Malignant Ventricular Tachyarrhythmias Research Articles

STAT4 Mediates IL-6 Trans-Signaling Arrhythmias in High Fat Diet Guinea Pig Heart.

Obesity is a major risk factor for the development of life-threatening malignant ventricular tachyarrhythmias (VT) and sudden cardiac death (SCD). Risks may be highest for patients with high levels of the proinflammatory cytokine interleukin (IL)-6. We used our guinea pig model of high-fat diet (HFD)-induced arrhythmias that exhibit a heightened proinflammatory-like pathology, which is also observed in human obesity arrhythmias, as well as immunofluorescence and confocal microscopy approaches to evaluate the pathological IL-6 trans-signaling function and explore the underlying mechanisms. Using blind-stick and electrocardiogram (ECG) techniques, we tested the hypothesis that heightened IL-6 trans-signaling would exhibit increased ventricular arrhythmia/SCD incidence and underlying arrhythmia substrates. Remarkably, compared to low-fat diet (LFD)-fed controls, HFD promoted phosphorylation of the IL-6 signal transducer and activator of transcription 4 (STAT4), leading to its activation and enhanced nuclear translocation of pSTAT4/STAT4 compared to LFD controls and pSTAT3/STAT3 nuclear expression. Overactivation of IL-6 trans-signaling in guinea pigs prolonged the QT interval, which resulted in greater susceptibility to arrhythmias/SCD with isoproterenol challenge, as also observed with the downstream Janus kinase (JAK) 2 activator. These findings may have potentially profound implications for more effective arrhythmia therapy in the vulnerable obese patient population.

Left ventricle mechanical dispersion is a new universal marker of malignant ventricular tachyarrhythmias in patients with structural heart disease

Aim. To evaluate the possibility to use parameters of global, segmental longitudinal left ventricle (LV) strain and LV mechanical dispersion (MD) as new possible markers of malignant ventricular tachyarrhythmias (MVT) in patients with structural heart disease and reduced and intermediate LV ejection fraction (EF).Methods. The study included 113 patients (105 male, age 66 [59;73] year) with ischemic (n=89) or non-ischemic (n=24) dilated cardiomyopathy and LVEF<50%, implanted cardioverter-defibrillators, cardiac resynchronization therapy devices-defibrillators, pacemakers or documented MVT. All patients underwent transthoracic echocardiography with an assessment of speckle-tracking echocardiography parameters (global and segmental longitudinal LV strain, LV MD). Comparative univariate and ROC-analyses were performed between patients with and without MVT separately for patients with LVEF <35% (n=60) and LVEF 36-50% (n=53) LVEF.Results. The group of patients with LVEF ≤35% with MVT (n=30) was characterized by lower values of longitudinal strain of the basal segment of the LV septum wall (-5[-6,5;-0,5] vs -6,8[-11;-4.4], р=0,01, respectively) and the middle segment of the LV inferior wall (-3[-6;2] vs -6[-9;-1,5], р=0,04, respectively). The group of patients with LVEF 36-50% with MVT (n=33) was distinguished by a large value of LV end-diastolic volume (166,5[146,3;193] vs 156[133,8;165,5], р=0,04, respectively). The greater values of LV MD were noted in both groups of patients with MVT. The optimal cut-off value of LV MD was 120 ms (area under the ROC curve 0.817, sensitivity-73,3%, specificity-80%) for patients with LVEF≤35%, and 90 ms (area under the ROC curve 0.761, sensitivity-72.7%, specificity-75%) for patients with LVEF 36-50%.Conclusion. Speckle-tracking echocardiography parameters may serve as additional markers of increased risk of MVT in patients with structural heart disease and impaired LVEF. Only LV MD is useful for risk stratification of MVT in patients with either reduced or intermediate LVEF.

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.

Assessing physical activity with the wearable cardioverter defibrillator in patients with newly diagnosed heart failure.

