Life-threatening Ventricular Tachyarrhythmias Research Articles

Effect of implantable cardioverter defibrillator intracardiac electrogram morphology changes on hospitalization and life quality

Abstract Background Implantable Cardioverter Defibrillators (ICD) are standard therapy for patients at risk of life-threatening ventricular tachyarrhythmias. ICDs use morphology discrimination to compare ventricular electrogram during tachycardia with reference template during baseline rhythm. Baseline morphology match score (MMS) changes may predict arrhythmic events, but usefulness as a parameter for heart failure (HF) is still unknown. Methods The prospective single-center study included consecutive 88 patients undergoing device control at cardiology department from July 2022 to May 2023. Inclusion criteria were patients implanted with ICD or CRT for at least 3 months; the exclusion criteria were defined as communication barriers (n=1), depleted device battery during checks (n=1), total AV block (n=3), and auto-template activation (n=4). The data were analysed for changes in the baseline (MMS) relationship with demographic, clinical characteristics, quality of life (QOL), and hospitalisation with HF. Results We analyzed 79 patients with a mean age 64,9 13,6 and an average MMS of 98 1,8 morphology. During follow-up there were 12 (15%) patients hospitalized due to HF. ROC curve analysis showed that a MMS ≤ 97% had 73% sensitivity and 59% specificity for hospitalization (p: 0,033 Area 0.695). No significant differences were observed in demographics between the two groups. Although there was no significant difference in EF and BNP levels, patients with MMS <97% had lower QOL scores and more hospitalizations for heart failure (HF). Conclusion EGM baseline MMS changes in ICD were associated with hospitalization for HF and QOL, apart from arrhythmia detection indications. It may be a follow-up parameter for HF, in addition to the current device algorithms.Graphical AbstractTable 1

Predictors of 30-day survival after emergent percutaneous coronary intervention following ventricular tachyarrhythmias complicating acute myocardial infarction

BackgroundLittle has been reported on the predictors of 30-day survival after emergent percutaneous coronary intervention (PCI) following life-threatening ventricular tachyarrhythmias associated with acute myocardial infarction (AMI). MethodsWe analyzed 55 consecutive patients who underwent an emergent PCI after ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) complicating AMI between September 2014 and March 2023 in our hospital. These patients were categorized into two groups: survival group (S group) who survived >30 days after the emergent PCI and death group (D group) who died by 30 days after the emergent PCI. We compared the patient characteristics, coronary angiographic findings, and PCI procedures between the two groups. ResultsS group consisted of 40 patients. In the univariate analysis, absence of diabetes mellitus, presence of immediate cardiopulmonary resuscitation (CPR), low arterial lactate, and single-vessel coronary artery disease (CAD) were associated with 30-day survival after the emergent PCI (P = 0.048, P < 0.001, P = 0.009, and P = 0.003, respectively). In the multivariate analysis, presence of immediate CPR and single-vessel CAD were independently associated with 30-day survival after the emergent PCI (P = 0.023 and P = 0.032, respectively). ConclusionsImmediate CPR and single-vessel CAD were significant predictors of 30-day survival after the emergent PCI following VF or pulseless VT complicating AMI. Absence of diabetes mellitus and low arterial lactate were associated with 30-day survival in the univariate analysis.

Clinical and genetic characterization of patients with catecholaminergic polymorphic ventricular tachycardia: a case series

AIM: of the study was to evaluate the clinical and genetic characteristics, including the development of adverse events and outcomes in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT).&#x0D; MATERIALS AND METHODS: The clinical phenotype of eight patients with CPVT, two of whom were relatives of probands, was observed over 4 years. The clinical and instrumental study included ECG-12, 24-hour Holter ECG monitoring, genealogical history collection and family history of sudden cardiac death (SCD), transthoracic echocardiography and cardiac magnetic resonance imaging to detect structural myocardial changes, electrophysiologic study according to indications, and ICD monitoring. High-throughput sequencing (NGS) was utilized to search for mutations in genes linked to the onset of channelopathies and other inherited rhythm disorders.&#x0D; RESULTS: In 8 patients, nucleotide variants of pathogenicity classes III-V were identified according to the ACMG (2015) criteria in the RYR2 gene associated with CPVT. Pathogenic (IV-V class) and likely pathogenic (IV class) mutations in the RYR2 gene were found in 6 (75%) probands, variants with uncertain clinical significance (VUS, class III) were found in 2 patients. At the time of diagnosis, transient QTc interval prolongation of more than 480 ms was detected in 4 (50%) patients; bradycardia less than 54 beats/min — in 2 (25%) patients, sequences of supraventricular tachycardia and ventricular tachyarrhythmia — in 2 (25%) patients. The most severe form of the disease with marked clinical manifestations and an episode of clinical death with subsequent resuscitation, as well as a transient QTc interval prolongation exceeding 500 ms was observed in patients with mutations c.11814C A (p.Ser3938Arg, rs794728704); c.463G A (p.Gly155Arg) and c.14876G A (p.Arg4959Gln, rs794728811) in the RYR2 gene. Three (37.5%) patients underwent ICD implantation; one for primary SCD prevention and two for secondary prevention.&#x0D; CONCLUSION: In this study, the spectrum of clinical manifestations in patients with genetically confirmed CPVT was examined. The findings highlight transient QTc interval extensions, significant sinus bradycardia, and sequences of supraventricular tachyarrhythmias, which can escalate into life-threatening ventricular tachyarrhythmias in CPVT patients.

