Treatment of irritable bowel syndrome with a novel colonic irrigation system: a pilot study.

BACKGROUND: Medical treatments for irritable bowel syndrome (IBS) are often disappointing. A colonic irrigation system, the Ashong colonic irrigation apparatus (ACIA), was designed as a patient-administered device for defecation disorders. This pilot study evaluated the efficacy and safety of ACIA for IBS. METHODS: Eighteen patients, 12 with constipation-dominant IBS (IBS-C) and 6 with diarrhea-dominant IBS (IBS-D) group, were studied. Patients were randomized into treatments of 1-4 weeks. Colonic irrigation was performed twice daily for 6 consecutive days per week. To determine the response to treatment, bowel movement frequency, stool consistency, abdominal pain, patient satisfaction with bowel movements, and distress/discomfort due to symptoms were assessed. RESULTS: The scores of abdominal pain (p < 0.001), satisfaction (p < 0.001), and distress/discomfort (p < 0.001) improved significantly. The frequency of bowel movements in the IBS-C group increased from 1.68 to 3.78 times per week (p < 0.001). The occurrence of Bristol Stool Scale type 1 and 2 stool passage decreased from 45 to 13 % (p = 0.009) in the IBS-C group and type 6 and 7 stools decreased from 62 to 28 % (p = 0.005) in the IBS-D group. Only mild adverse events occurred, and all patients completed treatment. CONCLUSIONS: Colonic irrigation with ACIA is safe and can improve abdominal pain, constipation, and diarrhea associated with IBS. Patients were more satisfied with their bowel movements and found their symptoms were less disturbing. Larger studies on long-term efficacy and quality of life and on placebo effects are needed.

Influences of approaching tropical cyclones on water vapor and aerosols in the atmospheric boundary layer of Guangdong-Hong Kong-Macau Greater Bay Area of China.

The outer circulation of tropical cyclones (TCs) on the western North Pacific has been reported to substantially influence the atmospheric environment over the Guangdong-Hong Kong-Macau Greater Bay Area (GBA) of China, whereas dynamic evolution and redistribution of water vapor and aerosol in the atmospheric boundary layer (ABL) responding to moving TCs have yet to be understood. This study aims to answer three key research questions related to the influences of the approaching TCs: (1) how do water vapor and aerosol particles over the GBA change during the TC approaching stage? (2) how does the ABL in terms of vertical wind structure respond to the approaching TCs? and (3) how does turbulence influence the vertical profile of aerosol during the approaching stage? Based on an intensive analysis of three-year reanalysis and Doppler LiDAR data, this study identified a dry-polluted time over the GBA when a TC was located at ~1000 km away on South China Sea. Before that, horizontal wind has consistently come from the northeast, creating a favorable condition for weak transboundary air pollution to the GBA. During the dry-polluted time, the highest surface PM2.5 concentration was resulted from the enhanced downdraft and early-stage wind shear, i.e., stronger wind started occurring at upper-level ABL, while the further turbulent mixing induced by wind shear enhancement and updrafts recovery pumped surface pollution upward to the upper level when TCs became closer. Our findings are expected to improve both weather and PM2.5 forecasts under the impacts of approaching TCs.

Autonomic dysfunction in ischemic stroke with carotid stenosis.

