Mechanisms and incidence of torsades de pointes tachycardia
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| Year of publication | 2020 |
| Type | Chapter of a book |
| MU Faculty or unit | |
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| Description | Torsades de pointes (TdP) is a specific polymorphic ventricular tachycardia related to specific condition – QT interval prolongation in majority of cases. Mechanisms of TdP initiation and perpetuation are still not fully understood and are discussed in detail in this article. TdP is initiated by early afterdepolarizations (EADs). The L-type Ca current (ICa,L) and the Na–Ca exchange current (INCX) are the major currents with potential to create EADs. Density and activity of these currents are influenced by sex hormones which may thus contribute to sex differences in the susceptibility to triggered activity. Female sex was confirmed as an independent risk factor for TdP. In patients with acquired atrioventricular block females developed TdP at QT intervals shorter than males. Thus, there must be other sex specific factors that increase the risk of arrhythmias. In other words, the effect of sex goes beyond the action potential duration. The incidence of TdP is difficult to estimate due to differences in the methodology of a particular study. Nevetheless, it is clearly higher in women. |