Abstract 19613: Ventricular Repolarization in Transient Apical And Midventricular Ballooning

Abstract

The aim of the present study was to assess potential differences in cardiac repolarization dynamics in patients with transient left ventricular apical ballooning syndrome (AB) and the midventricular variant (MB). Even though repolarization abnormalities and QT interval prolongation in the surface electrocardiogram (ECG) have been consistently reported, repolarization dynamics have not yet been investigated in the AB and MB variants. We hypothesized that differences in regional sympathetic denervation may induce differential effects on cardiac repolarization. METHODS: In a prospective single-center study, 49 consecutive patients with transient left ventricular dysfunction syndrome underwent 3-channel-Holter-ECG-recording on the third day after admission. A total of 27 recordings of patients with AB and 10 recordings of patients with MB were valid for beat-to-beat-QT-interval-analyses. RESULTS: There were no significant differences in baseline clinical characteristics between AB and MB patients. Patients with MB showed significantly lower values for mean RR interval (835 ± 104 vs. 908 ± 118 ms; P<.05). Both, Bazett- and Fridericia-corrected QT-intervals were significantly longer in MB patients (QTcB 441.9 ± 38 vs. 483.4 ± 40ms; P<.05; QTcF 435.0 ± 36 vs.469.4 ± 36.5 ms; P<.05). Parameters of QT-interval variability (QTSD) and QT-interval dynamicity (QT/RR-slope) also exhibited significant differences between groups (diagram). CONCLUSION: There are significant differences in cardiac repolarization between AB and MB syndromes. Patients with MB show more prolonged QT-intervals and a higher degree of heterogeneity of ventricular repolarization. Thus, regional midventricular sympathetic denervation may be associated with even higher arrhythmic risk in transient left ventricular dysfunction syndrome.