Treatment with catheter ablation for patients with arrhythmia-induced cardiomyopathy caused by atrial fibrillation promises a good prognosis.

Clinical outcomes after catheter ablation in patients with reduced left ventricular (LV) ejection fraction (EF) and atrial fibrillation (AF) remain unclear. This study aimed to explore the clinical outcomes of patients with arrhythmia-induced cardiomyopathy (AIC) and the influence of pharmacological treatment on clinical outcomes in patients with AIC after the procedure. Ninety-six patients with AF with a reduced LVEF (LVEF < 50%, 66.7 ± 10.9 years; 72 males) underwent AF ablation. AIC was defined as patients whose LVEF recovered ≥ 50% after catheter ablation (n = 67) and patients whose LVEF remained reduced were defined as non-AIC (n = 29). During a median follow-up of 25 (13-40) months, Kaplan-Meier analysis demonstrated that patients with AIC were associated with less frequent cardiovascular death (p = 0.025) and hospitalization for worsening heart failure (p < 0.001) than those without AIC. Freedom from AF recurrence was similar between the two groups (p = 0.47). In multivariate analysis, the LV end-diastolic diameter (p = 0.0002) and the CHA2DS2-VASc scores (p = 0.0062) were independent predictors of AIC. Among the 67 patients with AIC, no significant differences in baseline characteristics, except for LV chamber size and cryoballoon use, were observed between patients with AIC with (n = 31) and without renin-angiotensin system (RAS) inhibitors (n = 36). In the Kaplan-Meier analysis, cardiovascular death, hospitalization for worsening heart failure, and AF recurrence after catheter ablation did not differ between patients treated with and without RAS inhibitors (all p > 0.05). Catheter ablation in patients with AIC due to AF is associated with a good post-procedural prognosis.IRB information The study was approved by the Research Ethics Committee of the University of Fukui (No. 20220151) and clinical trial registration (UMIN000050391).

The P wave morphology in lead V7 on the synthesized 18-lead ECG is a useful parameter for identifying arrhythmias originating from the right inferior pulmonary vein.

Atrial tachyarrhythmias often originate from the superior vena cava (SVC), and right superior (RSPV) and inferior pulmonary veins (RIPV). However, a precise differentiation of those origins is challenging using the standard 12-lead electrocardiogram (ECG) P-wave morphology due to the anatomical proximity. The recently developed synthesized 18-lead ECG provides virtual waveforms of the right-sided chest and back leads. This study evaluated the utility of the synthesized 18-lead ECG to differentiate atrial arrhythmias originating from 3 adjacent structures. Synthesized 18-lead ECGs were obtained during SVC-, RSPV-, and RIPV-pacing in 20 patients with lone paroxysmal atrial fibrillation to develop an algorithm. The P-wave morphologies were classified into 4 patterns: positive, negative, biphasic, and isoelectric. Subsequently, the algorithm's accuracy was validated prospectively in another 40 patients. In retrospective analyses, isoelectric P-waves in synthesized V7 distinguished RIPV-pacing from the others (sensitivity = 81%, specificity = 92%) (first criteria). The P wave morphologies in Leads II (sensitivity = 83%, specificity = 94%) and V1 (sensitivity = 84%, specificity = 80%) distinguished SVC- and RSPV-pacing (second criteria). In a prospective evaluation, the sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], and accuracy of the first criteria for identifying RIPV-pacing was 97%, 90%, 78%, 99%, and 92%, respectively. The sensitivity, specificity, RPV, NPV, and accuracy of the second criteria (amplitudes > 1 mV in lead II or biphasic P-waves in lead V1) for discriminating SVC- and RSPV-pacing was 66%, 95%, 98%, 50%, and 74%, respectively. The P wave morphology pattern in lead V7 in synthesized 18-lead ECGs is useful for differentiating RIPV origins from RSPV/SVC origins.

Serum tenascin-C levels in atrium predict atrial structural remodeling processes in patients with atrial fibrillation.

