Tai Kojima

Left atrial global and regional function in patients with paroxysmal atrial fibrillation has already been impaired before enlargement of left atrium: velocity vector imaging echocardiography study.

AIMS Left atrial volume (LAV) has been proposed as a predictor of atrial fibrillation (AF) and LA function has been investigated by velocity vector imaging (VVI) echocardiography. The aim of this study was to determine whether LA function was associated with the existence of AF. METHODS AND RESULTS We examined emptying function (EF) as a global function and strain rate (SR) as a regional function of LA function during three phases of the cardiac cycle (reservoir, conduit, and booster pump phase). The parameters were measured (apical four-chamber view) by VVI in 302 subjects [126 sinus rhythm, 91 paroxysmal AF (PAF), and 85 chronic AF]. Global and regional LA function were significantly lower in PAF patients during sinus rhythm (LA total EF: 35 ± 8%; SR at atrial contraction: -0.8 ± 0.3s(-1)) and much lower in chronic AF patients (LA total EF 22 ± 8%) than in subjects with sinus rhythm (LA total EF: 47 ± 7%; SR at atrial contraction: -1.4 ± 0.4s(-1)). In multivariate logistic regression analysis, LA active EF and SR at atrial contraction were independent features of PAF. CONCLUSION LA function, particularly LA active relaxation and contraction, was lower in PAF patients than in subjects with sinus rhythm, regardless of LA size and age. LA functional impairment was observed regardless of hypertension before LA enlargement in patients with PAF. Reduced LA function, as assessed by VVI, is an important feature of AF as well as LA structure.

Association of a polymorphism of ABCB1 with obesity in Japanese individuals.

The aim of the present study was to identify gene polymorphisms that confer susceptibility to obesity. A total of 5448 unrelated Japanese individuals from two independent populations were examined: subject panel A comprised 4252 individuals who visited participating hospitals; subject panel B comprised 1196 community-dwelling elderly individuals. The genotypes for 95 polymorphisms of 67 candidate genes were determined. The chi(2) test revealed that six polymorphisms were related (p<0.05) to the prevalence of obesity in subject panel A; after application of Bonferronis correction, however, only the 2677G --> A/T polymorphism (rs2032582) of the ATP-binding cassette, subfamily B, member 1 gene (ABCB1) was significantly associated (p=0.0003) with obesity. Subsequent multivariable logistic regression analysis also revealed that the 2677G --> A/T polymorphism of ABCB1 was significantly associated with obesity. For validation of this association, the 2677G --> A/T polymorphism of ABCB1 was examined in subject panel B and again found to be significantly associated with obesity. Body mass index was significantly (p=0.01) greater for individuals with the variant T allele of this polymorphism than for those with the GG genotype in the combined subject panels A and B. Our results suggest that the ABCB1 genotype may prove informative for assessment of genetic risk for obesity in Japanese individuals.

Prospective randomized trial comparing a nitinol self-expanding coronary stent with low-pressure dilatation and a high-pressure balloon expandable bare metal stent

The recent SCORES trial demonstrated that lower dilatation pressures seen with self-expanding (SE) stents may be associated with lower rates of target lesion revascularization (TLR). To determine whether SE stents with low-pressure dilatation are as safe and effective as balloon expandable (BE) stents. We randomly assigned 254 patients with 279 coronary lesions to groups receiving either SE with low-pressure dilatation <12 atm (n = 143) or conventional BE stents (n = 136). Thereafter, acute results and long-term outcomes were compared. Baseline patient and angiographic characteristics were similar in two groups. The incidence of procedural complications, such as slow flow, side branch occlusion, and edge dissection were significantly lower in the SE group than in the BE group (overall: SE, 17; BE, 35; P < 0.01), and the occurrence of myocardial infarction tended to be lower in SE than in BE (SE, 1; BE, 4; not significant). Although acute gain was significantly smaller with SE than BE (SE, 2.21 ± 0.65 mm; BE, 2.42 ± 0.62; P < 0.01), probably due to gradual expansion of the SE stent, nearly identical minimum luminal diameters on follow-up angiography (SE, 2.14 ± 0.92 mm vs. BE, 2.22 ± 0.93; not significant) and similar angiographic restenosis (SE, 18.1% vs. BE, 20.5%). and TLR rates (SE, 16.1% vs. BE, 14.0%) were apparent. This prospective randomized trial demonstrates that SE stents with low-pressure dilatation is safe and effective strategy for treating coronary arterial stenosis.

