Biomedical subjects

T Oki

Publications and source records attributed to T Oki.

At least 73 records · Page 4Linked to original sources

PubMed1999

Inhibitory effect of alpha-glucosidase inhibitors varies according to its origin.

The inhibitory effect of alpha-glucosidase (AGH) inhibitors against its origins (baker's yeast and rat, rabbit, and pig small intestines) was investigated. All inhibitors used in this study showed quite different inhibitory activities according to AGH origins. Voglibose, acarbose and glucono-1,5-lactone strongly inhibited mammalian AGHs, whereas no or less inhibition was observed in yeast AGH. On the contrary, (+)-catechin, a good inhibitor against yeast AGH (IC(50) = 1.3 x 10(-)(1) mM) as well as voglibose (IC(50) = 2.6 x 10(-)(2) mM), did not retard the mammalian AGH activity. Subsequent inhibition study with various food components revealed that all of foods except for green (IC(50) = 0.735 mg/mL) and oolong teas (IC(50) = 1.34 mg/mL) showed no inhibitory activity against rat AGH, whereas they inhibited yeast AGH. Consequently, the magnitude of AGH inhibition was greatly affected by its origin, and more attention relating to AGH origin would be needed to evaluate in vitro AGH inhibitory effect.

Animals↗

PubMed1999

The interaction of cellular fibronectin with collagen during fibroblast-mediated contraction of collagen gels.

In the first instance highly hydrated collagen gels contract to dense and compact gels when populated by fibroblasts. We previously reported the involvement of fibronectin (FN) in an early process of the collagen gel contraction, utilizing a specific monoclonal antibody dubbed A3A5 (MoAb-A3A5) that inhibits the gel contraction. This study was performed to further characterize the role of the epitope for MoAb-A3A5 in the interaction between fibroblasts and collagen fibrils. Although both cellular FN (cFN) and plasma FN (pFN) were reactive with MoAb-A3A5, the FN that actually participates in a process of the gel contraction was shown to be cFN. The gel contraction was significantly accelerated when fibroblasts were pretreated with excess amounts of cFN and was significantly inhibited when the collagen molecules were pretreated with excess cFN. Such effects of the pretreatments were not observed for pFN. The involvement of cFN, but not pFN, in the interaction of fibroblasts with collagen fibrils was additionally shown by the similar inhibitory action of cFN, but not pFN, on the spreading and elongation of fibroblasts on collagen fibrils. The epitope for MoAb-A3A5 was strongly suggested to be a new functional domain responsible for the interactions between fibroblasts and native collagen molecules. This was not the case for those with denatured one, because fibroblasts on collagen fibrils were not stainable with MoAb-A3A5, whereas the interactions on gelatin were stainable. The lack of the reactivity of fibroblasts on collagen fibrils toward MoAb-A3A5 was not a result of the absence of FN on the cell membrane, but seemed to be a steric hindrance to the access of the antibody.

Antibodies, Monoclonal↗

PubMed1999

The contribution of menopause to changes in body-fat distribution.

OBJECTIVE: To investigate whether menopause contributes to changes in body-fat distribution, irrespective of aging or obesity. METHODS: The subjects were 545 premenopausal (aged 16-55 years; mean +/- standard deviation, 37.7 +/- 9.1 years) and 219 postmenopausal (aged 45-65 years, 58.0 +/- 5.0 years) women. Baseline characteristics included age, body mass index (BMI), and menopausal status (premenopause or postmenopause). The ratio of trunk fat to leg fat (trunk-leg ratio) was estimated by dual-energy X-ray absorptiometry. The trunk-leg ratio and baseline characteristics were compared between the 2 groups. In all subjects (n = 764), possible correlations between the trunk-leg ratio and the baseline characteristics were determined using univariate and multivariate analysis. In postmenopausal women, the relationship of the trunk-leg ratio to YSM or age after adjusting for BMI was investigated. RESULTS: The trunk-leg ratio and BMI were significantly higher in postmenopausal women than in premenopausal women. In all subjects, age and BMI were positively correlated with the trunk-leg ratio (r = 0.445 and 0.587, respectively, p < 0.0001). Menopause was also positively correlated with the trunk-leg ratio on univariate regression analysis (standardized regression coefficient = 0.369, p < 0.0001). On multiple regression analysis, age, BMI, and menopause were independently correlated with the trunk-leg ratio (p < 0.05). In postmenopausal women, age and YSM were positively correlated with the trunk-leg ratio, independent of the BMI (p < 0.01). CONCLUSIONS: Menopause contributes to a change in body-fat distribution, irrespective of aging or obesity.