The wearable cardioverter defibrillator (WCD), (LifeVest, ZOLL, Pittsburgh, PA, USA) is a medical device designed for the temporary detection and treatment of malignant ventricular tachyarrhythmias. WCD telemonitoring features enable the evaluation of the physical activity (PhA) of the patients. We sought to assess with the WCD the PhA of patients with newly diagnosed heart failure. We collected and analyzed the data of all patients treated with the WCD in our clinic. Patients with newly diagnosed ischemic, or non-ischemic cardiomyopathy and severely reduced ejection fraction, who were treated with the WCD for at least 28 consecutive days and had a compliance of at least 18 h the day were included. Seventy-seven patients were eligible for analysis. Thirty-seven patients suffered from ischemic and 40 from non-ischemic heart disease. The average days the WCD was carried was 77.3 ± 44.6 days and the mean wearing time was 22.8 ± 2.1 h. The patients showed significantly increased PhA measured by daily steps between the first two and the last two weeks (Mean steps in the first 2 weeks: 4,952.6 ± 3,052.7 vs. mean steps in the last 2 weeks: 6,119.6 ± 3,776.2, p-value: < 0.001). In the end of the surveillance period an increase of the ejection fraction was observed (LVEF-before: 25.8 ± 6.6% vs. LVEF-after: 37.5 ± 10.6%, p < 0.001). Improvement of the EF did not correlate with the improvement of PhA. The WCD provides useful information regarding patient PhA and may be additionally utilized for early heart failure treatment adjustment.

CE-454610-4 A CASE OF INAPPROPRIATE CLASSIFICATION OF VENTRICULAR FIBRILLATION AS SINUS TACHYCARDIA

Accurate differentiation between SVT and malignant ventricular tachyarrhythmias in ICDs is augmented with the use of device specific SVT discriminators. However, these enhancements rely on nonprogrammable algorithms that on occasion may be responsible for inappropriate withholding of VT/VF therapy. It is important to understand the reason for rhythm misclassifications so that opportunities for improvement in ICD programming can be identified. N/A A 46-year-old man with ischemic cardiomyopathy, severe left ventricular dysfunction, left bundle branch block, prior VF arrest, AF on amiodarone therapy with a Medtronic Claria CRT-D suffered a sudden cardiac arrest at home. ICD parameter settings are noted in Table. ICD electrograms showed initial monomorphic VT with cycle length 340 ms which was treated with burst anti-tachycardia pacing that resulted in a slower VT below the VT detection rate of 162 bpm. This was sustained for 5 minutes until the rhythm devolved to VF and met the criteria for VT/VF event using the combined count number of intervals to detect (CCNID, Figure). SVT discrimination was applied as the median V-V interval was greater than the programmed SVT limit of 260 ms due to occasional undersensing. The SVT discrimination feature is designed to confirm 1:1 AV conduction using pre-specified criteria. The algorithm then relies on a simultaneous sinus tachycardia (ST) count that is established using an analysis of expected RR intervals and successive PR intervals concurrently calculated. A minimum ST count of 6 was fulfilled leading to classification of the event as sinus tachycardia and withholding for VT/VF therapy (Figure). Hierarchy of sinus tachycardia in the SVT discrimination logic withholds application of waveform analysis. Criteria for VT/VF event was met 1 minute later again based on CCNID. A 36J shock was delivered unsuccessfully terminating the rhythm. Ongoing VF was undersensed in the presence of high output post shock pacing. This case illustrates several failures of tachyarrhythmia detection leading to a tragic failure of ICD therapy. Algorithm features such as the minimum requirements for 1:1 AV conduction, sinus tachycardia counter, and hierarchy of the SVT discrimination feature to withhold waveform analysis led to inappropriate withholding of therapy for VF. Understanding elements of these complex algorithms may be helpful for individualizing device program and in future development of additional SVT discrimination enhancements.

Sex differences in long QT syndrome.

