Stemming back to the days of Einthoven, ECG phenomena of “early ventricular repolarization” were often misinterpreted or dismissed without appropriate clinical consideration or detailed investigation. This ensued because of a prevailing opinion that the nature of these phenomena was largely "benign". Early repolarization changes consistent with Brugada Syndrome (BrS) were interpreted as "innoce...

BACKGROUND Myocardial ischemic electrophysiological alterations are associated with the generation of reactive oxygen species. However, electrophysiological effects of antioxidants are unclear. Our objective was to determine the effects of the antioxidant echinochrome on ventricular repolarization in a feline model of 30-min ischemia. METHODS AND RESULTS Activation-recovery intervals were mea...

BACKGROUND The restitution of the action potential duration (APDR) and conduction velocity (CVR) are mechanisms whereby cardiac excitation and repolarization adapt to changes in heart rate. They modulate the vulnerability to dangerous arrhythmia, but the mechanistic link between restitution and arrhythmogenesis remains only partially understood. METHODS This paper provides an experimental and...

The early rate of action potential (AP) repolarization varies in the mammalian heart regionally, during development, and in disease. We used confocal microscopy to assess the effects of changes in repolarization rate on spatially resolved sarcoplasmic reticulum (SR) Ca release. The kinetics and peak amplitude of Ca transients were reduced, and the amplitude, frequency, and temporal synchronizat...

The early rate of action potential (AP) repolarization varies in the mammalian heart regionally, during development, and in disease. We used confocal microscopy to assess the effects of changes in repolarization rate on spatially resolved sarcoplasmic reticulum (SR) Ca(2+) release. The kinetics and peak amplitude of Ca(2+) transients were reduced, and the amplitude, frequency, and temporal sync...

Knowledge of normal human cardiac excitation stems from isolated heart or intraoperative mapping studies under nonphysiological conditions. Here, we use a noninvasive imaging modality (electrocardiographic imaging) to study normal activation and repolarization in intact unanesthetized healthy adults under complete physiological conditions. Epicardial potentials, electrograms, and isochrones wer...

Transgenic mice have become important experimental models in the investigation of mechanisms causing cardiac arrhythmias because of the ability to create strains with alterations in repolarizing membrane currents. It is important to relate alterations in membrane currents in cells to their phenotypic expression on the electrocardiogram (ECG). The murine ECG, however, has unusual characteristics...

BACKGROUND Early repolarization, indicated on the standard 12-lead ECG, has recently been associated with idiopathic ventricular fibrillation in patients without structural heart disease. It is unknown whether there is an association between early repolarization and ventricular arrhythmias in the coronary artery disease (CAD) population. METHODS AND RESULTS Patients with CAD with implantable ...