Takotsubo cardiomyopathy and QT interval prolongation: who are the patients at risk for torsades de pointes?

Objectives: QT interval prolongation is prevalent among patients with Takotsubo cardiomyopathy (TC), whereas torsades de pointes (TdP) has rarely been reported in these patients. We studied all peer-reviewed reports oil TC-associated QT interval prolongation and all peer-reviewed reports on TC-associated UP to characterize the clinical circumstances leading to UP in patients with TC. Methods: The literature search yielded 14 reports oil TC-associated UP and 26 reports on TC-associated QT interval prolongation. Overall, 15 patients with TC-associated UP and 86 patients with TC-associated QT interval prolongation were reported. We systematically reviewed each report and recorded the risk factors for UP as well as the clinical circumstances of TC. Results: The prevalence of the male sex was higher among patients with TC-associated UP relative to patients with TC-associated QT interval prolongation (26.7% vs 5.8%; P = .01). There was a trend in the mean rnaximal corrected QT interval being longer among patients with TC-associated TdP relative to patients with TC-associated QT interval prolongation (679.9 +/- 230.6 vs 555.9 +/- 63.8 milliseconds; P = .06). There were no differences between patients with TC-associated UP and patients with TC-associated QT interval prolongation in mean age, maximal troponin levels, and lowest ejection fraction. Overall, 12 (80.0%) patients with TC-associated UP had risk factors for UP other than the female sex and systolic dysfunction, including suspicion of congenital long QT syndrome, bradycardia, hypokalemia, recent conversion from atrial fibrillation to sinus rhythm, and using QT prolonging agents. Conclusions: Men with TC-associated QT interval prolongation are at risk for TdP. Most patients with TC-associated UP have risk factors for UP other than the female sex and systolic dysfunction. (c) 2009 Elsevier Inc. All rights reserved.