Understanding the effect of oxide components on proton mobility in phosphate glasses using a statical analysis approach.

The models to describe the proton mobility (µ H) together with the glass transition temperature (T g) of proton conducting phosphate glasses employing the glass composition as descriptors have been developed using a statical analysis approach. According to the models, the effects of additional HO1/2, MgO, BaO, LaO3/2, WO3, NbO5/2, BO3/2 and GeO2 as alternative to PO5/2 were found as following. µ H at T g is determined first by concentrations of HO1/2 and PO5/2, and µ H at T g increases with increasing HO1/2 concentration and decreasing PO5/2. The component oxides are categorized into three groups according to the effects on µ H at T g and T g. The group 1 oxides increase µ H at T g and decrease T g, and HO1/2, MgO, BaO and LaO3/2 and BO3/2 are involved in this group. The group 2 oxides increase both µ H at T g and T g, and WO3 and GeO2 are involved in this group. The group 3 oxides increase T g but do not vary µ H at T g. Only NbO5/2 falls into the group 3 among the oxides examined in this study. The origin of the effect of respective oxide groups on µ H at T g and T g were discussed.

Proton transport properties of proton-conducting phosphate glasses at their glass transition temperatures.

The proton transport properties of 32 kinds of proton-conducting phosphate glasses with broad ranges of glass transition temperature, proton conductivity, and the proton carrier concentration were studied. Almost constant proton mobility of around 2 × 10-8 cm2 V-1 s-1 at the glass transition temperature, corresponding to a diffusion coefficient of approximately 4 × 10-10 cm2 s-1, was found for the glasses. The reason why the diffusion coefficient of protons is almost constant in various proton-conducting phosphate glasses was discussed based on the role of the protons as a cross-linker within the phosphate framework via hydrogen bonding. We evaluated the highest proton conductivity of the phosphate glasses and melts based on the almost constant mobility at their glass transition temperatures and obtained a highest expected proton conductivity of 7.5 × 10-3 S cm-1 at 300 °C. The potential of proton-conducting phosphate glasses as electrolytes in intermediate temperature fuel cells was also discussed.

Chromosome 4q25 Variant rs6817105 Bring Sinus Node Dysfunction and Left Atrial Enlargement.

Genome-wide association studies have reported a strong association of the single nucleotide polymorphism (SNP) rs6817105 (T > C) on chromosome 4q25 with atrial fibrillation (AF), but phenotype alterations conferred by this SNP have not been described. We genotyped SNP rs6817105 and examined the relationships among rs6817105 genotype, clinical characteristics, echocardiographic parameters, and electrophysiological parameters in 574 AF patients and 1,554 non-AF controls. Further, multiple microRNAs (miRNAs) are reported to be involved in atrial remodeling and AF pathogenesis, so we investigated relationships between rs6817105 genotype and serum concentrations of 2555 miRNAs. The rs6817105 minor allele frequency was significantly higher in AF patients than non-AF controls (66% vs. 47%, odds ratio 2.12, p = 4.9 × 10-26). Corrected sinus node recovery time (CSRT) was longer and left atrial volume index (LAVI) was larger in AF patients with the rs6817105 minor allele than patient non-carriers (CSRT: CC 557 ± 315 ms, CT 486 ± 273 ms, TT 447 ± 234 ms, p = 0.001; LAVI: CC 43.6 ± 12.1, CT 42.4 ± 13.6, TT 39.8 ± 11.6, p = 0.030). There were no significant differences between rs6817105 genotype and the serum concentrations of miRNAs. These findings strongly implicate rs6817105 minor allele in sinus node dysfunction and left atrial enlargement.

Maintenance of low inflammation level by the ZFHX3 SNP rs2106261 minor allele contributes to reduced atrial fibrillation recurrence after pulmonary vein isolation.

