Risk Stratification For Sudden Death Research Articles

Left ventricular non-compaction: Challenges in the etiopathogenesis and risk stratification of sudden cardiac death in clinical practice

Left ventricular non-compaction: Challenges in the etiopathogenesis and risk stratification of sudden cardiac death in clinical practice

Relationship between ventricular repolarization parameters and the inducibility of ventricular arrhythmias during electrophysiological study in patients with coronary artery disease.

Risk stratification of sudden cardiac death in patients with coronary artery disease is of great importance. We evaluated the association between ventricular repolarization and induction of malignant ventricular arrhythmias on electrophysiological study of patients with coronary artery disease. A total of 177 patients (65±10.1 years, 83.6% male, mean left ventricular ejection fraction [LVEF] 37.5±13.6%) were analyzed. For each 10 ms increment in the QT interval, there was a 7% increase in malignant ventricular arrhythmias inducibility; QT cutoff point of 452 ms had an accuracy of 0.611 for predicting malignant ventricular arrhythmias (p=0.011). Male gender (odds ratio [OR]=4.18, p=0.012), LVEF <35% (OR=2.32, p=0.013), amiodarone use (OR=2.01, p=0.038), and prolonged QT (OR=1.07, p=0.023) were associated with malignant ventricular arrhythmias. In patients with ventricular dysfunction, QT >452 ms was associated with significantly increased risk of malignant ventricular arrhythmias (OR=5.44, p=0.0004). In those with LVEF ³35%, QT dispersion (QTd) was significantly higher in patients with inducible malignant ventricular arrhythmias. QTd >20 ms had 0.638 accuracy and 81.3% negative predictive value in predicting malignant ventricular arrhythmias. QT interval is an independent factor associated with malignant ventricular arrhythmias in patients with coronary artery disease. The combination of ventricular dysfunction and prolonged QT interval is associated with a 5.44-fold increase of malignant ventricular arrhythmias induction. Male gender, amiodarone use, and decreased left ventricular ejection fraction are also associated with increased risk of inducibility of malignant ventricular arrhythmias on the electrophysiological study.

Utility of electrophysiologic testing for sudden death risk stratification in cardiac sarcoidosis patients with mildly impaired left ventricular function

BackgroundVentricular arrhythmias (VA) account for at least 25% of deaths caused by cardiac sarcoidosis (CS) and may arise in patients with mildly impaired LVEF (>35%). ObjectiveIn the current study, we examine whether EP study may be used for sudden death risk stratification in CS patients who have mildly impaired LVEF and a diagnosis of highly probable or probable CS according to the World Association of Sarcoidosis and Other Granulomatous Diseases Sarcoidosis Organ Assessment Instrument (WASOGI). MethodsAll patients: (1) exhibited a diagnosis of highly probable or probable CS according to the WASOGI, (2) exhibited cardiac MRI findings consistent with CS, (3) exhibited LVEF >45% and (4) underwent EP study. Device interrogations, transmissions and medical records were reviewed for all patients. ResultsWe identified 46 CS patients with mildly impaired LVEF. VA were induced in 11 patients and 10/11 patients underwent ICD placement. Thirty-five patients had no VA and 24/35 patients underwent placement of an ILR. During the follow-up period, the VA event rate was 6.5%. The negative and positive predictive values of the EP study for the development of VA were 100% and 27.2%, respectively. ConclusionsIn CS patients with mildly impaired LVEF and a diagnosis of highly probable or probable CS, a negative EP study was highly predictive of the absence of VA. The successful execution of future prospective studies is contingent upon enrollment of phenotypically homogenous cardiac sarcoidosis patients.

Ambulatory electrocardiographic markers predict serious cardiac events in patients with chronic kidney disease: The Japanese Noninvasive Electrocardiographic Risk Stratification of Sudden Cardiac Death in Chronic Kidney Disease (JANIES-CKD) study.

