Evaluation of Index of Cardio‐Electrophysiological Balance (iCEB) as a New Biomarker for the Identification of Patients at Increased Arrhythmic Risk. Issue 3 (25th August 2015)

• Record Type: Journal Article
• Authors: Robyns, Tomas; Lu, Hua Rong; Gallacher, David J.; Garweg, Christophe; Ector, Joris; Willems, Rik; Janssens, Stefan; Nuyens, Dieter
• Is Part Of: Annals of noninvasive electrocardiology. Volume 21:Issue 3(2016:May)
• Page Start: 294
• Page End: 304
• Publication Date: 2015-08-25
• Subjects: index of cardio‐electrophysiological balance -- iCEB, risk stratification -- sudden cardiac death -- cardiac wavelength; Electrocardiography -- Periodicals; Arrhythmia -- Periodicals; 616.1207547
• DOI: 10.1111/anec.12309
• Languages: English
• ISSNs: 1082-720X

Abstract

Abstract : Background: Recently a new risk marker for drug‐induced arrhythmias called index of cardio‐electrophysiological balance (iCEB), measured as QT interval divided by QRS duration, was evaluated in an animal model. It was hypothesized that iCEB is equivalent to the cardiac wavelength λ (λ = effective refractory period (ERP) x conduction velocity) and that an increased or decreased value of iCEB would potentially predict an increased susceptibility to TdP or non‐TdP mediated VT/VF, respectively. Methods: First, the correlation between QT interval and ERP was evaluated by invasively measuring ERP during a ventricular stimulation protocol in humans (N = 40). Then the effect of administration of sotalol and flecainide on iCEB was measured in 40 patients with supraventricular tachycardias. Finally iCEB was assessed in carriers of a long QT syndrome (LQTS, N = 70) or Brugada syndrome (BrS, N = 57) mutation and compared them with genotype negative family members (N = 65). Results: The correlation between QT interval and ERP was established (Pearson R 2 = 0.25) which suggests that iCEB≈ERPxCV≈QT/QRS. Sotalol administration increased iCEB (+ 0.23; P = 0.01), while it decreased with the administration of flecainide (–0.21, P = 0.03). In the LQTS group iCEB was increased (5.22 ± 0.93, P < 0.0001) compared to genotype negative family members (4.24 ± 0.5), while it was decreased in the BrS group (3.52 ± 0.43, P < 0.0001). Conclusions: Our data suggest that iCEB (QT/QRS) is a simple but effective ECG surrogate of cardiac wavelength. iCEB is increased in situations that predispose to TdP and is decreased in situations that predispose to non‐TdP mediated VT/VF. Therefore, iCEB might serve as a noninvasive and readily measurable marker to detect increased arrhythmic risk.