INTRODUCTION: The single nucleotide polymorphism (SNP) rs2106261 in the transcription factor gene ZFHX3 (16q22), a major regulator of inflammation, has been reported linking to atrial fibrillation (AF) by genome-wide association studies. Inflammation is known to be a strong predictor of atrial fibrillation recurrence after ablation, so we examined the association of the ZFHX3 SNP rs2106261 to inflammation marker expression and recurrence after AF ablation. METHODS: We genotyped ZFHX3 SNP rs2106261 and compared the minor (T) allele frequency between 362 paroxysmal AF (PAF) patients underwent pulmonary vein isolation (PVI) and 627 non-AF controls. We also analyzed associations between ZFHX3 SNP rs2106261 genotype and recurrence rate after pulmonary vein isolation and the inflammation markers. RESULTS: The minor (T) allele frequency of the ZFHX3 SNP rs2106261 was significantly higher in AF patients than non-AF controls (odds ratio 1.52, p = 2.2×10-5). Multivariable analysis revealed that the minor allele (T) decreased AF recurrence rate after pulmonary vein isolation (hazard ratio 0.53, p = 0.04). Further, neutrophil/lymphocyte (N/L) ratio, C-reactive protein (CRP), and interleukin-6 (IL-6) expression levels were lower in PAF patients with the ZFHX3 SNP rs2106261 minor allele (TT+TC) than in CC patients (N/L ratio: CC 2.22 ± 0.08, TT+TC 1.98 ± 0.06, p = 0.018; CRP: CC 0.103 ± 0.009 mg/dl, TT+TC 0.076 ±0.007 mg/dl, p = 0.016; IL-6: CC 60.3 ± 3.0 pg/ml, TT+TC 52.8 ± 2.3 pg/ml, p = 0.04). CONCLUSIONS: The ZFHX3 SNP rs2106261 minor allele is associated with lower AF recurrence rate after pulmonary vein isolation. Low baseline inflammation conferred by this allele may reduce AF recurrence risk.

The mobility of proton carriers in phosphate glasses depends on polymerization of the phosphate framework.

Proton conducting phosphate glasses were prepared by electrochemical substitution of sodium ions with protons applied to glasses with the compositions xNaO1/2-1WO3-8NbO5/2-5LaO3/2-(86 - x)PO5/2 (x = 28, 32, 35, 38, and 40). The mobilities of proton carriers in the glasses were studied in terms of the polymerization degree of the phosphate framework. The proton mobility at 200 °C increased as the depolymerization of the phosphate framework developed up to x = 38, and decreased at x = 40. On the basis of Raman and infrared spectra measurements of the O-H stretching vibration region, the decreasing mobility at x > 38 was attributed to the increasing concentration of protons trapped by non-bridging oxygen in P2O74- ions, owing to strong O-H bonding. We found that the highly polymerized phosphate framework decreased the mobility of proton carriers, not because of suppression of the proton dissociation from oxygen atoms but rather the suppression of the proton migration. The compositions at which the phosphate framework was sufficiently depolymerized and did not contain P2O74- ions as a main component, achieved high mobility of proton carriers in phosphate glasses.

Formation of Amorphous H3Zr2Si2PO12 by Electrochemical Substitution of Sodium Ions in Na3Zr2Si2PO12 with Protons.

The sodium ions in Na3Zr2Si2PO12 (NASICON) were substituted with protons using an electrochemical alkali-proton substitution (APS) technique at 400 °C under a 5% H2/95% N2 atmosphere. The sodium ions in NASICON were successfully substituted with protons to a depth of <400 µm from the anode. Completely protonated NASICON, i.e., H3Zr2Si2PO12, was obtained to a depth <40 µm from the anode, although complete protonation of NASICON cannot be achieved by ion exchange in aqueous acid. H3Zr2Si2PO12 was amorphous, whereas the partially protonated NASICON was crystalline, and its unit cell volume decreased with an increase in the extent of substitution. Amorphous H3Zr2Si2PO12 was prepared by pressure-induced amorphization of the NASICON framework, in which an internal pressure of ∼3.5 GPa was induced by the substitution of large sodium ions with small protons during APS at 400 °C.

Radiofrequency catheter ablation is effective for atrial fibrillation patients with hypertrophic cardiomyopathy by decreasing left atrial pressure.