BackgroundNoninvasive electrocardiographic markers (NIEMs) are promising arrhythmic risk stratification tools for assessing the risk of sudden cardiac death. However, little is known about their utility in patients with chronic kidney disease (CKD) and organic heart disease. This study aimed to determine whether NIEMs can predict cardiac events in patients with CKD and structural heart disease (CKD‐SHD).MethodsWe prospectively analyzed 183 CKD‐SHD patients (median age, 69 years [interquartile range, 61−77 years]) who underwent 24‐h ambulatory electrocardiographic monitoring and assessed the worst values for ambulatory‐based late potentials (w‐LPs), heart rate turbulence, and nonsustained ventricular tachycardia (NSVT). The primary endpoint was the occurrence of documented lethal ventricular tachyarrhythmias (ventricular fibrillation or sustained ventricular tachycardia) or cardiac death. The secondary endpoint was admission for cardiovascular causes.ResultsThirteen patients reached the primary endpoint during a follow‐up period of 24 ± 11 months. Cox univariate regression analysis showed that existence of w‐LPs (hazard ratio [HR] = 6.04, 95% confidence interval [CI]: 1.4−22.3, p = .007) and NSVT [HR = 8.72, 95% CI: 2.8−26.5: p < .001] was significantly associated with the primary endpoint. Kaplan–Meier analysis demonstrated that the combination of w‐LPs and NSVT resulted in a lower event‐free survival rate than did other NIEMs (p < .0001). No NIEM was useful in predicting the secondary endpoint, although the left ventricular mass index was correlated with the secondary endpoint.ConclusionThe combination of w‐LPs and NSVT was a significant risk factor for lethal ventricular tachyarrhythmias and cardiac death in CKD‐SHD patients.

Abstract 9715: Feasibility of Using Machine Learning to Establish a Risk Prediction Model for Sudden Cardiac Death in Patients with Hypertrophic Cardiomyopathy

Introduction: Risk stratification for sudden cardiac death (SCD) is a great challenge in managing hypertrophic cardiomyopathy (HCM). Hypothesis: This study attempted for the first time to build a machine learning (ML) model for SCD risk prediction. Methods: The present study consisted of 1631 consecutive adult HCM patients without a history of SCD events. Extreme gradient boosting (XGBoost) was applied for ML model construction. We compared the predictive performance of the ML model with that of conventional models by calculating C-statistics and interpreted the ML model output using the SHapley Additive exPlanation (SHAP) value. Results: Fifty patients reached SCD endpoints during a median follow-up of 4.6 years. The C-statistic of the ML model was 0.745 [95% confidence interval (CI), 0.723-0.766], which was significantly higher than that of the model recommended in the 2014 European Society of Cardiology guidelines (C-statistics =0.609; 95% CI 0.585-0.623) and the model recommended in the 2020 American College of Cardiology/American Heart Association guidelines (C-statistics =0.628; 95% CI 0.604-0.652). The ML model incorporated 12 features as predictors, including 5 conventional SCD risk markers (NSVT, quantification of LGE, family history of SCD, LVEF 50%, unexplained syncope), WBC, creatine, uric acid, TBIL and cholesterol, NT-proBNP and family history of HCM. Using SHAP values, we quantified the contribution of each feature within the ML model to the final prediction and visualized the relationship between features and SCD risk. Conclusion: Our study constructed an ML model for the prediction of SCD risk in patients with HCM and provided a clinically intuitive interpretation. The ML model showed better discrimination performance than conventional models, demonstrating the feasibility of ML in SCD risk prediction for patients with HCM.

Abstract 10353: Independent Validation of the Ecg Risk Score for Sudden Death Risk Stratification in Pediatric Hypertrophic Cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is the leading cause of sudden cardiac death (SCD) in children and young adults. An ECG risk score tested in a Swedish cohort of 155 children with HCM had 97% sensitivity, 80% specificity, 45% positive predictive value (PPV), and 99% negative predictive value (NPV) for SCD risk prediction. Our goal was to validate the ECG risk score in an independent HCM cohort. Methods: Phenotype-positive pediatric HCM patients seen at a single center between 1987-2019 with at least 5 years follow-up from diagnosis, or a SCD event within 5 years of diagnosis, were retrospectively identified. First-evaluation ECGs were analyzed by a single operator blinded to patient outcomes. ECG risk score was calculated using QRS electrical axis, amplitude, duration, ST/T-wave abnormalities and QTc duration. The primary outcome was a composite of SCD, aborted sudden cardiac arrest, and appropriate shock from a prophylactic ICD. Results: Of 144 eligible patients with a median follow-up 14.6 yrs, 22 experienced SCD events within five years from diagnosis at a median age 12.1 yrs. The ECG risk score in patients experiencing a SCD event was 2-fold higher i.e. 8 (IQR 7-10) compared to the remaining cohort i.e. 4 (IQR 2-8) (p&lt;0.001). An ECG risk score &gt;5 had a sensitivity of 95% (CI 77%-100%), specificity 56% (46%-65%), PPV 28% (24%-33%), NPV 99% (91%-100%), and a receiver operating characteristic area under the curve of 0.76 for its ability to discriminate between patients with and without SCD events ( Figure 1 ). Compared to the discovery cohort, the score had strong sensitivity and NPV, but lower specificity and PPV. Conclusions: The ECG risk score for SCD risk stratification performed well in an independent Canadian validation cohort but overestimated SCD risk. Futher analysis will determine if inclusion of the ECG risk score can enhance the performance of currently available SCD risk prediction models for pediatric HCM.

