159 Pilot Study exploring the regional repolarisation instability index in relation to myocardial heterogeneity and prediction of ventricular arrhythmia and death

W. B. Nicolson, C. D. Steadman, P. Brown, M. Jeilan, S. Yusuf, S. Kundu, A. J. Sandilands, P. J. Stafford, F. S. Schlindwein, G. P. McCann, G. A. Ng
2011 Heart  
Introduction There is a need for better sudden cardiac death (SCD) risk markers. Mounting evidence suggests that the mechanism underlying risk of ventricular arrhythmia (VA) is increased heterogeneity of electrical restitution. We investigated a novel measure of action potential duration (APD) restitution heterogeneity: the Regional Repolarisation Instability Index (R2I2) and correlated it with peri-infarct zone (PIZ) a cardiac magnetic resonance (CMR) anatomic marker of VA risk. Methods
more » ... retrospective study of 30 patients with ischaemic cardiomyopathy assessed for an implantable cardioverter defibrillator. The R2I2 was derived from high resolution 12 lead ECG recorded during programmed electrical stimulation (PES). ECG surrogates were used to plot APD as a function of diastolic interval; the R2I2 was the maximal value of the mean squared residuals of the mean points for anterior, inferior and lateral leads normalised to the mean value for the total population. PIZ was measured from late gadolinium enhanced CMR images using the full width half maximum technique. Results Seven patients reached the endpoint of VA/death (median follow-up 24 months). R2I2 > median was found to be predictive of VA/death independent of PES result, left ventricular ejection fraction and QRS duration (6/14 vs 1/15 p¼0.031). Modest correlation was seen between the R2I2 and PIZ (r¼0.41 p¼0.057) (Abstract 159 figure 1 ).
doi:10.1136/heartjnl-2011-300198.159 fatcat:xhvxdliifvc63hwgru6fjsd5gq