Is abnormal myocardial repolarization associated with the occurrence of malignant tachyarrhythmias in Takotsubo cardiomyopathy?

BACKGROUND: Abnormalities of cardiac repolarization are a hallmark of Takotsubo cardiomyopathy (TC), but their association with the occurrence of syncope and ventricular tachyarrhythmias is unknown. This study sought to assess the relationship between myocardial repolarization and malignant tachyarrhythmias in TC.

METHODS: Clinical data and electrocardiographic repolarization parameters of 28 patients with TC and ventricular tachyarrhythmias (n = 26) or syncope (n = 2) were compared to data from 20 randomly selected patients with TC but without ventricular tachyarrhythmias or syncope.

RESULTS: Study patients had significantly lower ejection fraction (EF) compared with controls (35 ± 14% vs. 46 ± 10%, p = 0.006). On day 1, no significant differences in repolarization parameters were observed. However, in the subgroup with ventricular fi brillation ([VF]; n = 10), Tpeak-Tend in lead V6 was significantly prolonged (97 ± 20 vs. 85 ± 19 ms; p = 0.04). Similarly, in the subgroup with torsade de pointes ([TdP]; n = 5) Tpeak-Tend in lead V4 was prolonged (127 ± 21 vs. 94 ± 27 ms; p = 0.001). On day 3, Tpeak-Tend in lead V3 (130 ± 51 vs. 105 ± 21 ms, p = 0.049) and Tpeak-Tend dispersion (56 ± 33 vs. 36 ± 21 ms; p = 0.03) were significantly longer in study patients. The difference in Tpeak-Tend in lead V3 was borderline in the VF subgroup, but significant in the subgroup with TdP. The latter group had also longer Tpeak-Tend in lead V4 and longer corrected QT interval in leads V3 and V4.

CONCLUSIONS: Patients with TC who experience malignant tachyarrhythmias have lower EF and a more pronounced alteration of the spatial dispersion of ventricular repolarization.