Abstract 11553: Sudden Cardiac Death in Type 1 and Type 2 Diabetes

Introduction: Diabetes is a known risk factor for sudden cardiac death (SCD). Whether type 1 diabetes mellitus (T1D) and type 2 diabetes mellitus (T2D) confer a similar risk of SCD remains unclear. Our aim was to determine and compare the association of T1D and T2D with SCD. Hypothesis: Given the differences in the pathophysiology, clinical presentation, and management, the likelihood of having SCD in T1D and T2D is different. Methods: Using data collected from 2002-19, we performed a case-control study of 2,771 cases of SCD (age ≥18 years) from the Oregon Sudden Unexpected Death Study and 8,313 control patients from Kaiser Permanente Northwest (matched for age, sex, and race/ethnicity) who did not have SCD or prior cardiac arrest. We used medical records to determine diabetes status and used logistic regression to evaluate the independent association between diabetes and SCD. Results: Our cases and matched controls had a mean age of 65 ± 16 years, were 33% female and 24% non-White race. In total, 37% (n=1,016) of cases and 24% (n=1,981) of controls had diabetes. In those with diabetes, the proportion of T1D was 6% (n=66) among cases and 2% among controls (n=40; P&lt;0.001). The presence of diabetes was associated with a 1.5- times higher odds of SCD. Compared to those without diabetes, the odds ratio (OR) and 95% confidence interval (CI) for SCD was 4.36 (2.81–6.75; P&lt;0.001) in T1D and 1.45 (95% CI, 1.30–1.63; P&lt;0.001) in T2D after adjustment for age, sex, race/ethnicity, body mass index, and relevant comorbidities. Within the diabetic population (n=2,997), the odds of having SCD were 2.4 times higher in T1D than in T2D (adjusted OR: 2.41; 95% CI, 1.53–3.80; P&lt;0.001). Conclusions: Individuals with T1D and T2D have a higher risk of SCD than those without diabetes. In the diabetic population, T1D is more strongly associated with SCD compared to T2D. These findings have implications for sudden death risk stratification in diabetics.

Repetitive Squat-to-Stand Provocation of Dynamic Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy

Left ventricular outflow tract (LVOT) obstruction is a determinant in the management of patients with hypertrophic cardiomyopathy, including candidacy for septal reduction therapy and risk stratification for sudden cardiac death. 1 Elliott P.M. Gimeno J.R. Tomé M.T. Shah J. Ward D. Thaman R. et al. Left ventricular outflow tract obstruction and sudden death risk in patients with hypertrophic cardiomyopathy. Eur Heart J. 2006; 27: 1933-1941 Crossref PubMed Scopus (262) Google Scholar ,2 Ommen S.R. Mital S. Burke M.A. Day S.M. Deswal A. Elliott P. et al. 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2020; 76: e159-e240 Crossref PubMed Scopus (136) Google Scholar Obstruction is defined as a maximal instantaneous gradient ≥ 30 mm Hg, and severe obstruction is defined as a maximal instantaneous gradient ≥ 50 mm Hg. 2 Ommen S.R. Mital S. Burke M.A. Day S.M. Deswal A. Elliott P. et al. 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy. J Am Coll Cardiol. 2020; 76: e159-e240 Crossref PubMed Scopus (136) Google Scholar Several provocative maneuvers have been used to elicit latent obstruction, including the Valsalva maneuver, amyl nitrite inhalation, and exercise on a treadmill or bike. 3 Marwick T.H. Nakatani S. Haluska B. Thomas J.D. Lever H.M. Provocation of latent left ventricular outflow tract gradients with amyl nitrite and exercise in hypertrophic cardiomyopathy. Am J Cardiol. 1995; 75: 805-809 Abstract Full Text PDF PubMed Scopus (74) Google Scholar , 4 Jensen M.K. Havndrup O. Pecini R. Dalsgaard M. Hassager C. Helqvist S. et al. Comparison of Valsalva manoeuvre and exercise in echocardiographic evaluation of left ventricular outflow tract obstruction in hypertrophic cardiomyopathy. Eur J Echocardiogr. 2010; 11: 763-769 Crossref PubMed Scopus (24) Google Scholar , 5 Shah J.S. Esteban M.T.T. Thaman R. Sharma R. Mist B. Pantazis A. et al. Prevalence of exercise-induced left ventricular outflow tract obstruction in symptomatic patients with non-obstructive hypertrophic cardiomyopathy. Heart. 2008; 94: 1288-1294 Crossref PubMed Scopus (165) Google Scholar During a recent shortage of amyl nitrite, our practice implemented a repetitive squat-to-stand maneuver as an adjunct to the Valsalva maneuver when assessing for LVOT obstruction. We sought to evaluate the efficacy of this repetitive squat-to-stand maneuver in eliciting LVOT obstruction compared with the Valsalva maneuver in a retrospective study.

