Background—QRS-ST changes in the inferior and lateral ECG leads are frequently observed in athletes. Recent studies have suggested a potential arrhythmogenic significance of these findings in the general population. The aim of our study was to investigate whether QRS-ST changes are markers of cardiac arrest (CA) of unexplained cause or sudden death in athletes. Methods and Results—In 21 athlete...

BACKGROUND Ventricular tachycardia (VT) isthmuses can be defined by fixed or functional block. During sinus rhythm, pace mapping near the exit of an isthmus should produce a QRS similar to that of VT. Pace mapping at sites proximal to the exit may produce a similar QRS with a longer stimulus-to-QRS interval (S-QRS). The aim of the study was to determine whether a VT isthmus could be identified ...

On the surface electrocardiogram, an abnormally wide QRS|T angle reflects changes in the regional action potential duration profiles and in the direction of the repolarization sequence, which is thought to increase the risk of ventricular arrhythmia. We investigated the relation between an abnormal QRS|T angle and mortality in a nationally representative sample of subjects without clinically ev...

BACKGROUND There is a controversy regarding the association between QRS width and ventricular arrhythmias (VAs). We hypothesized that predictive value of the QRS width could be improved if QRS width were considered in the context of the sum magnitude of the absolute QRST integral in 3 orthogonal leads sum absolute QRST integral (SAI QRST). We explored correlations between QRS width, SAI QRST, a...

Homocysteine levels in the low to moderate range for cardiovascular risk have been previously associated with left ventricular cardiac hypertrophy (LVH). Electrocardiogram (ECG) derived QRS duration has also been used as an epidemiological screening marker for cardiac hypertrophy risk. QRS duration cut offs have not been previously modeled to assess homocysteine levels in community populations....

Microvolt QRS alternans on the surface ECG, induced with rapid ventricular pacing, has been reported by our group to predict tachycardia (VT) in ischemic cardiomyopathy (ICM). The presence of intracardiac depolarization and its relation VT not defined. To characterize spatial distribution patients ICM, relationship diastolic pathway. Intraoperative mapping was performed 9 ICM VT. Bipolar electr...

In this paper a learning system is presented that is able to learn both the syntax (from an over-generalized grammar) and semantic rules (containing threshold values and relations) of an ECG grammar. These rules are used to direct the classiication of QRS complexes and to distinquish between QRS and non-QRS patterns. The system demonstrates how theory revision method can be used to reene large ...

In patients with latent dual atrioventricular nodal pathways a 2:1 ventriculoatrial block often occurs during ventricular pacing and is generally associated with the concomitant appearance of QRS alternans. This type of QRS alternans is related to retrograde conduction, and a concealed retrograde conduction in the His Purkinje system could explain the QRS alternans. A case that confirms the hyp...

To elucidate the abnormalities in ventricular activation sequence in human left bundle branch block (LBBB), epicardial mapping was performed in five patients, ages 52-58 years, undergoing coronary bypass surgery, and the results were compared with similar data published from patients without conduction defect. Three patients had chronic and two patients intraoperative LBBB. ECGs during LBBB rev...

INTRODUCTION The aim of this study was to evaluate the changes in ventricular complex voltage associated with narrow QRS supraventricular tachycardia (SVT). METHODS AND RESULTS One hundred forty-five patients undergoing catheter ablation for SVT, 85 with AV nodal reentrant tachycardia (AVNRT) and 60 with AV reentrant tachycardia (AVRT) due to a concealed accessory pathway, were studied. Four ...