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Title: A novel surface electrocardiogram-based marker of ventricular arrhythmia risk in patients with ischemic cardiomyopathy.
Authors: Nicolson, William B.
McCann, Gerry P.
Brown, Peter D.
Sandilands, Alastair J.
Stafford, Peter J.
Schlindwein, Fernando Soares
Samani, Nilesh J.
Ng, G. André
First Published: 27-Jun-2012
Publisher: Wiley-Blackwell on behalf of the American Heart Association
Citation: Journal of the American Heart Association, 2012, 1 (4), e001552
Abstract: Background: Better sudden cardiac death risk markers are needed in ischemic cardiomyopathy (ICM). Increased heterogeneity of electrical restitution is an important mechanism underlying the risk of ventricular arrhythmia (VA). Our aim was to develop and test a novel quantitative surface electrocardiogram–based measure of VA risk in patients with ICM: the Regional Restitution Instability Index (R2I2). Methods and Results: R2I2, the mean of the standard deviation of residuals from the mean gradient for each ECG lead at a range of diastolic intervals, was measured retrospectively from high-resolution 12-lead ECGs recorded during an electrophysiology study. Patient groups were as follows: Study group, 26 patients with ICM being assessed for implantable defibrillator; Control group, 29 patients with supraventricular tachycardia undergoing electrophysiology study; and Replication group, 40 further patients with ICM. R2I2 was significantly higher in the Study patients than in Controls (mean ± standard error of the mean: 1.09±0.06 versus 0.63±0.04, P<0.001). Over a median follow-up period of 23 months, 6 of 26 Study group patients had VA or death. R2I2 predicted VA or death independently of demographic factors, electrophysiology study result, left ventricular ejection fraction, or QRS duration (Cox model, P=0.029). R2I2 correlated with peri-infarct zone as assessed by cardiac magnetic resonance imaging (r=0.51, P=0.024). The findings were replicated in the Replication group: R2I2 was significantly higher in 11 of 40 Replication patients experiencing VA (1.18±0.10 versus 0.92±0.05, P=0.019). In combined analysis of ICM cohorts, R2I2 ≥1.03 identified subjects with significantly higher risk of VA or death (43%) compared with R2I2 <1.03 (11%) (P=0.004). Conclusions: In this pilot study, we have developed a novel VA risk marker, R2I2, and have shown that it correlated with a structural measure of arrhythmic risk and predicted risk of VA or death in patients with ICM. R2I2 may improve risk stratification and merits further evaluation.
DOI Link: 10.1161/JAHA.112.001552
ISSN: 2047-9980
eISSN: 2047-9980
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright 2012: The American Heart Association, Inc. The copyright in each Contribution published in the Journal of the American Heart Association shall be in the name of the author(s) or other owner of copyright as appropriate. Compilation and layout copyright American Heart Association, Inc., published on behalf of the American Heart Association, Inc., by Wiley‐Blackwell. Deposited with reference to the publisher's Open Access Agreement. This paper is Open Access under the terms of the Creative Commons Attribution Non‐Commercial License ( licenses/by‐nc/3.0/) which permits use, distribution, and reproduction in any medium, provided that the Contribution is properly cited and is not used for commercial purposes.
Appears in Collections:Published Articles, Dept. of Engineering

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