Risk factors and stratification for sudden cardiac death using inflammation / metabolomics and high-resolution electrocardiograph

It is difficult for health practitioners to clearly determine the risk of sudden cardiac death but only by determining the risk can risk factors be reduced or eliminated. Dr Atsushi Suzuki, Department of Cardiology, Tokyo Women's Medical University, Japan, is conducting exploratory research on gene expression and high-resolution electrocardiogram index for predicting the effects of antiarrhythmic drugs in collaboration with the University's Department of Pathology and the University of Tokyo. Suzuki and the team are using blood tests and genetic tests, high-resolution electrocardiograph (ECG) indicators and metabolome analysis in this work. Metabolome analysis has not previously been considered as a risk factor for sudden death and the high-resolution ECG indicators Suzuki and the team are using are currently only adopted in a few facilities, making this research highly innovative. In order to develop a suitable risk assessment method and enable more accurate stratification of the risk of sudden cardiac death, the researchers are using a high-resolution ECG called DREAM-ECG to detect the arrhythmic matrix of heart failure patients and compare this to the results of inflammation, T cell subset and comprehensive metabolome search. In addition the team is working to shed light on the causes of lethal arrhythmia. Furthermore, Suzuki wants to reduce incidence of the unnecessary implantation of implantable cardioverter defibrillators (ICDs) and is seeking to accomplish this through his work.

Heart rate turbulence as potential adjuvant index for optimal treatment guidance in severe pulmonary artery hypertension

Abstract Purpose Despite significant progress achieved in the management of pulmonary arterial hypertension (PAH), the prognosis remains poor. Sudden cardiac death is one main cause of death in advanced disease. It is already known that in pts with PAH there is an alteration in cardiac autonomic nervous activity. Heart rate turbulence (HRT) is an ECG–related autonomic marker, helpful in risk stratification of proarrhythmia and sudden cardiac death. Aim of the study was to examine HRT in patients with severe idiopathic PAH (IPAH) and its relation to disease's progress. Methods The study population consisted of 46 pts, (32 men and 14 women), mean age 50±9 years, Group A 20 pts: NYHA III, III–IV diagnosed as severe IPAH and Group B 26 pts: NYHA II, II–III diagnosed as moderately severe IPAH. They underwent 24h Holter monitoring-HRT analysis with calculation of 2 parameters, turbulence onset (TO) and turbulence slope (TS) (Abnormal values: TO&amp;gt;0, TS&amp;lt;2.5msec/RR). Pts were defined as HRT(+) when TO and/or TS were abnormal and as HRT(−) when both TO and TS were normal or when HRT could not be calculated because of none or too few suitable PVCs. Reassessment of HRT was undertaken in 6 mo and 1 year in case of change in clinical status. Six pts from group A and 7 pts from group B underwent HRT reassessment because of change in clinical status. Results Initially abnormal HRT was found in 12 out of 20 pts (n=12, 60%) in group A and in none out of 26 (n=0, 0%) in group B (p=0,001). In 5 pts out of 8 with clinical improvement and 4 pts with clinical deterioration who had HRT reassessed, significant positive correlation was found between TS and change of clinical status (r=0,64, p=0,04). There was a tendency to greater normal TS mean values with clinical improvement even in group where TS was already normal (6,95±4,5 vs 3±0,3 p=0.077). Conclusion In severe IPAH cardiac autonomic system impairment was demonstrated mainly as abnormal TS in HRT. Significant positive correlation between normalization of TS and clinical improvement was revealed and that raises promises for use of HRT optimization as adjuvant index to guide optimal IPAH therapy and efficacy. Funding Acknowledgement Type of funding sources: None.

