Presence of transient ST segment deviations is the most commonly used noninvasive indicator of acute myocardial ischemia. Changes in R- and S-wave amplitudes have been proposed as additional electrocardiographic (ECG) markers of ischemia. These amplitude changes have been primarily described during subendocardial ischemia and ST depressions, but they have also been seen with transmural ischemia and ST elevations. While some investigators have found that the behavior of these QRS wave forms is consistent and a valuable aid in assessing presence of myocardial ischemia and dysfunction,others have reported that these changes are variable and not reliable. Whether the growth or the diminution of the QRS amplitudes is a reflection of myocardial ischemia is, by itself, not totally clear and appears to be dependent on several factors.
The purpose of our investigation was to (1) determine R- and S-wave amplitude changes during acute left anterior descending artery (LAD) occlusion and anterior transmural ischemia, (2) define the relationship between changes in R and S waves and magnitude of ST elevations, and (3) evaluate the relationship between R- and S-wave changes and ST elevations and the changes in pulmonary capillary wedge pressures (PW). Coronary angioplasty served as the model of acute coronary occlusion and transmural ischemia. Viagra Soft Tabs