One-Year Outcome of Patients with Chest Pain in the Rule-Out Group According to the 0-Hour/1-Hour Algorithm.

The European Society of Cardiology recommends the 0/1-hour algorithm for risk stratification of patients with suspected non-ST-elevation myocardial infarction as class I, level B; however, there are few reports on the long-term prognosis, resulting in a rule-out group. We aimed to determine whether implementation of the 0-hour/1-hour algorithm is safe and effective in emergency department (ED) patients with possible acute coronary syndrome (ACS) through a 1-year follow-up period. Our study analyzed the 1-year follow-up data from a prospective pre-post study of 1106 ED patients with possible ACS from 4 hospitals in Japan and Taiwan. Patients were 18 years or older. Accrual occurred for 1 year after implementing the 0-1-hour algorithm from November 2014 to December 2018. Overall, 520 patients were stratified into the rule-out group. Major advanced cardiovascular events (all-cause death, acute myocardial infarction [AMI], stroke, unstable angina, and revascularization) at 1-year were determined using data from health records and phone calls. The 0-1-hour algorithm stratified 47.0% of patients in the rule-out group. Over the 1-year follow-up period (follow-up rate = 86.9%), cardiovascular death and subsequent AMI did not occur in the rule-out group. Among the 27 patients who underwent the procedure within 30 days post-index visit, 3 patients (0.7%) had a stroke, 6 patients (1.3%) died of non-cardiovascular cause, and 30 patients (6.7%) underwent coronary revascularization within 1 year. At the 1-year follow-up, implementation of the 0-hour/1-hour algorithm was associated with very low rates of adverse event among patients in the rule-out group.

Trend in Age at the Initial Pacemaker Implantation in Patients With Bradyarrhythmia　- A 50-Year Analysis (1970-2019) in Japan.

BACKGROUND: This study investigated whether the age of patients undergoing pacemaker implantation is increasing.Methods and Results: This study retrospectively reviewed the consecutive cases of 3,582 patients who underwent an initial pacemaker implantation at our hospitals because of symptomatic bradyarrhythmias between 1970 and 2019. The exclusion criteria were: patients with AV block due to cardiac surgery or AV junction ablation, and patients aged <20 years. The patients were divided into 5×10-year groups: those treated in the 1970s (1970-1979), 1980s (1980-1989), 1990s (1990-1999), 2000s (2000-2009), and 2010s (2010-2019). A total of 3,395 patients satisfied the study criteria. The average age at which the patients underwent a first pacemaker implantation increased across the 10-year periods: 63.7±13.2 years in the 1970s, 66.2±12.6 years (1980s), 69.1±12.4 years (1990s), 72.0±11.1 years (2000s), and 75.8±10.0 years (2010s) and advanced significantly in the 1990s, 2000s, and 2010s compared to the 1970s (all P<0.001). The ratio of patients aged ≥80 and ≥90 years increased from 10.6% and 0% in the 1970 s to 38.2% (P<0.001) and 5.2% (P= 0.017) in the 2010s, respectively. CONCLUSIONS: The average age at initial pacemaker implantation increased by 12.1 years over the last 50 years in Japan. In particular, the ratios of ≥80 and ≥90 years as the patients age increased significantly.

Clinical Evaluation of a New High-Sensitivity Cardiac Troponin I Assay for Diagnosis and Risk Assessment of Patients with Suspected Acute Myocardial Infarction.