Microvolt t-wave alternans its clinical significance in the assessment of the risk of sudden cardiac death among patients with hypertrophic cardiomyopathy

Abstract Summary Some patients with hypertrophic cardiomyopathy (HCM) are at significant risk of premature sudden death. Identification of the risk factors may enable effective prevention of adverse cardiac events in these patients. Assessment of the microvolt T-wave alternans (MTWA) is a recognized non-invasive diagnostic test used in risk stratification of sudden cardiac death (SCD). However, the number of reports on the frequency of occurrence of MTWA in HCM is small. Aim: Evaluation of the prognostic value of MTWA in predicting the risk of arrhythmic events (sudden cardiac death, documented VT/VF, appropriate ICD discharge) in patients with HCM. Material and methods 122 patients with HCM underwent detailed clinical assessment and ECG- and echocardiographic examination. They underwent 24-hour ambulatory ECG monitoring, and the following elements were analysed: 1) arrhythmias, 2) heart rate variability (HRV) and the QT segment, 3) the presence of ventricular late potentials (LP), 4) heart rate turbulence (HRT). MTWA assessment was made during a test on a treadmill (Cambridge Heart). In accordance with the adopted criteria, the test was interpreted as negative, positive or indeterminate. Subsequently, positive and indeterminate results were described collectively as MTWA(+) and negative results as MTWA(−). Then the patients were divided into two groups: Group 1 – 57 patients (46,7%) with MTWA(−), and Group 2 – 65 patients (53,2%) with MTWA(+). In order to stratify the risk, the following were adopted as composite primary endpoints: sudden cardiac death or hospitalization for life-threatening arrhythmias (VT/VF), and appropriate ICD discharge. Results The mean follow-up period of the patients was 57±8 months; during that time, events that met the criteria for the endpoint occurred in 16 patients. On the basis of univariate analysis, 10 variables with a significant influence on the occurrence of an event were selected (unexplained syncope, NT-proBNP values elevated above 411 pg/ml, size of the left atrium over 44mm, diastolic thickness of the interventricular septum over 25 mm, the presence of MTWA(+), the QRS width &amp;gt;90 msec, QTc &amp;gt;467 msec, QTd &amp;gt;70 msec, SDNN &amp;lt;110 msec, and sinus rhythm turbulence parameters TS &amp;lt;2,9 ms/2RR). These variables were then included in a multivariate analysis. The model from a Cox regression analysis showed that the presence of unexplained syncope (HR=1,4), MTWA(+) (HR=1,5), size of the left atrium over 44mm (HR=5), and the thickness of the interventricular septum over 25 mm (HR=1,5) increased the risk of sudden events. Conclusions 1) Patients with hypertrophic cardiomyopathy had a significant percentage of positive results of the microvolt T-wave alternans test (MTWA+), 2) Positive MTWA test result in patients with hypertrophic cardiomyopathy can help to identify patients at risk of sudden cardiac death. Funding Acknowledgement Type of funding sources: None.

Risk stratification of cardiac arrhythmias and sudden cardiac death in type 2 diabetes mellitus patients receiving insulin therapy: A population-based cohort study.