OBJECTIVES: Impaired autonomic function is common in acute ischemic stroke. Previous limited studies have suggested that atherosclerosis may affect the distensibility of the carotid sinus and then impair the cardiovascular autonomic function. This study sought to investigate cardiovascular autonomic function in patients with ischemic stroke with carotid stenosis. METHODS: Eighty-five patients with ischemic stroke (58 ones without carotid stenosis and 27 ones with carotid stenosis, average 6 months after stroke onset) and 37 elderly controls were recruited. All performed Ewing's battery autonomic function tests. RESULTS: From Ewing's battery of autonomic function tests, atypical, definite, or severe autonomic dysfunction was identified in 69.0% patients without carotid stenosis and 88.9% with carotid stenosis, with significant difference between the two groups, and the prevalence of autonomic dysfunction in both groups was higher than that in controls (21.6%). Patients with carotid stenosis showed impairment of all parasympathetic tests (all P < 0.05) and one of the sympathetic tests [Mean fall in systolic blood pressure (BP) on standing: P = 0.051], and those without carotid stenosis only showed impairment in two parasympathetic tests (Valsalva ratio: P = 0.014; heart rate response to deep breathing: P < 0.001) in comparison with controls. Patients with carotid stenosis had significantly more impairment than those without carotid stenosis in some autonomic parameters (Valsalva ratio: P < 0.05; mean fall in systolic BP on standing: P < 0.05). CONCLUSIONS: Cardiovascular autonomic function is impaired in patients with ischemic stroke, but patients with carotid stenosis show more severely impaired parasympathetic and sympathetic functions.

Regularized multiframe phase-shifting algorithm for three-dimensional profilometry.

In many industrial inspection systems, it is required to have a high-precision three-dimensional measurement of an object under test. A popular technique is phase-measuring profilometry. In this paper, we develop some phase-shifting algorithms (PSAs). We propose a novel smoothness constraint in a regularization framework; we call this the R-PSA method and show how to obtain the desired phase measure with an iterative procedure. Both the simulation and experimental results verify the efficacy of our algorithm compared with current multiframe PSAs for interferometric measurements.

Impaired neurovascular coupling in ischaemic stroke patients with large or small vessel disease.

BACKGROUND AND PURPOSE: There is limited data of neurovascular coupling on stroke patients, especially on comparison of different etiologies. We aim to test the hypothesis that patients with small vessel disease (SVD) are impaired on neurovascular coupling rather than stroke patient with large intracranial artery stenosis (LIAS), because small vessel is more associated with microcirculatory function. To assess microcirculatory integrity of stroke patients, we performed a functional transcranial Doppler test using a standardized visual stimulation test. METHODS: The neurovascular coupling was measured in the asymptomatic occipital cortex in ischaemic stroke patients with LIAS, SVD, and healthy elder controls. Bilateral posterior cerebral arteries were monitored to measure evoked flow velocity during resting and visual stimulation phase. Peak systolic flow velocity responses were recorded, and time course of hemodynamic response was modeled according to a control system analysis with the parameters gain, natural angular frequency, attenuation, and rate time. RESULTS: Reproduced for both sides, the functionally induced flow velocity changes (gain) were significantly lower in LIAS and SVD compared with controls (P < 0.001). Reductions in both stroke groups were in the same order. Neurovascular coupling in LIAS group did not show difference at the side of vessel stenosis compared with non-stenosis side or at different stenotic degrees. CONCLUSIONS: Interestingly, both LIAS and SVD showed an uncoupling of the blood supply of active neurons. This points to an additional small vessel dysfunction in patients with LIAS.

Assessment of SARS-CoV-2 Immunity in Convalescent Children and Adolescents.

Persistence of protective immunity for SARS-CoV-2 is important against reinfection. Knowledge on SARS-CoV-2 immunity in pediatric patients is currently lacking. We opted to assess the SARS-CoV-2 adaptive immunity in recovered children and adolescents, addressing the pediatrics specific immunity towards COVID-19. Two independent assays were performed to investigate humoral and cellular immunological memory in pediatric convalescent COVID-19 patients. Specifically, RBD IgG, CD4+, and CD8+ T cell responses were identified and quantified in recovered children and adolescents. SARS-CoV-2-specific RBD IgG detected in recovered patients had a half-life of 121.6 days and estimated duration of 7.9 months compared with baseline levels in controls. The specific T cell response was shown to be independent of days after diagnosis. Both CD4+ and CD8+ T cells showed robust responses not only to spike (S) peptides (a main target of vaccine platforms) but were also similarly activated when stimulated by membrane (M) and nuclear (N) peptides. Importantly, we found the differences in the adaptive responses were correlated with the age of the recovered patients. The CD4+ T cell response to SARS-CoV-2 S peptide in children aged <12 years correlated with higher SARS-CoV-2 RBD IgG levels, suggesting the importance of a T cell-dependent humoral response in younger children under 12 years. Both cellular and humoral immunity against SARS-CoV-2 infections can be induced in pediatric patients. Our important findings provide fundamental knowledge on the immune memory responses to SARS-CoV-2 in recovered pediatric patients.