BACKGROUND: Fibro-inflammatory processes in the extracellular matrix are closely associated with progressive structural remodeling in atrial fibrillation (AF). Serum concentrations of tenascin-C (TNC), an extracellular matrix glycoprotein, and of high-sensitivity C-reactive protein (CRP) might serve as a marker of remodeling and progressive inflammation of the aorta and in myocardial diseases. This study aimed to clarify relationships between TNC and CRP in patients with AF. METHODS: This study included 38 patients with AF and five controls without left ventricular dysfunction who underwent catheter ablation. Blood was collected immediately before ablation from the left atrium (LA), right atrium (RA), and femoral artery (FA), and left and right atrial pressure was measured. Levels of TNC in the LA (TNC-LA), RA (TNC-RA), and FA (TNC-FA) and high-sensitivity C-reactive protein (CRP) were measured. Atrial size was also determined by echocardiography. RESULTS: Levels of TNC corrected by atrial size were maximal in the LA, followed by the RA (3.69 ± 0.32 and 2.87 ± 0.38 ng/mL/cm, respectively). Mean transverse diameter corrected by body surface area was larger and mean atrial pressure was greater in the LA than the RA. A relationship was found between CRP from the femoral vein and TNC-LA and TNC-RA, but not TNC-FA. None of TNC-LA, TNC-RA, or TNC-FA correlated with ANP or BNP in the femoral vein. CONCLUSIONS: Intracardiac (atrial) TNC expression plays an important role in the development of remodeling processes in the atrium with AF. Tenascin-C from the LA and RA (but not TNC, ANP, and BNP from FA) might serve as novel markers of these processes.

Pressure-guided second-generation cryoballoon pulmonary vein isolation: Prospective comparison of the procedural and clinical outcomes with the conventional strategy.

BACKGROUND: The utility of pressure waveform analyses to assess pulmonary vein (PV) occlusions has been reported in cryoballoon PV isolation (CB-PVI) using first-generation CBs. This prospective randomized study compared the procedural and clinical outcomes of pressure-guided and conventional CB-PVI. METHODS AND RESULTS: Sixty patients with paroxysmal atrial fibrillation underwent CB-PVI with 28-mm second-generation CBs. PV occlusions were assessed either by real-time pressure waveforms without contrast utilization (pressure-guided group) or contrast injections (conventional group) and randomly assigned. Before the randomization, 24 patients underwent pressure-guided CB-PVIs. In the derivation study, a vein occlusion was obtained in 88/96 (91.7%) PVs among which 86 (97.7%) were successfully isolated by the application. In the validation study, the nadir balloon temperature and total freezing time did not significantly differ per PV between the two groups. The positive predictive value of the vein occlusion for predicting successful acute isolations was similar (93 of 103 [90.2%] and 89 of 98 [90.8%] PVs; P = 1.000), but the negative predictive value was significantly higher in pressure-guided than angiographical occlusions (14 of 17 [82.3%] vs 7 of 22 [31.8%]; P = .003). Both the procedure (57.7 ± 14.2 vs 62.6 ± 15.8 minutes; P = .526) and fluoroscopic times (16.3 ± 6.4 vs 20.1 ± 6.1; P = .732) were similar between the two groups, however, the fluoroscopy dose (130.6 ± 97.7 vs 353.2 ± 231.4 mGy; P < .001) and contrast volume used (0 vs 17.5 ± 7.7 mL; P < .001) were significantly smaller in the pressure-guided than conventional group. During 27.8 (5-39) months of follow-up, the single procedure arrhythmia freedom was similar between the two groups (P = .438). CONCLUSIONS: Pressure-guided second-generation CB-PVIs were similarly effective and as safe as conventional CB-PVIs. This technique required no contrast utilization and significantly reduced radiation exposure more than conventional CB-PVIs.

Effects of Sitagliptin on the Coronary Flow Reserve, Circulating Endothelial Progenitor Cells and Stromal Cell-derived Factor-1alpha.