IntroductionMetabolic abnormalities may exacerbate the risk of adverse outcomes in patients with type 2 diabetes mellitus. The present study aims to assess the predictive value of HbA1c and lipid variability on the risks of sudden cardiac death (SCD) and incident atrial fibrillation (AF).MethodsThe retrospective observational study consists of type 2 diabetic patients prescribed with insulin, who went to publicly funded clinics and hospitals in Hong Kong between January 1, 2009 and December 31, 2009. Variability in total cholesterol, low‐density lipoprotein‐cholesterol (LDL‐C), high‐density lipoprotein‐cholesterol (HDL‐C), triglyceride, and HbA1c were assessed through their SD and coefficient of variation. The primary outcomes were incident (1) ventricular tachycardia/ventricular fibrillation, actual or aborted SCD and (2) AF.ResultsA total of 23 329 patients (mean ± SD age: 64 ± 14 years old; 51% male; mean HbA1c 8.6 ± 1.3%) were included. On multivariable analysis, HbA1c, total cholesterol, LDL‐C and triglyceride variability were found to be predictors of SCD (p < .05).ConclusionHbA1c and lipid variability were predictive of SCD. Therefore, poor glucose control and variability in lipid parameters in diabetic patients are associated with aborted or actual SCD. These observations suggest the need to re‐evaluate the extent of glycemic control required for outcome optimization.

Smartwatch-based detection of cardiac arrhythmias: Beyond the differentiation between sinus rhythm and atrial fibrillation.

Within the span of a few years, watches have functionally morphed from objects that tell time to wearable minicomputers that allow real-time recording of electrocardiograms (ECGs). Considerable information can be deduced from these single lead tracings, and it is now not uncommon to see patients in whom diagnostic tracings of clinically relevant but elusive arrhythmias are captured using a smartwatch. Empowering individuals to record their own ECG tracings in scenarios such as palpitations, syncope, and for risk stratification of sudden death intuitively has considerable potential, but its value remains to be robustly demonstrated. The main objective of this review is to describe the information that can be obtained from smartwatch-based single-lead ECG recordings beyond simply differentiating between sinus rhythm and atrial fibrillation. We also review the strengths and limitations of using these devices in clinical settings and offer potential solutions to address the latter.

Electrocardiographic and imaging methods in risk stratification of sudden cardiac death in patients with chronic heart failure

Ventricular arrhythmias (in particular, episodes of ventricular fibrillation and paroxysmal ventricular tachycardia) are associated with a significant increase in the risk of sudden cardiac death (SCD) in patients with chronic heart failure (CHF). The most widely used strategy for stratification of SCD risk in patients with CHF uses low left ventricular ejection fraction as the main criterion, but modern epidemiological studies confirm the need to search for new SCD markers, in particular, electrocardiographic and imaging ones. The most reasonable and promising is an integrated approach that implies a combination of sequential use of non-invasive and invasive techniques, which makes it possible to improve the identification of high-risk individuals who need an invasive strategy to prevent SCD, but who do not always meet the “classical” criteria for ICD implantation.

Validation of the 2020 AHA/ACC Risk Stratification for Sudden Cardiac Death in Chinese Patients With Hypertrophic Cardiomyopathy

Background: Sudden cardiac death (SCD) is a common cause of death in hypertrophic cardiomyopathy (HCM), but identification of patients at a high risk of SCD is challenging. The study aimed to validate the three SCD risk stratifications recommended by the 2011 ACCF/AHA guideline, the 2014 ESC guideline, and the 2020 AHA/ACC guideline in Chinese HCM patients.Methods: The study population consisted of a consecutive cohort of 511 patients with HCM without a history of SCD event. The endpoint was a composite of SCD or an equivalent event (appropriate implantable cardioverter defibrillator therapy or successful resuscitation after cardiac arrest).Results: During a follow-up of 4.7 ± 1.7 years, 15 patients (2.9%) reached the SCD endpoint and 12 (2.3%) were protected by implantable cardioverter defibrillator for primary prevention. A total of 13 (2.8%) patients experiencing SCD events were misclassified as low-risk patients by the 2011 ACCF/AHA guideline, 12 (2.3%) by the 2014 ESC model, and 7 (1.6%) by the 2020 AHA/ACC guideline. The SCD risk stratification in the 2020 AHA/ACC guideline showed greater area under the curve (0.71; 95% CI 0.56–0.87, p < 0.001) than the one in the 2011 ACCF/AHA guideline (0.52; 95% CI 0.37–0.67, p = 0.76) and 2014 ESC guideline (0.68; 95% CI 0.54–0.81, p = 0.02).Conclusion: The SCD risk stratification recommended by the 2020 AHA/ACC guideline showed a better discrimination than previous stratifications in Chinese patients with HCM. A larger multicenter, independent, and prospective study with long-term follow-up would be warranted to validate our result.

Towards an improved and personalized risk stratification of sudden cardiac death in dilated non-ischaemic cardiomyopathy: is the time for ejection fraction coming to an end?

