Distribution of triggers foci and outcomes of catheter ablation in atrial fibrillation patients in different age groups.

BACKGROUND: Atrial fibrillation (AF) prevalence increases with age. Aging affects the substrate properties of the left atrium (LA) and the outcomes of catheter ablation for treating AF. We investigated the AF trigger distribution and catheter ablation outcomes in patients of different ages with AF. METHODS: 1585 patients with AF (1181 paroxysmal and 404 non- paroxysmal AF) who had undergone catheter ablation were enrolled. The patients were divided into young (20-40 year-old, n = 175), middle-aged (41-64 year-old, n = 1134), and old (≥ 65 year-old, n = 276) groups. Electrophysiological characteristics and AF trigger sites were recorded. RESULT: The incidence of AF with only non-pulmonary vein (non-PV) foci was higher in the young group than in the other groups (8.6% vs. 3.6% vs. 3.3%, p < 0.01). Non-PV foci were more commonly located in the superior vena cava (SVC) in the young group than in the other groups (13.1% vs. 7.8% vs. 6.5%, p = 0.03). The left atrium (LA) mean voltage was higher and the incidence of very late recurrence after AF ablation was lower in the young group than in the other groups. However, the final AF recurrence rate after multiple procedures and complication rates were similar among all the groups at a mean follow-up of 5.6 years. CONCLUSION: The young patients with AF had a higher incidence of only non-PV foci, mostly located in SVC, than the middle-aged and old patients. Our study highlights the importance of identifying the non-PV foci in catheter ablation of young patients with AF.

Comparison of lesion characteristics between conventional and high-power short-duration ablation using contact force-sensing catheter in patients with paroxysmal atrial fibrillation.

BACKGROUND: Transmural lesion creation is essential for effective atrial fibrillation (AF) ablation. Lesion characteristics between conventional energy and high-power short-duration (HPSD) setting in contact force-guided (CF) ablation for AF remained unclear. METHODS: Eighty consecutive AF patients who received CF with conventional energy setting (power control: 25-30 W, force-time integral = 400 g s, n = 40) or with HPSD (power control: 40-50 W, 10 s, n = 40) ablation were analyzed. Of them, 15 patients in each conventional and HPSD group were matched by age and gender respectively for ablation lesions analysis. Type A and B lesions were defined as a lesion with and without significant voltage reduction after ablation, respectively. The anatomical distribution of these lesions and ablation outcomes among the 2 groups were analyzed. RESULTS: 1615 and 1724 ablation lesions were analyzed in the conventional and HPSD groups, respectively. HPSD group had a higher proportion of type A lesion compared to conventional group (P < 0.01). In the conventional group, most type A lesions were at the right pulmonary vein (RPV) posterior wall (50.2%) whereas in the HPSD group, most type A lesions were at the RPV anterior wall (44.0%) (P = 0.04). The procedure time and ablation time were significantly shorter in the HPSD group than that in the conventional group (91.0 ± 12.1 vs. 124 ± 14.2 min, P = 0.03; 30.7 ± 19.2 vs. 57.8 ± 21 min, P = 0.02, respectively). At a mean follow-up period of 11 ± 1.4 months, there were 13 and 7 patients with recurrence in conventional and HPSD group respectively (P = 0.03). CONCLUSION: Optimal ablation lesion characteristics and distribution after conventional and HPSD ablation differed significantly. HPSD ablation had shorter ablation time and lower recurrence rate than did conventional ablation.

Identification of critical isthmus using coherent mapping in patients with scar-related atrial tachycardia.

INTRODUCTION: Accurate identification of slow conducting regions in patients with scar-related atrial tachycardia (AT) is difficult using conventional electrogram annotation for cardiac electroanatomic mapping (EAM). Estimating delays between neighboring mapping sites is a potential option for activation map computation. We describe our initial experience with CARTO 3 Coherent Mapping (Biosense Webster Inc,) in the ablation of complex ATs. METHODS: Twenty patients (58 ± 10 y/o, 15 males) with complex ATs were included. We created three-dimensional EAMs using CARTO 3 system with CONFIDENSE and a high-resolution mapping catheter (Biosense Webster Inc). Local activation time and coherent maps were used to aid in the identification of conduction isthmus (CI) and focal origin sites. System-defined slow or nonconducting zones and CI, defined by concealed entrainment (postpacing interval < 20 ms), CV < 0.3 m/s and local fractionated electrograms were evaluated. RESULTS: Twenty-six complex ATs were mapped (mean: 1.3 ± 0.7 maps/pt; 4 focal, 22 isthmus-dependent). Coherent mapping was better in identifying CI/breakout sites where ablation terminated the tachycardia (96.2% vs 69.2%; P = .010) and identified significantly more CI (mean/chamber 2.0 ± 1.1 vs 1.0 ± 0.7; P < .001) with narrower width (19.8 ± 10.5 vs 43.0 ± 23.9 mm; P < .001) than conventional mapping. Ablation at origin and CI sites was successful in 25 (96.2%) with long-term recurrence in 25%. CONCLUSIONS: Coherent mapping with conduction velocity vectors derived from adjacent mapping sites significantly improved the identification of CI sites in scar-related ATs with isthmus-dependent re-entry better than conventional mapping. It may be used in conjunction with conventional mapping strategies to facilitate recognition of slow conduction areas and critical sites that are important targets of ablation.

Role of Pediatricians in the Ambulatory Care of Children in Taiwan, 1999-2011.

BACKGROUND: Pediatricians are physicians trained to provide comprehensive nonsurgical health care for children, but parents may consult other specialists when seeking medical help for their children. This study was designed to analyze the role of pediatricians and the changes in the patterns of ambulatory visits among different specialties for children under the age of 18 years in Taiwan during the past 13 years. METHODS: Data on ambulatory visits of children aged 0-17 years from 1999 to 2011 were retrieved from the National Health Insurance Research Database. The physician's specialty, level of the hospital, year of visit, age of the patient, and diagnoses of each ambulatory visit were analyzed. Four of the most commonly visited specialties-pediatrics, otolaryngology, family medicine, and internal medicine-were compared. The yearly trend of ambulatory visits to different specialties, difference in various age groups, influence of hospital levels, and the top 10 diagnoses were analyzed. RESULTS: A total of 1,618,033 ambulatory visits were identified and enrolled into our study. A comparison of the proportions of ambulatory visits between 1999-2003 and 2007-2011 showed that the proportions of visits increased from 27.1 ± 1.3% to 35.4 ± 1.0% for pediatricians, decreased from 32.8 ± 1.8% to 17.0 ± 0.8% for family physicians, and did not change for otolaryngologists and internal medicine physicians. Specifically, pediatricians were visited more often if the children were younger, or if the health-care facility (level of hospital) was either a medical center or a regional hospital. Upper respiratory tract infection was the top diagnosis, followed by acute bronchitis, and acute and chronic tonsillitis. CONCLUSIONS: The role of pediatricians in children's ambulatory care increased in importance from 1999 to 2011 in Taiwan. However, approximately two thirds of children sought ambulatory medical help from nonpediatric physicians. Thus, it is important to educate and encourage parents to visit pediatricians if their children require medical help.