Objective To observe the alteration of heart rate turbulence(HRT) before and after left atrium circumferential ablation surrounding pulmonary veins(LACA) in patients with paroxysmal atrial fibrillation(PAF) in order to determine whether concealed vagal denervation occurred during the procedure.Methods Forty-four patients(26 male,aged 53?11 years) with paroxysmal atrial fibrillation who had received catheter ablation treatment from Mar 2006 to Dec 2006 were included in the study.The mean diameter of left atrium was 36?5 cm and the mean ejection fracion was 0.65?0.04 in these patients.The left atrium circumferential ablation surrounding pulmonary veins were performed in all the patients to achieve complete electrical isolation of both ipsilateral pulmonary veins.RS2 extrastimulus were delivered from right ventricular apex to obtain heart rate turbulence with 60% of basic sinus cycle length and at twice diastolic threshold before and after the procedure.Turbulence onset(TO)(%) and turbulence slope(TS)(msec/beat) were obtained using average five respective ventricular premature beats.Thirty-seven patients who had received catheter ablation of supraventricular tachycardia were included as control.Results There was no significant difference between AF and control group in HRT [TO:-0.021 6%?0.023 6% vs-0.023 6%?0.018 5%(P=0.67);TS: 7.331 8?6.983 5 vs 9.667 9?6.065 2(P=0.12)].TO and TS changed significantly after LACA [-0.021 6?0.023 6 to 0.000 9?0.013 3(P

Heart Atria ; Humans ; Speech ; Tachycardia

Objective Chronic atrial fibrillation (AF) results in dedifferentiation of atrial cardiomyocytes that plays an important role in the perpetuation of AF.In this study,we aimed to investigate the changes of titin and α-smooth muscle actin (α-SMA) after long time of AF reversal.Methods Twenty-four goats were randomized into four groups:(1) sinus rhythm (SR),(2) 3 months AF (3-mo AF),(3) 3 months SR after 3 months AF (3-mo post AF),(4) 6 months SR after 3-mo AF (6-mo post AF),with 6 in each group.By pacing on the anterior bottom of left atria appendage (LAA),we established a goat model of chronic AF.Atria effective refractory period (AERP) was measured with electrophysiological methods.Ultra-structure was studied with echocardiography,light and electron microscopy.Titin and α-SMA protein expressions were determined by Western blot.Results The animals underwent high rate pacing on LAA for a mean of 42.23±21.70 days before presenting AF.Electrophysiological analysis revealed that AERP completely resumed in 3-mo post AF goats.Echocardiography displayed that the size of left atrium resumed almost in 6-mo post AF goats (P＜ 0.01).Pathological and electron microscopic examination revealed the disorder of myofibrils,augmentation of intercellular space,myolysis,accumulation of glycogen,and numerous bigger mitochondria among atrial cardiomyocytes in 3-mo AF goats.They recovered mostly in 6-mo post AF goats.Western blot showed that the band density of titin significantly reduced in 3-mo AF goats compared to SR ones [1826±319 vs 5012±854,P＜0.01].In 3-and 6-mo post AF goats,titin increased gradually and it reversed completely in 6-mo post AF goats (3841±601 and 4523±833 respectively,P ＜ 0.01).Conversely,the band density of α-SMA was significantly higher in 3-mo AF goats (5324±948) than in SR ones (1619± 271,P＜0.01).In 3-and 6-mo post-AF goats,α-SMA decreased gradually,and it recovered mostly in 6mo post AF goats (4437± 792 and 2205±540 respectively,P＜0.01,).Conclusions These data indicate that the reversal of dedifferentiation of atrial cardiomyocyts is a very slow process,and it is definitely essential for normal cardiac function.