Towards an improved and personalized risk stratification of sudden cardiac death in dilated non-ischaemic cardiomyopathy: is the time for ejection fraction coming to an end?

B-PO05-196 PREDICTIVE INDICES OF VENTRICULAR STIMULATION PROTOCOLS IN TETRALOGY OF FALLOT PATIENTS WITH ICDS AND SUBSEQUENT THERAPIES

Patients with repaired Tetralogy of Fallot (ToF) are at increased risk for ventricular arrhythmias (VA). Utility of a peri-surgical pulmonary valve replacement (PVR) ventricular stimulation protocol to assist with risk stratification for sudden cardiac death has been well established in this population. However, current protocol-guided ICD implantation may lack specificity. We sought to evaluate post-surgical PVR electrophysiology study (EPS) indices in protocol-guided ICD patients to define potential predictive markers of subsequent, appropriate ICD therapies. All ToF patients with protocol-guided ICD implants (N=14) at two centers were included for retrospective analysis. Patients with appropriate ICD therapies were compared to those without or with only inappropriate therapy using chi-square tests and unpaired t-tests. Six patients received appropriate ICD therapies and eight received no therapy. Inducibility with double extrastimuli, during post-PVR EPS, was predictive of appropriate therapy (P=0.024) while inducibility only with extrastimuli <200 ms was predictive of no therapy (P=0.01). Isoproterenol use (P=0.19) and site of pacing that led to induction (P=0.277) did not correlate with subsequent ICD therapies. Inappropriate shocks were not significantly different between groups (P=0.1). Aggressive pacing protocols, including triple and extrastimuli <200 ms, are more likely to induce VAs without subsequent appropriate clinical therapies in patients with repaired Tetralogy of Fallot.

Validation of the new American College of Cardiology/American Heart Association Guidelines for the risk stratification of sudden cardiac death in a large Mediterranean cohort with Hypertrophic Cardiomyopathy

BackgroundThe aim of our study was to assess the performance of the new American College of Cardiology (ACC)/American Heart Association (AHA) Guidelines, with respect to sudden cardiac death (SCD) prevention, in comparison with the established risk score of the European Society of Cardiology (hypertrophic cardiomyopathy [HCM] Risk-SCD), in a large Mediterranean cohort of HCM patients. MethodsThe clinical and imaging characteristics of 784 HCM patients (mean age at first evaluation 52 ± 16 years, 67.2% males) were analyzed retrospectively. The sensitivity, specificity, and negative predictive value for SCD events of the presence of ≥1 risk factor for SCD according to the ACC/AHA Guidelines 2020 and of the HCM Risk-SCD≥6% and HCM Risk-SCD≥4% were estimated during follow-up. ResultsDuring follow-up, 47 (6%) patients suffered an SCD event. The presence of ≥1 major risk factor for SCD according to the new ACC/AHA Guidelines had 96% sensitivity (95% CI 85.5-99.5%) with modest specificity of 59% (95% CI 55-62.2%) and negative predictive value of 99.5% (95% CI 98.2-99.9%). On the contrary, HCM- Risk-SCD≥6% had a relatively low sensitivity (32%, 95% CI 19.1-47.1%) and high specificity of 95% (95% CI 93.1-96.4%), whereas, HCM-Risk-SCD≥4% had sensitivity of 60% (95% CI 44-74%) and specificity of 83.9% (95% CI 80-85.6%). Both the HCM Risk-SCD cut-off values demonstrated lower negative predictive value but higher accuracy than the ACC/AHA algorithm for SCD prediction. ConclusionThe novel ACC/AHA proposed algorithm identifies most of the patients with an SCD event with the cost of numerous defibrillator implantations. HCM-Risk-SCD demonstrated higher specificity, whereas its sensitivity and negative predictive value are modest.