ФЕНОМЕН ИЛИ СИНДРОМ БРУГАДА?

The Brugada syndrome (BrS) is an inherited disorder associated with increased risk of sudden cardiac death (SCD). Despite the rare occurrence of BrS, timely diagnosis and risk stratification are important tasks today. The presence of syncope of arrhythmic origin in conjunction with a spontaneous ECG pattern of BrS type 1 is a reliable indicator of a poor prognosis. Conversely, in the group with non-arrhythmic syncope, there is no increased risk of life-threatening ventricular tachyarrhythmias. However, the etiology of syncope is difficult to determine in 30% of cases. It is known that data obtained using implantable loop recorders can change therapy strategy in 20–36% of patients with BrS with unexplained syncope, what is a factor in stratifying the cardiac risk of sudden death in this group of patients. The article provides a brief overview of the medical literature and illustrates instances of the diagnosis of syncope in a patient with BrS. Modern approaches of diagnosis and treatment of BrS including catheter ablation and gene therapy are discussed. The clinical characteristics of the disease and the data of laboratory and instrumental studies of presented case are given.

QRS Morphology and the Risk of Ventricular Tachyarrhythmia in Cardiac Resynchronization Therapy Recipients

BackgroundThere are conflicting data on the effect of cardiac resynchronization therapy with a defibrillator (CRT-D) on the risk of life-threatening ventricular tachyarrhythmia in heart failure patients. ObjectivesThe authors aimed to assess whether QRS morphology is associated with risk of ventricular arrhythmias in CRT recipients. MethodsThe study population comprised 2,862 patients implanted with implantable cardioverter defibrillator (ICD)/CRT-D for primary prevention who were enrolled in 5 landmark primary prevention ICD trials (MADIT-II [Multicenter Automated Defibrillator Implantation Trial], MADIT-CRT [Multicenter Automated Defibrillator Implantation Trial-Cardiac Resynchronization Therapy], MADIT-RIT [Multicenter Automated Defibrillator Implantation Trial-Reduction in Inappropriate Therapy], MADIT-RISK [Multicenter Automated Defibrillator Implantation Trial-RISK], and RAID [Ranolazine in High-Risk Patients With Implanted Cardioverter Defibrillators]). Patients with QRS duration ≥130 ms were divided into 2 groups: those implanted with an ICD only vs CRT-D. The primary endpoint was fast ventricular tachycardia (VT)/ventricular fibrillation (VF) (defined as VT ≥200 beats/min or VF), accounting for the competing risk of death. Secondary endpoints included appropriate shocks, any sustained VT or VF, and the burden of fast VT/VF, assessed in a recurrent event analysis. ResultsAmong patients with left bundle branch block (n = 1,792), those with CRT-D (n = 1,112) experienced a significant 44% (P < 0.001) reduction in the risk of fast VT/VF compared with ICD-only patients (n = 680), a significantly lower burden of fast VT/VF (HR: 0.55; P = 0.001), with a reduced burden of appropriate shocks (HR: 0.44; P < 0.001). In contrast, among patients with non-left bundle branch block (NLBBB) (N = 1,070), CRT-D was not associated with reduction in fast VT/VF (HR: 1.33; P = 0.195). Furthermore, NLBBB patients with CRT-D experienced a statistically significant increase in the burden of fast VT/VF events compared with ICD-only patients (HR: 1.90; P = 0.013). ConclusionsOur data suggest a potential proarrhythmic effect of CRT among patients with NLBBB. These data should be considered in patient selection for treatment with CRT.

