Risk Predictor For Sudden Cardiac Death Research Articles

Abstract 17497: Natural History of the Left Ventricular Ejection Fraction in Heart Failure and Sudden Cardiac Death

Background: A clinical diagnosis of heart failure (HF) is associated with increased risk of sudden cardiac death (SCD), but only HF with severely reduced LV ejection fraction (HFrEF, EF ≤35%) is utilized for risk stratification. Guideline-directed medical therapy and heart disease processes may improve or reduce the LVEF. Hypothesis: There is significant variation of LVEF over time among HF patients with SCD. Methods: From a large, prospective population-based study of SCD in the Northwest US (catchment population 1 million, 2002-2018), we identified all consecutive patients with a diagnosis of HF and prior assessment of LVEF. The sub-group of patients with at least 2 prior LVEF evaluations (earliest and latest in relation to SCD) was determined. Results: A total of 1622 individuals suffered SCD with a known diagnosis of HF (65% male, age 72±14) of which 434 had 2 LVEF evaluations at least 1 yr apart prior to their SCD. At earliest evaluation, 100 (23%) had HFrEF (73% male, age 67±13), 88 (20%) had HF with moderately reduced EF (HFmrEF, 35<ef<50) (71% male, age 72±12), and 246 (57%) had hf with preserved ef (hfpef, ef≥50) (57% 72±12). comparing the earliest latest assessment of lvef, mean lvef in hfref increased by 9±14 percentage points (p<0.001) from 27±6 to 36±14; hfmref decreased over time -4±14 (p="0.003)" 43±4 39±14; hfpef -8±13, 62±7 54±14. each subtype changed substantially (mean 2.9±1.5 yrs), sizeable proportions re-classified into different subtypes (Figure). Overall, the HF LVEF subtype was unchanged in 58% and altered in 42% (p<0.001). Conclusions: Based on the LVEF, at least 40% of HF sub-types were re-classified prior to SCD and risk assessment would be variable depending on when LVEF was measured. These findings highlight the limitations of using the LVEF as the only risk predictor of SCD.

PO-646-06 PERIODIC REPOLARIZATION DYNAMICS (PRD) AS A POTENTIAL BIOMARKER TO PREDICT SUDDEN CARDIAC DEATH DURING ACUTE MYOCARDIAL INFARCTION IN A PRECLINICAL PIG MODEL

Ischemic heart failure (IHF) predisposes to arrhythmogenesis and sudden cardiac death (SCD). The ECG-derived biomarker periodic repolarization dynamics (PRD) is linked to sympathetic activity-driven modulations of repolarization and is a risk predictor of SCD in heart failure patients.

Prevalence of sudden cardiac death in dogs with atrial fibrillation.

BackgroundAtrial fibrillation (AF) is associated with increased risk of sudden cardiac death (SCD) in humans, independent of secondary risk factors such as thrombogenic disorders. In dogs, SCD is described in a number of heart diseases, but an association between AF and SCD is unreported.Hypothesis(a) A higher proportion of dogs with AF will experience SCD, and (b) SCD will be associated with complex ventricular arrhythmias.AnimalsOne‐hundred forty‐two dogs with AF, and 127 dogs without AF.MethodsRetrospective, multicenter, case‐control study. Dogs included in the AF group were compared to a control group of dogs in sinus rhythm, matched for echocardiographic diagnosis. Descriptive statistics were used to identify proportions of each group suffering SCD, compared using chi‐squared testing. Risk factors for SCD in dogs with AF were evaluated at the univariable and multivariable level using binary logistic regression. Significance was P < .05.ResultsA significantly higher proportion of dogs with AF suffered SCD than dogs in the control group (14.8% vs 5.5%; P = .01). Younger age at diagnosis, larger left atrial size, and a history of syncope all were independent predictors of SCD in dogs with AF (χ 2, 16.3; P = .04).Conclusions and Clinical ImportanceAtrial fibrillation was associated with a higher prevalence of SCD in dogs. A history of syncope may be a useful predictor of SCD risk.

Prediction of the estimated 5-year risk of sudden cardiac death and syncope or non-sustained ventricular tachycardia in patients with hypertrophic cardiomyopathy using late gadolinium enhancement and extracellular volume CMR.

To evaluate the ability of late gadolinium enhancement (LGE) and mapping cardiac magnetic resonance (CMR) including native T1 and global extracellular volume (ECV) to identify hypertrophic cardiomyopathy (HCM) patients at risk for sudden cardiac death (SCD) and to predict syncope or non-sustained ventricular tachycardia (VT). A 1.5-T CMR was performed in 73 HCM patients and 16 controls. LGE size was quantified using the 3SD, 5SD and full width at half maximum (FWHM) method. T1 and ECV maps were generated by a 3(3)5 modified Look-Locker inversion recovery sequence. Receiver-operating curve analysis evaluated the best parameter to identify patients with increased SCD risk ≥4% and patients with syncope or non-sustained VT. Global ECV was the best predictor of SCD risk with an area under the curve (AUC) of 0.83. LGE size was significantly inferior to global ECV with an AUC of 0.68, 0.70 and 0.70 (all P < 0.05) for 3SD-, 5SD- and FWHM-LGE, respectively. Combined use of the SCD risk score and global ECV significantly improved the diagnostic accuracy to identify HCM patients with syncope or non-sustained VT. Combined use of the SCD risk score and global ECV has the potential to improve HCM patient selection, benefiting most implantable cardioverter defibrillators. • Global ECV identified the best HCM patients with increased SCD risk. • Global ECV performed equally well compared to a SCD risk score. • Combined use of the SCD risk score and global ECV improved test accuracy. • Combined use potentially improves selection of HCM patients for ICD implantation.