Long QT Syndrome (LQTS) is a rare, inherited channelopathy characterized by cardiac repolarization dysfunction, leading to a prolonged rate-corrected QT interval in patients who are at risk for malignant ventricular tachyarrhythmias, syncope, and even sudden cardiac death. A complex genetic origin, variable expressivity as well as incomplete penetrance make the diagnosis a clinical challenge. In the last 10 years, there has been a continuous improvement in diagnostic and personalized treatment options. Therefore, several factors such as sex, age diagnosis, QTc interval, and genetic background may contribute to risk stratification of patients, but it still currently remains as a main challenge in LQTS. It is widely accepted that sex is a risk factor itself for some arrhythmias. Female sex has been suggested as a risk factor in the development of malignant arrhythmias associated with LQTS. The existing differences between the sexes are only manifested after puberty, being the hormones the main inducers of arrhythmias. Despite the increased risk in females, no more than 10% of the available publications on LQTS include sex-related data concerning the risk of malignant arrhythmias in females. Therein, the relevance of our review data update concerning women and LQTS.

Aggressive Treatment of Refractory Coronary Artery Vasospasm in a Patient with Malignant Ventricular Tachyarrhythmia and Cardiac Arrest

Coronary artery vasospasm (CAVS) is a clinical entity that can cause angina, but also unstable angina pectoris, acute myocardial infarction, fatal arrhythmias, and sudden death. Although it is a condition that is usually controlled with medical treatment, more aggressive treatments may rarely be required. In this case, the patient with a known diagnosis of CAVS had multiple arrests despite optimal medical treatment. We observed that fatal arrhythmias persisted in the Implantable Cardioverter Defibrillator (ICD) records, even though we implanted a stent and gave the patient maximal medical treatment. We performed sympathectomy as a last resort and we did not detect any recurrence in the 6-month follow-up of the patient. ICD implantation and sympathectomy should always be considered in resistant CAVS cases.

New markers of malignant ventricular tachyarrhythmias in speckle-tracking echocardiography and 24-hour ECG monitoring in patients with chronic heart failure and reduced left ventricular ejection fraction

New markers of malignant ventricular tachyarrhythmias in speckle-tracking echocardiography and 24-hour ECG monitoring in patients with chronic heart failure and reduced left ventricular ejection fraction

Updated risk assessments for sudden cardiac death in hypertrophic cardiomyopathy patients with implantable cardioverter-defibrillator.

Hypertrophic cardiomyopathy (HCM) is a genetic disease associated with a risk of malignant ventricular tachyarrhythmias and sudden cardiac death (SCD). Assessment of the SCD risk is crucial for its clinical management, and there has been considerable interest in developing risk stratification strategies. An implantable cardioverter-defibrillator (ICD) is a life-saving treatment for patients with HCM who are at a high-risk of ventricular tachyarrhythmias and SCD. However, a substantial number of ICD recipients experience adverse effects arising from inappropriate device therapy and implant-related complications. This has led to numerous investigations of the risk of SCD and the indications for ICD implantation. American guidelines were recently updated to include new risk markers, including left ventricular systolic dysfunction, apical aneurysm, and extensive late gadolinium enhancement, while European guidelines recommend individualized estimated 5-year SCD risk assessment models. Studies evaluating other risk factors for SCD in patients with HCM have also been published. Drawing on recent guidelines and publications on clinical risk factors, we focus this review on updated risk assessments for SCD with ICD therapy in patients with HCM.

