). Evidence is rapidly growing for the impact of myocardial scar identified by late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMR) on cardiovascular events. We aim to assess the prognostic value of LGE on long-term arrhythmic and mortality outcomes in patients with NIDCM. PubMed, Scopus, and Cochrane databases were searched from inception to January 21, 2022. Studies that included disease-specific subpopulations of NIDCM were excluded. Data were independently extracted and combined via random-effects meta-analysis using a generic inverse-variance strategy. Data from 60 studies comprising 15,217 patients were analyzed with a 3-year median follow-up. The presence of LGE was associated with major ventricular arrhythmic events (pooled OR: 3.99; 95% CI 3.08, 5.16), all-cause mortality (pooled OR: 2.14; 95% CI 1.81, 2.52), cardiovascular mortality (pooled OR 2.83; 95% CI 2.23, 3.60), and heart failure hospitalization (pooled OR: 2.53; 95% CI 1.78, 3.59). Real-world evidence suggests that the presence of LGE on CMR was a strong predictor of adverse long-term outcomes in patients with NIDCM. Scar assessment should be incorporated as a primary determinant in the patient selection criteria for primary prophylactic implantable cardioverter-defibrillator placement.

Analysis of risk stratification and prevention of sudden death in pediatric patients with hypertrophic cardiomyopathy: Dilemmas and clarity.

Hypertrophic cardiomyopathy (HCM) has been considered the most common cause of sudden death (SD) in the young. However, introduction of implantable cardioverter-defibrillators (ICDs) in HCM has proved highly effective and the mainstay of preventing SD in children, adolescents, and adults by terminating malignant ventricular tachyarrhythmias. Nevertheless, ICD decision making is generally regarded as more difficult in pediatrics, and the strategy for selecting ICD patients from this population remains without consensus. Prospective studies in HCM children and adolescents have shown the American Heart Association/American College of Cardiology traditional major risk marker strategy to be reliable with >90% sensitivity in selecting patients for SD prevention. International data in >2000 young HCM patients assembled over 20 years who were stratified by major risk markers showed ICDs effectively prevented SD in 20%. Alternatively, novel quantitative risk scoring initiatives provide 5-year risk estimates that are potentially useful as adjunctive tools to facilitate discussion of prophylactic ICD risks vs benefit but are as yet unsupported by prospective outcome studies. Risk scoring strategies are characterized by reasonable discriminatory statistical power (C-statistic 0.69-0.76) for identifying patients with SD events but with relatively low sensitivity, albeit with specificity comparable with the risk marker strategy. While some reticence for obligating healthy-appearing young patients to lifelong device implants is understandable, underutilization of the ICD in high-risk children and adolescents can represent a lost opportunity for fulfilling the long-standing aspiration of SD prevention. This review provides a critical assessment of the current strengths and weaknesses of SD risk stratification strategies in young HCM patients in an effort to clarify clinical decision making in this challenging subpopulation.

Outcomes in Dutch DPP6 risk haplotype for familial idiopathic ventricular fibrillation: afocused update.

The genetic risk haplotype DPP6 has been linked to familial idiopathic ventricular fibrillation (IVF), but the associated long-term outcomes are unknown. DPP6 risk haplotype-positive family members (DPP6cases) and their risk haplotype-negative relatives (DPP6 controls) were included. Clinical follow-up data were collected through March 2023. Implantable cardioverter-defibrillator (ICD) indication was divided in primary or secondary prevention. Cumulative survival and event rates were calculated. We included 327 DPP6cases and 315 DPP6 controls. Median follow-up time was 9years (interquartile range: 4-12). Of the DPP6cases, 129 (39%) reached the composite endpoint of appropriate ICD shock, sudden cardiac arrest or death, at amedian age of 45years (range: 15-97). Median overall survival was 83years and 87years for DPP6cases and DPP6 controls, respectively (p < 0.001). In DPP6cases, median overall survival was shorter for males (74years) than females (85years) (p < 0.001). Of the DPP6cases, 97 (30%) died, at amedian age of 50years. With aprophylactic ICD implantation advise based on risk haplotype, sex and age, 137 (42%) of DPP6cases received an ICD, for primary prevention (n = 109) or secondary prevention (n = 28). In the primary prevention subgroup, 10patients experienced atotal of 34 appropriate ICD shocks, and there were no deaths during follow-up. DPP6cases with asecondary prevention ICD experienced atotal of 231 appropriate ICD shocks. Patients with the DPP6 risk haplotype, particularly males, are at an increased risk of IVF and sudden cardiac death. Using arisk stratification approach based on risk haplotype, sex and age, asubstantial proportion of patients with aprimary prevention ICD experienced appropriate ICD shocks, showing the benefit of prophylactic ICD implantation with this strategy.