Long-term outcomes of ischemic stroke patients with concurrent intracranial and extracranial stenoses and ischemic heart disease.

BACKGROUND AND PURPOSE: Coexisting ischemic heart disease (IHD) and concurrent atherosclerosis of intracranial and extracranial vessels is common in Asians. This study aims to investigate the long-term outcomes of ischemic stroke patients with concurrent stenoses and IHD. METHODS: This was a prospective cohort study in Hong Kong. Consecutive Chinese patients with acute ischemic stroke underwent MRI, magnetic resonance angiography and carotid duplex sonography. RESULTS: A total of 428 patients were included. The mean follow-up period was 65 months (up to 87 months). Ninety-three patients (22%) died of any cause and 104 patients (22%) suffered from nonfatal vascular events. Fifty-four patients (13%) had IHD. Among them, 27 patients (50%) had concurrent stenoses. In patients with concurrent stenoses and IHD, only 3 (11%) were free of death and recurrent vascular events. Eight (30%) had recurrent nonfatal stroke, 7 (26%) had nonfatal myocardial infarct (MI) and 11 (41%) died, 6 (22%) of them due to fatal MI. The overall 5-year cumulative rates of mortality, recurrent vascular events and combined poor outcomes were 21, 23 and 43%, respectively. In patients with concurrent stenoses and IHD, these rates were 40, 50 and 83%, respectively. More deaths (log rank: 6.56; p = 0.01), recurrent vascular events (log rank: 25.24; p < 0.001) and poor outcomes (log rank: 27.50; p < 0.001) were found among patients with concurrent stenoses and IHD. CONCLUSIONS: Ischemic stroke patients with concurrent stenoses and IHD had high risks of death and recurrent vascular events. Future studies on aggressive medical therapy and early cardiac interventions in this high-risk group of stroke patients are warranted.

The significance of microembolic signals and new cerebral infarcts on the progression of neurological deficit in acute stroke patients with large artery stenosis.

BACKGROUND: Early neurological deterioration is common in the acute phase after stroke. We sought to investigate the correlation between the progression of microembolic signal (MES), ischemic infarcts and the neurological deficits in the acute phase of stroke patients with large artery occlusive disease. METHODS: Transient ischemic attack or stroke patients with relevant significant large artery stenosis (> or =50% diameter reduction) and admitted within 7 days of the symptom onset were recruited in this study. MES, infarcts on diffusion-weighted imaging and National Institutes of Health Stroke Scale (NIHSS) score were assessed on days 1 and 7 of recruitment. RESULTS: Among 67 patients, 50.7% (34 of 67) had MES on day 1. Presence of MES correlated with both a higher number of infarcts (p = 0.006) and the incidence of multiple infarcts (chi(2) test, p = 0.002), but not with the NIHSS score. On day 7, MES was detected in 25.4% of the patients (17 of 67), 11.8% of them (2 of 17) displayed new or extended infarct on DWI (p = 0.14) and 29.4% (5 of 17) showed neurological improvement (p = 0.039). Among the patients with positive MES at baseline, NIHSS reduction was positively correlated with disappearance of MES on day 7 (MES disappearance vs. persistence group, 2.05 vs. 0.73, p = 0.023). CONCLUSIONS: Neither the disappearance of MES nor the changes in NIHSS score correlated with the progression of infarct. Disappearance of MES indicated better neurological improvement in the acute phase.

Use of magnetic resonance angiography to predict long-term outcomes of ischemic stroke patients with concurrent stenoses in Hong Kong.

