Intracardiac J-point elevation before the onset of polymorphic ventricular tachycardia and ventricular fibrillation in patients with an implantable cardioverter-defibrillator

Abstract

Background The clinical importance of the J-point elevation on ECG is controversial. Objective Study intracardiac J-point amplitude before ventricular arrhythmia. Methods Baseline 12-lead ECGs and far-field (FF) right ventricular (RV) intracardiac ICD electrograms (EGMs) were recorded at rest in 494 patients [mean age 60.4±13.1; 360 (72.9%) men] with structural heart disease [278 (56.3%) ischemic cardiomyopathy] who received primary [463 (93.9%) patients] or secondary prevention ICD. Ten-second intracardiac FF EGMs before the onset of arrhythmia were compared with the baseline. The J-point amplitude was measured on the baseline 12-lead surface ECG and the intracardiac FF EGM. The relative J-point amplitude was calculated as the ratio of J-point amplitude to peak-to-peak R-wave. Results The paired t-test showed that the relative intracardiac J-point amplitude was significantly higher before polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) onset (0.28±0.08 vs. −0.19±0.39; p=0.012) than at baseline. In a mixed-effects logistic regression model, adjusted for multiple episodes per patient, each 10% increase in relative J-point amplitude increased the odds of having VT/VF by 13% [OR 1.13 (95% CI 1.07–1.19); P<0.0001] and increased the odds of having PVT/VF by 27% [OR 1.27 (95% CI 1.11–1.46); P=0.001]. Conclusion The relative intracardiac J-point amplitude is augmented immediately before the onset of PVT/VF in patients with structural heart disease.

A Novel Method to Capture the Onset of Dynamic Electrocardiographic Ischemic Changes and its Implications to Arrhythmia Susceptibility

“…Recent clinical studies investigating the predictive role of intracardiac electrograms to detect life‐threatening ventricular arrhythmias or flow‐limiting coronary obstruction have successfully demonstrated that intracardiac ST‐segment monitoring can predict arrhythmic events. Specifically, Fischell et al reported early detection of the presence of acute MI in patients at high risk for acute coronary syndromes.…”

“…ST‐segment changes have been well established as strong predictors of acute MI and VTEs . Also, several studies have reported changes in the depolarization phase following acute MI, in both animals and humans …”

“…ST-segment changes have been well established as strong predictors of acute MI 1,3-5 and VTEs. 25 Also, several studies have reported changes in the depolarization phase following acute MI, in both animals 26,27 and humans. 28,29 We devised an index that reflects MI-induced changes of both ventricular depolarization and repolarization on a beat-tobeat basis.…”

Racial differences in sudden cardiac death

“…Both J-waves and J-point elevation (JPE) with a notch or slur have been associated with an increased risk of ventricular fibrillation and polymorphic ventricular tachycardia in several studies (23-25). At the same time, J-point elevation known as benign early repolarization, is a common finding in healthy young people and is particularly prevalent in patients of African descent.…”

Construction of intracardiac vectorcardiogram from implantable cardioverter-defibrillator intracardiac electrograms

“…Analysis of intracardiac electrograms (EGMs) is a vital part of ICD function [1-4]. Vectorcardiogram (VCG) characterizes movement of the heart vector over the cardiac cycle and was proven to be more informative than projection of the heart vector on a limited number of leads axes.…”