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Index of T-wave variation as a pbkp_redictor of sudden cardiac death in chronic heart failure patients with atrial fibrillation

Abstract:

Chronic heart failure (CHF) and atrial fibrillation (AF) are worldwide leading causes of morbidity and mortality in elders, a large part due to sudden cardiac deaths (SCD). The high irregularity of ventricular response in AF patients makes the use of standard SCD-risk markers inappropriate in this target population. The aim of this study was twofold: i) to propose a new index, suitable for AF patients, able to quantify ventricular repolarization changes; and ii) to evaluate its prognostic value in a CHF population with AF. Holter ECG recordings from 176 consecutive CHF patients with AF (22 SCD) were analyzed. The index of T-wave variation (ITV), quantifying the average T-wave changes in pairs of consecutive beats under stable rhythm conditions, was computed using a fully-automatic method. Survival analysis was performed considering SCD as an independent endpoint. ITV was higher for SCD than non-SCD victims (median (Q1;Q3): 24.9 (14.4;85.4) μV vs 17.1 (11.3;28.2) μV, p=0.06). In a survival analysis where the threshold was set on the third quartile of ITV values, ITV (+) outcome was successfully associated to SCD (Hazard Ratio (CI):3.22 (1.36, 7.58)per μV, p=0.008). In conclusion, we show in this work that Ijy stratifies CHF patients with AF according to their risk of SCD, with larger ITV associated to lower survival probability.