Clinical significance of changes in the corrected QT interval in stress-induced cardiomyopathy

Lee, Jung Hee; Uhm, Jae Sun; Shin, Dong Geum; Joung, Boyoung; Pak, Hui Nam; Ko, Young Guk; Hong, Geu Ru; Lee, Moon Hyoung

Abstract

BACKGROUND/AIMS
Although transient changes in the electrocardiogram (ECG) of patients with stress-induced cardiomyopathy (SCMP) are common, there are little data about ECG changes in patients with SCMP and the clinical implications of these variations.
METHODS
We investigated a total of 128 patients (age, 63.2 ± 15.4 years; female, 60.9%) diagnosed with SCMP. We compared the ECGs taken after SCMP diagnosis and during the recovery phase to those taken before SCMP diagnosis under baseline conditions. All patients were divided into two groups according to corrected QT (QTc) interval changes: recovered QTc group (QTc in SCMP > QTc in recovery phase, n = 77) and nonrecovered QTc group (QTc in SCMP â‰¤ QTc in recovery phase, n = 51).
RESULTS
In comparison of baseline, SCMP, and recovery phase, we found the mean heart rate (81.5 ± 18.7, 96.8 ± 25.3, and 83.0 ± 19.4/min, respectively; p < 0.001), frequencies of ST segment elevation (0.0%, 8.6%, and 1.6%, p = 0.004), ST segment depression (0.0%, 6.3%, and 1.6%, p = 0.007), T wave inversion (4.4 %, 43.8%, and 61.7%, p < 0.001), and QTc (447.4 ± 35.3, 488.9 ± 67.1, and 468.0 ± 49.5, p < 0.001) showed significant changes. In-hospital mortality (9.1% vs. 25.5%, p = 0.012) and critical care (54.5% vs. 72.5%, p = 0.040) occurred more frequently in the nonrecovered QTc group than in recovered QTc group.
CONCLUSIONS
The QTc can be prolonged in patients with SCMP. Short-term mortality was increased in patients where the QTc did not recover.