P440Nonlinear dynamics of cardiac repolarization add unique prognostic value to cardiac MRI of myocardial scar for prediction of appropriate shock and cardiac death in primary prevention ICD recipients
Year: 2018
Type: conference-abstract
Abstract: On behalf of: Critical Health Assessment & Outcomes Study/Score (CHAOS) Funding Acknowledgements: NIH NHLBI R00 HL 130662 Introduction: Appropriate selection of patients for ICD implantation remains a major clinical and public health challenge. Cardiac MRI (cMRI) with late gadolinium enhancement (LGE) is the in vivo gold standard for quantifying myocardial scar. Independent of ejection fraction (EF) and other risk factors, cMRI characterization of left ventricular (LV) scar predicts adverse events in primary prevention ICD recipients. Similarly, nonlinear characteristics of cardiac repolarization [i.e., EntropyX(QT)] predict potentially lethal ventricular tachyarrhythmias (VT/VF) and all-cause mortality. Because cMRI characteristics and EntropyX(QT) are distinct measures, we hypothesized that EntropyX(QT) adds unique prognostic value to cMRI for VT/VF and mortality. Methods: In 220 consecutive patients with heart failure (HF) in normal sinus rhythm and receiving optimal medical therapy at baseline (time of ICD implantation), we quantified the amount of heterogeneous myocardial tissue (gray zone), dense core, and total scar on cMRI with LGE, and EntropyX(QT) from 5-min ECGs. The primary endpoint was appropriate ICD shock or cardiac deaths not prevented by ICD. Results: Over 4.4±2.8 years, 68 patients experienced appropriate ICD shocks (N=46) or died (N=22). In multivariate analysis, adjusted hazard ratios comparing the third to the first tertile of EntropyX(QT) and cMRI characteristics were 2.9 (95% CI 1.5-5.7) and 2.0 (1.0-3.7), respectively, regardless of the absence or presence of other risk factors. Addition of EntropyX(QT) to a model comprised of LVEF and cMRI characteristics improved the ROC curve area from 63% (51-70) to 70% (61-77) and continuous net reclassification by 54% (19-80). Similar improvements in prognostic discrimination were noted when EntropyX(QT) was added to conventional risk predictors. Conclusions: EntropyX(QT) is a novel, inexpensive and readily available measure, which expands on the simpler concepts of cardiac repolarization variability and provides unique prognostic insight. EntropyX(QT) complements cMRI characteristics by independently predicting VT/VF and mortality in primary prevention ICD recipients. This robust and non-invasive personalized approach for risk stratification based on EntropyX(QT) may be used to better identify those who would and would not benefit from ICD implantation. This novel approach for identifying individuals at higher mortality risk has potential for broader clinical application, e.g., in those classified as low risk based on conventional risk predictors.
Source: EP Europace
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2792419270