Impact of neuromuscular assessment on arrhythmic risk in LMNA cardiomyopathy

Abstract Background The current Risk Score for Life-Threatening Ventricular Tachyarrhythmias (LTVT) in LMNA cardiomyopathy does not consider the frequent association between cardiac and neuromuscular phenotypes as a part of a multisystemic disease. In particular, the prognostic value of tendon retractions (TR) has been recently described. Objectives We aimed to assess the prognostic role of TR in a cohort of probands with LMNA cardiomyopathy undergoing multidisciplinary workup at a referral center. Methods We included 28 probands with LMNA cardiomyopathy undergoing regular, prospective follow-up at a national referral center for laminopathies. All patients underwent extensive baseline characterization, including complete neuromuscular examination and systematic assessment of TR. Indications to implantable cardioverter defibrillators (ICD) for the primary prevention of sudden cardiac death were guideline-based. Patients were clustered in tertiles according to their baseline LMNA-Risk Score. The primary endpoint was the 5-year occurrence of LTVT, namely arrhythmic cardiac death, VF, sustained VT, or appropriate ICD shocks. Results Of the 28 probands with LMNA cardiomyopathy (mean age 33±15 years, 50% males, mean LVEF 55±14 %), neurological assessment identified 14 patients (50%) with TR, including 8 cases with no other signs of neuromuscular involvement. At baseline assessment, the median LMNA-Risk Score was 10% (IQR 6-20%). By 5-year follow-up, 9 patients (32%) met the primary endpoint, including three patients in the lowest tertiles of risk (median LMNA-Risk Score 23, range 6-15%). While other variables showed no remarkable differences between groups, the prevalence of TR was 78% among cases experiencing LTVT and 37% otherwise. The presence of either baseline LMNA-Risk score at the highest tertile (&amp;gt;17%) or TR was 100% predictive of 5-year LTVT (9/9 vs. 7/19, p=0.003). Results did not change after reassessment by the end of follow-up (15±5 years). Conclusions Our preliminary data suggest that the inclusion of TR in risk stratification may result in a better patient selection for primary prevention ICD implant in LMNA cardiomyopathy.

Impact of Age on Subcutaneous Implantable Cardioverter-Defibrillator in a Large Patient Cohort: Mid-Term Follow-Up

BackgroundThe subcutaneous implantable cardioverter-defibrillator (S-ICD) is an accepted alternative to transvenous (TV) ICD to provide defibrillation therapy to treat life-threatening ventricular tachyarrhythmias in high-risk patients. S-ICD outcomes by age group have not been reported. ObjectivesIn this study, the authors sought to report S-ICD outcomes in different age groups in a multicenter S-ICD post-approval study (PAS) involving the largest cohort of patients ever reported. MethodsPatients were prospectively enrolled in the S-ICD PAS and stratified based on age: young, aged 15-34 years; adult, aged 35-69 years; and elderly, aged ≥70 years. Patient characteristics and clinical outcomes through 3 years of follow up after implantation were compared. ResultsThe S-ICD PAS enrolled 1,637 patients. Elderly patients were more likely to receive an S-ICD as a replacement of a TV-ICD (15.1% elderly vs 12.3% adult vs 7.4% young). Secondary prevention indication decreased with age (32.7% young vs 22.2% adult vs 20.5% elderly). Mortality rate was significantly higher in the elderly group (24.0% elderly vs 13.0% adult vs 7.4% young; P < 0.0001), whereas the complication rate did not differ significantly (12.3% young vs 11.3% adult vs 8.1% elderly). Rates of appropriate shock (12.7% young vs 13.0% adult vs 13.8% elderly) and inappropriate shock (7.8% young vs 9.1% adult vs 8.8% elderly) rates did not differ between groups (P = 0.96 and P = 0.98, respectively). ConclusionsImplant complications and appropriate and inappropriate shock rates were similar among age groups. S-ICD for secondary prevention was more common in the young group. Replacing a TV-ICD for an S-ICD increases with age. (S-ICD System Post-Approval Study; NCT01736618)

Precision Medicine for Cardiac Ion Channelopathies in Hong Kong: From Case Reports to Identification of Novel Genetic Variants and Development of Risk Prediction Tools using Population-based Datasets