Objective Circulating endothelial progenitor cells (EPCs) are regulated by stromal cell-derived factor-1alpha (SDF-1α) and are reduced in type 2 diabetes mellitus (DM). SDF-1α is a substrate of dipeptidyl-peptidase-4 (DPP-4), so we investigated whether or not DPP-4-inhibitors modulate EPC levels in type 2 DM patients with coronary artery disease (CAD). Methods Thirty patients with CAD and type 2 DM treated using an ordinary regimen were enrolled. EPC and SDF-1α levels were compared between those receiving additional 24-week treatment with a DPP-4-inhibitor (n=11) and no additional treatment (n=19). We determined the HbA1c, 1.5-Anhydro-D-glucitol (1,5-AG), coronary flow reserve (CFR), brain natriuretic peptide (BNP), E/e', and circulating EPC proportion and SDF-1α levels at baseline and the end of follow-up. The CFR was assessed using a dual-sensor-equipped guidewire. The primary endpoints were changes in the EPC count, SDF-1α levels, and CFR from baseline to the end of follow-up. The secondary endpoints were changes in the HbA1c and 1,5-AG, which are useful clinical markers of postprandial hyperglycemia, as well as the BNP and E/e'. Results After the 6-month follow-up, compared with ordinary regimen subjects, the patients receiving a DPP-4-inhibitor showed no significant increase in the EPC proportion (-0.01±0.50 vs. 0.02±0.77%, p=0.87), SDF-1α level (-600.4±653.6 vs. -283.2±543.1 pg/mL, p=0.18), or CFR (0.0±0.2 vs. 0.1±0.6, p=0.20), whereas both the 1.5-AG level (2.4±4.6 vs. -0.7±2.5 µg/dL, p=0.07) and HbA1c (-0.8±1.8 vs. 0.0±0.7%, p=0.02) were improved. There were no significant differences between the two groups in changes in the BNP and E/e'. Conclusion DPP-4 inhibition with sitagliptin did not increase or decrease the EPC proportion, SDF-1α level, or CFR, although the glycemic control was improved.

Intra-procedural evaluation of the cavo-tricuspid isthmus anatomy with different techniques: comparison of angiography and intracardiac echocardiography.

Cavo-tricuspid isthmus (CTI) anatomies are highly variable, and specific anatomies lead to a difficult CTI ablation. This study aimed to compare the clinical utility of angiography and intracardiac echocardiography (ICE) in evaluating CTI anatomies, and to investigate the impact of the CTI anatomy on the procedure when the ablation tactic was adjusted to the anatomy. This study included 92 consecutive patients who underwent a CTI ablation. The CTI morphology was assessed with both right atrial angiography and ICE before the ablation, and the ablation tactic was adjusted to the anatomy. The mean CTI length was 34 ± 9 mm. On ICE imaging, 21 (23%) patients had a flat CTI, while 41 (45%) had a concave CTI with a mean depth of 5.6 ± 2.7 mm. The remaining 30 (32%) had a distinct pouch with a mean depth of 6.4 ± 2.3 mm, located at the posterior, middle, and anterior isthmus in 15, 14, and 1 patients, respectively. The Eustachian ridge (ER) was visualized in 46 (50%) patients. On angiography, a pouch and ER were detected in 22 and 15 patients, but not in the remaining 8 and 31, respectively. A complete CTI block line was created in all patients without any complications. The CTI anatomy did not significantly impact any procedural parameters. ICE was superior to angiography in evaluating the detailed CTI anatomy, especially pouches and the ER. An adjustment of the ablation tactic to the anatomy could overcome the procedural difficulties of the CTI ablation in cases with specific anatomies.

A Slower Heart Rate and Therapeutic Hypothermia Unmasked Early Repolarization Syndrome in a Ventricular Fibrillation Survivor.

Patients presenting with aborted cardiac arrest who display early repolarization generally are diagnosed with early repolarization syndrome. Therapeutic hypothermia is a standard strategy to improve neurological outcome in comatose patients after cardiac arrest. We present here a patient in whom therapeutic hypothermia exacerbated the J-wave amplitude and morphology, which resulted in episodes of refractory ventricular fibrillation.

Recruitment of Complete Right Bundle Branch Block by Permanent Para-Hisian Pacing.