Motion of left atrial appendage as a determinant of thrombus formation in patients with a low CHADS2 score receiving warfarin for persistent nonvalvular atrial fibrillation

BackgroundThe aim of this study was to define the independent determinants of left atrial appendage (LAA) thrombus among various echocardiographic parameters measured by Velocity Vector Imaging (VVI) in patients with nonvalvular atrial fibrillation (AF) receiving warfarin, particularly in patients with a low CHADS2 score.MethodsLAA emptying fraction (EF) and LAA peak longitudinal strain were measured by VVI using transesophageal echocardiography in 260 consecutive patients with nonvalvular persistent AF receiving warfarin. The patients were divided into two groups according to the presence (n=43) or absence (n=217) of LAA thrombus. Moreover, the patients within each group were further divided into subgroups according to a CHADS2 score ≤1.ResultsMultivariate logistic regression analysis showed that LAAEF was an independent determinant of LAA thrombus in the subgroup of 140 with a low CHADS2 score. Receiver operating characteristics curve analysis showed that an LAAEF of 21% was the optimal cutoff value for predicting LAA thrombus.ConclusionsLAA thrombus formation depended on LAA contractility. AF patients with reduced LAA contractile fraction (LAAEF ≤21%) require strong anticoagulant therapy to avoid thromboembolic events regardless of a low CHADS2 score (≤1).

Over 10 years clinical outcomes in patients with mitral stenosis with unilateral commissural calcification treated with catheter balloon commissurotomy : Single-center experience

OBJECTIVES Treatment of mitral valve stenosis with catheter balloon commissurotomy (CBC) yields acceptable immediate results even when one commissure shows calcification. However, the long-term outcomes in such cases remain unclear. METHODS We examined the immediate and long-term (mean: 11+/-5 years) outcomes of 57 patients who underwent 58 CBC procedures. Patients were classified into group A (no commissural calcification, n=44) or group B (unilateral commissural calcification, n=13). From the appearance of the mitral valve just after CBC, commissurotomy was judged to be bilateral, incomplete, or excessive. End points were death, recurrence of congestive heart failure necessitating hospitalization, embolism, repeat CBC, or mitral valve replacement. RESULTS There were significant numbers of unfavorable mitral valve morphologies evaluated according to Sellors classification, estimated by echocardiograms; Sellors class I: 20 patients in group A vs. none in group B (p<0.05). Class II: 24 in group A vs. 10 in group B. and class III: none in group A vs. 3 in group B (p<0.05). CBC increased the mitral valve area (Gorin formula) from 1.3+/-0.3 to 2.1+/-0.5 cm2 in patients in group A and from 1.1+/-0.2 to 1.8+/-0.4 cm2 in those in group B (p=n.s.). Among the latter, there were significantly more excessive commissurotomies than in group A and no bilateral commissurotomy. The overall or event-free survival rate during the follow-up of group B showed a lower tendency than in group A (overall: group A: 86.2% vs. group B: 84.6%, p, n.s. event-free: 56.8% vs. 46.2%, respectively, p=n.s.). Univariate predictors of all events in group B included post-CBC pulmonary arterial pressure, and the pattern of commissurotomy after CBC (p<0.05). Excessive commissurotomy increased clinical events some years later, after the procedure. CONCLUSIONS In this study, involving a small number of subjects, long-term outcomes of patients with unilateral commissural calcification receiving CBC showed no significant difference as compared to those with commissural calcification absence. However, it is necessary to perform careful follow-up of CBC patients with unilateral commissural calcium.

LEFT ATRIAL STRUCTURE AND FUNCTION IN HYPERTENSIVE PATIENTS ASSESSED BY REAL-TIME THREE-DIMENSIONAL SPECKLE TRACKING ECHOCARDIOGRAPHY: A COMPARATIVE STUDY WITH NORMAL SUBJECTS AND TWO-DIMENSIONAL SPECKLE TRACKING

Major advantage of 3-dimensional speckle tracking echocardiography (3-DSTE) is the improvement of accuracy in the evaluation of cardiac chamber volume without any geometrical assumption. However, there have been few studies regarding to left atrial (LA) structure and function using 3-DSTE. The aim

LEFT ATRIAL PHASIC FUNCTION ASSESSED BY SPECKLE TRACKING ECHOCARDIOGRAPHY IS A USEFUL PREDICTOR FOR FIRST ATRIAL FIBRILLATION: RESULTS OF PROSPECTIVE STUDY OF 2 YEARS FOLLOW-UP

Methods: LA total, passive and active emptying function (EF) as a global function and LA strain rate (SR) at systole, early diastole and atrial contraction as a regional function were measured in apical 4-chamber view by speckle tracking in consecutive 420 adults without mitral valve disease and atrial arrhythmia (age 68±14, 251 men). LA volume, left ventricular (LV) mass, ejection fraction, and E/e’ as a diastolic function were measured.

DIFFERENTIATION OF LEFT ATRIAL VOLUME BY TIME (DV/DT) IS A NOVEL AND USEFUL ECHO INDEX TO ASSESS LEFT ATRIAL GLOBAL AND PHASIC FUNCTION

Background: Left atrial (LA) strain rate (SR) which represents a regional function is proposed to assess LA active relaxation, conduit function and active contraction. However, analysis of LA global and phasic function using differentiation of LA volume by time (dV/dt) has not yet been elucidated. Using velocity vector imaging (Siemens), timeLA volume and dV/dt curve can be automatically and rapidly provided. Thus, the aim of this study was to evaluate the usefulness of LA dV/dt as a new index of LA global and phasic function by comparing it with SR.