Abdomen↗

PubMed1999

Development of a self-cloning system for Actinomadura verrucosospora and identification of polyketide synthase genes essential for production of the angucyclic antibiotic pradimicin.

A self-cloning system for Actinomadura verrucosospora, a producer of the angucyclic antibiotic pradimicin A (PRM A), has been developed. The system is based on reproducible and reliable protoplasting and regeneration conditions for A. verrucosospora and a novel plasmid vector that consists of a replicon from a newly found Actinomadura plasmid and a selectable marker cloned from the Actinomadura strain. The system has an efficiency of more than 10(5) CFU/microgram of DNA. Using this system, we have cloned and identified the polyketide synthase (PKS) genes essential for PRM A biosynthesis from A. verrucosospora. Nucleotide sequence analysis of the 3.5-kb SalI-SphI fragment showed that ketosynthase subunits (open reading frame 1 [ORF1] and ORF2) of the essential PKS genes have strong similarities (59 to 89%) to those for angucyclic antibiotic biosynthesis.

Actinomycetales↗

PubMed1999

Coronary flow velocity immediately after reperfusion reflects myocardial microcirculation in canine models of acute myocardial infarction.

Recent reports indicate that the coronary microcirculation is sometimes injured, despite successful reperfusion in acute myocardial infarction (AMI). However, it is difficult to evaluate the coronary microcirculation immediately after reperfusion by using only angiography. The purpose of this study was to examine the relationship between the pattern of coronary blood flow velocity and myocardial microcirculatory injury immediately after reperfusion in AMI. The authors recorded the left circumflex coronary flow velocity by using the Doppler guide wire method 10 minutes after reperfusion in a canine model of AMI. In addition, myocardial contrast echocardiography was performed with the injection of contrast medium into the left circumflex coronary artery before clamping of the coronary artery and 15 minutes after release of the clamp. From these images, the ratio of the normalized gray-level postreperfusion to preclamping in the contrast-enhanced area was determined. It was compared with coronary flow velocity variables. In the 10 dogs with a diastolic-to-systolic velocity ratio (DSVR) < 4.0, this velocity ratio 10 minutes after reperfusion correlated positively (r = 0.75, p < 0.01) with the normalized gray-level ratio. However, the remaining three dogs with a DSVR > or = 4.0 markedly deviated from this pattern. Coronary flow velocities in the three dogs were characterized by a greater decrease in systolic flow velocity and occurrence of early systolic retrograde flow. Myocardial contrast echocardiographic images in these three dogs demonstrated a lower normalized gray-level ratio. In conclusion, the coronary flow velocity pattern immediately after reperfusion may reflect myocardial microcirculatory injury.

Albumins↗

PubMed1999

Assessment of the temporal relationship between left ventricular relaxation and filling during early diastole using pulsed Doppler echocardiography and tissue Doppler imaging.

The study investigated the temporal relationship between left ventricular (LV) relaxation and filling during early diastole. The transmitral flow (TMF) velocity by pulsed Doppler echocardiography and LV wall motion velocity by pulsed tissue Doppler imaging (TDI) were evaluated in 57 patients with various heart diseases and 33 normal controls. The patients were classified into 2 groups according to the ratio of the peak early diastolic to atrial systolic TMF velocity (E/A): (1) the high A group included 44 patients with an E/A < or = 1, and (2) the pseudonormalization group included 13 patients with an E/A > 1. The isovolumic relaxation time (IRT) from the aortic component of the second heart sound (IIA) to the onset of the E wave of the TMF was measured. The peak early diastolic velocity of the LV posterior wall (Ew) and time from the IIA to the onset of the early diastolic wave (IIA-Ewo) were determined from the LV wall motion velocity assessed by pulsed TDI. The Ew was lower in the pseudonormalization and high A groups than in the control group. The IIA-Ewo was significantly longer in the pseudonormalization and high A groups than in the control group. The time constant of the LV pressure decay at isovolumic diastole (tau) correlated negatively with the Ew, and correlated positively with the IIA-Ewo in all groups. The IIA-Ewo was equal to or shorter than the IRT in control subjects, and was longer than the IRT in patients in the pseudonormalization group. In conclusion, the temporal relationship between LV relaxation and filling during early diastole varied according to the subjects' hemodynamic status. Analysis of TMF by pulsed Doppler echocardiography and LV wall motion velocity by pulsed TDI was useful for detailed evaluation of early diastolic LV hemodynamics.

