Objective: This study analyses dynamicchangesin dispersion of ventricularrepolarization over the time course of takotsubo cardiomyopathy (TC), and their relationships with clinical features and life-threatening arrhythmias.
Methods and results: All consecutive patients admitted to our division between January 2008 and December 2011 with a diagnosis of TC were analysed. Patients with prior myocardial infarction, symptoms-onset-to-admission time greater than 12 hours, an implanted pacemaker, or under treatment with drugs affecting QTinterval, were excluded. Standard 12-lead ECG recordings during the acute, subacute and chronic phases were collected for each patient. Twenty-four patients (23 women, 63 +/- 14 years) were includedin our analysis. Only one patient experienced ventricular arrhythmias (4.2%). Significant increases were observed in QT and QTc intervals (from 420 ?423 to 505 +/- 66 ms, P < 0.00001, and from 479 +/- 33 to 551 +/- 51 ms, P < 0.00001, respectively), QTdispersion (from 59 +/- 18 to 100 +/- 44 ms, P=0.0006), Tpeak-to-Tend (from 82 +/- 20 to 123 +/- 39 ms, P=0.00006) and Tpeak-to-Tend/QT (from 0.20 +/- 0.33 to 0.26 +/- 0.57, P=0.0003) during the subacute phase. All these parameters returned to baseline values in the chronic phase and did not show any significant differences between the acute and chronic phases.
Conclusions: A marked increase in QTc, QT dispersion, Tpeak-to-Tend and Tpeak-to-Tend/QT was observed during the subacute phase; this increase was transient and reverted in allpatients before hospital discharge. Ofnote, these findings were not associated with an increased risk of life-threatening arrhythmias.