His-bundle pacing has recently emerged as a means to maintain a physiological ventricular activation and eliminate the risk of pacing-induced myopathy associated with traditional right ventricular pacing. With His-bundle pacing, the exact stimulated structure and resulting excitation wavefront may be highly dependent on the pacing output, dimensions of the stimulatory electrodes, and orientation of the cathode and anode relative to the approximated conduction tissue and surrounding myocardium, owing to the juxtaposition of tissues with very different conduction properties. We herein present an 89-year-old woman with an infra-Hisian conduction disease in whom lower output pacing resulted in pure His-bundle pacing, and higher output pacing resulted in para-Hisian pacing that recruited diseased portions of the conduction system, narrowing the QRS complex.

Endothelial damage and thromboembolic risk after pulmonary vein isolation using the latest ablation technologies: a comparison of the second-generation cryoballoon vs. contact force-sensing radiofrequency ablation.

Experimental data suggest that cryoenergy is associated with less endothelial damage and thrombus formation than radiofrequency energy. This study aimed to compare the impact of pulmonary vein isolation (PVI) on the endothelial damage, myocardial damage, inflammatory response, and prothrombotic state between the two latest technologies, second-generation cryoballoon (CB2) and contact force-sensing radiofrequency catheter (CFRF) ablation. Eighty-six paroxysmal atrial fibrillation (AF) patients (55 men; 65 ± 12 years) underwent PVI with either the CB2 (n = 64) or CFRF (n = 22). Markers of the endothelial damage (L-arginine/asymmetric dimethylarginine [ADMA]), myocardial injury (creatine kinase-MB [CK-MB], troponin-T, and troponin-I), inflammatory response (high-sensitive C-reactive protein), and prothrombotic state (D-dimer, soluble fibrin monomer complex, and thrombin-antithrombin complex) were determined before and up to 24-h post-procedure. The total application time was shorter (1,460 ± 287 vs. 2,395 ± 571 [sec], p < 0.01) and total procedure time tended to be shorter (199 ± 37 vs. 218 ± 38 [min], p = 0.06) with CB2 than CFRF ablation. The amount of myocardial injury was greater (CK-MB: 45 ± 17 vs. 11 ± 3 [IU/l], p < 0.01) with CB2 than CFRF ablation. The L-arginine/ADMA ratio was lower (160 ± 51 vs. 194 ± 38, p = 0.028) after CB2 than CFRF ablation. Inflammatory and all prothrombotic markers were significantly elevated post-ablation; however, the magnitude was similar between the two groups. During a mean follow-up of 20 ± 6 months, the single-procedure AF freedom was similar between the CB2 and CFRF groups (60/64 vs. 20/22, p = 0.82). CB2-PVI produces significantly lesser endothelial damage with greater myocardial injury than CFRF-PVI; however, similar anticoagulant regimens are required during the peri-procedural periods in both technologies.

Association of plasma pentraxin-3 levels with coronary risk factors and the lipid profile: a cross-sectional study in Japanese patients with stable angina pectoris.

The aim of this study was to evaluate the relationships among the traditional risk factors, lipid profile, and pentraxin-3 in stable angina (SAP). Plasma pentraxin-3 and serum LDL, HDL, and high-sensitivity CRP levels were measured in 163 SAP and 28 non-coronary artery disease (CAD) patients. Their relationships with five risk factors, hypertension (HT), dyslipidemia (DL), diabetes mellitus (DM), obesity (body mass index: BMI > 25 kg/m2), and high age (> 75 years), were evaluated. No significant difference was observed in the pentraxin-3 level between patients in SAP and in non-CAD [2.1 (1.4-3.5) ng/ml versus off 2.6 (1.6-3.8) ng/ml, P = 0.56). In SAP patients, pentraxin-3 levels decreased with more risk factors, according to the number of 3 traditional risk factors (HT, DL, and DM) and the number of 5 expanded risk factors (HT, DL, DM, obesity, and high age) (P for trend = 0.01 and 0.05, respectively). Pentraxin-3 showed a positive association with HDL (rs = 0.229; P = 0.050) and an inverse association with LDL (rs = - 0.224; P = 0.045). On multiple logistic regression, the number of 3 traditional risk factors was a significant predictor of pentraxin-3 levels (odds ratio = 0.444; 95% confidence interval 0.205-0.963, P = 0.040) in SAP patients. In SAP patients, the cardiovascular risk factor burden remained a negative impact on pentraxin-3 levels after multivariate analysis, suggesting that they have distinct roles in atherosclerosis.Trial registration: UMIN000023837.