Congenital cardiac ion channelopathies refer to a set of inherited conditions characterized by abnormalities in the structure and/or function of ion channels, their associated proteins or other signalling components, predisposing affected individuals to life-threatening ventricular tachyarrhythmias and therefore sudden cardiac death. This is a literature review focusing on the progress of clinical research on congenital cardiac ion channelopathies in Hong Kong, from case reports in the 1990s to population-based studies in the 2020s. Locally, patients with Brugada syndrome, long QT syndrome and catecholaminergic polymorphic ventricular tachycardia have been studied. Leveraging the power of linked electronic health records data in the public sector, the epidemiology, clinical characteristics, genetics, genotype-phenotype relationship and predictive factors of arrhythmic events have received attention. Future efforts should focus on multidisciplinary collaborations between clinicians, scientists and data scientists the use of genomic data combined with clinical data for personalised risk prediction. With the Government’s drive for innovations and recent announcement of the Strategic Development of Genomic Medicine in Hong Kong, future efforts should be focused on the development of a national registry linking the databases and standardizing the data fields and reporting in different centres in Hong Kong, other cities in the Greater Bay Area and the wider mainland. Eventually the goal is to incorporate the vast amount of genomic information with clinical details to achieve personalised risk prediction through multidisciplinary collaborations.

РЕПЕРФУЗИОННЫЙ СИНДРОМ ПРИ ЭНДОВАСКУЛЯРНОЙ РЕВАСКУЛЯРИЗАЦИИ МИОКАРДА: КЛИНИЧЕСКОЕ НАБЛЮДЕНИЕ

CHD retains a leading position worldwide due to high rates of mortality and disability. The best and proven strategy aimed at saving the damaged myocardium in ST-segment elevation myocardial infarction (STEMI) is rapid and effective reperfusion of the ischemic heart muscle through primary percutaneous coronary intervention (PCI) or pharmacoinvasive therapy. However, the restoration of blood flow by itself can lead to reperfusion damage to the affected myocardium. In acute coronary catastrophe caused by acute occlusion of the coronary artery, myocardial stun and hibernation develop locally. With STEMI, hibernation can be observed both near the infarction zone and in more distant areas of the myocardium. In patients with STEMI, the appearance of life-threatening arrhythmias (ventricular tachycardia and ventricular fibrillation) occurs in 4.3 % of cases and is primarily associated with reperfusion after PCI. In most cases, arrhythmias that occur during the procedure are stopped spontaneously; however, when accompanied by ventricular tachyarrhythmia, hemodynamic instability, the use of electric pulse therapy (EIT) is provided. The article presents a clinical case of a patient C., 52, whose reperfusion syndrome manifested itself by the development of life-threatening ventricular tachyarrhythmias: unstable ventricular tachycardia «torsade de points» with transformation into VF, which were stopped by EIT: defibrillation. No recurrence of ventricular tachyarrhythmia was observed in this patient. At this stage, we explain the resulting episode of unstable ventricular tachycardia with short-term myocardial stunning due to short-term ischemia and myocardial damage.

Timing of cardioverter-defibrillator implantation in patients with cardiac laminopathies—External validation of the LMNA-risk ventricular tachyarrhythmia calculator

LMNA genotype-positive patients have high risk of experiencing life-threatening ventricular tachyarrhythmias (VTAs). The LMNA-risk VTA calculator published in 2019 has not been externally validated. The purpose of this study was to validate the LMNA-risk VTA calculator. We included LMNA genotype-positive patients without previous VTAs from 2 large Scandinavian centers. Patients underwent electrocardiography, 24-hour Holter monitoring, and echocardiographic examinations at baseline and repeatedly during follow-up. Validation of the LMNA-risk VTA calculator was performed using Harrell's C-statistic derived from multivariable Cox regression analysis. We included 118 patients (age 37 years [IQR 27-49 years]; 39 [33%] probands; 65 [55%] women; 100 [85%] with non-missense LMNA variants). Twenty-three patients (19%) experienced VTA during 6.1 years (interquartile range 3.0-9.1 years) follow-up, resulting in 3.0% (95% confidence interval 2.0%-4.5%) yearly incidence rate. Atrioventricular block and reduced left ventricular ejection fraction were independent predictors of VTAs, while nonsustained ventricular tachycardia, male sex, and non-missense LMNA variants were not. The LMNA-risk VTA calculator showed 83% sensitivity and 26% specificity for identifying patients with VTAs during the coming 5 years, and a Harrell's C-statistic of 0.85, when applying ≥7% predicted 5-year VTA risk as threshold. The sensitivity increased to 100% when reevaluating risk at the time of last consultation before VTA. The calculator overestimated arrhythmic risk in patients with mild and moderate phenotype, particularly in men. Validation of the LMNA-risk VTA calculator showed high sensitivity for subsequent VTAs, but overestimated arrhythmic risk when using ≥7% predicted 5-year risk as threshold. Frequent reevaluation of risk was necessary to maintain the sensitivity of the model.

