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Background QRS fragmentation (fQRS) is believed to reflect myocardial scar formation in patients with coronary disease. Whether early formation of fQRS in patients with ST-segment elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI) is correlated with infarct size and prognosis is unknown. We assessed the prognostic value of fQRS at 60 min post-PCI and its correlation with infarct size in patients with anterior STEMI managed with primary PCI. Methods The INFUSE-AMI trial enrolled 452 patients with anterior STEMI undergoing primary PCI. Electrocardiograms (ECGs) were performed at baseline and 60 min post-PCI. Infarct size was evaluated using cardiac magnetic resonance imaging at 30 days post-PCI. Target vessel failure (TVF) was defined as the composite of cardiac death, target vessel myocardial infarction, or ischemia-driven target vessel revascularization. Study groups were defined as patients with versus without fQRS at 60 min post-PCI. Results Out of 421 patients with ECG data 60 min post-PCI, 68 patients (16.2%) had fQRS. Patients with versus without fQRS had similar baseline characteristics and infarct size (16.9% ± 8.7% vs. 16.1% ± 10.5%, p = 0.62), but patients with fQRS had higher adjusted risk of 1-year TVF (adjusted HR 2.27, 95% CI 1.06–4.89, p = 0.036) and a trend toward a higher risk of the composite cardiac death or target vessel myocardial infarction (9.0% vs. 4.1%, p = 0.08) at 1 year. Conclusion fQRS in patients with STEMI is associated with TVF but does not correlate with infarct size. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]