The impact of the CartoSound® image directly acquired from the left atrium for integration in atrial fibrillation ablation.

PURPOSE: Intracardiac echocardiographic (ICE) imaging might be useful for integrating three-dimensional computed tomographic (CT) images for left atrial (LA) catheter navigation during atrial fibrillation (AF) ablation. However, the optimal CT image integration method using ICE has not been established. METHODS: This study included 52 AF patients who underwent successful circumferential pulmonary vein isolation (CPVI). In all patients, CT image integration was performed after the CPVI with the following two methods: (1) using ICE images of the LA derived from the right atrium and right ventricular outflow tract (RA-merge) and (2) using ICE images of the LA directly derived from the LA added to the image for the RA-merge (LA-merge). The accuracy of these two methods was assessed by the distances between the integrated CT image and ICE image (ICE-to-CT distance), and between the CT image and actual ablated sites for the CPVI (CT-to-ABL distance). RESULTS: The mean ICE-to-CT distance was comparable between the two methods (RA-merge = 1.6 ± 0.5 mm, LA-merge = 1.7 ± 0.4 mm; p = 0.33). However, the mean CT-to-ABL distance was shorter for the LA-merge (2.1 ± 0.6 mm) than RA-merge (2.5 ± 0.8 mm; p < 0.01). The LA, especially the left-sided PVs and LA roof, was more sharply delineated by direct LA imaging, and whereas the greatest CT-to-ABL distance was observed at the roof portion of the left superior PV (3.7 ± 2.8 mm) after the RA-merge, it improved to 2.6 ± 1.9 mm after the LA-merge (p < 0.01). CONCLUSIONS: Additional ICE images of the LA directly acquired from the LA might lead to a greater accuracy of the CT image integration for the CVPI.

Association between matrix metalloproteinase-9 and worsening heart failure events in patients with chronic heart failure.

AIMS: Matrix metalloproteinase (MMP) is up-regulated during heart failure (HF) and influences ventricular remodeling. We hypothesized that disparity between MMP-9 and tissue inhibitors of MMP-1 (TIMP-1) results in clinical manifestations and is related to prognostic risk in patients with chronic HF. METHODS AND RESULTS: Plasma levels of MMP-9, TIMP-1, and brain natriuretic peptide (BNP) were measured in 173 patients with chronic HF. Combined endpoints of worsening HF events were assessed during follow-up (median 109 months). MMP-9 and TIMP-1 levels and the MMP-9/TIMP-1 ratio increased with increasing severity of the New York Heart Association class (P for trend = 0.003, 0.011, and 0.005, respectively). Patients with HF events (n = 35) had significantly higher MMP-9 than those without HF events (P = 0.004). Kaplan-Meier analysis demonstrated a higher probability of HF events with high MMP-9 values (>23.2 ng/mL; P = 0.005). A multivariate Cox proportional hazard model showed that high MMP-9 values were an independent predictor of HF events (hazard ratio, 3.73; 95% confidence interval (CI), 1.03-13.46; P = 0.043). In patients with lower BNP levels (≤210 pg/mL), the adjusted hazard ratio for HF events was 3.63 (95% CI, 1.20-11.02; P = 0.023) among patients with high MMP-9 values compared with patients with low BNP and low MMP-9 values. CONCLUSIONS: MMP-9 and TIMP-1 levels correlate with the severity of chronic HF. MMP-9 is a strong predictor of HF events, suggesting that a disparity between MMP-9 and TIMP-1 levels and increased MMP-9 levels may help predict HF events.

A multicenter study of the need of additional freezing for cryoballoon ablation in patients with atrial fibrillation: The AD-Balloon study.