Improved Risk Stratification for Ventricular Arrhythmias and Sudden Death in Patients With Nonischemic Dilated Cardiomyopathy

BackgroundRisk stratification for ventricular arrhythmias (VA) and sudden death in nonischemic dilated cardiomyopathy (DCM) remains suboptimal. ObjectivesThe goal of this study was to provide an improved risk stratification algorithm for VA and sudden death in DCM. MethodsThis was a retrospective cohort study of consecutive patients with DCM who underwent cardiac magnetic resonance with late gadolinium enhancement (LGE) at 2 tertiary referral centers. The combined arrhythmic endpoint included appropriate implantable cardioverter-defibrillator therapies, sustained ventricular tachycardia, resuscitated cardiac arrest, and sudden death. ResultsIn 1,165 patients with a median follow-up of 36 months, LGE was an independent and strong predictor of the arrhythmic endpoint (hazard ratio: 9.7; p < 0.001). This association was consistent across all strata of left ventricular ejection fraction (LVEF). Epicardial LGE, transmural LGE, and combined septal and free-wall LGE were all associated with heightened risk. A simple algorithm combining LGE and 3 LVEF strata (i.e., ≤20%, 21% to 35%, >35%) was significantly superior to LVEF with the 35% cutoff (Harrell’s C statistic: 0.8 vs. 0.69; area under the curve: 0.82 vs. 0.7; p < 0.001) and reclassified the arrhythmic risk of 34% of patients with DCM. LGE-negative patients with LVEF 21% to 35% had low risk (annual event rate 0.7%), whereas those with high-risk LGE distributions and LVEF >35% had significantly higher risk (annual event rate 3%; p = 0.007). ConclusionsIn a large cohort of patients with DCM, LGE was found to be a significant, consistent, and strong predictor of VA or sudden death. Specific high-risk LGE distributions were identified. A new clinical algorithm integrating LGE and LVEF significantly improved the risk stratification for VA and sudden death, with relevant implications for implantable cardioverter-defibrillator allocation.

In-vivo endocardial and epicardial quantitative comparison of multi-wave based non-invasive inverse electrocardiography

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the Dutch Heart Foundation Introduction Non-invasive mapping of ventricular activation using inverse electrocardiography (iECG) in patients with cardiomyopathy during sinus rhythm, may improve risk stratification for sudden cardiac death. However, iECG is complicated by multiple simultaneous endocardial activation waves (multi-wave) mediated by the His-Purkinje system, especially when the QRS complex is narrow. The activation estimation should be based on a realistic physiological model of the His-Purkinje system combining multiple waves initiated at His-Purkinje associated endocardial locations. Equivalent double layer based iECG provides an estimation of both the endocardial and epicardial surface. To improve accuracy, equivalent double layer based iECG was supplemented with electro-anatomical structures associated with the His-Purkinje system to test initial ventricular activation (Figure, Panel C). Multi-wave iECG local activation timing (LAT) maps and invasive LAT maps during sinus rhythm were quantitatively compared. Purpose Quantitative comparison of multi-wave iECG in His-Purkinje mediated cardiac activation using invasive activation maps in patients. Methods Thirteen patients referred for invasive electro-anatomical mapping (EAM) of the endocardial and epicardial surface were included. Prior to EAM, each subject underwent 64 electrode body surface potential mapping, cardiac computed tomography (CT) imaging, and 3D imaging of electrode positions. Anatomical models of the ventricles, lungs and thorax were created using CT images and supplemented with electrode positions (Figure, Panel A-B). Electro-anatomical structures associated with the His-Purkinje system were incorporated in ventricular anatomical models (Figure, Panel C) and multiple simultaneous activation waves were simulated. Invasive endocardial and epicardial LAT maps were quantitatively compared to iECG LAT maps. Invasive EAM LAT maps were quantitatively compared to estimated iECG LAT maps (Figure, Panel D) using inter-map correlation coefficients (CC, Pearson’s) and absolute differences (AD). Results Mean inter-map CC and AD were 0.54 ± 0.19 and 18 ± 7 ms respectively for the epicardial surface (n = 13). Similar to the RV endocardial surface (n = 10, CC = 0.50 ± 0.29, AD = 20 ± 8 ms) and the LV endocardial surface (n = 4, CC = 0.44 ± 0.26, AD = 25 ± 7 ms). Conclusion(s): Quantitative comparison of the multi-wave iECG method showed overall moderate performance. This novel iECG method provides a physiologically more realistic and more robust estimation of sinus rhythm and may serve as a tool for detection of electro-anatomical substrates and risk stratification. Compared to other available non-invasive ECG methods, multi-wave iECG captures His-Purkinje mediated ventricular activation better. This method might also be useful for the accurate detection and localization of structural conduction disorders. Abstract Figure. Multi-Wave inverse electrocardiography