An Electrophysiologist Perspective on Risk Stratification in Heart Failure: Can Better Understanding of the Condition of the Cardiac Sympathetic Nervous System Help?

Prediction of sudden cardiac death in chronic heart failure patients with reduced ejection fraction by ADMIRE-HF risk score and early repolarization pattern

BACKGROUND

AdreView myocardial imaging for risk evaluation in heart failure (ADMIRE-HF) risk score is a novel risk score to predict serious arrhythmic risk in chronic heart failure patients with reduced ejection fraction (HFrEF). Moreover, early repolarization pattern (ERP) has been shown to be associated with an increased risk of sudden cardiac death (SCD) in HFrEF patients. We sought to investigate the prognostic value of combining ADMIRE-HF risk score and ERP to predict SCD in HFrEF patients.

METHODS

We studied 90 HFrEF outpatients with LVEF< 40% in our prospective cohort study. In cardiac MIBG imaging, the heart-to-mediastinum (H/M) ratio was measured on the delayed planar image. ADMIRE-HF risk score was derived from the sum of the point values of LVEF, H/M ratio, and systolic blood pressure. We also assessed ERP on the standard electrocardiogram.

RESULTS

During a median follow-up of 7.5(4.5-12.0) years, 22 patients had SCD. At multivariate Cox analysis, ADMIRE-HF risk score and ERP were independently associated with SCD. Patients with both intermediate/high ADMIRE-HF score and ERP had a higher SCD risk than those with either and none of them.

CONCLUSION

The combination of ADMIRE-HF risk score and ERP would provide the incremental prognostic information for predicting SCD in HFrEF patients.

In-depth proteomic profiling of left ventricular tissues in human end-stage dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is caused by reduced left ventricular (LV) myocardial function, which is one of the most common causes of heart failure (HF). We performed iTRAQ-coupled 2D-LC-MS/MS to profile the cardiac proteome of LV tissues from healthy controls and patients with end-stage DCM. We identified 4263 proteins, of which 125 were differentially expressed in DCM tissues compared to LV controls. The majority of these were membrane proteins related to cellular junctions and neuronal metabolism. In addition, these proteins were involved in membrane organization, mitochondrial organization, translation, protein transport, and cell death process. Four key proteins involved in the cell death process were also detected by western blotting, indicated that cell death was activated in DCM tissues. Furthermore, S100A1 and eEF2 were enriched in the “cellular assembly and organization” and “cell cycle” networks, respectively. We verified decreases in these two proteins in end-stage DCM LV samples through multiple reaction monitoring (MRM). These observations demonstrate that our understanding of the mechanisms underlying DCM can be deepened through comparison of the proteomes of normal LV tissues with that from end-stage DCM in humans.

Novel Imaging Approaches for Predicting Arrhythmic Risk

Determination of ventricular arrhythmic risk is crucial for guiding management of cardiac disease. Although for patients at increased risk an implantable cardioverter-defibrillator is recommended, it is widely acknowledged that current criteria for device use based predominantly on left ventricular ejection fraction are deficient. Genesis of ventricular arrhythmias involves a complex interaction of myocardial substrate abnormalities, precipitating triggers, and modulating factors. There are much data showing that by more directly assessing these factors, noninvasive imaging using echocardiography, radionuclide imaging, and cardiac magnetic resonance enhances arrhythmic risk stratification beyond ejection fraction and commonly used electrocardiographic and serum biomarkers. It is anticipated that further technological advancements studied in well-designed clinical trials will provide both more precise determination of risk and guide therapies to enhanced survival and patient well-being.