Dynamic changes of repolarization abnormalities in takotsubo cardiomyopathy

Abstract

Objective This study analyses dynamic changes in dispersion of ventricular repolarization 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 aff ecting QT interval, were excluded. Standard 12-lead ECG recordings during the acute, subacute and chronic phases were collected for each patient. Twentyfour patients (23 women, 63 ± 14 years) were included in our analysis. Only one patient experienced ventricular arrhythmias (4.2%). Signifi cant 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), QT dispersion (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 signifi cant diff erences 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 all patients before hospital discharge. Of note, these fi ndings were not associated with an increased risk of life-threatening arrhythmias.

Key Words:

• QT dispersion
• TpTe
• repolarization abnormalities
• dispersion of ventricular repolarization
• takotsubo cardiomyopathy
• ventricular arrhythmias