The Role of Angle in the Evaluation of Ablation Accuracy in Pulmonary Vein Isolation Navigated by Image Integration.

BACKGROUND: The conventional index for ablation accuracy is to compare the distance between mapping points with and without treatment by using image integration. We attempted to quantitatively evaluate the role of angle as an index in the ablation accuracy in patients with atrial fibrillation (AF). METHODS: A total of 48 patients with AF were included in the present study. Virtual fluoroscopy planes were predicted by pulmonary vein (PV) angiography, and the standard image planes were defined on the basis of the computed tomography images. Ablations were performed, guided by image integration; and the ablation planes were defined by the actual ablation rings. The predicted angle (distance) was defined as the angle (distance) between the fluoroscopy (predicted) plane and image (standard) plane, whereas the actual angle (distance) was defined as the angle (distance) between the ablation (actual) planes and the image (standard) planes. RESULTS: We found that all actual angles were significantly smaller than the predicted angles (P <.05), but only the actual distances in the left PV, right inferior PV, right superior PV, and right PV were significantly smaller; the distances in the left inferior PV and left superior PV were not significantly different (P >.05). CONCLUSION: Our finding indicates that both the angle and the distance can be significantly reduced by navigation with image integration, but that the angle exhibited better sensitivity than the conventional index of distance. We suggest that the angle should be considered as a new index for ablation accuracy.

Common variants predict recurrence after nonfamilial atrial fibrillation ablation in Chinese Han population.

BACKGROUND: Genome-wide association studies (GWAS) have identified several loci associated with atrial fibrillation (AF) and have been reportedly associated with response to catheter ablation for AF in patients of European ancestry; however, associations between susceptibility loci and clinical recurrence of AF after catheter ablation have not been examined in Chinese Han populations. To the personalization of catheter ablation for AF, we examined whether these single nucleotide polymorphisms (SNPs) can predict clinical outcomes after catheter ablation for AF in Chinese Han population. METHODS AND RESULTS: The association between 8 SNPs and AF was studied in 1418 AF patients and 1424 controls by the unconditional logistic regression analysis. The survival analyses were used to compare AT/AF recurrence differences among 438 AF patients, which were classified by the genotype of rs2200733. rs2200733 and rs6590357 were significantly associated with AF in Chinese Han population. In addition, rs2200733 was associated with clinical recurrence of AF after catheter ablation. In Kaplan-Meier survival analysis, the recurrence-free rates for AF with TT and with TC+CC were 35.5% and 61.9%, respectively (P=0.0009). In multivariate Cox regression analysis, rs2200733 was strong independent risk factor for recurrence. CONCLUSION: rs2200733 risk allele at the 4q25 predicted impaired clinical response to catheter ablation for AF in Chinese Han population. Our findings suggested rs2200733 polymorphism may be used as a clinical tool for selection of patients for AF catheter ablation.

Polymorphisms of renin-angiotensin-aldosterone system gene in chinese han patients with nonfamilial atrial fibrillation.

BACKGROUND: Atrial fibrillation(AF) is the most common arrhythmia in the adult population. The activated renin-angiotensin-aldosterone system (RAS) has been reported to play an important role in the pathogenesis of atrial fibrillation. The aim of this study was to investigate the association between nonfamilial AF and polymorphisms in RAS gene. METHODS: A total of 931 patients with nonfamilial AF, 663 non-AF heart disease patients and 727 healthy subjects were selected. 10 tagSNPs (tSNPs) (ACE gene rs8066114, AGT gene rs7539020, rs3789678, rs2478544, rs11568023, rs2478523, rs4762, rs699 and CYP11B2 rs3802230, rs3097) were chosen and genotyped in our study. Single-locus analysis and haplotype analysis were used in this study. RESULTS: In single-locus analysis, we found rs11568023 and rs3789678 in AGT gene were associated with nonfamilial AF in Chinese Han population. AF risk was associated with rs3789678 between the AF group and control groups. Under dominant model, the significant AF risk was observed in rs3789678 between the AF group and non AF heart control group; And the protective effect was found in rs11568023, compared with the non-AF heart disease control group. In multilocus haplotype analysis, the association between frequencies of the haplotypes and AF risk was showed in AGT gene (rs7539020-rs3789678), compared 'TT' haplotype with the common 'TC' haplotype, adjusted for age, gender, LVEF, LVEDD, LAD and frequency of hypertension and diabetes. The diplotype with 'TC', carrying rs3789678-C-allele, was associated with reduced risk of AF between the AF group and the healthy control group. The diplotype with 'TT' haplotype in the same block, carrying rs3789678-T-allele, was associated with increased risk of AF. CONCLUSIONS: Via a large-scale case-control study, we found that rs3789678 site was potential susceptible locus of AF whereas rs11568023 was protective factor.

Lysophosphatidic acid increases the electrophysiological instability of adult rabbit ventricular myocardium by augmenting L-type calcium current.

Lysophosphatidic acid (LPA) has diverse actions on the cardiovascular system and is widely reported to modulate multiple ion currents in some cell types. However, little is known about its electrophysiological effects on cardiac myocytes. This study investigated whether LPA has electrophysiological effects on isolated rabbit myocardial preparations. The results indicate that LPA prolongs action potential duration at 90% repolarization (APD(90)) in a concentration- and frequency-dependent manner in isolated rabbit ventricular myocytes. The application of extracellular LPA significantly increases the coefficient of APD(90) variability. LPA increased L-type calcium current (I(Ca,L)) density without altering its activation or deactivation properties. In contrast, LPA has no effect on two other ventricular repolarizing currents, the transient outward potassium current (I(to)) and the delayed rectifier potassium current (I(K)). In arterially perfused rabbit left ventricular wedge preparations, the monophasic action potential duration, QT interval, and Tpeak-end are prolonged by LPA. LPA treatment also significantly increases the incidence of ventricular tachycardia induced by S(1)S(2) stimulation. Notably, the effects of LPA on action potentials and I(Ca,L) are PTX-sensitive, suggesting LPA action requires a G(i)-type G protein. In conclusion, LPA prolongs APD and increases electrophysiological instability in isolated rabbit myocardial preparations by increasing I(Ca,L) in a G(i) protein-dependent manner.