Objective To study the role of ventricular responses(VR) in radiofrequency catheter ablation (RFCA) of idiopathic ventricular tachycardia(VT).Methods Thirteen patients underwent RFCA by using a combination of surface ECG,activition mapping and VR.The ablation targets were primarily selected by activition mapping and was determined by the VR in RFCA,and then,the final ablation target was determined and ablated where VR and VT had the same ECG results.Results Thirteen patients were successfully ablated.The VRs showed:the VR induced by RFCA in sinus rhythm was just the same as VT;intermittent sinus rhythm appeared between VT;two couple or couplets,or premature beats appeared intermittently in sinus rhythm,and finally sinus rhythm appeared;the VR induced by RFCA was not the same as VT.Conclusion The ablation target should be the site where the VR induced by RFCA is just the same as VT;the occurence of VR that is just the same as VT can be the predictor of successful ablation.

OBJECTIVETo evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers.

METHODSIn a randomized, double-blind, placebo-controlled trial, a total of 216 patients with atrophic gastritis were randomly assigned to one of the four groups: (1) folate (FA, 20 mg per day plus vitamin B(12) 1 mg, intramuscularly, per month for one year, then 20 mg two times a week plus 1 mg per three months for the next year); (2) natural beta-carotene (N-betaC, 30 mg per day for first year, then 30 mg two times a week for the next); (3) synthetic beta-carotene (S-betaC, administered as in N-betaC); and (4) placebo. Follow-ups continued from 1994 to 2001.

RESULTSA total of 7 new cases of gastrointestinal cancers were diagnosed with 3 stomach, 1 colon and 1 esophageal cancers occurring in the placebo group; 1 stomach cancer in both of the N-betaC and S-betaC groups, and no cancer occurring in FA group. In terms of GI cancers, there was a significant reduction in the FA group, compared with the placebo group (P = 0.04). A similar trend was observed in both N-betaC and S-betaC groups (P = 0.07 - 0.08). Taken together, the three intervention groups displayed a highly significant decrease in occurrence (P = 0.004, vs placebo), and a lower risk for GI cancers (OR = 0.12; 95% confidence interval, 0.03 - 0.51). For development of gastric cancer, any one of the three active-treated groups did not reach statistically significant reduction. The FA group showed obvious improvement of the gastric mucosal lesions with more patients displaying lesions reversed or stable atrophy and inflammation (P = 0.04), reversed intestinal metaplasia (P = 0.06) at the end of follow-up, and reversed displasia (P = 0.017) at 12 months. Two cases of false jaundice were found in beta-carotene groups with no influence on administration, and no side-effects were reported in FA group.

CONCLUSIONSThis trial revealed the interventional effect of folic acid on the development of GI cancers, a similar effect of beta-carotene was also detected. Also, folic acid may be of use to treat atrophic gastritis by preventing or reversing the precancerous lesions.

Adult ; Aged ; Anticarcinogenic Agents ; therapeutic use ; Double-Blind Method ; Female ; Folic Acid ; adverse effects ; therapeutic use ; Gastric Mucosa ; pathology ; Gastrointestinal Neoplasms ; prevention & control ; Humans ; Male ; Middle Aged ; Patient Compliance ; Stomach Neoplasms ; prevention & control ; beta Carotene ; therapeutic use