Blood Flow Velocity↗

PubMed1999

Regional left ventricular myocardial contraction abnormalities and asynchrony in patients with hypertrophic cardiomyopathy evaluated by magnetic resonance spatial modulation of magnetization myocardial tagging.

Global left ventricular (LV) pump function is generally preserved in patients with hypertrophic cardiomyopathy (HCM). However, it is unknown whether regional myocardial contractility is impaired, especially in nonhypertrophied regions. The purpose of this study was to evaluate regional LV myocardial contraction in patients with HCM using magnetic resonance (MR) spatial modulation of magnetization (SPAMM) myocardial tagging. The study group comprised 20 patients with asymmetric septal hypertrophy (HCM group) and 16 age-matched normal patients (control group), and data were collected using transthoracic M-mode and 2-dimensional echocardiography, and MR SPAMM myocardial tagging. The systolic strain ratio, maximum systolic strain velocity, and time from end-diastole to maximum systolic strain (deltaT) in the anterior, ventricular septal, inferior and lateral regions for 2 LV short-axis sections at the levels of the chordae tendineae and papillary muscles were measured at 50-ms intervals by MR myocardial tagging. The end-diastolic anterior and ventricular septal wall thicknesses and LV mass index were significantly different between the HCM and control groups. The systolic strain ratio for all 4 walls, particularly the anterior and ventricular septal regions, was significantly lower in the HCM group. In the HCM group, the maximum systolic strain velocity was significantly lower and deltaT was significantly shorter for all 4 walls, particularly the anterior and ventricular septal regions. The standard deviation for the deltaT, calculated from the deltaT for the 8 regions of the 2 LV short-axis sections, was significantly greater in the HCM group. In conclusion, regional LV myocardial contraction is impaired in both hypertrophied and nonhypertrophied regions, and systolic LV wall asynchrony occurs in patients with HCM.

Adult↗

PubMed1999

Evaluation of the hemodynamic relationship between the left atrium and left ventricle during atrial systole by pulsed tissue Doppler imaging in patients with left heart failure.

The objective of the present study was to evaluate the hemodynamic relationship between the left atrium (LA) and left ventricle (LV) during atrial systole in the presence of an elevated left ventricular end-diastolic pressure (LVEDP) and LV failure using pulsed tissue Doppler imaging (TDI). Fifty-three patients with LV systolic dysfunction and no regional LV asynergy were divided into 3 groups: relaxation failure group (RF, n=20) with a ratio of peak early diastolic to atrial systolic velocity of the transmitral flow (E/A) < or = 1; pseudonormalization group (PN, n=19) with 1 or =2. In addition, 20 normal patients (E/A > or = 1) were studied as a control group. The transmitral and pulmonary venous flow velocities were recorded by transesophageal pulsed Doppler echocardiography. The wall motion velocity patterns were recorded at the middle portion of the LV posterior wall (LVPW) and at the mitral annulus (MA) of the LVPW site in the apical LV long-axis view by transthoracic pulsed TDI. The LVEDP was significantly greater in the PN and RS groups than in the RF and control groups. The moan pulmonary capillary wedge pressure was greatest in the RS group. The percent fractional change of the LA area during atrial systole determined by 2-dimensional echocardiography was significantly lower in the RS group than in the PN group. The peak atrial systolic pulmonary venous flow velocity was significantly greater in the PN group than in the RS group. The peak atrial systolic motion velocity (Aw) at the LVPW was significantly lower in the PN and RS groups than in the RF and control groups. The Aw at the MA was significantly lower in the RS group than in the other groups. There was no significant difference in Aw between the LVPW and MA in the RS group, whereas Aw at the MA was significantly greater than that at the LVPW in the PN group. In conclusion, the measurements of Aw at the LVPW and MA can be used to noninvasively evaluate the hemodynamic relationship between the LA and LV during atrial systole in patients with LV failure.