Impact of late gadolinium enhancement extent, location, and pattern on ventricular tachycardia and major adverse cardiac events in patients with ischemic vs. non-ischemic cardiomyopathy.

Left ventricular late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) has been associated with increased risk for life-threatening ventricular tachyarrhythmias. The differences in association between LGE characteristics and prognosis in patients with ischemic (ICM) vs. non-ischemic (NICM) cardiomyopathy is incompletely understood. A total of 168 consecutive patients who underwent CMR imaging with either ICM or NICM were included in our study. LGE extent, location and pattern were examined for association to the primary endpoint of ventricular tachycardia (VT) and secondary endpoint of major adverse cardiac events (MACE). Of 68 (41%) patients with ICM and 97 (59%) patients with NICM, median LGE mass was 15% (IQR 9-28) for the ICM group and 10% (IQR 6-15) for the NICM group. On multivariate analysis for both groups, LGE characteristics were prognostic while LVEF was not. In patients with ICM, septal and apical segment LGE, and involvement of multiple walls predicted both endpoints on multivariate analysis. LGE extent (≥median) and inferior wall LGE independently predicted the primary endpoint. In patients with NICM, anterior, inferior and apical segment LGE, and involvement of multiple walls predicted both endpoints on multivariate analysis. LGE extent (≥median, number of LGE segments, LGE stratified per 5% increase) and midwall LGE were independent predictors of the primary endpoint. Although LGE was an independent predictor of prognosis in both groups, LGE extent, location, and pattern characteristics were more powerful correlates to worse outcomes in patients with NICM than ICM.

Звено патогенеза ночной внезапной смерти при сердечной недостаточности

Patients with chronic heart failure (CHF) constitute the bulk of the group at the highest risk of sudden death (SD). The majority of SDs occur at night. However, CHF grade and ejection fraction do not always determine the risk of SD in the outcome of the disease. The following view has been expressed based on the research on the topic and the described mechanisms underlying SD: impaired QT interval adaptation (“hyperadaptation”: QT/RR slope &gt; 0.24) to HR in patients with CHF who show maximum QT interval prolongation during the night, capable of triggering life-threatening ventricular tachyarrhythmias that trigger the mechanism of SD associated with CHF, can play some role. It is possible that identification of QT interval hyperadaptation in patients with CHF makes it possible to form the group at high risk of SD associated with HF and can become an additional indication for implantation of cardioverter-defibrillator.

Sex Differences in the Risk of First and Recurrent Ventricular Tachyarrhythmias Among Patients Receiving an Implantable Cardioverter-Defibrillator for Primary Prevention

Current guidelines for primary implantable cardioverter-defibrillator (ICD) therapy do not account for sex differences in arrhythmic risk in ICD candidates. To evaluate the association between sex and risk of ventricular tachyarrhythmia (VTA) and mortality. This cohort study compared differences in the risk of VTA and mortality between 4506 men and women enrolled in the 4 Multicenter Automatic Defibrillator Implantation Trials (MADIT) between July 1, 1997, and December 31, 2011. Data from prospective randomized controlled multicenter studies were analyzed retrospectively. Men and women with an ICD or cardiac resynchronization therapy defibrillator who were enrolled in all MADIT studies were included. Data were analyzed between January 10 and June 10, 2021. ICD implant. The primary end point was sustained VTA, defined as ICD-recorded, treated or monitored VTA at least 170/min or ventricular fibrillation. Secondary VTA end points included VTA at least 200/min, appropriate ICD shocks, and appropriate antitachycardia pacing. All end points were included in a first and recurrent event analysis. Of the 4506 study participants, 3431 were men (76%). Mean (SD) age of the cohort was 64 (12) years. For women vs men, the mean (SD) age (64 [12] years vs 64 [11] years) and left ventricular ejection fraction (24% vs 25%) were similar, but women exhibited a higher frequency of nonischemic cardiomyopathy (454 of 1075 women [42%] vs 2535 of 3431 men [74%]). Women had significantly lower 3-year cumulative probability of sustained VTA (16% vs 26%), fast VTA (9% vs 17%), and appropriate ICD shocks (7% vs 15%) compared with men (P < .001 for all). Multivariable analysis showed that female sex was independently associated with at least 40% lower risk of all first and recurrent VTA end points (P < .001 for all), including the primary end point (first event, HR = 60 [95% CI, 50-73], P < .001; recurrent event, HR = 49 [95% CI, 43-55], P < .001), after accounting for the competing risk of all-cause mortality and nonarrhythmic mortality. The lower VTA risk associated with female sex was consistent in risk subsets but was significantly more pronounced in patients with nonischemic cardiomyopathy (female vs male in the ischemic group: hazard ratio, 0.73 [95% CI, 0.56-0.95], P = .02; nonischemic group: hazard ratio, 0.50 [95% CI, 0.38-0.66], P < .001; P = .03 for interaction between female sex and cardiomyopathy). Findings suggest that women display a significantly lower risk of first and recurrent life-threatening VTA events than men, and that it is more pronounced in patients with nonischemic cardiomyopathy, suggesting a need for sex-specific risk assessment for primary prevention ICD therapy.

