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Background Early repolarization (ER) and acute ST segment elevation myocardial infarction (STEMI) are sharing the pathophysiology of J wave syndromes. It is speculated that early ventricular arrhythmias (VAs) during STEMI may be predisposed by ER. Our aim was to study the association between ER pattern and risk of VAs during acute STEMI. Methods The study included 102 male patients with acute STEMI who were divided into two groups: cases and controls. Cases included 52 patients with sustained VAs during the first 48 hours from the onset of STEMI, while controls included 50 patients with no VAs. On 12-lead surface electrocardiogram, ER was defined as ≥ 1 mm elevation of J point in at least two inferior or lateral leads with or without ST segment elevation. Results Mean age was 48.44 ± 10.08 years and mean left ventricular ejection fraction (LVEF) was 42.25 ± 11.1%. ER pattern was more frequent in cases than controls (29 vs 14 patients, P = 0.008). Notched J wave (P = 0.0007) and horizontal ST segment (P = 0.033) were more frequent in cases than controls. On adjusted regression model, LVEF (OR: 0.95, 95% CI: 0.91–0.99, P = 0.015) and ER (OR: 3.39, 95% CI: 1.41–8.12, P = 0.006) could predict VAs, while QTc interval (P = 0.24) and QTd (P = 0.86) did not have predictive effect. Inferior/inferolateral and global ER pattern (P = 0.044 and 0.031 respectively), notched J wave (P = 0.001), increasing J wave amplitude (P = 0.042), and ST segment elevation (P = 0.001) were associated with a higher risk of VAs. Conclusions ER is associated with increased risk of VAs in the setting of acute STEMI.

In this letter, we evaluate the performance of multicarrier code division multiple access (MC-CDMA) in terms of average bit error probability (BEP) in Nakagami fading channels. The results are applicable to MC-CDMA systems employing coherent demodulation with maximal-ratio combining (MRC) or equal gain combining (EGC) reception. The effects of fading parameters and number of users are presented. The accuracy of the proposed analysis is demonstrated by computer simulations. The BEP performance of the EGC receiver in the uplink is highly influenced by the fading parameter compared with that of the MRC receiver. The EGC receiver outperforms the MRC receiver in the downlink, but the MRC receiver gives almost the same performance as the EGC in the uplink. Copyright © 2004 AEI