Assessing the efficacy of saline flush in frequency-domain optical coherence tomography for intracoronary imaging.

BACKGROUND: The increased amount of contrast media in frequency-domain optical coherence tomography (FD-OCT) imaging during percutaneous coronary intervention (PCI) has raised potential concerns regarding impairment of renal function. OBJECTIVES: This study aimed to evaluate the effectiveness of heparinized saline flush in FD-OCT-guided PCI and identify clinical factors contributing to optimal image quality. METHODS: We retrospectively collected 100 lesions from 90 consecutive patients, and a total of 200 pullbacks were analyzed for the initial and final evaluation in which saline was used as the flushing medium. RESULTS: The study population had a mean age of 73, with 52% having chronic kidney disease (CKD). The median amount of contrast used was 28 ml, and no complications were observed associated with saline flush OCT. Imaging quality was then categorized as excellent, good, or unacceptable. Among the total runs, 87% demonstrated clinically acceptable image quality, with 66.5% classified as excellent images and 20.5% classified as good images. Independent predictors of excellent images included lumen area stenosis ≥ 70% (adjusted odds ratio [OR] 2.37, 95% confidence interval [CI] 1.02-5.47, P = 0.044), and the use of intensive flushing (adjusted OR 2.06, 95% CI 1.11-3.86, P = 0.023) defined as a deep engagement of guiding catheter (GC) or a selective insertion of guide extension catheter (GE). Intensive flushing was performed in 60% of the total pullbacks, and it was particularly effective in improving image quality in the left coronary artery (LCA). CONCLUSION: The use of saline flush during FD-OCT imaging was safe and feasible, which had a benefit in renal protection with adequate imaging quality.

Deteriorative Effect of a Combination of Hypertriglyceridemia and Low High-Density Lipoprotein Cholesterolemia on Target Lesion Revascularization after Everolimus-Eluting Stent Implantation.

AIM: This study aimed to investigate the association between a combination of elevated triglyceride (TG) and reduced high-density lipoprotein cholesterol (HDL-C) levels and target lesion revascularization (TLR) following everolimus-eluting stent (EES) implantation. The adverse impact of clinical, lesion, and procedural characteristics on TLR in patients with elevated TG and reduced HDL-C levels was also assessed. METHODS: We retrospectively collected data on 3,014 lesions from 2,022 consecutive patients, who underwent EES implantation at Koto Memorial Hospital. Atherogenic dyslipidemia (AD) is defined as a combination of non-fasting serum TG ≥ 175 mg/dL and HDL-C ＜40 mg/dL. RESULTS: AD was observed in 212 lesions in 139 (6.9%) patients. The cumulative incidence of clinically driven TLR was significantly higher in patients with AD than in those without AD (hazard ratio [HR] 2.31, 95% confidence interval [CI] 1.43-3.73, P=0.0006). Subgroup analysis showed that AD increased the risk of TLR with the implantation of small stents (≤ 2.75 mm). Multivariable Cox regression analysis showed that AD was an independent predictor of TLR in the small EES stratum (adjusted HR 3.00, 95% CI 1.53-5.93, P=0.004), whereas the incidence of TLR was similar in the non-small-EES stratum, irrespective of the presence or absence of AD. CONCLUSIONS: Patients with AD had a higher risk of TLR after EES implantation, and this risk was greater for lesions treated with small stents.

Epicardial adipose tissue affects the efficacy of left atrial posterior wall isolation for persistent atrial fibrillation.