INTRODUCTION: Current assays based on the 0-hour/1-hour (0-/1-h) algorithm using high-sensitivity cardiac troponin (hs-cTn) are limited to only Abbott Architect hs-cTnI, Siemens Vista hs-cTnI, and Roche Elecsys hs-cTnT. OBJECTIVE: This study aimed to evaluate this new hs-cTnI assay, LumipulsePresto hs Troponin I, for diagnosis of acute myocardial infarction (AMI) on admission and on 0-/1-h algorithm to stratify AMI patients precisely. METHODS: This prospective cohort study included 442 patients with suspected non-ST-elevation myocardial infarction in three hospitals in Japan and Taiwan from June 2016 to January 2019. We enrolled patients presenting to the emergency department with symptoms suggestive of AMI and collected blood samples on admission and 1 hour later. Two independent cardiologists centrally adjudicated final diagnoses; all clinical information was reviewed twice: first, using serial hs-cTnT (Roche-Elecsys, primary analysis) and Lumipulse Presto Lumipulse Presto, second, using the Lumipulse Presto hs-cTnI measurements. At first, we compared diagnostic accuracy quantified using receiver operating characteristic (ROC) curves for AMI. Then, we evaluated major adverse cardiovascular events (cardiac death, AMI) in the rule-out group according to a 0-hour/1-hour algorithm at the 30-day follow-up. RESULTS: Diagnostic accuracy at presentation by the ROC curve for AMI was very high and similar for the LumipulsePresto hs-cTnI and hs-cTnT,(area under the curve [AUC]: LumipulsePresto hs-cTnI, 0.89, 95% confidence interval [CI] 0.86-0.93; hs-cTnT, 0.89, 95% CI 0.85-0.93; p = 0.82). In early presenters, the LumipulsePresto hs-cTnI appeared to maintain the diagnostic performance of hs-cTn for patients with <3 h (AUC: LumipulsePresto hs-cTnI, 0.87, 95% CI 0.81-0.92; hs-cTnT, 0.86, 95% CI 0.80-0.92; p = 0.81). The algorithm using the LumipulsePresto hs-cTnI ruled out AMI in 200 patients with negative predictive value and sensitivity of 100% (95% CI 97.3%-100%) and 100% (95% CI 92.7%-100%), respectively, in the rule-out group. CONCLUSION: Diagnostic accuracy and clinical utility of the novel LumipulsePresto hs-cTnI assay are high and comparable with the established hs-cTn assays.

A Case of J Wave Syndrome Due to Severe Hypercalcemia with Ventricular Fibrillation Storm and Successful Treatment of Isoproterenol Infusion.

A case of J wave syndrome with ventricular fibrillation (VF) storm and severe hypercalcemia due to primary hyperparathyroidism is presented. VF storm subsided with an isoproterenol infusion. Prominent J waves and a Brugada-like electrocardiogram pattern disappeared after parathyroidectomy. Ventricular tachyarrhythmia was not induced during an electrophysiological study. The patient remained asymptomatic up to the 12-month follow-up.

Elevated Heart Rate in Combination with Elevated Blood Pressure Predicts Lower Cardiovascular Mortality in Acute Decompensated Heart Failure.

Despite its clinical relevance, a subclass of acute decompensated heart failure (ADHF) with elevated blood pressure, known as hypertensive ADHF (HT-ADHF), has been less intensively evaluated. This study aimed to characterize the prognostic nature and pathophysiology of HT-ADHF. A total of 509 consecutive patients with first-time ADHF hospitalization were subjects of the study. Participants were divided into two groups: an HT-ADHF group (systolic blood pressure, SBP > 140 mmHg at presentation) and a non-HT-ADHF group (SBP ≤ 140 mmHg). Median follow-up duration measured 253 days. Unadjusted Kaplan-Meier analysis demonstrated both a lower cardiovascular mortality rate in the HT-ADHF group and similar incidences of heart failure rehospitalization in both groups. Adjusted Cox hazard analysis showed an association of elevated SBP at presentation with significantly lower cardiovascular mortality, though no such association was observed with heart failure rehospitalization. Moreover, elevated heart rate in combination with elevated SBP at presentation predicted a significantly lower risk of cardiovascular mortality (Hazard Ratio: 0.32, 95% CI: 0.14-0.77, P = 0.01). Also, significantly lower cardiovascular mortality was observed in this subtype, compared with other types of ADHF.