Survival, ventricular arrhythmia, and implantable cardioverter-defibrillator usefulness in toxic cardiomyopathy due to substance abuse.

Toxic dilated cardiomyopathy (T-DCM) due to substance abuse is now recognized as a potential cause of severe left ventricular dysfunction. The burden of ventricular arrhythmias (VA) and the role of a prophylactic implantable cardioverter-defibrillator (ICD) are not well documented in this population. We aim to assess the usefulness of ICD implantation in a T-DCM cohort. Patients younger than 65 years with a left ventricular ejection fraction (LVEF)<35% followed at a tertiary center heart failure (HF) clinic between January 2003 and August 2019 were screened for inclusion. The diagnosis of T-DCM was confirmed after excluding other etiologies, and substance abuse was established according to the DSM-5 criteria. The composite primary endpoints were arrhythmic syncope, sudden cardiac death (SCD), or death of unknown cause. The secondary endpoints were the occurrence of sustained VA and/or appropriate therapies in ICD carriers. Thirty-eight patients were identified, and an ICD was implanted in 19 (50%) of these patients, only one for secondary prevention. The primary outcome was similar between the two groups (ICD vs. non-ICD; p=1.00). After a mean follow-up of 33±36 months, only two VA episodes were reported in the ICD group. Three patients received inappropriate ICD therapies. One ICD implantation was complicated with cardiac tamponade. Twenty-three patients (61%) had an LVEF ≥35% at 12 months. VA are infrequent in the T-DCM population. The prophylactic ICD benefit was not observed in our cohort. The ideal timing for potential prophylactic ICD implantation in this population needs further studies.

The tip of the eventberg: incidental rhythm disturbances by remote monitoring following pulmonary vein isolation

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Implantable loop recorders (ILR) are increasingly used for continuous rhythm monitoring following pulmonary vein isolation (PVI) for atrial fibrillation (AF). However, the impact of non-AF episodes in this patient population is unknown. Purpose Firstly, the aim of our study was to asses the incidence of clinically important non-AF events. Secondly, we wanted to identify possible risk factors leading to incidental non-AF events. Methods In this retrospective single center study, all patients implanted with ILR following PVI in our center between 2016 and 2022 were analysed. The indication to ILR implantation and remote monitoring after successful PVI was based on patient preference. Transmissions were carefully reviewed by two independent electrophysiologists. Bradycardic events were defined as documented symptomatic bradycardia, AV-Block II˚, AV-Block III˚ or Sick-Sinus Syndrom. Tachycardic events were defined as documented symptomatic supraventricular tachycardia (non-AF) or ventricular tachycardia &amp;gt;160/min with at least 30 seconds duration. Results A total of 219 patients underwent PVI and consequent ILR implantation. We evaluated a mean 2.1±1.1 years of follow up (FU) with a median 68 events/patient (25th–75th IQR: 13-590 events/patient). Overall, 49 patients (22.4%) developed at least one bradycardic event, 6 patients (2.7%) were later implanted with a pacemaker. In univariate logistic regression analysis age, persistent AF, left atrial diameter and prior cardioversion correlated with an increased risk of bradycardic events. Upon a multivariate logistic regression age and prior cardioversion predicted bradycardic events. At least one tachycardic non-AF event was observed in a total of 9 patients (3.6%). Supraventricular tachycardia was observed by 4 patients (1.8%), one (0.4%) were ablated by an atrioventricular nodal reentry tachycardia (AVNRT), others (1.4%) were ectopic atrial tachycardia treated conservatively. Sustained wide complex tachycardia was recorded in 5 patients (2.2%), thereof two (0.9%) received a secondary prophylactic implantable cardioverter defibrillator (ICD). The multivariate analysis did not show any statistically significant value predicting tachycardic events. Conclusion Use of ILR for rhythm monitoring following PVI could increase the early detection of incidental rhythm events, especially bradycardic episodes. However, to asses this possibly beneficial effect further prospective, multicenter studies are needed.