The joint role of collagen turn-over biomarkers and late gadolinium enhancement to predict cardiovascular outcome in nonischemic dilated cardiomyopathy

Abstract Background Myocardial scarring is a primary pathogenetic process in nonischemic dilated cardiomyopathy (NIDCM) which is responsible for progressive cardiac remodeling and heart failure, severely impacting the survival of these patients. Although several collagens turn-over biomarkers have been associated with myocardial fibrosis, their clinical utility is still limited. Late gadolinium enhancement (LGE) determined by cardiac magnetic resonance imaging (CMR) has become a feasible method to detect myocardial replacement fibrosis. Purpose We sought to evaluate the association between collagen turn-over biomarkers and replacement myocardial scarring by CMR and, also, to test their ability to predict outcome in conjunction with LGE in patients with NIDCM. Method We conducted a prospective study on 194 patients (48.7±14.3 years of age; 74% male gender) with NIDCM. CMR was used to determine the presence and extent of LGE. Several collagen turn-over biomarkers were determined at the diagnosis, comprising galectin-3 (Gal3), procollagen type I carboxy-terminal pro-peptide (PICP) and N-terminal pro-peptide of procollagen type III (PIIINP). A composite outcome (all-cause mortality, ventricular tachyarrhythmias, heart failure hospitalization) was ascertained over a median of 26 months. Of all, 17% (n=33) of patients reached the outcome: all-cause mortality (n=6), malignant ventricular tachyarrhythmia (n=14) and HF hospitalization (n=13). Results Gal3, PICP and PIIINP were considerably increased in those with LGE+ (p&amp;lt;0.001), being also directly correlated with LGE mass (r2=0.42; r2=0.44; r2=0.31; all p&amp;lt;0.001). Receiver operating characteristic (ROC) analysis revealed significant ability to diagnose LGE, with area under the ROC: 0.816 for Gal3, 0.705 for PICP, and 0.757 for PIIINP (all p&amp;lt;0.0001). Kaplan-Meier analysis showed that at a threshold of &amp;gt;13.8 ng/dL for Gal3 and &amp;gt;97 ng/dL for PICP, they significantly predicted the outcome (HR=2.66, p&amp;lt;0.001; HR=1.93, p&amp;lt;0.002). Moreover, for a combined model of LGE+/Gal3+/PICP+, time-to-event analysis demonstrated the highest ability to predict composite outcome, as compared to any other models (p=0.004). Nevertheless, in multivariate analysis, after adjustment for covariates, only LGE+ and Gal3+ remained independent predictors for outcome (p=0.008; p=0.04). Conclusion In patients with NIDCM, serum collagen turn-over biomarkers such as Gal3, PICP and PIIINP are closely related to the presence and extent of LGE and can significantly predict cardiovascular outcome. The joint use of LGE with Gal3 and PICP significantly improved outcome prediction. Funding Acknowledgement Type of funding sources: None.

700 The role of Impella CP in the management of malignant arrhythmias: a case of asymptomatic ventricular fibrillation

Abstract Introduction The Impella Heart Pump device (Abiomed, Danvers, MA, USA) is commonly used to provide mechanical circulatory support during high-risk percutaneous coronary intervention (PCI) and has demonstrated both efficacy and safety in patients with cardiogenic shock. Left ventricular assist devices (LVADs) alter the pathophysiological impact of ventricular arrhythmias in advanced heart failure; for example, life-threatening arrhythmias such as ventricular fibrillation (VF). We present a case of sustained VF tolerance in a patient with IMPELLA CP® support. Methods and results A 64-year-old man was admitted with typical chest pain that began 3 days earlier and an anterior myocardial infarction with ST-segment elevation. Urgent coronary angiogram showed a left anterior descending artery treated with angioplasty and stent implantation (TIMI 3). An initial echocardiogram, performed after PCI, showed a reduced left ventricular ejection fraction (LVEF) of approximately 35% with good right ventricular function. Two days later, the ECG tracing showed persistence of the ST elevation, and the patient developed recurrent ventricular tachycardia and an episode of acute pulmonary oedema; the echocardiogram showed a significant worsening of LVEF (15%). A percutaneous mechanical circulatory support device (Impella CP; Abiomed) was inserted through the right common femoral artery in order to preserve adequate systemic perfusion (Figure 1A). Twelve hours later, the patient developed rapid VT degenerating into VF without loss of consciousness (Figure 1C). During the arrhythmia, the patient was alert and his mental status was normal, Impella flow was 2.4–3.0 l/min, and invasive blood pressure (IBP) was 80/65 mmHg (Figure 1D). Intravenous lidocaine was administered without effect. After approximately 10 min of incessant VF, the patient received sedation with propofol from the anesthesiologist. A single unsynchronized DC shock of 200 J converted the patient to sinus rhythm. A bedside transthoracic echocardiogram was performed to check the optimal position of the Impella device (Figure 1B). In the following days, the patient had two new episodes of asymptomatic VF treated with DC-shock after sedation and was transferred to the cardiac surgery department to undergo urgent LVAD implantation. Conclusions Impella CP was helpful in the management of this patient with severe heart failure and malignant ventricular tachyarrhythmias, reducing the hemodynamic and neurological impact of this latter catastrophic arrhythmic event.