Plasma Biomarkers for Prediction of Sudden Cardiac Death

Sudden cardiac death (SCD) accounts for most cardiovascular deaths in the United States, claiming an estimated 300 000 lives per year.1 Despite intense efforts to develop resuscitation techniques, survival rates are still low, at ≈5%.2 This has led to a renewed focus in this field directed toward optimizing risk prediction to identify the candidate that would qualify for prophylactic or preventive interventions.3 At present, the clinical risk stratification is largely limited to the use of left ventricular ejection fraction (LVEF) for identifying primary prophylaxis candidates, but specificity of this predictor is modest.4 Moreover, the absolute numbers of these high-risk patients in the general population are low. Instead, the highest prevalence of SCD is likely observed among previously asymptomatic individuals, even though it is well-known that coronary artery disease (CAD) is present in most SCD cases.5 This underscores the need for the development of risk stratification models that can be applied to the general population where the largest health benefit is likely to be realized. The underpinnings of SCD are complex, and it is reasonable to believe that the risk stratification instrument of the future is likely to involve other components beyond clinical risk markers. Novel genomic variants show promise but are still in early phases of development as risk stratification targets. However, the “unbiased” approaches made possible through genomewide association studies have led to the recent identification of specific genetic variants that could predict SCD.6,7 This has reignited the interest in plasma biomarkers as a means for risk stratification. This article will review the emerging evidence and role of plasma biomarkers in predicting SCD in the general population and suggest a blueprint for future studies of potential utility. ### Uniform Definition of SCD Given the complexity and dynamic nature of the condition, there has been some variability …

Abstract 2852: Cystatin C is an Independent Predictor of Sudden Cardiac Death among Elderly Persons

Background - Cystatin C is a novel measure of kidney function that is superior to estimated glomerular filtration rate in predicting cardiovascular disease. Objective - We evaluated whether kidney function was an independent predictor of sudden cardiac death (SCD) risk. Methods - Subjects were participants in the Cardiovascular Health Study. Measures of kidney function were cystatin C and creatinine-based estimated glomerular filtration rate (eGFR). SCD was defined as a sudden pulseless condition from a cardiac origin in a previously stable individual occurring out of the hospital or in the emergency room. Results - Among the 5157 participants, there were 156 adjudicated SCD events over a median follow-up of 11.2 years. The incidence of SCD events increased across cystatin C quintiles: 0.15% per year in quintile 1, 0.27% per year in quintile 2, 0.32% per year in quintile 3, 0.42% per year in quintile 4, and 0.53% per year in quintile 5. In addition, the rate of SCD events increased as eGFR decreased (0.28% per year among those with eGFR ≥ 60 ml/min/1.73m 2 and 0.49% per year among those with eGFR &lt; 60 ml/min/1.73m 2 . SCD risk increased across cystatin C quintiles after multivariate adjustment with a greater than two fold odds of risk in the highest quintiles compared to the lowest [HR = 1.62, 95% CI (0.86 –3.07) in quintile 2; HR = 1.81, 95% CI (0.96 –3.39) in quintile 3; HR = 2.29, 95% CI (1.24 – 4.22) in quintile 4; HR = 2.28, 95% CI (1.21– 4.30)] in quintile 5]. Low eGFR was predictive of SCD risk in unadjusted analysis [HR = 1.72, 95% CI (1.20 –2.47)] but did not achieve statistical significance after multivariate analysis [1.33, 95% CI (0.91–1.92)]. High cystatin C concentrations remained predictive of SCD risk even among participants without chronic kidney disease after multivariate analysis [HR = 1.84, 95% CI (1.18 –2.86)]. Finally, we noted excess SCD risk occurred in the 1633 participants with prevalent or incident MI or CHF; although, elevated cystatin C concentrations still remained predictive of SCD events in those without prevalent or incident cardiovascular disease (p for interaction = 0.05). Conclusions - Cystatin C is a sensitive measure of kidney function that is an independent predictor of SCD risk among elderly persons.

The novel role of Micro T-Wave alternans in arrhythmic risk stratification of patients with left ventricular dysfunction

According to the recent class I recommendation of ACC/AHA guidelines, all patients with an ischemic and non-ischemic cardiomyopathy, New York Heart Association (NYHA) functional class II­III and left ventricular ejection fraction (LVEF) ≤ 30% could benefit from implantable cardioverter defibrillator (ICD) therapy for primary prevention of sudden cardiac death (SCD). Nevertheless, trials have highlighted a small absolute reduction in annual mortality from ICD therapy in this population. Moreover, costs of these devices would be excessive for medical care. For these reasons, it is nowadays mandatory to further identify in this big population a low arrhythmic risk subgroup of patients who is unlikely to benefit from ICD placement. On the other hand, by focusing only on LVEF ≤ 30% as risk predictor for SCD, there is the danger of missing a significant number of patients with LVEF beyond this value that might benefit from ICD therapy. In the last few years, several clinical studies have demonstrated that micro T-wave alternans (MTWA), a new stratifier for arrhythmic risk, is an effective tool to identify patients with LVEF ≤ 30% who are at low risk of SCD, and who are unlikely to require ICD therapy. Moreover, recent data have confirmed that MTWA is a promising stratifier for malignant arrhythmias in patients with LVEF ranging from 30 to 40%, so that this new non-invasive test could be useful also in this “borderline” population to identify high risk patients not meeting ICD eligibility criteria of current guidelines.