Reduced Number of Platelets During Intra-Aortic Balloon Pumping Counterpulsation Predicts Higher Cardiovascular Mortality After Device Removal in Association with Systemic Inflammation.

Thrombocytopenia is a frequent complication in patients requiring intra-aortic balloon pumping (IABP) counterpulsation. However, its prognostic impact has not been fully addressed. The objective of this study is to evaluate the impact of the change in the platelet number during IABP use on the prognosis after device removal.This is a retrospective observational study. Patients in the intensive cardiac care unit at three Juntendo University hospitals who underwent percutaneous implantation of IABP with or without veno-arterial extracorporeal membrane oxygenation (V-A ECMO), since 2012-2016, were enrolled in the study (n = 439). Patients who died during mechanical circulatory support (n = 47) were excluded. We evaluated the prognostic impact of the ratio of platelet reduction from the baseline (% PLT reduction) during IABP use on cardiovascular mortality after device removal.The median and the range of follow-up period were 298 days and 0-1,869 days, respectively. Unadjusted Kaplan-Meier analysis demonstrated that patients with a higher % PLT reduction had higher cardiovascular (CV) mortality. An adjusted Cox proportional hazard analysis demonstrated that a 10% higher % PLT reduction was associated with higher cardiovascular (CV) mortality (Hazard ratio: 1.3, 95% Confidence interval: 1.1-1.6, P < 0.001). Moreover, % PLT reduction and the maximum C-reactive protein (CRP) level during IABP use were positively correlated (r = 0.326, P < 0.001).The reduced number of platelets during IABP use was associated with an increased risk of CV mortality.

Impact of atrial fibrillation type (paroxysmal vs. non-paroxysmal) on long-term clinical outcomes: The RAFFINE registry subanalysis.

BACKGROUND: The type of atrial fibrillation (AF) (paroxysmal or non-paroxysmal) is important in determining its therapeutic management. However, the prognostic impact of AF type on the incidence of cardiovascular events remains uncertain. METHODS: We investigated patients with AF who were selected from an observational, multicenter, prospective registry (RAFFINE) comprising 4 university hospitals and 50 general hospitals/clinics in Japan between 2013 and 2015. In this subanalysis study, patients were divided into two groups according to their AF pattern at the time of enrollment. The primary outcome was the composite of death, ischemic stroke, and heart-failure-related hospitalization. RESULTS: Among 3845 patients, 1472 (38.3 %) and 2373 (61.7 %) had paroxysmal and non-paroxysmal type AF, respectively. Patients with non-paroxysmal AF were older and had higher CHADS2 score and prevalence of comorbidities. During median follow-up of 3.7 years, 681 (17.7 %) primary endpoints were identified. Cumulative incidences of the primary endpoint were significantly higher in the non-paroxysmal AF group; however, rates of bleeding events were not significantly different between the groups. Multivariate Cox hazard analysis showed that non-paroxysmal AF had significantly higher risk of cardiovascular events compared with paroxysmal AF (hazard ratio, 1.38; 95 % confidence interval, 1.17-1.64; p = 0.0002). CONCLUSIONS: Non-paroxysmal AF was significantly associated with cardiovascular events. Long-term clinical outcomes might be improved if transition from paroxysmal to non-paroxysmal AF can be prevented.

Transbrachial intra-aortic balloon pumping for a patient with fulminant myocarditis.

A 57-year-old man with acute myocarditis was transferred to our hospital from a local clinic. The patient experienced unexpected sudden cardiac arrest 16 h after admission. Mechanical cardiopulmonary support was started using percutaneous cardiopulmonary support, intra-aortic balloon pumping (IABP), continuous hemodialysis filtration, and temporary cardiac pacing with percutaneous cannulation of the femoral vessels. Hematoma developed at the IABP insertion site on the 5th day after admission. The IABP was removed, and another IABP system was inserted via the left brachial artery. The patient's condition improved, and the IABP was removed on the 9th day after admission. The remainder of the patient's in-hospital treatment was uneventful, and he showed near-normal left ventricular systolic function 1 year after discharge.