Supraventricular Tachycardia Without Preexcitation as a Cause of Sudden Cardiac Arrest in Pediatric Patients.

Sudden cardiac arrest in pediatric patients is a rare occurrence. Supraventricular tachycardia without the presence of ventricular preexcitation in pediatric patients with a structurally normal heart is generally considered benign. Previous literature in adults reported a subset of patients in whom SVT was suspected to be the primary trigger of sudden cardiac arrest. We performed a single-center, retrospective cohort study of pediatric patients without known heart disease, 1-21years of age, presenting with aborted SCA between 2009 and 2019. We collected diagnostic studies in all patients to identify the etiology of the aborted SCA. Thirty patients met the inclusion criteria. The median age at the time of SCA was 15.2years. The etiology of SCA was identified in 23 (77%) patients. Of the seven patients with unknown diagnosis after initial diagnostic studies, three patients subsequently developed fast SVT that was presumed to be the etiology of the initial SCA. These three patients had varying diagnoses of atrioventricular nodal reentry tachycardia, ectopic atrial tachycardia, and a concealed accessory pathway with atrioventricular reentrant tachycardia. After ablation or medical treatment of the SVT substrate, no further tachyarrhythmias were observed. Pediatric patients presenting with an aborted SCA of unknown etiology ought to be considered for electrophysiology testing to elicit occult SVT substrates that may lead to a malignant ventricular tachyarrhythmia.

Case reports of a c.475G>T, p.E159* lamin A/C mutation with a family history of conduction disorder, dilated cardiomyopathy and sudden cardiac death

BackgroundPatients with some mutations in the lamin A/C (LMNA) gene are characterized by the presence of dilated cardiomyopathy (DCM), conduction abnormalities, ventricular tachyarrhythmias (VT), and sudden cardiac death (SCD). Various clinical features have been observed among patients who have the same LMNA mutation. Here, we show a family with cardiac laminopathy with a c.475G > T, p.E159* LMNA mutation, and a family history of conduction disorder, DCM, VT, and SCD.Case presentationA proband (female) with atrial fibrillation and bradycardia was implanted with a pacemaker in her fifties. Twenty years later, she experienced a loss of consciousness due to polymorphic VT. She had a serious family history; her mother and elder sister died suddenly in their fifties and sixties, respectively, and her nephew and son were diagnosed as having DCM. Genetic screening of the proband, her son, and nephew identified a nonsense mutation (c.475G > T, p.E159*) in the LMNA gene. Although the proband’s left ventricular ejection fraction remained relatively preserved, her son and nephew’s left ventricular ejection fraction were reduced, resulting in cardiac resynchronization therapy by implantation of a defibrillator.ConclusionsIn this family with cardiac laminopathy with a c.475G > T, p.E159* LMNA mutation, DCM, SCD, and malignant VT occurred. Clinical manifestation of various atrial and ventricular arrhythmias and heart failure with reduced ejection fraction occurred in an age-dependent manner in all family members who had the nonsense mutation. It appears highly likely that the E159* LMNA mutation is related to various cardiac problems in the family of the current report.