Genetic risk factors for dilated cardiomyopathy

Aim. To study the diagnostic significance of genetic testing in patients with dilated cardiomyopathy (DCM), identify predictors of life-threatening ventricular tachyarrhythmias (VTAs) and assess adverse clinical outcomes in different genetic groups.Material and methods. The study included 126 unrelated patients with verified DCM as follows: 70 (55,6%) probands with criteria for familial DCM and 56 (44,4%) individuals with a probable hereditary component. All patients (age, 43,1±11,3 years; men, 92 (73%); left ventricular ejection fraction, 30,6±8,43%; left ventricular enddiastolic diameter, 68,3±8,36 mm; follow-up period — median, 49 months) receive a complex of diagnostic investigations, including genetic screening using nextgeneration sequencing, followed by verification of variants by the Sanger method.Results. Pathogenic and likely pathogenic genetic variants were found in 61 (48,4%) of 126 patients with DCM. The dominant mutations were titin-truncating variants (TTNtvs), identified in 16 individuals (12,7%), and variants of lamin A/C (LMNA), identified in 13 probands (10,3%). Mutations in the other 19 genes were found in 32 (25,4%) patients. The following primary endpoints were assessed: sudden cardiac death (SCD), episodes of VTA (sustained ventricular tachycardia/ventricular fibrillation) and appropriate shocks of implanted cardiac resynchronization therapy (CRT)/cardioverter defibrillators (CVD) devices. As a result of ROC analysis, the following independent risk factors for SCD were identified: mutations in the LMNA gene (AUC, 0,760; p=0,0001) and non-sustained ventricular tachycardia (cut-off heart rate ≥161 bpm: AUC, 0,788; p=0,0001). When comparing the phenotypes and genotypes of DCM, TTNtv genotype was associated with a lower prevalence of complete left bundle branch block (χ2=7,46; p=0,024), a lower need for CRT/CVD implantation (χ2=5,70; p=0,017) and more rare episodes of sustained ventricular tachycardia/ventricular fibrillation (χ2=30,1; p=0,0001) compared with LMNA carriers. Kaplan-Meier analysis showed the worst prognosis in carriers of LMNA mutations both in relation to life-threatening VTA (log rang χ2=88,5; p=0,0001) and in achieving all unfavorable outcomes (χ2=27,8; p=0,0001) compared with groups of genenegative individuals, carriers of TTNtv and other genotypes.Conclusion. The phenotypes of DCM with TTNtv did not significantly differ in the incidence of VTAs and adverse outcomes compared with the gene-negative group and other genotypes (with the exception of LMNA). The contribution of the associations of LMNA mutations with VTAs on prognosis was confirmed, which shows the important role of LMNA genotype diagnosis for SCD risk stratification in patients with DCM.