PURPOSE: To determine the long-term outcome of ischemic stroke patients with concurrent intracranial and extracranial atherosclerosis using magnetic resonance angiography. METHODS: A prospective cohort of patients in Hong Kong with acute ischemic stroke was studied with magnetic resonance angiography of the brain and carotid duplex. All patients were followed up regularly for the development of recurrent stroke, cardiac events, or death. RESULTS: Totally 343 patients with acute ischemic stroke were included, of whom 104 (30%) had concurrent intracranial and extracranial lesions. The follow-up period was up to 76 months (mean 44.5 months). Overall, 55 patients (15.5%) died of any cause and 91 patients (26.5%) suffered a further nonfatal vascular event. The overall 5-year cumulative rates of mortality, restroke and poor outcomes (combined death and further vascular events) were 18, 27 and 37%, respectively. In patients with concurrent lesions, these rates were 31, 41 and 51%, respectively. The corresponding rates were 13, 22 and 31% in patients without concurrent lesions. The risks were highest in the first year after stroke. More deaths (log rank, 16.3; p = 0.0001), restrokes (log rank, 9.71; p = 0.002) and poor outcomes (log rank, 13.87; p = 0.0001) were found among patients with concurrent lesions. The presence of concurrent vascular lesions, advanced age, smoking, hyperlipidemia and previous history of stroke were independent predictors of poor outcomes. CONCLUSIONS: The long-term prognosis of ischemic stroke patients with concurrent atherosclerosis of intracranial and extracranial vessels is poor. They are at high risk of further vascular events or death.

Nuclear accident consequence assessment in Hong Kong using JRODOS.

The JRODOS (Java-based Real-time Online DecisiOn Support) is a decision support system for off-site emergency management for releases of radioactive material into the environment. This paper documents the application of JRODOS by the Hong Kong Observatory in accident consequence assessment and emergency preparedness studies. For operational considerations, the most computational efficient dispersion model in JRODOS, ATSTEP, is adopted. Verification studies for JRODOS's ATSTEP model have been conducted. Comparison with tracer experiment results showed that under neutral atmospheric conditions and distances up to 50 km, the JRODOS simulation outputs were in general of the same order of magnitude with the tracer data. To further evaluate the capability of JRODOS in short-range simulation, a case study on the Fukushima nuclear power plant accident was also carried out. JRODOS was able to produce realistic simulation results which were comparable to the actual airborne monitoring data of the Cs-137 ground deposition from the Fukushima accident. Furthermore, the results of a comprehensive study to assess the potential consequences of accidents at a nearby nuclear power station are presented. Simulation using the French S3 source term for the Guangdong Nuclear Power Station at Daya Bay showed that the projected effective doses within Hong Kong remain far below the IAEA generic criteria of projected dose for urgent protective actions in sheltering/evacuation, while the projected equivalent dose in thyroid may meet the IAEA generic criteria for use of thyroid blocking agent at some areas in the northeastern part of Hong Kong, at distances of up to about 40 km from Daya Bay depending on the prevailing weather conditions in different seasons.

Clinical impact of minimal residual disease in children with different subtypes of acute lymphoblastic leukemia treated with Response-Adapted therapy.

To determine the clinical significance of minimal residual disease (MRD) in patients with prognostically relevant subtypes of childhood acute lymphoblastic leukemia (ALL), we analyzed data from 488 patients treated in St Jude Total Therapy Study XV with treatment intensity based mainly on MRD levels measured during remission induction. MRD levels on day 19 predicted treatment outcome for patients with hyperdiploid >50 ALL, National Cancer Institute (NCI) standard-risk B-ALL or T-cell ALL, while MRD levels on day 46 were prognostic for patients with NCI standard-risk or high-risk B-ALL. Patients with t(12;21)/(ETV6-RUNX1) or hyperdiploidy >50 ALL had the best prognosis; those with a negative MRD on day 19 had a particularly low risk of relapse: 1.9% and 3.8%, respectively. Patients with NCI high-risk B-ALL or T-cell ALL had an inferior outcome; even with undetectable MRD on day 46, cumulative risk of relapse was 12.7% and 15.5%, respectively. Among patients with NCI standard-risk B-ALL, the outcome was intermediate overall but was poor if MRD was ⩾1% on day 19 or MRD was detectable at any level on day 46. Our results indicate that the clinical impact of MRD on treatment outcome in childhood ALL varies considerably according to leukemia subtype and time of measurement.

