Combining noninvasive risk stratification parameters improves the prediction of mortality and appropriate ICD shocks

Abstract

Background: Sudden cardiac death (SCD) results from a complex interplay of abnormalities in autonomic function, myocardial substrate and vulnerability. We studied whether a combination of noninvasive risk stratification tests reflecting these key players could improve risk stratification. Methods:Patients implanted with an ICD in whom 24-hr holter recordings were available prior to implant were included. QRS fragmentation (fQRS) was selected as measure of myocardial substrate and a high ventricular premature beat count (VPB >10/hr) for arrhythmic vulnerability. From receiver operating characteristics analysis, detrended fluctuation analysis (DFA), turbulence slope, and deceleration capacity were selected for autonomic function. Adjusted Cox regression analysis with comparison of C-statistics was performed to predict first appropriate shock (AS) and total mortality. Results:A total of 220 patients were included in the analysis with an overall followup of 4.3 ± 3.1 years. A model including VPB >10/hr, inferior fQRS, and abnormal nonedited DFA was the best for prediction of AS after 1 year of follow-up with a trends toward improvement of the C-statistics compared to baseline (p = 0.055). The risk increased significantly with every abnormal test (HR 1.793, 95%CI 1.255-2.564).A model including fQRS in any region and abnormal edited DFA was the best for prediction of mortality after 3 years of follow-up with significant improvement of the C-statistics (p = 0.023). Each abnormal test was associated with a significant increase in mortality (HR 5.069, 95%CI 1.978-12.994). Conclusion:Combining noninvasive risk stratification tests according to their physiological background can improve the risk prediction of SCD and mortality. K E Y W O R D Sheart rate variability, implantable cardioverter-defibrillator, sudden cardiac death

Ventricular Arrhythmias in Ischemic Cardiomyopathy—New Avenues for Mechanism-Guided Treatment

“…A potential Holter-based parameter is beat-to-beat variability of repolarisation that shows promise of translation to ICD monitoring [33][34][35]. Repolarisation parameters derived from standard 12-lead electrocardiogram (ECG) analysis include QT-interval and its dispersion, T-peak to T-end and microvolt T-wave alternans, which may reflect the dynamic substrate for arrhythmias as well as depolarisation, and parameters such as QRS duration and QRS fragmentation that reflect conduction abnormalities [36,37]. These new parameters still need to be assessed comprehensively before recommendation to clinical practice [38].…”

Repeating noninvasive risk stratification improves prediction of outcome in ICD patients

“…If it is noticed before replacement however, we would currently still consider the patient for replacement despite their improved prognosis because other studies showed that the incidence of appropriate shocks, hence the arrhythmic risk, remains clinically important (Schliamser et al, 2013;Vandenberk et al, 2017;Zhang et al, 2015 We believe our results show promise for developing a practical algorithm of repeated risk stratification to guide the decision on when and whether or not a patient should receive a first ICD implantation or ICD replacement. Combining noninvasive risk stratification tests according to their physiological background and their predictive value, based on optimal sensitivity and/or specificity can improve the risk prediction of SCD and mortality (Exner et al, 2007;Vandenberk et al, 2019). Of course, this should be tested in a prospective trial comparing it with current guidelines and determine whether it could expand ICD indications beyond LVEF or minimize implants in patients with a high nonarrhythmic mortality risk and low arrhythmic risk.…”