Possibilities for predicting ventricular tachyarrhythmias in patients with heart failure with reduced ejection fraction based on surface electrocardiography. First results from a single-center prospective study

According to current clinical guidelines, the risk of life-threatening ventricular tachyarrhythmias (VTAs) in patients with heart failure (HF) is determined by left ventricular ejection fraction (LVEF). The available clinical and experimental data indicate the imperfection of this one-factor approach, which specifies the need to search for new predictors of VTAs. In this prospective study, we performed a comparative analysis of surface electrocardiographic parameters in HF patients with LVEF ≤35% without syncope or sustained ventricular arrhythmias in history, who were implanted with cardioverter defibrillator as a primary prevention of sudden cardiac death. During the two-year follow-up, the primary endpoint (new-onset persistent VTA episode, or VTA/ventricular fibrillation that required electrotherapy) was recorded in 42 patients (25,5%). The secondary endpoint (an increase in LVEF by 5% or more of the initial level against the background of cardiac resynchronization therapy) was more often recorded in the group of patients without VTAs (41 (33%) vs 4 (9,5%), p=0,005). The studied cohort of patients was characterized by a left axis deviation (72%), LV hypertrophy signs (84%), impaired intra-atrial (P wave duration of 120 (101-120) ms) and intraventricular conduction (QRS duration of 140 (110-180) ms), ventricular electrical systole prolongation (QTcor — 465 (438-504) ms). Differences between the groups divided depending on reaching the primary endpoint in terms of the Cornell product, Cornell voltage index and ICEB, as well as the detection rate of complete left bundle branch block morphology had levels of significance close to critical (p=0,09; p=0,05; p=0,1; p=0,09, respectively). The multivariate predictive model included following factors: Cornell product, Tp-Te/ QRS, P wave duration (diagnostic efficiency of the model was 60%: sensitivity, 61,1%, specificity, 59,6%; p=0,007).

Post-discharge arrhythmic risk stratification of patients with acute myocarditis and life-threatening ventricular tachyarrhythmias.

The outcomes of patients presenting with acute myocarditis and life-threatening ventricular arrhythmias (LT-VA) are unclear. The aim of this study was to assess the incidence and predictors of recurrent major arrhythmic events (MAEs) after hospital discharge in this patient population. We retrospectively analysed 156 patients (median age 44 years; 77% male) discharged with a diagnosis of acute myocarditis and LT-VA from 16 hospitals worldwide. Diagnosis of myocarditis was based on histology or the combination of increased markers of cardiac injury and cardiac magnetic resonance (CMR) Lake Louise criteria. MAEs were defined as the relapse, after discharge, of sudden cardiac death or successfully defibrillated ventricular fibrillation, or sustained ventricular tachycardia (sVT) requiring implantable cardioverter-defibrillator therapy or synchronized external cardioversion. Median follow-up was 23 months [first to third quartile (Q1-Q3) 7-60]. Fifty-eight (37.2%) patients experienced MAEs after discharge, at a median of 8months (Q1-Q3 2.5-24.0months; 60.3% of MAEs within the first year). At multivariable Cox analysis, variables independently associated with MAEs were presentation with sVT [hazard ratio (HR) 2.90, 95% confidence interval (CI) 1.38-6.11]; late gadolinium enhancement involving ≥2 myocardial segments (HR 4.51, 95% CI 2.39-8.53), and absence of positive short-tau inversion recovery (STIR) (HR 2.59, 95% CI 1.40-4.79) at first CMR. Among patients discharged with a diagnosis of myocarditis and LT-VA, 37.2% had recurrences of MAEs during follow-up. Initial CMR pattern and sVT at presentation stratify the risk of arrhythmia recurrence.

Syncope associated with supraventricular tachycardia: Diagnostic role of implantable loop recorders.

Syncope represents a relatively uncommon symptom of supraventricular tachycardia (SVT). It is likely that an impaired autonomic vasomotor response to the hemodynamic stress of tachycardia is the determinant of hemodynamic changes leading to cerebral hypoperfusion and syncope. In this regard, tilt‐table test may detect abnormalities in the autonomic nervous function and predict the occurrence of syncope during SVT. Electrophysiology studies may reproduce the SVT, distinguish it from other life‐threatening ventricular tachyarrhythmias, and exclude other causes of syncope. Not infrequently mixed syncope mechanisms are revealed during the above diagnostic workup raising doubts about the operating mechanism in the clinical setting. In such cases of uncertainty, an implantable loop recorder, providing long‐term cardiac monitoring, may play a pivotal role in the establishment of the diagnosis, confirming the association of an arrhythmic event with the symptom. Herein, we present four such cases with recurrent unexplained syncope finally attributed to paroxysmal SVT guiding them to a potentially radical treatment through radiofrequency catheter ablation.

Inherited arrhythmia syndrome predisposing to sudden cardiac death.