Expression of an immunologically reactive merozoite surface protein (MSP-1(42)) in E. coli.

The 42-kDa carboxyl-terminal processing fragment of Plasmodium falciparum merozoite surface protein-1 (PfMSP-1(42)) is one of the anti-malarial vaccine candidate antigens. In the present study, recombinant MSP-1(42) was expressed as a fusion protein in a novel E. coli host. The average yield of the recombinant protein was 48 mg/l of bacterial culture. The antigenicity and immunogenicity of the purified protein were evaluated by comparing the results with those obtained from a well-characterized recombinant MSP-1(42) (Bmp42) expressed in the baculovirus expression system previously described from our laboratory. We observed that there is a high degree of similarities between the two recombinant proteins. Based on the results from T and B cell response, in vitro parasite growth inhibition, as well as cross-reactivities with several well-characterized MSP-1 specific Mabs, the bacterial expressed protein is apparently comparable to Bmp42 in terms of immunoreactivities. Our results suggest that the bacterial expression system could be employed to express immunologically active recombinant MSP-1(42) at elevated levels. This system may be an attractive alternative for producing a protective vaccine for human use at lower cost.

Coronary vasoconstriction after angioplasty of total occlusions: relation to change in coronary perfusion pressure.

OBJECTIVES: This study evaluated the coronary vasomotor response after successful angioplasty of chronic total coronary occlusions and tested the hypothesis that the degree of distal vasoconstriction is dependent on the change in perfusion pressure. BACKGROUND: Although distal coronary vasoconstriction has been observed to occur frequently after successful percutaneous transluminal coronary angioplasty, little is known about this vasomotor response after angioplasty of chronic total occlusions. METHODS: Thirty patients with successful angioplasty of chronic total occlusions of the left coronary artery were studied. Quantitative coronary measurements were made at 0, 15 and 30 min after angioplasty and again after intracoronary nitroglycerin administration in coronary artery segments distal to the dilated lesion and in a control vessel. The change in distal perfusion pressure was defined as mean systemic arterial pressure minus residual mean trans-stenotic pressure gradient minus mean coronary wedge pressure. RESULTS: The distal segments showed greater vasoconstriction (vs. nitroglycerin) at 15 and 30 min compared with that at 0 min after angioplasty (32.3 +/- 2.2% and 35.2 +/- 2.5% vs. 12.5 +/- 1.8%, respectively, p < 0.005) and compared with control segments (32.3 +/- 2.2% vs. 12.1 +/- 2.0%, p < 0.005, and 35.2 +/- 2.5% vs. 12.5 +/- 2.0%, p < 0.005, respectively). The degree of vasoconstriction at 30 min in the distal segments was found to correlate closely with the change in distal perfusion pressure (r = 0.73, p < 0.001). CONCLUSIONS: Coronary distal vasoconstriction occurs frequently after successful angioplasty of chronic total occlusions and correlates closely with the change in coronary perfusion pressure. These findings support the hypothesis of reset epicardial coronary autoregulation in chronic hypoperfusion such that restoration of normal perfusion pressure after successful angioplasty may provoke reflex vasoconstriction.

Effects of severity of the residual stenosis of the infarct-related coronary artery on left ventricular dilation and function after acute myocardial infarction.