Trends of anticoagulant use and outcomes of patients with non-valvular atrial fibrillation: Findings from the RAFFINE registry.

BACKGROUND: The management of non-valvular atrial fibrillation (AF) has evolved with the development of direct oral anticoagulants (DOACs). However, data regarding the effectiveness and safety of DOACs outside clinical trial settings are limited, and off-label dosing of DOACs has not been thoroughly investigated. METHODS: We examined the clinical outcomes of patients with non-valvular AF in the RAFFINE registry, a prospective registry of Japanese patients with AF who were followed-up for more than 3 years. RESULTS: Among 3706 patients with non-valvular AF, 42.5% received warfarin and 44.7% received DOACs at baseline. The administration of DOACs increased annually. The mean CHADS2 and HAS-BLED scores were significantly higher in the warfarin group. The unadjusted all-cause mortality, cardiovascular mortality, and incidence of major bleeding events were higher in the warfarin group. The incidence of ischemic stroke/systemic embolism was not different between groups. After adjustment for baseline characteristics, the incidence of these events was not different between groups. Off-label dosing was performed for 32% of patients in the DOAC group, but this did not affect clinical outcomes. CONCLUSIONS: The all-cause mortality, cardiovascular mortality, and incidence of major bleeding events were higher in the warfarin group than in the DOAC group. After adjustment, warfarin use was not associated with an increase in these events. Off-label dosing of DOACs is not rare and is not associated with reduced effectiveness. The impact of off-label dosing of each DOAC on clinical events should be assessed using a larger population.

Azelnidipine and amlodipine anti-coronary atherosclerosis trial in hypertensive patients undergoing coronary intervention by serial volumetric intravascular ultrasound analysis in Juntendo University (ALPS-J).

BACKGROUND: A previous study reported that amlodipine retarded coronary plaque progression in patients with coronary artery disease. The goal of this multicenter study was to determine which calcium-channel blockers (CCBs) other than amlodipine attenuated the progression of plaque volume (PV) accessed by intravascular ultrasound (IVUS). METHODS AND RESULTS: ALPS-J was a prospective, randomized open-label study conducted at 5 centers. Patients who had hypertension and were scheduled for coronary intervention were enrolled. Subjects were randomly assigned to receive 16 mg/day of azelnidipine or 5mg/day of amlodipine administered for 48 weeks. The primary endpoint was the percent change in coronary PV measured by IVUS. Between 2007 and 2009, 199 patients were enrolled; 115 had evaluable IVUS images at both baseline and after 48 weeks of treatment. Blood pressure significantly reduced to 128/68 mmHg at follow-up. The lipid profiles in the 2 groups were comparable (low-density lipoprotein cholesterol: 97 mg/dl). The %change in PV showed a significant regression of 4.67 and 4.85% in the azelnidipine and amlodipine groups, respectively. The upper limit of the 95% confidence interval of the mean difference in %change PV between the 2 groups (0.18%, 95% confidence interval 4.62 to 4.98%) did not exceed the pre-defined non-inferiority margin of 6.525%. CONCLUSIONS: ALPS-J demonstrated that azelnidipine was not inferior to amlodipine for primary efficacy. In addition to standard medical therapy, dihydropyridine CCBs will retard PV progression in hypertensive patients.

Ultrasound-guided puncture reduces bleeding-associated complications, regardless of calcified plaque, after endovascular treatment of femoropopliteal lesions, especially using the antegrade procedure: A single-center study.