Diagnostic and prognostic role of electrocardiogram in acute myocarditis: A comprehensive review

BackgroundAcute myocarditis represents a challenging diagnosis as there is no pathognomonic clinical presentation. In patients with myocarditis, electrocardiogram (ECG) can display a variety of non‐specific abnormalities. Nevertheless, ECG is widely used as an initial screening tool for myocarditis.MethodsWe researched all possible ECG alterations during acute myocarditis evaluating prevalence, physiopathology, correlation with clinical presentation patterns, role in differential diagnosis, and prognostic yield.ResultsThe most common ECG abnormality in myocarditis is sinus tachycardia associated with nonspecific ST/T‐wave changes. The presence of PR segment depression both in precordial and limb leads, a PR segment depression in leads with ST segment elevation, a PR segment elevation in aVR lead or a ST elevation with pericarditis pattern favor generally diagnosis of perimyocarditis rather than myocardial infarction. In patients with acute myocarditis, features associated with a poorer prognosis are: pathological Q wave, wide QRS complex, QRS/T angle ≥ 100°, prolonged QT interval, high‐degree atrioventricular block and malignant ventricular tachyarrhythmia. On the contrary, ST elevation with a typical early repolarization pattern is associated with a better prognosis.ConclusionsECG alterations in acute myocarditis could be very useful in clinical practice for a patient‐tailored approach in order to decide appropriate therapy, length of hospitalization, and frequency of followup.

Ventricular Dysrhythmias During Long-Term Follow-Up in Patients With Inherited Cardiac Arrhythmia

Reports on development of frequent ventricular premature complexes (fVPC), (non)sustained ventricular tachycardias ([n]sVT), or ventricular fibrillation (VF) and their interrelationship in patients with different inherited cardiac arrhythmia (ICA) have sofar not been reported. The aim of this study is therefore to examine incidences and recurrences rates of sVT and VF ("malignant ventricular tachyarrhythmias, VTA") in addition to the incidence of fVPC and nsVT ("ventricular dysrhythmias, VDR") in patients with various ICA during long-term follow up. Patients (N = 167, 88 male, age 45 ± 15 years) with ICA including definite/borderline arrhythmogenic right ventricular cardiomyopathy (ARVC, N = 47), Brugada syndrome (BrS, N = 71), catecholaminergic polymorphic ventricular tachycardia (CPVT, N = 7), long QT syndrome (LQTS, N = 41) or short QT syndrome (SQTS, N = 1) who had frequent 24-hour Holter monitoring during a follow-up period of 4.6 ± 4.4 years. During the initial screening visit, 15 patients had a history of malignant VTA. fVPC and nsVT was observed in respectively 19% (OHCA/VF/sVT: N = 9) and 13% (OHCA/VF/sVT: N = 4) of all patients. Compared with the ARVC group, patients with BrS and LQTS had less frequent fVPC and nsVT (fVPC: odds ratio [OR] 0.20, 95% confidence interval [CI] 0.08 to 0.49, p <0.000 and OR 0.09, 95% CI 0.02 to 0.33, p <0.000; nsVT:OR 0.17, 95% CI 0.06 to 0.50, p = 0.001 and OR 0.09, 95% CI 0.02 to 0.46, p = 0.003). The recurrence rate of malignant VTA was 33%. In conclusion, variety of VDR and malignant VTA were found during long-term follow-up in patients with ICA. During nearly a 5 years follow-up period, the recurrence rate of malignant VTA was considerable. fVPC, nsVT, and malignant VTA were most often found in patients with an ARVC.