Adult↗

PubMed1999

High-mannose type oligosaccharide-dependent apoptosis in U937 cells induced by pradimicin, a mannose-binding antibiotic.

Cell surface oligosaccharides play a role in a variety of biological events such as cell adhesion and signal transduction. We have shown that BMY-28864, a semi-synthetic analog of pradimicin, induced apoptosis of U937 cells which had been incubated with 1-deoxymannojirimycin, an inhibitor of mannosidase I. BMY-28864 was not cytotoxic to the cells which had been cultivated with other glycosidase inhibitors such as castanospermine and swainsonine. We thus propose that BMY-28864 induces apoptosis by acting on a specific mannose-rich oligosaccharide, presumably (Man)9(GlcNAc)2+.

1-Deoxynojirimycin↗

PubMed1999

Involvement of Ca2+ ion and reactive oxygen species as a mediator in pradimicin-induced apoptosis.

Pradimicin (PRM) induces apoptosis in mammalian cells which had been incubated with 1-deoxymannojirimycin (DMJ). Flow cytometric analysis revealed that PRM preferentially induced apoptosis to the cells of the G1 phase. Two possible mediators in this apoptotic cascade were identified. Exposure of DMJ-treated cells to PRM resulted in a rapid (approximately 5 seconds) and slow (approximately 30 minutes) elevation of the intracellular calcium level. Reactive oxygen species (ROS) were proved to be involved in this system by the fact that the apoptosis was completely inhibited by treating the cells with a ROS scavenger, N-acetylcysteine in prior to the PRM stimulation.

1-Deoxynojirimycin↗

PubMed1998

Cloning of 5'-flanking region and a polymorphic CTT trinucleotide repeat within 5'-untranslated region of mouse R-type calcium channel alpha1-subunit (Cchra1) gene, and its genetic mapping.

The 5'-flanking region of the mouse R-type calcium channel (Cchra1) gene was cloned, and a transcriptional start point (tsp) was determined by rapid amplification of 5'-cDNA end (5'RACE) method. The putative promoter region of the gene contained no obvious TATA or CCAAT element in the expected positions, but multiple putative binding sites for transcriptional factors, such as Sp1, AP-1, AP-2, AP-3, EGR-1, EGR-2, NF-kappaB and HIP1, were detected. We found the existence of a tandem CTT trinucleotide repeat within the 5'-untranslated region (UTR) of the gene, and its polymorphism between C57BL/6J and Mus spretus. Using this polymorphism, the Cchra1 was mapped to the region of chromosome 1 where the synteny to human chromosome 1q was conserved.

Amino Acid Sequence↗

PubMed1998

The effect of menopause on regional and total body lean mass.

OBJECTIVES: To investigate the effect of menopause on regional and total body lean mass. METHODS: Evaluation of 123 healthy premenopausal women (40.6 +/- 10.8 years) and 123 healthy postmenopausal women (61.8 +/- 7.5 years). All subjects were right side dominant. Regional (head, bilateral arms, trunk, and bilateral legs) and total body lean mass were measured using whole-body scanning by dual-energy X-ray absorptiometry. Baseline characteristics including age, height, weight, and menopausal state were recorded. These variables were compared between pre- and postmenopausal women. In all subjects, correlations between regional or total body lean mass and baseline characteristics were investigated using univariate and multiple regression analyses. RESULTS: Height, and lean mass of the trunk, bilateral legs and total body were significantly lower in postmenopausal women than in premenopausal women, while lean mass of the bilateral arms did not differ between the two groups. On univariate regression analysis, bilateral arms lean mass was positively correlated with height (P < 0.001). Trunk, bilateral legs, and total body lean mass were inversely correlated with age and menopausal state (P < 0.001), but were positively correlated with height (P < 0.001). After adjusting for age and height, trunk lean mass was still correlated with menopausal state (P < 0.01). CONCLUSIONS: Menopause induces lean mass loss, independent of aging and height. Trunk lean mass is more prone to decline with menopause than lean mass of other sites.

Adult↗

PubMed1998

Right and left ventricular wall motion velocities as diagnostic indicators of constrictive pericarditis.

