OBJECTIVETo study the effects of modified Mahuang Fuzi Xixin Decoction extract (MFXDE) on ischemia/reperfusion induced atrioventricular (A-V) block in rabbits model.

METHODSNew Zealand rabbits were randomly divided into six groups, three test groups (Group TA, TB, TC) and three control groups (Group CA, CB, CC), 10 in each. MFXDE 2 mL/kg was given twice a day by gastrogavage to the test groups, while to the control groups, equal volume of normal saline was given instead, for 3 successive days. Twenty minutes after the last gastrogavage, right coronary artery ligation was performed in rabbits under anesthesia with 1.2 g/kg of 20% urethane via ear marginal vein injection, and lasted for 15 min (Group TA and CA), 60 min (Group TB and CB), and 120 min (Group TC and CC), respectively. ECG lead-II and His Bundle ECG were recorded at different time points to observe P-R interval and A-H interval.

RESULTSP-R interval and A-H interval in the test groups were shorter than in the control groups significantly (all P < 0.05) at the time point of 5 min after ischemia; and at the reperfusion stage, a re-extending phenomenon of P-R and A-H could be found in the CC group after 60 min reperfusion (P < 0.05), but it didn't occure in all the other test groups.

CONCLUSIONMFXDE could improve the ischemia/reperfusion induced A-V conductive function.