BACKGROUND: A common complication of endovascular treatment for femoropopliteal lesions is bleeding at the vascular access site. Although risk factors of bleeding-associated complications at the approach site have been reported, the results have been inconclusive. Hence, this study aimed to assess the predictors of bleeding-associated complications at the approach site in patients undergoing endovascular treatment for femoropopliteal lesions. METHODS: This retrospective, single-center, observational study included consecutive patients who underwent endovascular treatment (n = 366, 75% male, 72.4±9.9 year) for peripheral arterial disease with claudication and critical limb ischemia in our hospital from January 2010 to December 2017. We divided the patients into bleeding and non-bleeding groups, depending on whether bleeding-associated complications occurred at the approach site. Bleeding-associated complications were defined according to the Bleeding Academic Research Consortium criteria types 2, 3, and 5. RESULTS: Altogether, 366 endovascular treatment procedures and 404 arterial accesses were performed for femoropopliteal lesions in 335 peripheral arterial disease patients with claudication and 69 critical limb ischemia patients. We recorded 35 postprocedural bleeding-associated complications at the approach site (9%), all of which were hematomas. The predictors of increased bleeding-associated complications were age ≥ 80 years (bleeding vs. non-bleeding group, 43% vs. 25%, p<0.05) and antegrade cannulation of the common femoral artery (48% vs. 69%, p<0.05). Ultrasound-guided puncture reduced bleeding-associated complications (odds ratio, 0.28; 95% confidence interval, 0.004-0.21; p<0.05). In contrast, there was no significant difference in puncture site calcification between the groups (bleeding vs. non-bleeding groups, 29% vs. 21%, p = 0.29). CONCLUSION: Ultrasound-guided puncture is associated with a decrease in bleeding-associated complications at the approach site, regardless of the presence of calcified plaque. It is particularly effective and should be more actively used in patients aged ≥80 years and for antegrade cannulation of the common femoral artery.

The association between impairment of HDL cholesterol efflux capacity and atrial remodeling in atrial fibrillation.

This cross-sectional study enrolled 202 patients with atrial fibrillation (AF) who had undergone catheter ablation and evaluated the association between high-density lipoprotein (HDL) functionality, cholesterol efflux capacity (CEC) of HDL, and the pathophysiology of left atrial structural remodeling. Participants were divided into two groups, based on their left atrial volume index (LAVI) (< 34 mL/m2, n = 60 vs. LAVI ≥ 34 mL/m2, n = 142). We quantified three types of HDL CECs by the presence or absence of cyclic-AMP, as entire, and CEC dependent or not dependent on ATP binding cassette transporter A1 (ABCA1) and termed them Global CEC, ABCA1 CEC, and Non-ABCA1 CEC, respectively. Consequently, Global and Non-ABCA1 CECs were significantly impaired in patients with an enlarged LA (Global CEC: p = 0.039, Non-ABCA1 CEC: p = 0.022). Logistic regression analyses demonstrated that Non-ABCA1 CEC was significantly associated with an enlarged LA after adjusting for the conventional risk factors of AF. Furthermore, the association of higher Non-ABCA1 CEC with an enlarged LA was independent of serum levels of HDL cholesterol and serum myeloperoxidase (Odds ratio of 1 standard deviation higher: 0.64, 95% confidence interval: 0.43-0.95, p = 0.027). The findings of this study indicate the potential contribution of reduced Non-ABCA1 CEC in HDL to the pathophysiology in left atrial structural remodeling of patients with AF.

Clinical characteristics of defecation syncope compared with micturition syncope.

BACKGROUND: Defecation syncope (DS) and micturition syncope (MS) are daily excretion-related syndromes that are both classified as situational. However, their clinical features seem to be very different, so the present comparative study aimed to clarify those of DS. METHODS AND RESULTS: The study population consisted of 20 consecutive patients with DS and 37 consecutive patients with MS. The DS patients were significantly older than the MS patients (63+/-15 vs 52+/-17 years, P=0.026). Gender was significantly different (P=0.026): women predominated in the DS group (60%) whereas men more commonly had MS (70%). The diurnal distribution of syncope differed (P=0.0054): 88% of MS episodes occurred between 6 pm and 6 am, whereas DS occurred almost equally throughout the 24 h. Syncope after drinking alcohol was less common with DS (10%) than with MS (60%) (P=0.0003), whereas gastrointestinal tract (GIT) symptoms as a premonitory sign were more common with DS (55%) than with MS (3%) (P<0.0001). Positive responses to head-up tilt testing did not differ between the DS and MS groups. CONCLUSIONS: DS tends to occur in elderly women and without any significant daily distribution. Alcohol-related syncope was uncommon in patients with DS, and preceding GIT symptoms may be important as predictors or triggering factors.

