QRS prolongation as an indicator of risk of ischemia-related ventricular tachycardia and fibrillation induced by exercise

Changes during exercise of ECG intervals related to increased risk for ventricular arrhythmia in repaired tetralogy of Fallot and their relationship to right ventricular size and function

“…Previous papers reported a decrease of QRS duration with exercise in healthy subjects [21][22][23]. In coronary artery disease QRS prolongation during exercise indicated ischemia [22,24], with the largest increase found in patients with documented exercise induced ventricular arrhythmia [25]. These observations have been explained by local exercise induced ischemia with subsequent local conduction delay [25].…”

Exercise Electrocardiogram Testing

“…Modest exercise QRS shortening in normal subjects was found by Michaelides et al 51 The magnitude of change in these studies was small, in the range of 3 ms of shortening in normal subjects and 6 to 8 ms of lengthening in coronary disease patients. Berntsen et al 52 were able to associate more marked exercise-induced QRS prolongation, in the range of 15 ms, with increased risk for subsequent ischemia-related ventricular tachycardia. Computer-based optical scanning for more precise measurement of QRS duration during exercise testing was introduced by Cantor et al 53 and was found to outperform standard ST-segment criteria for identification of disease in women 54,55 and for the detection of post-percutaneous transluminal coronary angioplasty restenosis.…”

QRS prolongation during exercise stress testing: Beyond ST segment depression

“…However the magnitude of change in these studies was small, in the range of 3 ms of shortening in normal subjects and 6 to 8 ms of lengthening in patients with CAD. On the other hand Berntsen and coworkers found more marked exerciseinduced QRS prolongation (in the range of 15 ms) with increased risk for subsequent ischemia-related ventricular tachycardia [6]. Computer-based optical scanning for more precise measurement of QRS duration during exercise testing was found to outperform standard ST-segment criteria for identification of disease in women and for the detection of post-percutaneous transluminal coronary angioplasty restenosis [7][8][9][10].…”