The purpose of this study was to examine the usefulness of pulsed tissue Doppler imaging for diagnosing constrictive pericarditis. Motion velocities of the ventricular septum (VS) and left ventricular (LV) posterior wall along the short axis, and those of the anterior right ventricular (RV) wall, VS, and LV posterior wall along the long axis were recorded using pulsed tissue Doppler imaging in 12 patients with constrictive pericarditis, who were diagnosed by cardiac catheterization, and also in 20 normal subjects. Peak early diastolic and atrial systolic velocities (Ew and Aw, respectively) were calculated, and the time between the aortic component of the second heart sound and the peak of the early diastolic velocity (IIA-Ew) was determined. The peak Ew and II A-Ew along the short and long axes were significantly higher and shorter, respectively, in the patient group than in the normal group. In the patient group, the motion velocity of the VS along the short axis showed a "backward" motion with a sharp and marked peak velocity immediately before Ew, or a biphasic early diastolic wave; a clear "downward" motion immediately after Ew was observed in the motion velocities of the anterior RV wall, VS, and LV posterior wall along the long axis. These distinctive backward and downward motions were not observed in any of the ventricular walls of the normal subjects. In conclusion, the early diastolic RV and LV wall motion velocity patterns along the short and long axes as measured by pulsed tissue Doppler imaging provide important information for the diagnosis of constrictive pericarditis.

Adult↗

PubMed1998

Role of left atrial appendage in left atrial reservoir function as evaluated by left atrial appendage clamping during cardiac surgery.

We evaluated the role of left atrial appendage (LAA) in the left atrial (LA) reservoir function by assessing the changes in LA flow dynamics after LAA clamping during cardiac surgery. The subjects were 8 patients who had undergone coronary artery bypass grafting (CABG) and 7 who had undergone mitral valvular surgery due to mitral regurgitation. We recorded transmitral, pulmonary venous and LAA flow velocity patterns by intraoperative transesophageal pulsed Doppler echocardiography, monitoring LA pressure before and 5 minutes after LAA clamping. The maximal LAA area was significantly greater, and the peak late diastolic LAA emptying flow velocity was significantly lower before LAA clamping in the mitral regurgitation group than in the CABG group. In both groups, the peak early and late diastolic transmitral and pulmonary venous flow velocities significantly increased, and the peak second systolic pulmonary flow velocity significantly decreased during LAA clamping. There were no significant changes in heart rate and systemic systolic blood pressure during LAA clamping, whereas mean LA pressure and maximal LA dimension significantly increased in both the groups. The LA pressure-volume relation during ventricular systole shifted upward and to the left during LAA clamping, and the slope was steeper in the MR group than in the CABG group. We conclude that the LAA is more compliant than the LA main chamber, and plays an important role in LA reservoir function in the presence of LA pressure and/or volume overload.

Aged↗

PubMed1998

Characteristics of coronary flow velocity in constrictive pericarditis.

A 50-yr-old man developed constrictive pericarditis following an episode of acute pericarditis. Cardiac catheterization revealed a typical early diastolic dip and plateau configuration in both the right and left ventricular pressure curves. The coronary flow velocity pattern determined using an intracoronary Doppler guidewire showed an abrupt decrease in peak velocity at early diastole and followed by plateau until late diastole, the so-called dip and plateau configuration. After a successful pericardiectomy, cardiac catheterization no longer showed the dip and plateau configuration, but the early diastolic dip in the coronary flow velocity persisted probably because of infiltration of the organic involvement into the myocardium.

Blood Flow Velocity↗

PubMed1998

Evaluation of left atrial filling using systolic pulmonary venous flow velocity measurements in patients with atrial fibrillation.