Prevalence of the Brugada-type electrocardiogram and incidence of Brugada syndrome in patients with sick sinus syndrome.

BACKGROUND: In the present study, clarification of the prevalence of the Brugada-type electrocardiogram (ECG) and the incidence of spontaneous ventricular fibrillation (VF) that occurred with the Brugada-type ECG in patients with sick sinus syndrome (SSS) was determined. METHODS AND RESULTS: A total of 487 consecutive patients (men 45%, mean age 69.9+/-12.3 years), who were defined as having an indication for cardiac pacemaker (PM) for SSS, were investigated. The ECG before an initial PM implantation and occurrence of VF or sudden cardiac death (SCD) was examined retrospectively. Brugada-type ECG was found in 14 patients (2.87%) including 4 (0.82%) with type 1 and 10 (2.05%) with type 2. During the follow-up period of 7.2+/-5.4 years, 2 out of the 4 patients with type 1 ECG had experienced a VF episode after the device implantation. In 10 patients with type 2 ECG, none had VF or SCD. The incidence of spontaneous VF (Brugada syndrome) in SSS patients was calculated as 14.1 per 100 person-years with type 1 ECG. CONCLUSIONS: The prevalence of typical Brugada-type (type 1) ECG in SSS patients seems to be higher compared with the general population. In addition, SSS patients with the typical Brugada-type ECG might be a high risk for spontaneous VF.

Changes of matrix metalloproteinase-9 level is associated with left ventricular remodeling following acute myocardial infarction among patients treated with trandolapril, valsartan or both.

BACKGROUND: Inhibition of the renin-angiotensin system (RAS) with angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) can suppress left ventricular (LV) remodeling after acute myocardial infarction (AMI), possibly through the modifications of matrix metalloproteinase (MMP)-9. Whether LV remodeling is suppressed in association with MMP-9 suppression in post-AMI/-percutaneous coronary intervention (PCI) patients treated with ACE inhibitor and/or ARB was examined. The presence of any differences in LV remodeling and MMP-9 levels across the groups was also investigated. METHODS AND RESULTS: Sixty-five patients were initiated into each of 3 treatments; trandolapril, valsartan or a combination of both (half-dose-trandolapril plus half-dose-valsartan). Changes in MMP-9, LV end-diastolic and end-systolic volume index (LVEDVI and LVESVI) after 12 months were assessed. Overall, MMP-9 significantly decreased, although neither LVEDVI nor LVESVI increased significantly. DeltaMMP-9 was significantly correlated with DeltaLVEDVI (r=0.36) or DeltaLVESVI (r=0.39). In comparison, across groups, it was found that MMP-9, LVEDVI and LVESVI at 12 months were significantly lower in the combination therapy group than in the trandolapril group. There were no significant differences between the valsartan group and combination therapy group, or between the valsartan group and the trandolapril group. CONCLUSIONS: LV remodeling might be suppressed in association with MMP-9 suppression in AMI patients treated with PCI and regular dose or half-dose-combination of RAS inhibitors. Furthermore, a half-dose-combination might suppress LV remodeling more effectively than trandolapril alone.

A case of paroxysmal atrioventricular block with atrial pacemaker shift during ventricular arrest.

We present a case of paroxysmal atrioventricular block with atrial pacemaker shift, focusing on the change of P-wave morphology.

Primary Cardiac Diffuse Large B-cell Lymphoma Promptly and Safely Diagnosed with Pericardial Effusion Cytology.