QRS complex and T wave planarity for the prediction of death and appropriate shocks in recipients of prophylactic implantable defibrillators

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Community’s 7th Framework Programme (HEALTH-F2-2009-602299) Ministry of Health, Czech Republic Background Three-dimensional (e.g., vectorcardiography) loops of normal physiologic QRS complex and T wave are known to be planar. Non-planarity of these electrocardiogram (ECG) loops was described in cardiac patients, mainly in relation to ischemic heart disease, but predictive values of the extent of non-planarity of the loops have not been systematically researched. Methods Pre-implantation digital ECGs were collected in 1948 cardiac patients (381 females, median age 65, inter-quartile range 56 – 72 years, 62% ischemic heart disease) who obtained an implantable cardioverter-defibrillator (ICD) for primary prophylactic reasons. In each ECG, QRS and T wave 3-dimensional loops were constructed using singular value decomposition and the non-planarity of the loops was measured as the relative power of the 3rd, least significant decomposition component. The non-planarity (i.e., the spatial twist) of the loops was related to all-cause mortality and to appropriate ICD shocks that occurred during the first 5 years after device implantation. This predictive power was compared to that of age, heart rate, left ventricular ejection fraction, QRS duration, spatial QRS-T angle, QTc interval, and T-peak to T-end interval. Results Non-planarity of the QRS loop was significantly associated with follow-up deaths despite ICD protection (p&amp;lt;0.001 both univariably and in multivariable Cox regression analysis) but was less powerfully associated with appropriate ICD shocks. Non-planarity of the T wave loop was significantly associated with appropriate ICD shocks during follow-up (p&amp;lt;0.001 both univariably and in multivariable Cox regression analysis) but was not associated with mortality during follow-up (Table). This was also seen in significant separation of Kaplan-Meier event probability curves (Figure). Conclusions The analysed data of recipients of prophylactic ICDs suggest that non-planarity of QRS complex and T wave loops offers distinction between patients who are at greater risk of death despite ICD protection and those who are likely to utilize the defibrillator protection.

PO-03-230 LEFT VENTRICULAR FUNCTION IN SUDDEN CARDIAC DEATH DUE TO ISCHEMIC AND NONISCHEMIC HEART DISEASE

Sudden cardiac death (SCD) remains a major public health problem. Severe left ventricular (LV) dysfunction (EF ≤ 35%) increases the risk of SCD and is the most important indication for prophylactic implantable cardioverter defibrillator (ICD). Previous studies have shown that subjects with EF ≤ 35% represent a minority of all SCD cases. However, it has been unclear whether ischemic and nonischemic cardiac diseases present with different LVEF prior to SCD. We sought to evaluate the spectrum of LVEF among SCD victims with ischemic and nonischemic etiologies. Our study population is drawn from the Fingesture study, which has prospectively collected autopsy and clinical data from consecutive SCD victims from Northern Finland between 1998 and 2017. The cause of death was verified to be of cardiac origin in a medicolegal autopsy in all cases. Cases with ischemic SCD had evidence of coronary artery disease and ischemic cardiomyopathy at autopsy. Electronic health records were examined to identify subjects who underwent evaluation for LV function before SCD. LV function was categorized by quantitative assessment of LVEF as normal (EF ≥ 50%), reduced (50% > EF > 35%), and severely reduced (EF ≤ 35%). In all cases, echocardiography was unrelated to the SCD event. Left ventricular assessment was available in 717 SCD victims. The majority of subjects (n=449, 62.7%) had normal LVEF prior to SCD. The prevalence of reduced LVEF was 21.9%, while severely reduced LVEF was found only in 110 subjects (15.4%). Men were more likely to have LV dysfunction than women (45.9% vs 29.6%; p<0.001). In addition, LVEF was found to be severely reduced more commonly in men compared to women (17.4% vs 10.9% respectively; p<0.001). In SCD victims with ischemic and nonischemic heart disease, LV dysfunction was equally common (37.7% vs 36% respectively; p=0.72). The prevalence of severely reduced LVEF was also similar between ischemic SCD and nonischemic SCD (15.1% vs. 16.3%, respectively; p=0.72). Only one third of SCD cases had ventricular dysfunction and only one in seven had severely reduced LVEF prior to their SCD event, suggesting that only a minority of SCD victims meet the current criteria for primary prevention ICD. We found no difference in the spectrum of LVEF between ischemic and nonischemic heart diseases. However, women were found to have preserved LV function more often than men, highlighting the importance of developing novel SCD risk stratification tools beyond LVEF.