BACKGROUND: Pulmonary vein isolation (PVI) is a cornerstone of catheter ablation in patients with paroxysmal atrial fibrillation (PAF), and balloon-based ablation has been recently performed worldwide. Ablation using the second-generation cryoballoon (CB2) (Arctic Front AdvanceTM, Medtronic, MN, USA) is useful for PVI; however, there is some debate concerning the optimal freezing time and number of cycles after PVI is achieved. METHODS: The AD-Balloon study was designed as a prospective, multicenter, randomized clinical trial to evaluate the optimal strategy (freezing cycles) of CB2 ablation (UMIN Clinical Trials Registry UMIN000020130). The main objective of this study is to investigate the need for an additional freezing cycle after PVI in patients treated with CB2 ablation. Patients will be randomly assigned in a 1:1 ratio to treatment with additional freezing (AD group) or without additional freezing (non-AD group). In the AD group, 3 min of additional freezing time will be applied in all pulmonary veins after PVI is confirmed at the previous freezing cycle. In the non-AD group, no additional freezing will be applied in all pulmonary veins after PVI is confirmed. The primary endpoint of this study is the occurrence of atrial tachyarrhythmias within a 1-year follow-up period. We will enroll 110 consecutive patients with PAF. We will also investigate the usefulness of delayed-enhancement magnetic resonance imaging to assess the ablation lesions caused by CB2 ablation. RESULTS: The results of this study are currently under investigation. CONCLUSION: The AD-Balloon study would assess the need for an additional freezing cycle after PVI is achieved. Our findings may contribute to further improvement of the CB2 ablation procedure.

Impaired myocardial microcirculation in the flow-glucose metabolism mismatch regions in revascularized acute myocardial infarction.

BACKGROUND: In successfully revascularized acute myocardial infarction (AMI), microvascular function in a myocardial flow-glucose metabolism mismatch pattern has not been reported. We aimed to elucidate myocardial flow reserve (MFR) and myocardial viability in mismatch segments. METHODS: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and adenosine stress 13N-ammonia PET were performed in eighteen AMI patients to evaluate myocardial glucose metabolism, myocardial blood flow (MBF), and MFR. Infarct segments were classified into 3 groups: normal (preserved resting MBF), mismatch (preserved FDG uptake but reduced resting MBF), and match (reduced FDG uptake and resting MBF). Regional wall motion score (WMS) was assessed immediately after reperfusion and recovery periods. RESULTS: MFR in the mismatch group was significantly lower than that in non-infarct-related segments (1.655 ± 0.516 vs 2.282 ± 0.629, P < .01) and similar to that in the match group (1.635 ± 0.528, P = .999). WMS in the mismatch group was significantly improved (3.07 ± 0.48 vs 2.07 ± 1.14, P = .003); however, in recovery periods, WMS in the mismatch group was significantly higher than that in the normal group (1.05 ± 1.04, P < .01). CONCLUSIONS: In successfully revascularized AMI, microvascular function is impaired despite preserved myocardial glucose metabolism in mismatch segments.

Association of CD34/CD133/VEGFR2-Positive Cell Numbers with Eicosapentaenoic Acid and Postprandial Hyperglycemia in Patients with Coronary Artery Disease.

OBJECTIVES: Circulating endothelial progenitor cells (EPCs), which have the ability to differentiate into mature endothelial cells, can elicit angiogenesis, vasculogenesis and vessel repair in cardiac ischemia and vascular injuries caused by endothelial damage. Serum 1,5-anhydro-d-glucitol (1,5-AG), which is a useful clinical marker of postprandial hyperglycemia, eicosapentaenoic acid (EPA), and arachidonic acid (AA) are newly identified risk factors for coronary artery disease (CAD). However, no previous study has reported the associations between EPCs and 1,5-AG, EPA, and AA levels in CAD patients with type 2 diabetes mellitus (DM). METHODS: Peripheral EPCs, assessed as CD34+ cells co-expressing CD133 and vascular endothelial growth factor receptor-2, were studied in 76 CAD patients (mean age, 69.2±11.3years) with DM. Serum 1,5-AG, EPA, and AA levels were measured. RESULTS: EPC numbers showed a significant association with 1,5-AG and HbA1c (r=0.290; p=0.037 and r=-0.328; p=0.011, respectively). In addition, there were significant associations between EPC numbers and EPA and body mass index (BMI) (r=0.354; p=0.027 and r=-0.402; p=0.002, respectively). In multiple linear regression analysis, HbA1c, BMI, and EPA values had significant associations with EPC numbers (ß=-0.316, 95% confidence interval (CI) -0.256 to -0.008, p=0.037; ß=-0.413, 95% CI -0.099 to -0.017, p=0.007; and ß=0.400, 95% CI 0.004 to 0.002, p=0.010, respectively). CONCLUSIONS: EPC number is associated with HbA1c, 1,5-AG, EPA, and BMI values, suggesting that postprandial hyperglycemia and n-3 polyunsaturated fatty acids contribute to EPC recruitment in CAD patients with type 2 DM.