BACKGROUND: The pattern of pulmonary venous flow velocity is useful for understanding the hemodynamic relationship between the left atrium and left ventricle in patients with a variety of diseases, and the systolic flow wave, in particular, is considered a clinically important parameter that reflects left atrial filling. HYPOTHESIS: The study was undertaken to determine whether systolic pulmonary venous flow velocity patterns can be used to evaluate left atrial filling in patients with atrial fibrillation. METHODS: We performed transesophageal pulsed Doppler echocardiography and cardiac catheterization in 34 patients with chronic atrial fibrillation (10 with hypertrophic cardiomyopathy, 5 with dilated cardiomyopathy, 7 with previous myocardial infarction, and 12 with isolated atrial fibrillation) and 15 normal controls in sinus rhythm. RESULTS: Mean pulmonary capillary wedge pressure, V-wave height in the pulmonary capillary wedge pressure curve, and left ventricular end-diastolic pressure were significantly higher in the hypertrophic cardiomyopathy and dilated failing heart (previous myocardial infarction and dilated cardiomyopathy) groups than in the isolated atrial fibrillation and normal groups. The peak velocity and time-velocity integral of the systolic pulmonary venous flow velocity, and percent left atrial emptying fraction were significantly lower in the dilated failing heart group than in the isolated atrial fibrillation, hypertrophic cardiomyopathy, and normal groups. The peak velocity and time-velocity integral of the systolic pulmonary venous flow velocity, percent left atrial emptying fraction, and V-wave height were comparatively constant when the preceding R-R intervals were relatively stable in the isolated atrial fibrillation group and in 4 of the 10 patients with hypertrophic cardiomyopathy. However, changes in these variables correlated with the preceding R-R interval in all patients with dilated failing hearts and in 6 of the 10 patients with hypertrophic cardiomyopathy. CONCLUSION: Transesophageal pulsed Doppler echocardiographic measurements of systolic pulmonary venous flow velocity are valid indicators of left atrial filling in patients with atrial fibrillation.

Adult↗

PubMed1998

Assessment of abnormal left atrial relaxation by transesophageal pulsed Doppler echocardiography of pulmonary venous flow velocity.

BACKGROUND: Several studies on left ventricular relaxation have been undertaken in the past; however, left atrial (LA) relaxation has not been fully evaluated. HYPOTHESIS: The purpose of this study was to assess abnormalities in LA relaxation by evaluating pulmonary venous flow velocity and interatrial septal motion using transesophageal echocardiography. METHODS: The subjects were 56 untreated patients in sinus rhythm, including 25 with previous myocardial infarction, 9 with hypertrophic cardiomyopathy, 11 with dilated cardiomyopathy, as well as 11 with chest pain syndrome as controls. Peak first systolic velocity (PVS1), peak atrial systolic velocity (PVA), and their time-velocity integrals (PVS1-I and PVA-I, respectively) were calculated from the pulmonary venous flow velocity. RESULTS: The PVS1 and PVS1-I correlated negatively with the maximum LA dimension and mean pulmonary capillary wedge pressure, and correlated positively with the amplitude of the interatrial septal motion during LA relaxation and percent fractional LA relaxation. The PVA and PVA-I did not correlate with the mean pulmonary capillary wedge pressure. There was a weak positive correlation between PVA and PVS1, and a close positive correlation between the ratio of PVA to PVS1 and mean pulmonary capillary wedge pressure. Multiple regression analysis indicated that the PVS1 was most closely related to percent fractional LA relaxation, followed by mean pulmonary capillary wedge pressure. CONCLUSION: The PVS1 determined from the pulmonary venous flow velocity is closely related to parameters of LA relaxation which may be determined by transesophageal M-mode echocardiography, and the ratio of PVA to PVS1 is useful for noninvasive evaluation of LA pressure.

Adult↗

PubMed1998

Right atrial potential profiles during atrial fibrillation predict the success of atrial defibrillation.

The right atrial electric potential was measured in 29 patients with chronic atrial fibrillation, and the clinical utility of these measurements in predicting the success of atrial defibrillation was investigated. The endocardial electric potential was recorded at 12 sites within the right atrium (high, middle, and low loci of anterior, posterior, lateral, and medial sites of the right atrium) with an electrode catheter. The duration and polar displacement of the atrial waves were measured at the one site that showed the maximum atrial electric potential among the 12 sites. The ratio of the maximum to the minimum atrial electric potential (atrial wave ratio) was calculated. Patients were classified into two groups according to the success (n = 6) or failure (n = 23) of atrial defibrillation. Electrophysiologic data were compared between the two groups, and correlations were evaluated between the data and the maximal left atrial diameter obtained from M-mode echocardiography. The two groups did not differ in the duration and polar displacement of the atrial waves. However, the atrial wave ratio was significantly lower in the success group than in the failure group, and the success rate of atrial defibrillation was also significantly greater in the patients with an atrial wave ratio of 10 or lower. This ratio showed a positive correlation with the maximal left atrial diameter; it became more difficult to achieve atrial defibrillation as the atrial wave ratio increased. Thus, the right atrial electric potential profile of patients with atrial fibrillation is a useful predictor of the success of atrial defibrillation.

Adolescent↗