Reduced inferior wall longitudinal strain is associated with malignant arrhythmias in non-ischemic heart failure.

Reduced systolic myocardial function in the inferior region of the left ventricle has been suggested to be associated with malignant arrhythmias. We tested this hypothesis in patients with non-ischemic heart failure. Patients with non-ischemic heart failure (left ventricular ejection fraction [LVEF]<35%) were evaluated by 2D-speckle-tracking echocardiography. The regional longitudinal strain was calculated for each of the six left ventricular walls. The reduced regional function was defined as strain below the median. The outcome was a composite of sudden cardiac death, admission with sustained ventricular arrhythmia, resuscitated cardiac arrest, and appropriate therapy from a primary prophylactic implantable cardioverter defibrillator. Time-to-first-event analysis was performed using a Cox model. From two centers, 401 patients were included (median age: 63 years, 72% male) with a median LVEF of 25% (interquartile range [IQR] 20;30), and a median inferior wall strain of -9.0% (-12.5; -5.4). During a median follow-up of 4.0 years, 52 outcomes occurred. After multivariate adjustment for clinical and electrocardiographic parameters, inferior wall strain was independently associated with the outcome (HR 2.50 [1.35; 4.62], p=.003). No independent association was found between the composite outcome and reduced strain in any of the other left ventricular walls, Global Longitudinal Strain (HR 1.66 [0.93; 2.98], p=.09), or LVEF (HR 1.33 [0.75; 2.33], p=.33). Below median strain in the left ventricular inferior region was independently associated with a 2.5-fold increase in the risk of malignant arrhythmias and sudden cardiac death in patients with non-ischemic heart failure.

Clinical, electrocardiographic, and echocardiographic parameters associated with the development of pacing and implantable cardioverter-defibrillator indication in patients with transthyretin amyloid cardiomyopathy.

This study aimed to identify factors for attention leading to future pacing device implantation (PDI) and reveal the necessity of prophylactic PDI or implantable cardioverter-defibrillator (ICD) implantation in transthyretin amyloid cardiomyopathy (ATTR-CM) patients. This retrospective single-center observational study included consecutive 114 wild-type ATTR-CM (ATTRwt-CM) and 50 hereditary ATTR-CM (ATTRv-CM) patients, neither implanted with a pacing device nor fulfilling indications for PDI at diagnosis. As a study outcome, patient backgrounds were compared with and without future PDI, and the incidence of PDI in each conduction disturbance was examined. Furthermore, appropriate ICD therapies were investigated in all 19 patients with ICD implantation. PR-interval ≥220 msec, interventricular septum (IVS) thickness ≥16.9 mm, and bifascicular block were significantly associated with future PDI in ATTRwt-CM patients, and brain natriuretic peptide ≥35.7 pg/mL, IVS thickness ≥11.3 mm, and bifascicular block in ATTRv-CM patients. The incidence of subsequent PDI in patients with bifascicular block at diagnosis was significantly higher than that of normal atrioventricular (AV) conduction in both ATTRwt-CM [hazard ratio (HR): 13.70, P = 0.019] and ATTRv-CM (HR: 12.94, P = 0.002), whereas that of patients with first-degree AV block was neither (ATTRwt-CM: HR: 2.14, P = 0.511, ATTRv-CM: HR: 1.57, P = 0.701). Regarding ICD, only 2 of 16 ATTRwt-CM and 1 of 3 ATTRv-CM patients received appropriate anti-tachycardia pacing or shock therapy, under the number of intervals to detect for ventricular tachycardia of 16-32. According to our retrospective single-center observational study, prophylactic PDI did not require first-degree AV block in both ATTRwt-CM and ATTRv-CM patients, and prophylactic ICD implantation was also controversial in both ATTR-CM. Larger prospective, multi-center studies are necessary to confirm these results.

