Basic Arrhythmias With 12 Lead EKG's Practice Test

Hyperacute T waves are the earliest ECG sign of myocardial ischemia. When a region of the heart becomes ischemic, rapid changes in how the myocardial cells repolarize cause the T wave to become tall, broad-based, and peaked. These hyperacute T waves often appear within minutes of ischemia and can precede ST-segment elevation that develops as the injury becomes more severe. As ischemia evolves, ST elevation may appear and, later still, T waves can invert. A prolonged QT interval isn’t a typical early marker, and T‑wave inversion usually shows up later in the course.