BACKGROUND: Epicardial adipose tissue (EAT) contributes to atrial fibrillation (AF). However, its impact on the efficacy of left atrial posterior wall isolation (LAPWI) is unclear. METHODS: Forty-four nonparoxysmal AF patients underwent LAPWI after pulmonary vein isolation. EAT overlap on LAPWI was assessed by fusing computed tomography images with electro-anatomical mapping. RESULTS: During the 21 ± 7 months of follow-up, AF recurred in 10 patients (23%). The total and left atrial EAT volumes were 113 ± 36 and 33 ± 12 cm3, respectively. No differences were found between the AF-free and AF-recurrent groups regarding EAT volume. The EAT overlaps on LAPWI lines and LAPWI area were 1.2 ± 1.0 and 0.5 ± 0.9 cm2 respectively. Although no difference was found between groups regarding the EAT overlap on LAPWI area, the AF-free group had a significantly larger EAT overlap on LAPWI lines (1.4 ± 1.0 vs 0.6 ± 0.6 cm2, P = .014). Multivariate analysis identified EAT overlap on LAPWI lines as an independent predictor of AF recurrence (hazard ratio: 0.399, 95% confidence interval: 0.178-0.891, P = .025). Kaplan-Meier analysis revealed that, during follow-up, 92% of the large EAT overlap group (≥1.0 cm2) and 58% of the small EAT overlap group (<1.0 cm2) remained AF-free (P = .008). CONCLUSIONS: EAT overlap on LAPWI lines is related to a high AF freedom rate. Direct radiofrequency application to EAT overlap may be necessary to suppress AF.

Ripple map guided catheter ablation targeting abnormal atrial potentials during sinus rhythm for non-paroxysmal atrial fibrillation.

BACKGROUND: Abnormal atrial potential (AAP) during sinus rhythm may be a critical ablation target for atrial fibrillation. However, the assessment of local electrograms throughout the left atrium is difficult. Thus, we sought to investigate the effectiveness of Ripple map guided AAP ablation. METHODS AND RESULTS: AAP areas were determined by Ripple mapping on the CARTO system in 35 patients (Ripple group) by marking the area where small deflections persisted after the first deflection wavefront had passed. Following pulmonary vein isolation, AAP areas were ablated. If AAP areas were located on the left atrial posterior wall, the posterior wall was isolated. The outcome of this approach was compared with that of 66 patients who underwent an empirical linear ablation approach (control group). There were no differences in patient characteristics between the groups. The total radiofrequency application time and procedure time were shorter in the Ripple group than in the control group (radiofrequency application time, 48 ± 14 minutes vs 61 ± 13 minutes, P < .001; procedure time, 205 ± 30 minutes vs 221 ± 27 minutes, P = .013). Gastroparesis occurred in one patient in each group (P = .645), but in both cases this was relieved with conservative therapy. Kaplan-Meier analysis revealed that rate of freedom from atrial arrhythmia was higher in the Ripple group than in the control group (91% vs 74% during the 12 months' follow up; P = .040). CONCLUSION: Ripple map guided AAP ablation effectively suppressed atrial arrhythmia in patients with non-paroxysmal AF.

P-wave vector magnitude predicts the left atrial low-voltage area in patients with paroxysmal atrial fibrillation.

BACKGROUND: P-wave amplitude (PWA) parameters can be the surrogate measures of the left atrial low-voltage areas (LVAs). METHODS: We measured PWAs using an automated system in 50 patients with paroxysmal atrial fibrillation (AF). We examined the relationships between left atrial LVAs and PWA parameters, including P-wave vector magnitude, calculated as the square root of the sum of lead II PWA squared, lead V6 PWA squared, and a one-half lead V2 PWA squared. RESULTS: Lead I PWA was most strongly correlated with LVAs in the anterior wall and appendage (anterior wall, R = -0.391, P = 0.006; appendage, R = -0.342, P = 0.016), whereas lead II PWA was most strongly correlated with LVAs in the septum, posterior wall, and bottom wall (septum, R = -0.413, P = 0.003; posterior wall, R = -0.297, P = 0.039; bottom wall; R = -0.288, P = 0.045). Although maximum, minimum, mean, and lead I PWAs were not correlated with total LVA, P-wave vector magnitude and lead II PWA were significantly correlated with total LVA (P-wave vector magnitude, R = -0.430, P = 0.002; lead II PWA, R = -0.323, P = 0.023). P-wave vector magnitude achieved the highest accuracy for predicting significant LVA (total LVA > 10%) with an area under the curve of 0.772; sensitivity, specificity, and positive and negative predictive values were 64%, 88%, 85%, and 69%, respectively, for the cutoff value of 0.130 mV. CONCLUSION: P-wave vector magnitude is a useful electrocardiographic predictor of left atrial LVAs.

