Repolarization Heterogeneity and @entity944 Risk. INTRODUCTION: The aim of this study was to investigate whether the characteristics of endocardial ventricular repolarization are associated with differential risk for @entity944 . Prolonged surface QT interval is associated with increased arrhythmic risk after @entity583 ( @entity583 ), but the underlying mechanism of @entity1162 and its relation to lethal @entity943 are unclear. METHODS AND RESULTS: @entity2224 ( @entity2224 ) risk was assessed in 12 @entity235 1 month after anterior @entity583 during an exercise test coupled with brief circumflex @entity1563 . Susceptible @entity235 (n = 5) developed @entity2224 during the brief ischemic episode, whereas resistant @entity235 did not (n = 7). Surface QT interval was measured at rest. Endocardial electroanatomic catheter maps of left ventricular repolarization were obtained in four unique regions identified by echocardiography and compared between groups. Compared to resistant @entity235 , susceptible @entity235 were characterized by prolonged surface QT intervals (240 +/- 10 msec vs 222 +/- 7 msec, P = 0.04). In addition, they had lower baroreflex sensitivity (9.7 +/- 1.5 msec/mmHg vs 28 +/- 9.8 msec/mmHg, P < 0.01) and a tachycardic response to acute @entity63 suggesting higher propensity for stronger sympathetic reflexes. Surface @entity1162 in susceptible @entity235 was due to a marked heterogeneity of endocardial left ventricular repolarization (239 +/- 42 msec, basal anterior wall vs 197 +/- 35, lateral wall; P < 0.001). Resistant animals had no regional differences in endocardial repolarization. CONCLUSION: Sympathetic activation following @entity583 not only produces adverse structural remodeling but also contributes to adverse electrophysiologic remodeling resulting in heterogeneous ventricular repolarization and in a myocardial substrate conducive to lethal reentrant @entity943 .

Heterogeneous regional endocardial repolarization is associated with increased risk for XXXX -dependent @entity2224 after @entity583 .

@entity1162 :: ('MESH:D008133', 'Disease') :: ['QT prolongation', 'QT interval prolongation'] @entity944 :: ('MESH:D003645', 'Disease') :: ['sudden death', 'Sudden Death'] @entity235 :: ('9615', 'Species') :: ['dogs'] @entity1563 :: ('MESH:D054059', 'Disease') :: ['coronary occlusion'] @entity63 :: ('MESH:D007511', 'Disease') :: ['ischemia'] @entity2224 :: ('MESH:D014693', 'Disease') :: ['VF', 'Ventricular fibrillation'] @entity583 :: ('MESH:D009203', 'Disease') :: ['myocardial infarction', 'MI'] @entity943 :: ('MESH:D001145', 'Disease') :: ['arrhythmias']
@entity63 :: (MESH:D007511,Disease) :: ['ischemia']