Inherited arrhythmia (IA) is one of the main causes of sudden cardiac death (SCD) in young people, and is reported to be a more prevalent cause of SCD in Asia than in Western countries. IAs are a group of genetic disorders caused by mutations in genes encoding cardiac ion channels, leading to electrophysiological characteristics that often occur in the absence of structural abnormalities. Channelopathies, such as long QT syndrome and Brugada syndrome, carry a potential risk of life-threatening ventricular tachyarrhythmias that predispose to SCD, although early prediction and prevention of the risk remain challenging. Recent advances in genetic testing have facilitated risk stratification as well as a precise diagnosis for IA, despite ongoing debates about the implications. Herein, we provide epidemiological data, a pathophysiological overview, and the current clinical approach to IAs related to SCD. In addition, we review the general issues arising from genetic testing for IAs.

Hospitalization for HeartFailure and Subsequent Ventricular Tachyarrhythmias in Patients With LeftVentricular Dysfunction.

This study aimed to evaluate the risk of sustained life-threatening ventricular tachyarrhythmias (VTAs) after hospitalization for heart failure (HHF). HHF is common among patients with an implantable cardioverter-defibrillator (ICD). We analyzed all 5,511 ICD patients enrolled in the landmark MADIT (Multicenter Automatic Defibrillator Implantation Trial) and RAID (Ranolazine in High-Risk Patients With Implanted Cardioverter-Defibrillator) trials. Multivariate Cox regression was used to evaluate the association of in-trial HHF occurrence with the risk of subsequent VTA and the composite end point of VTA or cardiac death. Mean age was 64 ± 11 years, 23% were women, 62% were ischemic, and 40% had cardiac resynchronization therapy with defibrillators. The 3-year cumulative rate of VTA subsequent to HHF was significantly higher than the corresponding rate without HHF (44% vs. 24%, respectively; p<0.001). After multivariable adjustment, time-dependent HHF was shown to be associated with a 79% increased risk for VTA and a 2.9-fold increased risk for VTA/cardiac death (p<0.001 for both). In-trial development of atrial tachyarrhythmia (ATA) was also identified as an independent risk factor for the VTA and VTA/cardiac death end points (hazard ratio [HR]: 1.59 and 1.43, respectively; p≤ 0.001 for both) but did not affect the association of HHF with VTA. Subgroup analysis demonstrated that the association of HHF with the risk of subsequent VTA was maintained among risk subsets categorized by age, sex, history of ATA, and implantation indication, but was significantly more pronounced among patients with nonischemic versus ischemic cardiomyopathy (HR: 2.54 and 1.43, respectively; p for interaction = 0.017). HHF is a powerful risk factor for subsequent VTA in patients implanted with an ICD. These data may be used for improved risk stratification in this population.

Assessment of patients presenting with life-threatening ventricular arrhythmias and suspected myocarditis: The key role of endomyocardial biopsy

Life-threatening ventricular tachyarrhythmias (VAs) represent a significant cause of death in myocarditis. The purpose of this study was to identify predictors of sustained VAs in patients with myocarditis and ventricular phenotype diagnosed by workflow including endomyocardial biopsy (EMB) guided by 3D electroanatomic mapping (3D-EAM). We prospectively enrolled patients with suspected myocarditis and VAs, undergoing cardiac magnetic resonance imaging, coronary angiography, 3D-EAM, and EMB guided by 3D-EAM. At follow-up, sustained VAs were detected by device interrogation and 24-hour electrocardiographic Holter monitoring. We enrolled 54 consecutive patients (mean age 41 ± 14 years; 32(59%) men) with normal ventricular function; left ventricular and right ventricular (RV) late gadolinium enhancement was present, respectively, in 21 (46%) and 6 (13%) of the 46 patients who underwent cardiac magnetic resonance. In 31 patients, the histological diagnosis was myocarditis, while in 14 patients, focal replacement myocardial fibrosis (FRMF); in 9 patients, specimens were inadequate (diagnostic yield of EMB 83%). 3D-EAM showed a larger endocardial scar area for both ventricles in myocarditis than in FRMF (RV bipolar mean scar area 22 ± 16 cm2 vs 3 ± 2 cm2; P = .02; left ventricular bipolar mean scar area 13 ± 5 cm2 vs 4 ± 2 cm2; P = .02, respectively). At a follow-up of 21 months, freedom from sustained VAs was 58% in myocarditis and 92% in FRMF (log-rank, P = .008). Histological diagnosis of myocarditis and RV endocardial scar were independent predictors of sustained VAs (P = .02 for both). Our data highlight the need for 3D-EAM-guided EMB in apparently healthy young patients with suspected myocarditis and VAs.