Effect of Glycemic Control During Follow-up on Late Target Lesion Revascularization After Implantation of New-Generation Drug-Eluting Stents in Patients With Diabetes　- A Single-Center Observational Study.

Background: Few studies have investigated the importance of glycemic control in patients with diabetes mellitus (DM) for reducing the incidence of late target lesion revascularization (TLR) after implantation of new-generation drug-eluting stents (DES). Methods and Results: We retrospectively identified 1,568 patients who underwent new-generation DES implantation. Patients were divided into 3 groups based on diabetic status and glycemic control 1 year after the procedure: those without DM (non-DM group; n=1,058) and those with DM at follow-up with either good (HbA1c <7%; n=328) or poor (HbA1c ≥7%; n=182) control. The cumulative 5-year incidence of clinically driven late TLR after the index procedure was significantly higher in DM with poor control at follow-up than in those with good control at follow-up or non-DM (14%, 4.8%, and 2.9%, respectively; P<0.0001). Multivariate analysis revealed that poor control at follow-up was significantly associated with a higher risk of clinically driven late TLR compared with the non-DM group (hazard ratio [HR] 4.58, 95% confidence interval [CI] 2.50-8.16, P<0.0001). However, good control at follow-up group was not associated with a higher risk of clinically driven late TLR compared with the non-DM group (HR 1.35, 95% CI 0.68-2.56, P=0.38). Conclusions: DM patients with poor glycemic control at follow-up had a significantly higher risk of clinically driven late TLR than non-DM patients.

Left atrial wall thickness is associated with the low-voltage area in patients with paroxysmal atrial fibrillation.

PURPOSE: To identify a potential morphological marker of remodeling and electrophysiological dysfunction, we investigated if low wall thickness is associated with low-voltage areas (LVAs) in the left atrium. METHODS: Wall thickness was measured by computed tomography and LVA (% area with bipolar voltage < 0.5 mV) by voltage mapping in 43 paroxysmal AF patients. The left atrium was divided into five segments: septal wall, anterior wall, roof wall, posterior wall, and bottom wall in regional analysis. RESULTS: Left atrial wall thickness and LVA were 3.2 ± 0.6 mm and 14% ± 9%, respectively. Multivariate analysis identified left atrial wall thickness and volume as independent determinants of left atrial LVA (thickness, standardized ß - 0.374, 95%CI - 23.289 to - 4.534, P = 0.005; volume, standardized ß 0.452, 95%CI 0.049-0.214, P = 0.002). In regional analysis, significant LVA (> 10% of segment surface area) was observed in 123 of 215 segments (57%). Segments in the low tertile of wall thickness (< 1.76 mm) had larger LVAs compared with segments in middle (1.76-2.14 mm) and high tertiles (≥ 2.14 mm) (low tertile, 20.3% ± 14.9%; middle tertile, 12.6% ± 11.2%; high tertile, 12.5% ± 12.1%; low vs. middle tertile, P = 0.001; low vs. high tertile, P = 0.001). Area under the receiver operating curve of wall thickness was 0.706 for prediction of significant LVA. A thickness cut-off of 1.90 mm yielded 62% sensitivity, 73% specificity, 75% positive predictive value, and 59% negative predictive value for significant LVA. CONCLUSION: A thin left atrial wall is an independent predictor of LVA in patients with paroxysmal AF.

Correlation between the left atrial low-voltage area and the cardiac function improvement after catheter ablation for paroxysmal atrial fibrillation.