BACKGROUND: Radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) refractory to medical therapy remains controversial in patients with hypertrophic cardiomyopathy (HCM); the acute effects on the direct left atrial (LA) pressure are not completely understood. METHODS: We consecutively studied patients with HCM (n=15) and without HCM (NHCM, n=106) who underwent extensive encircling pulmonary vein isolation for drug-refractory AF. We compared clinical parameters, echocardiographic parameters, electrophysiological parameters, LA pressures using hemodynamic catheterization and recurrence rate in both groups. RESULTS: The LA volume index was significantly higher (51.9±13.6 mL/m2 vs. 41.6±12.7 mL/m2, p=0.02) in the HCM group than the NHCM group. The pre-ablation mean LA pressure was significantly higher in the HCM group than the NHCM group. Among the AF patients, the mean LA pressure decreased more significantly in the HCM group than the NHCM group (post-ablation minus pre-ablation pressures: 4.2±3.7 mmHg vs. 0.9±4.1 mmHg, p=0.03). The early recurrence rate (within 30 days after ablation) tended to be higher in the HCM group than the NHCM group (20% vs. 5.7%, p=0.08), but the rates of late recurrences (>30 days after ablation) were similar (13.3% vs. 7.6%, p=0.83). Discontinuation of antiarrhythmic drugs occurred at rates of 13% and 62% in the HCM and NHCM groups, respectively (p<0.001). CONCLUSIONS: The LA pressure in the HCM group decreased immediately after AF RFCA. Patients with HCM and drug-refractory AF may benefit from RFCA.

Dexmedetomidine Depresses Sinoatrial and Atrioventricular Nodal Function Without Any Change in Atrial Fibrillation Inducibility.

It has been reported that dexmedetomidine (dex) has an impact on the cardiac conduction system and even has potential antiarrhythmic actions. We examined the influence of dex on the cardiac electrophysiological properties and atrial fibrillation (AF) inducibility. Adult paroxysmal AF patients were randomly assigned to receive (N = 107) or not receive (N = 108) dex during cardiac electrophysiological studies. The corrected sinus node recovery time (558 ± 331 vs. 459 ± 260 milliseconds; P = 0.02), Wenckebach cycle length (P < 0.001), atrioventricular nodal effective refractory period (317 ± 76 vs. 252 ± 54 milliseconds; P < 0.001), and atrio-His interval (P < 0.001) were longer in patients with dex than in those without. We tested the induction of repetitive atrial firing (RFA) defined as the occurrence of ≥2 successive atrial activities induced by single premature atrial stimuli to determine the AF inducibility. RFA was seen with a similar proportion (41.1% vs. 44.4%), yet it was evoked at a longer stimulus coupling interval in the dex patients, which was potentially attributed to the longer atrial effective refractory period (237 ± 36 vs. 213 ± 27 milliseconds; P < 0.001) and more prolonged atrial conduction delay seen in the dex group. In conclusion, dex may depress the sinus and atrioventricular nodal function, however, it may not reduce the AF inducibility.

Risk stratification of ventricular fibrillation in Brugada syndrome using noninvasive scoring methods.

BACKGROUND: Risk stratification for ventricular fibrillation (VF) in patients with Brugada syndrome (BrS) remains controversial. OBJECTIVE: The purpose of this study was to construct a novel prediction model for VF risk in BrS patients using noninvasive parameters. METHODS: A total of 143 Japanese BrS patients with VF (n = 35) and without VF (n = 108) were retrospectively enrolled. We built a logistic regression model predicting VF occurrence and evaluated it by cross-validation. RESULTS: Frequencies of history of syncope and spontaneous type 1 ECG, r-J interval in V1, QRS duration in V6, and LAS40, Tpeak-Tend dispersion, and max T-wave alternans were significantly associated with VF occurrence in univariate analyses. The history of syncope, r-J interval in V1, QRS duration in V6, and Tpeak-Tend dispersion were identified as independent predictors by multivariate logistic regression analysis. The predictive model was constructed using all these parameters with good discrimination of VF occurrence (area under the curve 0.869 with 97.1% sensitivity and 65.7% specificity). The area under the curve based on leave-one-out cross-validation was 0.845, with 97.1% sensitivity and 63.0% specificity suggesting good performance of the model. Retrospective survival analysis revealed that the cumulative VF event rate was significantly higher in patients at high risk than in those with low risk using the log rank test (P = 2.97 × 10(-8)). Notably, no BrS patient below the cutoff value developed a subsequent VF event. CONCLUSION: This novel prediction method may effectively assesses VF risk in BrS patients, especially when determining implantable cardioverter-defibrillator placement for asymptomatic BrS patients.

