RESUMEN
Objective To evaluate the frequently used electrocardiographic criteria and propose a modified algorithm for differentiating typical atrioventricular node reentrant tachycardia(AVNRT)from atrioventricular reciprocating tachycardia(AVRT).Methods Twelve-lead electrocardiograms(ECGs)during sinus rhythm and atrioventricular node reentrant tachycardia(AVNRT)or atrioventricular reciprocating tachycardia(AVRT)with a narrow QRS complex were obtained from 154 patients who had received successful radiofrequency catheter ablation from Jan.2003 to Nov.2005.The ECGs of initial 104 patients were analyzed by 3 observers without knowledge of the electrophysiological diagnosis.According to these initial results,we proposed a modified stepwise ECG algorithm which used pseudo r′/S/Q waves,RP interval,and ST-segment elevation in lead aVR during tachycardia.Two observers assessed the algorithm in additional 50 patients.Results The algorithm was able to increase the overall accuracy from 77% and 79% with original algorithm to 84% and 87% with the modified algorithm,respectively.The inter-observer concordance was 85%.The intra-observer concordance was 89% in both investigators.Conclusion The modified algorithm can improve the accuracy of differential diagnosis between typical AVNRT and AVRT via concealed accessory pathway.
RESUMEN
Objective To investigate the effect of endovascular brachytherapy with Rhenium-188-filled catheter balloon on cell proliferation,phenotype of smooth muscle cell and secretion of transforming growth factor; to explore the possible mechanism of this method employed in restenosis prevention. Methods After the right common carotid arteries were overstretched by 3.5?20 mm balloon,twenty New Zealand White rabbits were randomized into irradiation (n=10) and control group (n=10). Endovascular bachytherapy was performed wth a 188[KG*2/2]Re filled 3.0?20 mm balloon catheter delivering a dosage of 16 Gy (0.5 mm underneath the luminal surface) in the irradiation group, whereas isovolume normal-sodium-filled balloon catheter was used in the control group for an equal period. After thirty days, analysis of the carotial arteries was made by measns of histological and immunohistochemical staining. Results (1) The positive staining index of proliferation cellular nuclear antigen (PCNA) and transforming growth factor (TGF) of the irradiation group is significantly less than the control group (0.028?0.005 vs 0.054?0.011, 0.033?0.008 vs 0.063?0.014, respectively); (2) The positive staining of ?-actin index in intima has no significant difference between the irradiatin group and the control group. Conclusion (1) The preventive effect on restenosis with endovascular brachytherapy is possibly achieved by suppression of cellular proliferation and transforming growth factor secretion. (2)The phenotype of smooth muscle cell is possibly unaffected by endovascular brachytherapy.