BACKGROUND: The impact of the left atrial low-voltage area (LVA) on the cardiac function improvement following ablation for atrial fibrillation (AF) is unclear. METHODS: In 49 patients with paroxysmal AF who underwent ablation, the left ventricular stroke volume index (SVI) was repeatedly measured using an impedance cardiography until 6 months after ablation. We defined the cardiac function improvement as a 20% increase in the SVI. The LVA (the area with the voltage amplitude of <0.5 mV) was assessed before ablation. RESULTS: The reduced baseline SVI (<33 mL/m2) was observed in 18 (37%) patients. The SVI increased following ablation (from 36 ± 5 to 39 ± 6 mL/m2, P < .001). We observed the cardiac function improvement in 14 (29%) patients. The LVA was smaller in patients with the improved cardiac function than in those without (8.3% ± 5.2% vs 14.0% ± 8.5%, P = .026). The multivariate analysis revealed that only the LVA was independently associated with the cardiac function improvement (odds ratio, 0.878; 95% confidence interval: 0.778-0.991, P = .036). Furthermore, LVAs of the anterior (7.9% ± 7.6% vs 18.2% ± 15.5%, P = .022), septal (12.0 ± 7.3% vs 20.7% ± 13.8%, P = .031), and roof walls (6.9% ± 6.0% vs 16.9% ± 15.2%, P = .022) were smaller in patients with the improved cardiac function than in those without. CONCLUSIONS: The LVA was related to the cardiac function improvement following ablation in patients with paroxysmal AF.

Left atrial posterior wall isolation affects complex fractionated atrial electrograms in persistent atrial fibrillation.

BACKGROUND: The impact of left atrial posterior wall isolation (LAPWI) on the complex fractionated atrial electrogram (CFAE) is unknown. METHODS: CFAE mapping was performed before and after LAPWI in 46 patients with persistent atrial fibrillation (AF). RESULTS: LAPWI decreased both the variable (fractionated index ≤ 120 ms; from 60 ± 4 cm2 to 50 ± 4 cm2, P < 0.001) and continuous (fractionated index ≤ 50 ms; from 4.2 ± 1.0 cm2 to 3.5 ± 0.9 cm2, P = 0.036) CFAE areas. Especially, the CFAE areas on the bottom and roof walls of the left atrium and on the posterior and bottom walls of the right atrium significantly decreased after LAPWI. The distribution of variable CFAE areas was not different between the AF-recurrence (n = 9) and AF-free (n = 37) groups before LAPWI; however, it was larger in the anterior and septal walls of the right atrium in the AF-recurrence group than in the AF-free group after LAPWI (anterior wall, 8% ± 2% vs 5% ± 1%, P = 0.048; septal wall, 23% ± 4% vs 16% ± 1%, P = 0.043). The distribution of continuous CFAE areas on the bottom wall of the right atrium was larger in the AF-recurrence group than in the AF-free group both before LAPWI (30% ± 20% vs 4% ± 2%, P = 0.008) and after LAPWI (25% ± 25% vs 3% ± 1%, P = 0.027). CONCLUSIONS: LAPWI decreased the CFAE areas and affected their distribution, which contributed to AF recurrence.

P-wave vector magnitude predicts recurrence of atrial fibrillation after catheter ablation in patients with persistent atrial fibrillation.

BACKGROUND: The predictive efficacies of parameters related to P-wave amplitude (PWA) for atrial fibrillation (AF) recurrence after catheter ablation are unclear. METHODS: We measured multiple PWA parameters using an automated system in 126 consecutive patients with persistent and long-standing persistent AF who underwent catheter ablation. The relationships between AF recurrence and various PWA parameters were examined, including the association with P-wave vector magnitude (calculated as the square root of the sum of lead II PWA squared, lead V6 PWA squared, and a one-half lead V2 PWA squared). RESULTS: Atrial fibrillation did not recur in 87 patients (69%) during 32 ± 15 months of follow-up. The maximum PWA, mean PWA, and P-wave vector magnitude were lower in patients with AF recurrence than those without (maximum PWA, 0.14 ± 0.05 mV vs. 0.16 ± 0.05 mV, p = 0.017; mean PWA, 0.05 ± 0.02 mV vs. 0.06 ± 0.02 mV, p = 0.003; P-wave vector magnitude, 0.09 ± 0.03 mV vs. 0.13 ± 0.04 mV, p < 0.001). A multivariate Cox regression analysis revealed that the predictive ability of P-wave vector magnitude for AF recurrence was independent of other clinical properties (hazard ratio: 0.153, 95% confidence interval: 0.046-0.507, p = 0.002). Atrial fibrillation freedom rates of patients with P-wave vector magnitude higher and lower than 0.13 mV were 93% and 57%, respectively. P-wave vector magnitude weakly correlated with left atrial dimension (R = -0.280, p = 0.004). CONCLUSIONS: P-wave vector magnitude can predict AF recurrence after catheter ablation in patients with persistent AF.

