The QT prolongation and clinical features in patients with takotsubo cardiomyopathy: Experiences of two tertiary cardiovascular centers

Abstract

Objective: There are few data regarding clinical characteristics, laboratory parameters, electrocardiographic and echocardiographic findings in takotsubo cardiomyopathy patients presenting with QT prolongation. Aim of this study was to investigate the differences in these parameters between takotsubo cardiomyopathy patients presenting with and those without QT prolongation.

Methods: We performed an observational retrospective study. One hundred five patients were enrolled from the takotsubo cardiomyopathy registry database and divided according to the presence of QT prolongation. Fifty patients presented with QT prolongation (QT group) and 55 did not (NQT group). Statistical analysis was performed using Student's t-test or Mann-Whitney U test and chi-square test.

Results: QT group had higher prevalence of dyspnea (66 versus 40%, p=0.008) and cardiogenic shock (46 versus 24%, p=0.016) than NQT group. QT group had higher prevalence of ST elevation (82 versus 64%, p=0.036), T wave inversion (96 versus 58%, p=0.001), ventricular tachycardia/ventricular fibrillation (8 versus 0%, p=0.032) and classic ballooning pattern (92 versus 66%, p=0.003), but lower left ventricular ejection fraction (mean, 39.2 versus 43.5%, p=0.005). In addition, QT group had significant higher hs-C-reactive protein (median, 6.6 versus 1.7 mg/L, p=0.023), creatine kinase-MB (median, 18.6 versus 7.6 ng/mL, p=0.032) and NT-pro-brain natriuretic peptide levels (median, 3637 versus 2145 pg/mL, p=0.044). QT group required more frequent use of inotropics (46 versus 24%, p=0.016) and diuretics (58 versus 38%, p=0.042) than NQT group.

Conclusion: The clinical features of takotsubo cardiomyopathy are different according to the presence of QT prolongation. The QT group was lesser likely to have preserved cardiovascular reserve and more likely to require hemodynamic support than the NQT group despite the entire prognosis of takotsubo cardiomyopathy is excellent regardless of QT prolongation.