Ventricular tachyarrhythmias and sudden cardiac death in light‐chain amyloidosis: a clash of cardio‐toxicities?

Abstract Background Prediction of sudden cardiac death in heart failure (HF) remains suboptimal. Blood levels of the S100A8/A9 heterodimer protein complex and the soluble receptor of advanced glucation end product (sRAGE) are promising biomarkers in HF, reflecting inflammatory/fibrotic and apoptotic pathways, possibly involved in ventricular arrhythmogenesis. The relation of S100A8/A9 and sRAGE with ventricular arrhythmias and sudden cardiac death risk has not been previously assessed. Purpose Purpose of the study was to investigate whether S100A8/A9 and sRAGE serum blood levels of patients (pts) with systolic heart failure are related to the occurrence of life-threatening ventricular tachyarrhythmias. Patients and methods We studied 60 pts with clinically stable heart failure due to coronary artery disease (n=37) and dilated cardiomyopathy (n=23), all with a chronically implanted ICD for primary (n=43) or secondary (n=16) sudden death prevention, all in sinus rhythm. Their mean age (±1 SE) was 62±2 years, NYHA class I-II, mean LVEF 28±1%, Nt-pro-BNP 893±85 pg/dl. Blood was drawn at study initiation for S100A8/A9 and sRAGE assessment (ELISA, R&D Systems). They all were systematically followed-up for 4 years regarding the occurrence of fast ventricular tachyarrhythmias (>180 bpm) necessitating antiarrhythmic intervention through the ICD. Results S100A8/A9 and sRAGE levels were 16±1.6 ng/ml and 1076±99 pg/ml respectively. S100A8/A9 levels were lower than in normal controls, while sRAGE levels were within normal limits. During the 4-year follow-up period, 39 pts had an uneventful course (Group I), while 16 pts exhibited fast ventricular tachyarrhythmic episodes necessitating ICD activation (anti-tachycardia pacing or shock, Group II). Three pts died of pump failure and 2 pts of non-cardiac causes. No differences were observed between Group I and Group II pts regarding mean NYHA class, Nt-pro-BNP levels. Group II patients had significantly lower LVEF as well as S100A8/A9 serum levels relative to pts without ventricular arrhythmias (LVEF: 30±1.2 vs, 25±1.3%, p<0.05, S1OOA8/A9: 18.9±2.2 vs 11.8±1.5 ng/ml, p<0.05), while no difference was observed between Groups regarding sRAGE levels 1097±101 1105±239 pg/ml, p:NS). S100A8/A9 levels were not related significantly to LVEF (r:-21, p=0.13). Conclusion S100A8/A9 protein levels are reduced in pts with stable HF and an implanted ICD. They are even lower among pts with rapid ventricular tachyarrhythmias occurring during follow-up. This finding implies that S100A8/A9 may constitute a biomarker of increased sudden cardiac death risk in HF, in addition to reduced LVEF.

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Pathophysiology and Risk Stratification of Sudden Cardiac Death in Ischemic Heart Disease

Internal Medicine Review ◽

10.18103/imr.v6i5.892 ◽

2020 ◽

Vol 6 (5) ◽

Author(s):

Nabil El-Sherif ◽

Mohamed Boutjdir ◽

Gioia Turitto

Keyword(s):

Heart Disease ◽

Sudden Cardiac Death ◽

Ejection Fraction ◽

Risk Stratification ◽

Ischemic Heart Disease ◽

Cardiac Death ◽

Implantable Defibrillator ◽

Left Ventricular ◽

Ventricular Tachyarrhythmias ◽

Arrhythmic Death

Sudden cardiac death accounts for approximately 360,000 annually in the United States and is the cause of half of all cardiovascular deaths. Ischemic heart disease is the major cause of death in the general adult population. Sudden cardiac death can be due to arrhythmic or non-arrhythmic cardiac causes, for example, myocardial rupture. Arrhythmic sudden cardiac death may be caused by ventricular tachyarrhythmia (ventricular tachycardia/ventricular fibrillation) or pulseless electrical activity/asystole. The majority of research in risk stratification centers on ventricular tachyarrhythmias simply because of the availability of a successful management strategy, the implantable cardioverter/ defibrillator. Currently the main criterion of primary defibrillator prophylaxis is the presence of organic heart disease and depressed left ventricular systolic function assessed as left ventricular ejection fraction. However, only one third of eligible patients benefit from the implantable defibrillator, resulting in significant redundancy in the use of the device. The cost to the health care system of sustaining this approach is substantial. Further, the current low implantation rate among eligible population probably reflects a perceived low benefit-to-cost ratio of the device. Therefore, attempts to optimize the selection process for primary implantable defibrillator prophylaxis are paramount. The present report will review the most recent pathophysiology and risk stratification strategies for sudden cardiac death beyond the single criterion of depressed ejection fraction. Emphasis will be placed on electrophysiological surrogates of conduction disorder, dispersion of repolarization, and autonomic imbalance, which represent our current understanding of the electrophysiological mechanisms that underlie the initiation of ventricular tachyarrhythmias. Further, factors that modify arrhythmic death, including noninvasive risk variables, biomarkers, and genomics will be addressed. These factors may have great utility in predicting sudden cardiac arrhythmic death in the general public.

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