Edoxaban suppresses the progression of atrial fibrosis and atrial fibrillation in a canine congestive heart failure model.

Coagulation factor Xa activates the protease-activated receptor 2 (PAR2) and causes tissue fibrosis; however, the effects of Xa inhibitor edoxaban on atrial fibrosis and atrial fibrillation (AF) have not been investigated. We examined the effect of edoxaban on the progression of atrial fibrosis in a canine congestive heart failure (CHF) model. Beagle dogs were assigned to sham, placebo, and edoxaban groups (n = 6/group). Dogs of the placebo or edoxaban groups received 19 days of medication with daily oral placebo or edoxaban, respectively, followed by 14 days of ventricular tachypacing. Dogs of the sham group had no medication or pacing. Ventricular tachypacing prolonged AF duration in dogs of the placebo group (159 ± 41 s, p < 0.01 vs. sham); however, this effect was suppressed by edoxaban treatment. Compared with the sham group, tachypacing alone also significantly increased the atrial fibrotic area (2.9 ± 0.1% vs. 7.8 ± 0.4%, p < 0.01), PAR2 expression (1.0 ± 0.1 vs. 1.8 ± 0.3, p < 0.05), and atrial fibronectin expression (1.0 ± 0.2 vs. 2.0 ± 0.2, p < 0.01). These responses were suppressed by edoxaban treatment (area 5.9 ± 0.4%, p < 0.01; PAR2 1.1 ± 0.1, p < 0.05; fibronectin 1.2 ± 0.2, p < 0.05 vs. placebo). Edoxaban showed suppressive effects on atrial remodeling, AF progression, and excessive expressions of PAR2 and fibronectin in a canine CHF model. The suppression of the Xa/PAR2 pathway might be a potential pharmacological target of edoxaban.

Coefficient of variation of P-wave duration measured using an automated measurement system predicts recurrence of atrial fibrillation.

BACKGROUND: P-wave parameters representing atrial conduction heterogeneity are associated with recurrence of atrial fibrillation (AF) after catheter ablation. However, intra- and inter-observer variabilities are unavoidable during manual measurement of P-wave parameters. METHODS: The study included 201 patients with paroxysmal AF who underwent catheter ablation. P-wave duration (PWD) was measured using a computerized automated measurement system with a surface 12-lead electrocardiogram. The coefficient of variation of PWD (CV-PWD) across the 12 electrocardiographic leads was determined as an index of atrial conduction heterogeneity. RESULTS: AF did not recur in 157 (78%) patients during a 12-month follow-up period. CV-PWD assessed before catheter ablation was not different between the AF-recurrent and AF-free groups (0.069 ±â€¯0.023 vs. 0.069 ±â€¯0.023, P = 0.090). However, CV-PWD measured after catheter ablation was significantly larger in the AF-recurrent group than in the AF-free group (0.090 ±â€¯0.037 vs. 0.073 ±â€¯0.024, P < 0.001). In receiver operating curve analysis, CV-PWD assessed after catheter ablation achieved an area under the curve of 0.702; the sensitivity, specificity, and positive and negative predictive values were 68%, 69%, 38%, and 88%, respectively, for the cut-off value of 0.080. During the follow-up period, AF freedom rates of high CV-PWD patients (CV-PWD ≥ 0.080) and low CV-PWD patients (CV-PWD < 0.080) were 65% and 88%, respectively. CONCLUSIONS: CV-PWD determined using an automated measurement system was associated with AF recurrence after catheter ablation in patients with paroxysmal AF.

Impacts of the body size on the left atrial wall thickness and atrial fibrillation recurrence after catheter ablation.