Bundle branch block in cardiac arrest survivors without ischemic heart disease.

Cardiac arrest (CA) survivors with left/right bundle branch block (LBBB/RBBB) and no ischemic heart disease (IHD) have not been previously characterized. The aim of this study was to describe heart failure, implantable cardioverter defibrillator (ICD) therapy and mortality in this population. Between 2009 and 2019 we consecutively identified all CA survivors with a consistent bundle branch block (BBB) defined as a QRS≥120ms, who had a secondary prophylactic ICD implanted. Patients with congenital and ischemic heart disease (IHD) were excluded. Among 701 CA-survivors who survived to discharge and received an ICD, a total of 58 (8%) were free from IHD and had BBB; 46 (79%) had LBBB, 10 (17%) had RBBB and 2 (3%) had non-specific BBB (NSBBB). The prevalence of LBBB was 7%. Pre-arrest ECG were available in 34 (59%) patients; 20 patients (59%) had LBBB, 6 (18%) had RBBB, 2 (6%) had NSBBB, 1 had (3%) incomplete LBBB, and 4 (12%) without BBB. At discharge, patients with LBBB had a significantly lower left ventricular ejection fraction (LVEF) than patients with other types of BBB, p<0.001. During follow-up, 7 (12%) died after a median of 3.6years (IQR: 2.6-5.1) with no difference between BBB subtypes. We identified 58 CA-survivors with BBB and no IHD. The prevalence of LBBB among all CA-survivors was high, 7%. During CA hospitalization LBBB patients presented with a significantly lower LVEF than patients with other types of BBB (P<0.001). ICD treatment and mortality did not differ between BBB subtypes during follow-up.

Association of late gadolinium enhancement in cardiac magnetic resonance with mortality, ventricular arrhythmias, and heart failure in patients with nonischemic cardiomyopathy: A systematic review and meta-analysis

Late gadolinium enhancement (LGE) on cardiac magnetic resonance is a predictor of adverse events in patients with nonischemic cardiomyopathy (NICM). This meta-analysis evaluated the correlation between LGE and mortality, ventricular arrhythmias (VAs) and sudden cardiac death (SCD), and heart failure (HF) outcomes. A literature search was conducted for studies reporting the association between LGE in NICM and the study endpoints. The primary endpoint was mortality. Secondary endpoints included VA and SCD, HF hospitalization, improvement in left ventricular ejection fraction (LVEF) to >35%, and heart transplantation referral. The search was not restricted to time or publication status. The minimum follow-up duration was 1 year. A total of 46 studies and 10,548 NICM patients (4610 with LGE, 5938 without LGE) were included; mean follow-up was 3 years (range 13-71 months). LGE was associated with increased mortality (odds ratio [OR] 2.9; 95% confidence interval [CI] 2.3-3.8; P < .01) and VA and SCD (OR 4.6; 95% CI 3.5-6.0; P< .01). LGE was associated with an increased risk of HF hospitalization (OR 3.4; 95% CI 2.3-5.0; P < .01), referral for transplantation (OR 5.1; 95% CI 2.5-10.4; P < .01), and decreased incidence of LVEF improvement to >35% (OR 0.2; 95% CI 0.03-0.85; P = .03). LGE in NICM patients is associated with increased mortality, VA and SCD, and HF hospitalization and heart transplantation referral during long-term follow up. Given these competing risks of mortality and HF progression, prospective randomized controlled trials are required to determine if LGE is useful for guiding prophylactic implantable cardioverter-defibrillator placement in NICM patients.