Experimental Realization of a Quantum Pentagonal Lattice.

Geometric frustration, in which competing interactions give rise to degenerate ground states, potentially induces various exotic quantum phenomena in magnetic materials. Minimal models comprising triangular units, such as triangular and Kagome lattices, have been investigated for decades to realize novel quantum phases, such as quantum spin liquid. A pentagon is the second-minimal elementary unit for geometric frustration. The realization of such systems is expected to provide a distinct platform for studying frustrated magnetism. Here, we present a spin-1/2 quantum pentagonal lattice in the new organic radical crystal α-2,6-Cl2-V [=α-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl]. Its unique molecular arrangement allows the formation of a partially corner-shared pentagonal lattice (PCPL). We find a clear 1/3 magnetization plateau and an anomalous change in magnetization in the vicinity of the saturation field, which originate from frustrated interactions in the PCPL.

Effect of postprandial hyperglycaemia on coronary flow reserve in patients with impaired glucose tolerance and type 2 diabetes mellitus.

BACKGROUND: This study investigated whether postprandial hyperglycaemia has an adverse effect on coronary microvascular function and left ventricular diastolic function. METHODS: In all, 28 patients with type 2 diabetes mellitus with no significant stenosis in left anterior descending artery were enrolled. In all subjects, plasma 1,5-anhydroglucitol was measured, and coronary flow reserve in the left anterior descending artery was evaluated using a Doppler wire. Membrane type-1 matrix metalloproteinase expression on circulating peripheral blood mononuclear cells was measured by flow cytometry. Correlation analyses were performed for coronary flow reserve and 1,5-anhydroglucitol, other coronary risk factors, membrane type-1 matrix metalloproteinase and E/e'. RESULTS: Strong correlations were found only between 1,5-anhydroglucitol and coronary flow reserve and membrane type-1 matrix metalloproteinase. On multiple regression analysis, 1,5-anhydroglucitol remained an independent predictor of coronary flow reserve (ß = 0.38, p = 0.048). CONCLUSION: Postprandial hyperglycaemia appears to have an adverse effect on coronary microvascular function, suggesting that improvement of postprandial hyperglycaemia may contribute to the improvement of coronary microvascular dysfunction.

Predictive utility of the changes in matrix metalloproteinase-2 in the early phase for left ventricular reverse remodeling after an acute myocardial infarction.

BACKGROUND: The relationship between the serum levels of matrix metalloproteinase (MMP) and tissue inhibitors of MMP (TIMP) and left ventricular (LV) reverse remodeling (LV-RR) after an acute myocardial infarction (AMI) has not been sufficiently examined. METHODS AND RESULTS: In 25 patients with successful reperfusion after an AMI and 15 normal control subjects, the serum MMP-2 and TIMP-2 levels were measured on days 1, 2, 3, and 7 and at 1 and 6 months after the AMI onset. LV-RR was defined as a >15% decrease in the LV end-systolic volume index at 6 months after the AMI. The MMP-2 level on day 1 and TIMP-2 levels throughout the study period were comparable between the patients with and without LV-RR. The MMP-2 on day 7 (P<0.05) and the changes in the MMP-2 from day 1 to day 7 (∆MMP-2; P<0.01) were lower in patients with than in those without LV-RR. The ∆MMP-2 was strongly correlated with the changes in the LV volume and ejection fraction from 1 month to 6 months after the AMI. The ∆MMP-2 value of <-158.5 ng/mL predicted LV-RR with a high accuracy (91.7% sensitivity and 76.9% specificity; area under the curve=0.82). CONCLUSIONS: Changes in MMP-2 are associated with LV-RR after an AMI. The ΔMMP-2 might be a useful predictor of subsequent LV-RR.