The increased body size correlates with the occurrence of atrial fibrillation (AF); however, the impact of the body size on the AF recurrence after ablation remains unclear. We enrolled 283 AF patients (179 paroxysmal, 51 persistent, and 53 long-standing persistent) who received ablation and assessed the correlation between the body surface area (BSA) and the AF recurrence. Furthermore, we measured the left atrial wall thickness using computed tomography. During the 12-month follow-up period, the AF freedom rates for patients with paroxysmal AF, persistent AF, and long-standing persistent AF were 83%, 76%, and 77%, respectively. The left atrial dimension, BSA, and body mass index (BMI) were higher in the AF-recurrent group compared with the AF-free group (left atrial dimension: 44.1 ± 7.5 mm vs. 41.7 ± 6.5 mm, P = 0.019; BSA: 1.81 ± 0.20 m2 vs. 1.72 ± 0.19 m2, P = 0.002; BMI 25.0 ± 3.2 kg/m2 vs. 24.0 ± 3.2 kg/m2, P = 0.035). The multivariate analysis revealed that only the BSA was an independent predictor of the AF recurrence after ablation (hazard ratio 6.843; 95% confidence interval 1.523-30.759, P = 0.012). The BSA significantly correlated with the left atrial wall thickness (R = 0.306, P < 0.001), and the left atrial wall thickness was higher in the AF-recurrent group compared with the AF-free group (2.00 ± 0.20 mm vs. 1.87 ± 0.17 mm, P < 0.001). The large body size correlates with the AF recurrence after ablation, which could be attributed to an increase in the left atrial wall thickness.

Improvement of Hemodynamic Parameters in Patients With Preserved Left Ventricular Systolic Function by Catheter Ablation of Atrial Fibrillation　- A Prospective Study Using Impedance Cardiography.

BACKGROUND: The effects of catheter ablation for atrial fibrillation (AF) on hemodynamic parameters in patients with preserved left ventricular (LV) systolic function are unclear. Methods and Results: We enrolled 178 patients with AF (paroxysmal, 108; persistent, 70) with preserved LV systolic function who underwent AF ablation. The stroke volume index (SVI) was repeatedly measured using impedance cardiography. Reduced SVI (SVI, <33 mL/m2) was observed in 55% of patients before ablation. In patients with paroxysmal AF, the SVI did not change immediately after ablation (from 35±6 mL/m2to 35±5 mL/m2; P=0.652); however, it increased 1 month after ablation and further increased 6 months after ablation (1 month, 37±6 mL/m2, P<0.001; 6 months, 38±6 mL/m2, P<0.001). In patients with persistent AF, the SVI increased immediately after ablation (from 30±5 mL/m2to 36±6 mL/m2; P<0.001) and further increased until 6 months after ablation (1 month, 37±6 mL, P<0.001; 6 months, 38±5 mL/m2, P<0.001). The baseline SVI was the strongest predictor of the cardiac function improvement with an area under the curve of 0.828. CONCLUSIONS: The restoration and maintenance of sinus rhythm using catheter ablation increased the SVI in patients with preserved LV systolic function.

Citrus fruits induced swallow syncope with atrioventricular block or sinus arrest.

Swallow syncope is a relatively rare syndrome and caused by various foods and drinks. A 76-year-old man was admitted with frequent syncope while eating. Holter electrocardiogram revealed frequent occurrence of atrioventricular block during meals. Both atrioventricular block and sinus arrest were induced by only eating citrus fruits, citrus jelly, and acidic foods but not by other drinks and foods. These arrhythmias were suppressed after administration of atropine. No further episodes of syncope recurred after the implantation of a DDD pacemaker. This case indicated that acidic stimulation of citrus induced a vasovagal reflex via esophageal nociceptors leading to syncope.

Heterogeneity in the left atrial wall thickness contributes to atrial fibrillation recurrence after catheter ablation.