Electrical Remodeling of the Atrioventricular Node Caused by Persistent Atrial Fibrillation in Humans.

BACKGROUND: An animal experiment showed that long-term atrial pacing or persistent atrial fibrillation (AF) caused electrical remodeling of the atrioventricular (AV) node. We aimed to test the hypothesis that persistent AF decreases the AV conductivity in human hearts. METHODS AND RESULTS: We retrospectively compared the cardiac electrophysiological properties between patients with paroxysmal AF who underwent catheter ablation (PXAF, N = 254) and those with persistent or longstanding persistent AF (PSAF, N = 213). The PSAF patients were more likely than PXAF patients to have longer atrial-His (AH) (96.3 ± 25.7 vs. 91.3 ± 20.4 milliseconds; P = 0.02) and His-ventricle (HV) (43.1 ± 9.4 vs. 41.2 ± 8.6 milliseconds; P = 0.02) intervals. The AV nodal effective refractory period (ERP) (299.1 ± 74.6 vs. 276.2 ± 58.9 milliseconds; P < 0.001) and Wenckebach cycle length (420.9 ± 80.3 vs. 386 ± 58.6 milliseconds; P < 0.001) were also more prolonged in the PSAF patients. We found a dual AV nodal physiology with a similar frequency in both groups. The AH interval, fast pathway ERP, and Wenckebach cycle length in the PSAF patients were more likely than in the PXAF patients to be prolonged among the patients without dual pathways, while those intergroup differences were never seen among the patients with dual pathways. In subgroup analyses including only PSAF patients, there was no difference in the AV conductivity between the patients with persistent AF and those with longstanding persistent AF. CONCLUSIONS: Persistent AF may cause a mild decrease in the AV nodal function in human hearts. Electrical remodeling may be uncommon if dual AV nodal pathways are present, and its extent may not depend on the duration of persistent AF.

Increased left atrial pressure in non-heart failure patients with subclinical hypothyroidism and atrial fibrillation.

BACKGROUND: The impact of subclinical hypothyroidism on the cardiovascular risk is still debated. We aimed to measure the relationship between subclinical hypothyroidism and the left atrial (LA) pressure. METHODS: The LA pressures and thyroid function were measured in consecutive patients undergoing atrial fibrillation (AF) ablation, who did not have any known heart failure, structural heart disease, or overt thyroid disease. RESULTS: Subclinical hypothyroidism (4.5≤ thyroid-stimulating hormone <19.9 mIU/L) was present in 61 (13.0%) of the 471 patients included. More subclinical hypothyroidism patients than euthyroid patients (55.7% vs 40.2%; P=0.04).'euthyroid patients had persistent or long-standing persistent AF (55.7% vs 40.2%; P = 0.04). The mean LA pressure (10.9 ± 4.7 vs 9.1 ± 4.3 mmHg; P = 0.002) and LA V-wave pressure (17.4 ± 6.5 vs 14.3 ± 5.9 mmHg; P < 0.001) were, respectively, higher in the patients with subclinical hypothyroidism than in the euthyroid patients. After an adjustment for potential confounders, the LA pressures remained significantly higher in the subclinical hypothyroidism patients. A multiple logistic regression model showed that subclinical hypothyroidism was independently associated with a mean LA pressure of >18 mmHg (odds ratio 3.94, 95% CI 1.28 11.2; P = 0.02). CONCLUSIONS: Subclinical hypothyroidism may increase the LA pressure in AF patients.

Common Variant Near HEY2 Has a Protective Effect on Ventricular Fibrillation Occurrence in Brugada Syndrome by Regulating the Repolarization Current.