FEATURES OF STRUCTURAL AND ELECTRICAL REMODELING OF THE HEART ASSOCIATED WITH HIGH RISK OF LIFETHREATENING VENTRICULAR TACHYARRHYTHMIAS IN PATIENTS WITH ISCHEMIC AND NON-ISCHEMIC CARDIOMYOPATHIES

Objective: to identify the features of myocardial fibrosis and ventricular repolarization disorders associated with malignant ventricular tachyarrhythmias (VT) in patients with ischemic (ICM) and non-ischemic cardiomyopathy (NICM).Material and Methods. Fifty consecutive patients (41 men and 9 women aged 60±13 years; 30 patients with ICM and 20 patients with NICM) underwent contrast magnetic resonance imaging (MRI) of the heart, QT dispersion analysis of 12-lead Holter ECG followed by implantation of cardioverter-defibrillator (ICD) or resynchronizing device with defibrillator (CRTD) to prevent sudden cardiac death.Results. According to data of 32 (28–43)-month follow up, VT paroxysms were registered in 20 of 30 patients (67%) with ICM and in 5 of 20 patients (25%) with NICM on follow-up. Data of successive univariate and ROC analyses of MRI indices differed between patients with and without recurrence of VTs in ICM and NICM patient groups. In ICM patients, VTs were associated with the values of QT (peak) interval dispersion over 80 mc according to data of Holter ECG monitoring and higher gray zone in the left ventricle (≥27%) according to contrast-enhanced MRI. Similar analyses in NICM patients showed that the most valuable diagnostic signs associated with the right ventricular tachycardias were the values of QT (peak) interval dispersion over 90 mc according to data of Holter ECG monitoring and the presence of non-transmural fibrosis of the left ventricle (≥27%) according to contrast-enhanced MRI.Conclusion. The features of structural remodeling of the left ventricle predisposing to VTs significantly differ in patients with ICM and NICM. Nevertheless, the presence of ventricular repolarization disorders, associated with onset of VTs, is universal in patients with ischemic and non-ischemic cardiomyopathies.

FEATURES OF STRUCTURAL AND ELECTRICAL REMODELING OF THE HEART ASSOCIATED WITH HIGH RISK OF LIFETHREATENING VENTRICULAR TACHYARRHYTHMIAS IN PATIENTS WITH ISCHEMIC AND NON-ISCHEMIC CARDIOMYOPATHIES

Objective: to identify the features of myocardial fibrosis and ventricular repolarization disorders associated with malignant ventricular tachyarrhythmias (VT) in patients with ischemic (ICM) and non-ischemic cardiomyopathy (NICM).Material and Methods. Fifty consecutive patients (41 men and 9 women aged 60±13 years; 30 patients with ICM and 20 patients with NICM) underwent contrast magnetic resonance imaging (MRI) of the heart, QT dispersion analysis of 12-lead Holter ECG followed by implantation of cardioverter-defibrillator (ICD) or resynchronizing device with defibrillator (CRTD) to prevent sudden cardiac death.Results. According to data of 32 (28–43)-month follow up, VT paroxysms were registered in 20 of 30 patients (67%) with ICM and in 5 of 20 patients (25%) with NICM on follow-up. Data of successive univariate and ROC analyses of MRI indices differed between patients with and without recurrence of VTs in ICM and NICM patient groups. In ICM patients, VTs were associated with the values of QT (peak) interval dispersion over 80 mc according to data of Holter ECG monitoring and higher gray zone in the left ventricle (≥27%) according to contrast-enhanced MRI. Similar analyses in NICM patients showed that the most valuable diagnostic signs associated with the right ventricular tachycardias were the values of QT (peak) interval dispersion over 90 mc according to data of Holter ECG monitoring and the presence of non-transmural fibrosis of the left ventricle (≥27%) according to contrast-enhanced MRI.Conclusion. The features of structural remodeling of the left ventricle predisposing to VTs significantly differ in patients with ICM and NICM. Nevertheless, the presence of ventricular repolarization disorders, associated with onset of VTs, is universal in patients with ischemic and non-ischemic cardiomyopathies.

Sudden Cardiac Death in Brugada Syndrome.