Primary cardiac lymphoma is a rare condition with a poor prognosis, and patients are at risk for sudden cardiac death. A prompt diagnosis and early treatment are therefore essential. A 68-year-old woman was admitted for shortness of breath and peripheral edema. Echocardiograms showed massive pericardial effusion and a mass on the free wall of the right atrium and ventricle. Subsequent pericardial effusion cytology revealed diffuse large B-cell lymphoma. We started chemotherapy with rituximab and achieved a good clinical course. This case is made unique by the use of pericardial effusion cytology, which allowed us to diagnose primary cardiac lymphoma promptly and safely.

Implementing the European Society of Cardiology 0-h/1-h algorithm in patients presenting very early after chest pain.

BACKGROUND: The European Society of Cardiology (ESC) recommends a 0-h/1-h (0/1-h) algorithm to classify patients with suspected non-ST-segment elevation myocardial infarction (NSTEMI). However, reliable evidence about patients who present early after the onset of symptoms is limited, likely because high-sensitivity cardiac troponin (hs-cTn) values cannot increase sufficiently within that time. This study aimed to evaluate the outcomes in real-world situations that utilized the 0/1-h algorithm. METHODS: In a prospective, international, multicenter cohort study that enrolled 1638 patients presenting with acute chest pain to the emergency department, we assessed the performance of the 0/1-h algorithm using hs-cTnT and the associated 30-day rates of major adverse cardiac events: death and acute myocardial infarction (AMI). RESULTS: Among 1074 patients, the prevalence of AMI was 16.0%. An approximately 60.1% (n = 645) of patients visited the hospital within 3 h after onset of chest pain (less than 1 h; 18.2% [n = 196], less than 2 h; 27.5% [n = 295], and less than 3 h; 14.3% [n = 154]). Moreover, the prevalence rates of AMI were similar at all times (1 h, 16.8%; 1-2 h, 20.7%; 2-3 h, 18.2%; p = .5). According to the ESC 0/1-h algorithm, the distribution patterns of rule-out, observe, and rule-in groups were similar; however, none of the patients was diagnosed with AMI or cardiac death in the rule-out group. CONCLUSION: This study revealed the applicability of the 0/1-h algorithm for the management of early presenters.

Enhanced monocyte migratory activity in the pathogenesis of structural remodeling in atrial fibrillation.

BACKGROUND AND AIMS: Pathophysiological roles of monocytes in atrial fibrillation (AF), particularly for the progression of structural remodeling of the left atrium (LA), remain elusive. This study examined the association between the characteristics of circulating and local monocytes and extent of structural remodeling in LA, gauged by LA size, in AF patients. METHODS: First, 161 AF patients who were referred for catheter ablation were enrolled and divided into two groups according to the median of LA diameter (≤39 mm: normal LA group, >39 mm: enlarged LA group). As a control group, 22 patients underwent catheter ablation for paroxysmal supraventricular tachycardia (PSVT) without history of AF were analyzed. Blood samples were collected for flow cytometric analyses to evaluate monocyte subsets based on the levels of CD14 and CD16. Moreover, monocytes were isolated from blood to measure CC chemokine receptor 2 (CCR2) transcripts and protein levels, and migratory activity toward monocyte chemoattractant protein 1 (MCP-1). Second, to characterize the local monocytes in the atrial wall in AF, the resected left atrial appendages (LAA) in AF patients underwent cardiac surgery were histologically evaluated (n = 20). RESULTS: The proportions of monocyte subsets based on CD14 and CD16 expressions were not significantly different between the normal and enlarged LA group. Both transcripts and total protein levels of CCR2 in monocytes were higher in the enlarged LA group compared to those in the normal LA group. In the enlarged LA group, monocytes exhibited more enhanced migratory activity than the normal LA group. Moreover, we found a significantly higher number of CCR2-positive monocytes/macrophages in the LAA in the enlarged LA group. CONCLUSION: Enhanced migratory activity in circulating and local monocytes may play a pivotal role in the pathogenesis of progression in atrial remodeling in AF patients.