BACKGROUND: Risk stratification of Brugada syndrome (BrS) remains controversial and the majority of patients with BrS have no genetic explanation. We investigated relationships between genotypes of 3 single-nucleotide polymorphisms reported in a recent genome-wide association study and BrS phenotypes. METHODS AND RESULTS: SCN10A (rs10428132), SCN5A (rs11708996), and downstream from HEY2 (rs9388451) single-nucleotide polymorphisms were genotyped and compared between 95 Japanese patients with BrS and 1978 controls. Relationships between the single-nucleotide polymorphisms and clinical characteristics, 12-lead ECG findings, signal-averaged ECG findings, and electrophysiological parameters were also examined in patients with BrS. Both rs10428132 and rs9388451 were significantly associated with BrS (P=2.7×10(-14); odds ratio, 3.0; P=9.2×10(-4); odds ratio, 1.7, respectively). Interestingly, the HEY2 risk allele C was less frequent in BrS patients with ventricular fibrillation than in those without (59% versus 74%; P=4.1×10(-2); odds ratio, 0.5). A significant linear correlation was found between HEY2 genotypes and QTc interval (CC: 422±27 ms; CT: 408±21 ms; and TT: 381±27 ms; P= 4.0×10(-4)). The HEY2 mRNA expression level in the right ventricular specimens from patients with BrS (n=20) was significantly lower in patients with CC genotype than the other genotypes (P=0.04). Additionally, during 63±28 months follow-up periods after implantable cardioverter defibrillator implantation (n=90), Kaplan-Meier event-free survival curves revealed that the cumulative rate of ventricular fibrillation events was significantly lower in cases with HEY2 CC genotype (P=0.04). CONCLUSIONS: Our findings suggest that HEY2 CC genotype may be a favorable prognostic marker for BrS, protectively acting to prevent ventricular fibrillation presumably by regulating the repolarization current.

Phase separation and crystallization in sodium lanthanum phosphate glasses induced by electrochemical substitution of sodium ions with protons.

Electrochemical substitution of sodium ions with protons (alkali-proton substitution; APS), and the injection of proton carriers was applied to sodium lanthanum phosphate glasses. A clear and homogeneous material was obtained for a glass of composition 25NaO1/2-8LaO3/2-66PO5/2-1GeO2 following APS, with a resulting proton conductivity of 4 × 10(-6) S cm(-1) at 250 °C. The glass underwent phase separation and crystallization at temperatures >255 °C, forming a highly hygroscopic and proton conducting H3PO4 phase in addition to LaP5O14 and other unidentified phases. A glass of composition 25NaO1/2-8LaO3/2-67PO5/2 underwent phase separation and crystallization during APS, forming both H3PO4 and LaP5O14 phases. Sodium lanthanum phosphate glasses are prone to phase separation and crystallization during APS unlike the previously reported NaO1/2-WO3-NbO5/2-LaO3/2-PO5/2 glasses. The phase separation was explained by a reduction in viscosity following APS and the introduction of protons, which exhibit high field strength. Thus, phase separation and crystallization of glasses during APS was difficult to avoid. An approach to suppress phase separation is discussed.

Structural change of NaO1/2-WO3-NbO5/2-LaO3/2-PO5/2 glass induced by electrochemical substitution of sodium ions with protons.

Structural changes of 35NaO1/2-1WO3-8NbO5/2-5LaO3/2-51PO5/2 glass (1W-glass) before and after the electrochemical substitution of sodium ions with protons by alkali-proton substitution (APS) are studied by Raman and (31)P magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopies. The glass before APS consists of (PO3(-))8.6(P2O7(4-)) chains on average and the terminal Q(1) units (-O-PO3(3-)) are bound to MO6 octahedra (M denotes niobium or tungsten) through P-O-M bonds. Some non-bridging oxygens (NBOs) in the MO6 octahedra are present in addition to the bridging oxygens (BOs) in P-O-M bonds. APS induces fragmentation of the phosphate chains because the average chain length decreases to (PO3(-))3.7(P2O7(4-)) after APS, despite the total number of modifier cations of sodium and lanthanum ions and protons being unaffected by APS. This fragmentation is induced by some of the NBOs in the MO6 octahedra before APS, changing to BOs of the newly formed M-O-P bonds after APS, because of the preferential formation of P-OH bonds over M-OH ones in the present glass. We show that APS under the conditions used here is not a simple substitution of sodium ions with protons, but it is accompanied by the structural relaxation of the glass to stabilize the injected protons.

Mechanical and substrate abnormalities of the left atrium assessed by 3-dimensional speckle-tracking echocardiography and electroanatomic mapping system in patients with paroxysmal atrial fibrillation.