The Brugada syndrome is an inherited channelopathy that alters the main transmembrane ion currents that constitute the cardiac action potential. These changes not only modify the resting electrocardiogram but also predispose patients to develop malignant ventricular tachyarrhythmias that can lead to syncope, cardiac arrest, and sudden cardiac death. This syndrome is responsible for nearly 20% of all sudden cardiac deaths in patients with structurally normal hearts and up to 12% of all sudden cardiac deaths. Brugada syndrome is diagnosed by its characteristic electrocardiogram consisting of a coved-type ST-segment elevation of at least 2 mm followed by a negative T wave in either one of the right precordial leads. These changes can be observed spontaneously or after administration of a sodium channel blocker. While our understanding of this disease has increased tremendously since its first description in 1992, the primary therapeutic option remains implantation of an implantable cardioverter-defibrillator to avoid sudden cardiac death. Therefore, tremendous effort is being made to effectively risk stratify patients to determine who would benefit from implantable cardioverter-defibrillator implantation.

Subcutaneous implantable cardioverter defibrillator in patients with arrhythmogenic right ventricular cardiomyopathy: Results from an Italian multicenter registry

BackgroundDespite expanding indication of the subcutaneous implantable cardioverter defibrillator (S-ICD) in clinical practice, limited data exists on safety and efficacy of S-ICD in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients. The aim of this multicenter study was to evaluate the safety and efficacy of S-ICD in ARVC patients. MethodsThe study population included 44 consecutive patients with definite ARVC diagnosis according to the 2010 ITF criteria (57% male, mean age 37 ± 17 years [range 10–75 years]) who received an S-ICD. Eighteen (41%) patients were implanted for secondary prevention. ResultsAt implant, all inducible patients (34/44) had conversion of ventricular fibrillation at 65 J. No early complications occurred. During a median follow-up of 12 months (7–19), 3 (6.8%) patients experienced complications requiring surgical revision. No local or systemic device-related infections were observed. Six patients (14%) received a total of 61 appropriate and successful shocks on ventricular arrhythmias. Six (14%) patients experienced 8 inappropriate shocks for oversensing of cardiac signal (4 cases) and non-cardiac signal (4 cases) with one patient requiring device explantation. No patients had the device explanted due to the need for antitachycardia pacing. ConclusionsThe study shows that S-ICD provides safe and effective therapy for termination of both induced and spontaneous malignant ventricular tachyarrhythmias with high energy shocks in ARVC patients, but the risk of inappropriate shocks and complications needing surgical revision should be considered.

Characteristic of fibrotic myocardial lesions associated with life-threatening ventricular tachyarrhythmias in patients with ischemic and non-ischemic cardiomyopathies.

To identify the features of myocardial scar and fibrosis associated with the occurrence of malignant ventricular tachyarrhythmias (VTs) in high-risk patients with ischemic (ICMP) and non-ischemic cardiomyopathy (NICMP). This prospective study included 50 patients (41 men, 9 women), age = 60 ± 13 years, 30 patients of them with ICMP and 20 patients with NICMP, who underwent echocardiography (Echo) and contrast magnetic resonance imaging (MRI) of the heart followed by implantation of cardioverter-defibrillators (ICD) or resynchronizing devices with defibrillator (CPTD) to prevent sudden cardiac death. Sustained VTs were reported in 20/30 (67%) patients with ICMP and in 5/20 (25%) patients with NICMP on follow-up [26 (22-37) months]. Successive univariate and ROC-analyses of Echo and MRI-indices between patients with and without recurrence of VTs found different results for ICMP and NICMP patients groups. In ICMP patients the VTs were associated with wide transmural fibrosis on contrast MRI that covered 3 or more segments of left ventricular. These segments were preferably localized in the middle parts of the inferior and inferolateral segments of the left ventricle. The independent predictors of VTs in NICMP patients were non-transmural fibrosis at 4.5% of the left ventricular mass by contrast MRI as well as low left ventricular ejection fraction (less than 26%) by Echo. To determine the indications for implantation of the ICD and CRTD for primary prevention of sudden cardiac death, it is advisable to take into account not only the value of ejection fraction of left ventricular, but also the features of the fibrosis of the left ventricle by contrast MRI of the heart.