Influence of left atrial wall thickness on outcome of catheter ablation for atrial fibrillation (AF) is unclear. Overall, 213 patients with AF (128 paroxysmal and 85 persistent) received ablation. We measured the wall thickness of 16 and 19 areas in the pulmonary vein antrum (PVWT) and left atrial body (LAWT), respectively. Coefficient of variation of wall thickness (CV-WT) was calculated to assess heterogeneity in the left atrial wall thickness. In patients with paroxysmal AF, maximum PVWT, mean PVWT, maximum LAWT, and CV-WT were higher in AF recurrent group than in AF-free group (maximum PVWT, 2.85 ± 0.52 vs. 2.50 ± 0.45 mm, P = 0.003; mean PVWT, 1.59 ± 0.13 vs. 1.50 ± 0.15 mm, P = 0.018; maximum LAWT, 3.85 ± 0.77 vs. 3.41 ± 0.61 mm, P = 0.005; CV-WT, 0.34 ± 0.06 vs. 0.32 ± 0.05, P = 0.039). In patients with persistent AF, maximum PVWT, mean PVWT, maximum LAWT, mean LAWT, and CV-WT were higher in the AF-recurrent group than in the AF-free group (maximum PVWT, 2.52 ± 0.36 vs. 2.31 ± 0.36 mm, P = 0.031; mean PVWT, 1.53 ± 0.12 vs. 1.45 ± 0.14 mm, P = 0.036; maximum LAWT, 3.68 ± 0.75 vs. 3.11 ± 0.50 mm, P < 0.001; mean LAWT, 2.34 ± 0.35 vs. 2.13 ± 0.21 mm, P = 0.002; CV-WT, 0.35 ± 0.06 vs. 0.31 ± 0.05, P = 0.005). Thick and heterogeneous left atrial wall contributes to AF recurrence after ablation.

Effect of irbesartan on development of atrial fibrosis and atrial fibrillation in a canine atrial tachycardia model with left ventricular dysfunction, association with p53.

Effects of an angiotensin II receptor blocker, irbesartan (IRB), on the development of atrial fibrosis and atrial fibrillation (AF) were assessed in a canine model of atrial tachycardia remodeling (ATR) with left ventricular dysfunction, together with its possible association with involvement of p53. Atrial tachypacing (400 bpm for 4 weeks) was used to induce ATR in beagles treated with placebo (ATR-dogs, n = 6) or irbesartan (IRB-dogs, n = 5). Non-paced sham dogs served as control (Control-dogs, n = 4). ATR- and IRB-dogs developed tachycardia-induced left ventricular dysfunction. Atrial effective refractory period (AERP) shortened (83 ± 5 ms, p < 0.05), inter-atrial conduction time prolonged (72 ± 2 ms, p < 0.05), and AF duration increased (29 ± 5 s, p < 0.05 vs. baseline) after 4 weeks in ATR-dogs. ATR-dogs also had a larger area of atrial fibrous tissue (5.2 ± 0.5 %, p < 0.05 vs. Control). All these changes, except for AERP, were attenuated in IRB-dogs (92 ± 3 ms, 56 ± 3 ms, 9 ± 5 s, and 2.5 ± 0.7 %, respectively; p < 0.05 vs. ATR for each). In ATR-dogs, p53 expression in the left atrium decreased by 42 % compared with Control-dogs (p < 0.05); however, it was highly expressed in IRB-dogs (+89 % vs. ATR). Transforming growth factor (TGF)-ß1 expression was enhanced in ATR-dogs (p < 0.05 vs. Control) but reduced in IRB-dogs (p < 0.05 vs. ATR). Irbesartan suppresses atrial fibrosis and AF development in a canine ATR model with left ventricular dysfunction in association with p53.

Paced QRS fragmentation is associated with spontaneous ventricular fibrillation in patients with Brugada syndrome.

BACKGROUND: Conduction abnormalities are involved in the pathogenesis of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS). OBJECTIVE: We investigated whether right ventricular apical pacing (RVAP) could enhance the conduction abnormality and predict the susceptibility to VF in patients with BrS. METHODS: Twenty patients with BrS (n = 15) or early repolarization syndrome (ERS) (n = 5) having an implantable cardioverter-defibrillator and 11 patients with complete atrioventricular block having a pacemaker were studied. RESULTS: In BrS, 7 patients had a history of spontaneous VF [VF(+) group] and the remaining 8 did not [VF(-) group]. The number of spikes in fragmented QRS was counted during sinus rhythm and RVAP at rates of 80 and 110 beats/min, respectively. Patients with complete atrioventricular block had no spikes during RVAP. During sinus rhythm, no significant difference was observed in QRS spike numbers among VF(+), VF(-), and ERS groups. During RVAP at 110 beats/min, the sum of spike numbers in leads V1 and V2 increased and the duration of QRS fragmentation increased in the VF(+) group as compared with VF(-) and ERS groups [VF(+): 10.7 ± 3.7, 2.4 ± 3.2, and 2.4 ± 1.8 ms; P < .001; VF(-): 173 ± 32, 45 ± 44, and 49 ± 45 ms; P < .001]. According to the receiver operating characteristic analysis, the cutoff value of the sum of spike numbers in leads V1 and V2 to best discriminate between VF(+) and VF(-) groups was 4 in patients with BrS. CONCLUSION: RVAP manifested QRS fragmented spikes, which could be associated with spontaneous VF in patients with BrS.

