Compression entropy contributes to risk stratification in patients with cardiomyopathy / Kompressionsentropie zur verbesserten Risikostratifizierung bei Patienten mit DCM

Abstract Sudden cardiac death (SCD) is a leading cause of mortality with an incidence of 3 million cases per year worldwide. Therapies for patients who have survived an SCD episode or have a high risk of developing lethal ventricular arrhythmia are well established and depend mainly on risk stratification. In this study we investigated the suitability of the non-linear measure compression entropy (H C) for improved risk prediction in cardiac patients. We recorded 24-h Holter ECG for 300 patients with congestive heart failure (CHF). During a mean follow-up period of 12 months, 32 patients died due to a cardiac event. H C depends on the compression parameters window length w and buffer length b, which were optimised by analysing a subgroup of patients. Compression entropies based on the beat-to-beat interval (BBI) were subsequently calculated and compared with standard heart-rate variability parameters. Statistical analysis revealed significant differences between high- and low-risk CHF patients in standard HRV measures, as well as compression entropy based on the BBI (cardiac death, p=0.005; SCD, p=0.02). In conclusion, the implementation of non-linear compression entropy analysis in multivariate analysis seems to be useful for enhanced risk stratification of cardiac death, especially SCD, in ischaemic cardiomyopathy patients. Der plötzliche Herztod (SCD) ist die Haupttodesursache weltweit (3 Millionen Fälle/Jahr). Moderne Methoden zur Therapie und Prävention des SCD sind abhängig von der Erkennung der Hochrisikopatienten. Das Ziel dieser Studie war die Untersuchung der Eignung des nichtlinearen Parameters der Kompressionsentropie (H C) zur Risikostratifizierung bei ischämischer Herzinsuffizienz (CHF). Von 300 CHF-Patienten wurden 24-h Holter-EKGs im Rahmen einer spanischen Multicenter-Studie (MUSIC) aufgezeichnet. Innerhalb der anschließenden Follow-up-Phase (12 Monate) verstarben 32 Patienten aufgrund eines kardialen Ereignisses (Hochrisikogruppe). Mittels einer Patientenuntergruppe wurden die in die H C-Analyse eingehenden Parameter Fenster- und Bufferlänge optimiert. Zusätzlich zu der Berechnung von H C wurden die Standardparameter der Herzfrequenzvariabilität (HRV) bestimmt. Die statistische Analyse zeigte signifikante Unterschiede zwischen CHF-Patienten mit hohem und niedrigem Risiko in den Standardparametern der HRV (kardialer Tod: p=0,02; SCD: p=0,04) sowie Parametern der H C (kardialer Tod: p=0,005; SCD: p=0,02). Diese Ergebnisse zeigen die prinzipielle Eignung der H C für die Risikoanalyse des kardialen Todes insbesondere des plötzlichen Herztodes bei Patienten mit ischämischer Kardiomyopathie. Durch eine anschließende multivariate Analyse dieses nichtlinearen Parameters soll die Verbesserung der Ergebnisse bezüglich Sensitivität und Spezifität bestätigt werden.

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