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AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part IV: the ST segment, T and U waves, and the QT interval: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the
| Content Provider | Semantic Scholar |
|---|---|
| Author | Rautaharju, Pentti M. Surawicz, Borys Gettes, Leonard S. Bailey, James J. Childers, Rory Deal, Barbara J. Gorgels, Anton P. M. Hancock, E. William Josephson, Mark Kligfield, Paul Kors, Jan A. Macfarlane, Peter Mason, J. Wright Mirvis, David M. Okin, Peter Pahlm, Olle Herpen, Gerard Van Wagner, Galen S. Wellens, Hein J. J. |
| Copyright Year | 2009 |
| Abstract | T he present article is the fourth in a series of 6 documents focused on providing current guidelines for the standardization and interpretation of the electrocardiogram (ECG). The project was initiated by the Council on Clinical Cardiology of the American Heart Association. The rationale for this project and the process for its implementation were described earlier. 1 Abnormalities in the ST segment, T wave, and duration of the QT interval reflect abnormalities in ventricular repolar-ization. These abnormalities are common and often difficult to interpret. The U wave most likely represents an electric-mechanical phenomenon that occurs after repolarization is completed. However, it is frequently included in discussions of repolarization and is discussed in this section. The ST segment corresponds to the plateau phase of the ventricular transmembrane action potential. Under normal conditions , the transmembrane voltage changes slowly during this phase and remains at approximately the same level in all ventricular myocardial cells. As a result, only small voltage gradients are present. This absence of pronounced voltage gradients is similar to that which occurs during electric diastole, ie, from the end of repolarization to the onset of the next depolarization, when ventricular myocardial cells are at their resting transmembrane potential of approximately Ϫ85 mV. This corresponds to the TP segment on the ECG. The absence of significant voltage gradients in ventricular myocardial cells during these 2 phases of the cardiac cycle explains why the ST and TP segments are normally nearly flat and at approximately the same level; that is, they are isoelectric. The T wave corresponds to the phase of rapid ventricular repolarization (phase 3) of the ventricular action potential. conflicts of interest that may arise as a result of an outside relationship or a personal, professional, or business interest of a member of the writing panel. Specifically, all members of the writing group are required to complete and submit a Disclosure Questionnaire showing all such relationships that might be perceived as real or potential conflicts of interest.or distribution of this document are not permitted without the express permission of the American Heart Association. Instructions for obtaining permission are located at http://www.americanheart.org/presenter.jhtml? identifierϭ4431. A link to the " Permission Request Form " appears on the right side of the page. |
| Starting Page | 385 |
| Ending Page | 408 |
| Page Count | 24 |
| File Format | PDF HTM / HTML |
| DOI | 10.1161/CIRCULATIONAHA.108.191096 |
| Alternate Webpage(s) | http://circ.ahajournals.org/content/circulationaha/119/10/e241.full.pdf?download=true |
| PubMed reference number | 19228821 |
| Alternate Webpage(s) | https://doi.org/10.1161/CIRCULATIONAHA.108.191096 |
| Journal | Medline |
| Volume Number | 119 |
| Issue Number | 10 |
| Journal | Circulation |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