BACKGROUND: Left atrial (LA) remodeling progresses to electrical remodeling, contractile remodeling, and subsequently structural remodeling. Little is known about the relationship between LA electrical and anatomical remodeling and LA mechanical function. OBJECTIVES: We aimed to clarify the relationship between LA mechanical function using 3-dimensional speckle-tracking echocardiography (3D-STE) and LA electrical remodeling using an electroanatomic mapping system (CARTO 3) and to estimate atrial fibrillation (AF) substrate in patients with paroxysmal AF (PAF). METHODS: A total of 52 patients with PAF (41 (79%) men; mean age 61 ± 11 years) undergoing their initial pulmonary vein isolation (PVI) were examined. The standard deviation of the time to peak strain in each LA segment (%SD-TPS) was analyzed as an index of LA dyssynchrony using 3D-STE before PVI. Contact LA bipolar voltage and activation maps were constructed during sinus rhythm before PVI using CARTO 3. The LA total activation time was measured and low-voltage zones (LVZs) were determined with a local bipolar electrogram amplitude of <0.5 mV. The patients were divided into those with an LVZ (LVZ group; n = 23) and those without an LVZ (non-LVZ group; n = 29). RESULTS: The %SD-TPS was significantly higher (14.1 ± 5.7 vs 8.0 ± 5.1; P=.0002) in the LVZ group than in the non-LVZ group and was an independent determinant of the LVZ (odds ratio 1.21; 95% confidence interval 1.04-1.49; P=.01). In addition, the LA total activation time was weakly correlated with the %SD-TPS. CONCLUSION: LA dyssynchrony and conduction delay exist in patients with PAF. The 3D-STE enabled noninvasive estimation of LA electrical remodeling and AF substrate.

Time-domain T-wave alternans is strongly associated with a history of ventricular fibrillation in patients with Brugada syndrome.

AIMS: T-wave alternans (TWA) is an indicator of vulnerability to ventricular arrhythmias and is useful for predicting sudden cardiac death (SCD) in patients with various structural heart diseases. We evaluated whether high levels of time-domain TWA on ambulatory ECG (AECG) are associated with a history of ventricular fibrillation (VF) in Brugada syndrome (BrS) patients. METHODS AND RESULTS: We examined the associations among VF history, family history of SCD, spontaneous type 1 electrocardiogram (ECG), late potentials, VF induction by programmed electrical stimulation, and TWA in 45 BrS patients (44 males; mean age, 45 ± 15 years). TWA analyzed from 24-h AECG recordings using the modified moving average method was positive in 13 of 43 patients (30%). Patients with a history of VF had a significantly higher incidence of a positive TWA test (82% vs. 13%; P < 0.001) and spontaneous type 1 ECG (92% vs. 38%; P = 0.007) than those without VF history. Multivariate analysis indicated that positive TWA (OR 7.217; 95% CI 2.503-35.504; P = 0.002) and spontaneous type 1 ECG (OR 5.530; 95% CI 1.651-34.337; P = 0.020) were closely associated with VF history. Spontaneous type 1 ECG had high sensitivity (92%) but low specificity (63%). Positive TWA was a reliable marker with high sensitivity and specificity (82% and 88%, respectively). CONCLUSION: Elevated time-domain TWA on AECG confirms arrhythmia risk in symptomatic BrS patients without the need for provocative stimuli.

Incomplete cure of tachycardia-induced cardiomyopathy secondary to rapid atrial fibrillation by heart rate control without sinus conversion.

BACKGROUND: It is uncertain whether rate or rhythm control is more favorable for patients experiencing tachycardia-induced cardiomyopathy (TIC) secondary to rapid atrial fibrillation (AF). METHODS AND RESULTS: We compared the electrophysiological and hemodynamic properties and outcome after AF ablation in 20 patients with a history of decompensated TIC who maintained sinus rhythm or had paroxysmal AF (group 1), 32 with a history of decompensated TIC who had persistent or longstanding persistent AF (group 2), 377 without TIC who had paroxysmal AF (group 3), and 225 without TIC who had persistent or longstanding persistent AF (group 4). The corrected sinus node recovery time was more prolonged in group 2 than in groups 1, 3, or 4 (1,066 ± 946 vs. 416 ± 188, 450 ± 322 and 590 ± 329 milliseconds; P < 0.001, respectively). The mean left atrial pressure in group 2 was greater than that in groups 1, 3, or 4 (13.9 ± 6.5 vs. 7.5 ± 3.1, 8.2 ± 4.1 and 10.8 ± 4.2 mmHg; P < 0.001, respectively). The left ventricular ejection fraction assessed after the recovery from the decompensation was more decreased in group 2 than in group 1; however, it almost returned to normal if sinus rhythm was maintained after the AF ablation in group 2. The presence of a history of TIC did not predict an AF recurrence after the ablation. CONCLUSIONS: Heart rate control during AF without sinus conversion may result in an incomplete cure of TIC, suggesting the advantages of rhythm control with ablation in patients with TIC.

