Erythropoietin Reduces Post-PCI Arrhythmias in Patients With ST-elevation Myocardial Infarction.

BACKGROUND: Arrhythmia is the foremost cause of sudden death after myocardial infarction (MI). Animal models have recently shown that erythropoietin (EPO) can reduce the incidence of arrhythmia after MI. METHODS: We investigated the effects of administrating 33,000 IU EPO on the occurrence of post-MI arrhythmia in 40 patients with ST-elevation MI who were randomly assigned in either EPO or placebo groups. Arrhythmias were blindly documented using full 12-lead configuration during 24 hours after percutaneous coronary intervention (PCI) by a cardiologist. Afterward, CK-MB, hematologic, and hemodynamic data were examined within 2 weeks after MI. RESULTS: A comparison made between the 2 groups showed significant differences in the incidence of arrhythmias (20% in EPO group and 35% in placebo group, P = 0.043). However, no significant differences in type of arrhythmias were observed between the groups. There was no significant difference between levels of CK-MB in the 2 groups during 24 hours (P = 0.186). Hematologic and hemodynamic data showed no significant changes 2 weeks after PCI. CONCLUSION: High-dose administration of EPO in patients with ST-elevation MI who have been treated by primary PCI and standard antiplatelet therapy reduces the occurrence of arrhythmias. For clinical interpretation of the results, further well-designed trials are required.

Electrophysiological characteristics of orthodromic reentrant tachycardia in patients with Wolf-Parkinson-White syndrome and atrial fibrillation.

The aim of this study was to evaluate differences in the electrophysiological features of atrioventricular reentrant tachycardia (AVRT) in patients with Wolf-Parkinson-White syndrome (WPW) associated with or without atrial fibrillation (AF). We included 119 patients with WPW and orthodromic AVRT during electrophysiological study. The patients were divided into two groups; group I with documented episodes of AF (n=39, mean age 33.3+/-11.5 years), and group II without AF (n=80, mean age 35.3+/-13.8). We compared parameters of accessory pathway (AP), atrium and ventricle between two groups and found no significant difference. We next assessed the electrophysiological parameters of AVRT in both groups in terms of conduction times and atrioventricular (AV) activation relations. A significant negative correlation was found in group II between anterograde and retrograde conduction times measured as AV and VA intervals at the site of the earliest atrial activation (r=-0.43, P<0.0001), whereas no significant correlation was seen in group I (r=-0.29, P=0.1). Comparative analysis between two groups revealed significant difference in A-V/V-V index (P=0.05). These data suggest the presence of different electrophysiological properties of AP during AVRT in only few respects in patients with AF compared to those without it.

Evaluation of post-radiofrequency myocardial injury by measuring cardiac troponin I levels.

BACKGROUND: The aim of this study was to investigate the extent of myocardial injury created by radiofrequency (RF) ablation. We assessed the changes in levels of cardiac biochemical markers in patients who underwent RF ablation and we sought to evaluate the utility of cardiac troponin I (cTnI) in detecting minor myocardial injury following RF ablation and determine its procedural correlates. METHODS: We analyzed the data of 115 consecutive patients who underwent RF ablation. The target sites of RF ablation were slow pathway in 56, left atrioventricular (AV) annulus in 31, right AV annulus in 14, atrial wall in 3, ventricular wall in 6 and AV node in 3 patients. The levels of creatine kinase (CK), CK-MB, cTnI and myoglobin were compared with procedural data and targeted arrhythmia. RESULTS: Post-RF ablation the concentration of cTnI, CM-MB, CK and myoglobin were significantly different than those of the initial sample. The mean and peak cTnI levels were raised above normal in 63 patients (54.8%). Mean levels of cTnI correlated with the site of RF ablation, being significant for slow pathway ablation, ventricular tachycardia and left AV annulus. We also found a significant association of mean CK-MB, CK levels and left AV annulus. CONCLUSION: Our results indicate that radiofrequency ablation results in only minor injury. This marker is effective for detection of RF current induced myocardial injury. Lesions applied to the mitral annulus at the ventricular endocardium are associated with significantly greater myocardial damage.