Coefficient of Variation of P-Wave Duration Is a Novel Atrial Heterogeneity Index to Predict Recurrence of Atrial Fibrillation After Catheter Ablation.

INTRODUCTION: Atrial conduction heterogeneity is associated with progression of atrial fibrillation (AF). However, the relationship between P-wave parameters representing atrial conduction heterogeneity and AF recurrence after catheter ablation (ABL) is still unclear. METHODS AND RESULTS: Subjects of the study were 126 consecutive patients with AF (78 paroxysmal and 48 persistent) who had received ABL. Coefficient of variation of P-wave duration (CV-PWD) was determined with all 12 surface electrocardiographic leads as an index of atrial conduction heterogeneity. Rates of freedom from AF recurrence were 78% and 77% in patients with paroxysmal and persistent AF, respectively, over a 12-month follow-up. CV-PWD measured before ABL was smaller in AF-free patients compared with AF-recurrent patients (0.089 ± 0.019 vs. 0.129 ± 0.042, P < 0.001). CV-PWD significantly decreased after ABL in AF-free patients, but did not change in AF-recurrent patients. CV-PWD after ABL was also smaller in AF-free patients compared with AF-recurrent patients (0.087 ± 0.025 vs. 0.133 ± 0.035, P < 0.001). In receiver operating curve analysis, CV-PWD before and after ABL achieved area under the curve of 0.829 and 0.854, respectively, for the ability to predict AF recurrence. CV-PWD correlated positively with left atrial (LA) diameter and negatively with LA appendage flow velocity. CONCLUSION: CV-PWD is a useful index to predict AF recurrence after ABL for both patients with paroxysmal and persistent AF. ABL may suppress AF by decreasing atrial conduction heterogeneity.

Differentiation of Slow-Slow Form of AVNRT from AVRT through a Posteroseptal Accessory Pathway by Retrograde P-Wave Amplitude.

BACKGROUND: This study aimed to clarify whether retrograde P-wave amplitude during tachycardia can be used to differentiate slow-slow form of atrioventricular nodal reentrant tachycardia (S/S-AVNRT) from atrioventricular reentrant tachycardia through a posteroseptal accessory pathway (PS-AVRT). METHODS: Sixteen patients with S/S-AVNRT and 14 patients with PS-AVRT constituted the study group. Electrocardiographic and electrophysiological parameters were compared between both the groups. HA(CS-His), which indicates the location of the earliest atrial activation site during tachycardia, was calculated as the difference of the shortest HA interval in the His bundle region and the coronary sinus region. RESULTS: Negative deflection of the retrograde P wave during tachycardia was significantly greater in S/S-AVNRT than in PS-AVRT in the inferior leads (lead aVF, -0.22 ± 0.04 mV vs -0.10 ± 0.07 mV; P < 0.001). Among the electrocardiographic parameters, retrograde P-wave amplitude in lead aVF had the highest diagnostic accuracy (area under the curve 0.975, sensitivity 93%, and specificity 88% for a cutoff value of -0.16 mV). HA(CS-His) was negatively greater in S/S-AVNRT than in PS-AVRT (-24 ± 13 ms vs -3 ± 18 ms; P = 0.001), and was significantly correlated with the retrograde P-wave amplitude in lead aVF (P = 0.004). CONCLUSION: Deeper negative deflection of the retrograde P wave in the inferior lead can help differentiate S/S-AVNRT from PS-AVRT.