Spontaneous disappearance of coronary pseudoaneurysm due to coronary artery perforation following percutaneous coronary intervention.

In recent years, while therapeutic outcome after percutaneous coronary intervention is improving due to the introduction of drug-eluting stent and device development, procedure-related complications including coronary perforation may ineluctably occur though at low-frequency, even if careful manipulations are performed under IVUS guidance. Meanwhile, coronary pseudoaneurysm subsequent to coronary perforation is one of the complications at chronic phase infrequently experienced following percutaneous coronary intervention. To date, the incidence and natural history of pseudoaneurysm following coronary artery perforation remain unclear. We experienced a case with coronary pseudoaneurysm developed 2 weeks after Ellis II-type coronary artery perforation which spontaneously disappeared 4 months later. As the mechanism of disappearance, thrombotic occlusion was confirmed upon intravascular ultrasound.

A case of idiopathic ventricular fibrillation in which implanted loop recorder was useful in application decision for implantation of implantable cardioverter-defibrillator.

Establishing a symptom-rhythm correlation in patients with unexplained syncope is complicated because of its sporadic, infrequent, and unpredictable nature. Recently, an implantable loop recorder (ILR) has become available to evaluate undiagnosed recurrent arrhythmic episodes particularly in unexplained syncopes, and its usefulness has been reported in patients with recurrent syncopes that remain unexplained after conventional work-up. A 65-year-old man was referred to our hospital for loss of consciousness with nocturnal paroxysmal seizures. He had experienced several similar episodes. No family history of sudden death was evident, and apparent structural heart disease was absent. Coronary angiography with intracoronary ergonovine provocation showed vasospasm in left coronary artery without organic stenosis. Ventricular tachyarrhythmias were not induced by programmed electrical stimuli. According to the guideline, he was at once categorized as having class IIb indication for implantable cardioverter defibrillator implantation. However, his symptoms were not relieved despite administration of anti-anginal medications including nitrates and calcium antagonist. Implantation of an ILR was performed and revealed an episode of ventricular fibrillation during generalized-convulsion attack during sleep. ILR is useful in determining the presence of fatal arrhythmias during syncope, although conventional diagnostic testing, such as electrocardiogram, Holter monitoring, and external loop recording, is inconclusive.

Cavity volume of ruptured plaque is an independent predictor for angiographic no-reflow phenomenon during primary angioplasty in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Plaque rupture plays a critical role for the development of acute myocardial infarction. However, whether quantitative parameters with regard to the cavity size of ruptured plaque are associated with no-reflow (NR) phenomenon following primary angioplasty remains to be elucidated. METHODS AND RESULTS: A total of 53 patients with de novo ST-elevation myocardial infarction (STEMI) who had plaque rupture at the culprit lesion defined by pre-intervention virtual histology intravascular ultrasound (VH-IVUS) were enrolled. Patients were divided into two groups according to the presence of NR phenomenon: NR group (n=19) and non-NR group (n = 34). By VH-IVUS, we evaluated cavity length, maximum area, and volume of ruptured plaque in culprit lesions. The cavity length, maximum area, and volume were significantly higher in the NR group than those of the non-NR group (4.8 ± 2.1 mm vs. 2.9 ± 4.8 mm, p < 0.001; 3.6 ± 1.4 mm² vs. 1.9 ± 0.5 mm², p < 0.001; 11.5 ± 6.3 mm³ vs. 3.7 ± 2.2 cm³, p < 0.001). A multiple logistic regression analysis revealed that the cavity volume was an independent risk for NR phenomenon. Receiver-operating characteristic analysis revealed that the cavity volume could predict NR phenomenon. CONCLUSIONS: The cavity size of ruptured plaque is closely associated with NR phenomenon in patients with STEMI. Evaluation of the cavity volume by VH-IVUS may provide useful information for the prediction of NR phenomenon.