Abstract
Background
There seems to be a significant arrhythmia burden in β-thalassemia major (TM) patients
without overt cardiomyopathy. Apart from conventional electrocardiographic (ECG) and
arrhythmic risk markers we studied novel markers of ventricular repolarization and
autonomic imbalance both at rest and after exercise testing.
Methods
We studied 47 adult TM patients without systolic heart failure and 47 age and sex-matched
healthy control subjects. The median age of the studied population was 36 [32–43]
years, 57% men. Baseline demographic and clinical characteristics were recorded while
12-lead electrocardiograms, 24-hour ECG Holter recordings, and treadmill exercise
stress tests were analyzed.
Results
TM patients exhibited increased QTc intervals in both 12-lead ECG recordings and in
24-hour Holter recordings. In addition, they had increased indexes of ventricular
repolarization heterogeneity such as QT dispersion, and T peak-to-end/QT ratios. Furthermore,
TM patients had decreased indexes of heart rate variability while the heart rate recovery
after exercise was significantly attenuated compared to controls. Also, they had increased
P wave and QRS duration while the QRS fragmentation was very prevalent. Finally, premature
atrial extrasystoles and paroxysmal atrial fibrillation episodes were more frequent
in TM patients.
Conclusions
TM patients with preserved left ventricular systolic function have several ECG abnormalities
including alterations in ventricular depolarization and repolarization. Also, cardiac
autonomic dysfunction is evident in 24-hour ECG monitoring as well as in the recovery
phase after exercise testing. The prognostic value of specific arrhythmic risk indexes
in this setting remains to be elucidated.
Keywords
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Article info
Publication history
Published online: July 04, 2016
Accepted:
July 4,
2016
Received:
May 4,
2016
Footnotes
☆This work presented in the Abstract form in the Europace-Cardiostim congress, Milano, Italy, June 2015.
Identification
Copyright
© 2016 Elsevier Ireland Ltd. All rights reserved.