OBJECTIVES: This study was designed to evaluate the relation between the severity of the residual stenosis of the infarct-related artery and changes in left ventricular volume and function after a first anterior myocardial infarction. BACKGROUND: Although thrombolytic therapy improves clinical outcome after acute myocardial infarction, the relations between the severity of the residual stenosis of the infarct-related artery and postinfarction left ventricular remodeling and function are unclear. METHODS: Fifty-eight patients with a first anterior myocardial infarction and significant disease only in the left anterior descending coronary artery on arteriography performed after 7 to 10 days were evaluated. All patients received thrombolytic therapy. Residual stenosis of the infarct-related artery was measured with quantitative coronary arteriography. Left ventricular volumes and ejection fraction were measured by echocardiography and radionuclide angiography, respectively, 7 to 10 days, 6 months and 1 year after infarction. End-diastolic and end-systolic left ventricular volumes were measured by two-dimensional echocardiography and normalized to body surface area. Patients were classified into three groups according to baseline residual stenosis severity: total occlusion (Group I), minimal lesion diameter less than 1.5 mm (Group II) and minimal diameter greater than or equal to 1.5 mm (Group III). RESULTS: Group I patients had significantly greater left ventricular end-diastolic and end-systolic volumes at 6 months and 1 year than did the other groups. Group II patients had greater end-diastolic and end-systolic volumes than did Group III patients at 1 year. In addition, Group I patients had a lower ejection fraction at 1 year than that of the other groups. The minimal lesion diameter was significantly correlated with percent change in end-diastolic volume at 1 year. CONCLUSIONS: The severity of the baseline residual stenosis of the infarct-related artery is an important predictor of change in left ventricular volumes in the 1st year after infarction. Total occlusion of the infarct-related artery is associated with greater left ventricular dilation and functional impairment.

Quantitative arteriography of apparently normal coronary segments with nearby or distant disease suggests presence of occult, nonvisualized atherosclerosis.

OBJECTIVES: The aim of this study was to evaluate, using quantitative arteriography, whether the diameter of visually normal coronary segments might be influenced by the relative proximity of visually apparent disease. BACKGROUND: Severity of coronary artery lesions is commonly referenced against a presumed normal nearby coronary segment with the presumption that visually smooth segments are relatively free of atherosclerotic disease. METHODS: Angiograms from 136 male patients with focal coronary disease were examined, and visually normal segments in the proximal portions of the major vessels were identified for measurement of mean segment diameters. Normal segments with immediately adjacent disease were compared with normal segments with distal disease in the same vessel and compared with normal segments in vessels for which the only other visible disease was in distant vessels. Angiograms with entirely normal findings from 26 age-matched men with atypical chest pain were used as controls. Segments were measured after nitroglycerin administration by means of computer-assisted quantitation. RESULTS: Mean diameters of visually normal segments with distant disease were smaller than those of control segments (p < 0.05). Normal left main and proximal left anterior descending coronary artery segments in patients with disease within the same vessel were significantly smaller than normal segments in patients with distant disease (p < 0.05). Normal segments with immediately adjacent disease had smaller mean diameters than normal segments with distal disease in the same vessel (p < 0.05). CONCLUSIONS: Visually normal coronary segments have progressively smaller lumen diameters, depending on the relative proximity of visible disease. Measurement of percent stenosis on the basis of the diameter of apparently normal adjacent reference segments can result in underestimation of coronary lesion severity.

Association between antiphospholipid antibodies and cardiac abnormalities in patients with systemic lupus erythematosus.

PURPOSE: Although the antiphospholipid antibodies are well recognized to be associated with thrombosis, recurrent abortion, and thrombocytopenia in patients with systemic lupus erythematosus (SLE), their relationship with cardiac disease is less clear. The purpose of this study was to evaluate the association between anti-phospholipid antibodies and cardiac abnormalities in patients with SLE. PATIENTS AND METHODS: A total of 75 consecutive SLE patients and 60 healthy sex- and age-matched control subjects were evaluated in a case-control study. All participants underwent M-mode, two-dimensional, and Doppler echocardiography. Antiphospholipid antibodies levels were assayed in each patient. The prevalence of antiphospholipid antibodies in patients with and without echocardiographic abnormalities was compared. RESULTS: Compared with the control group, SLE patients had significantly more pericardial abnormalities, left ventricular hypertrophy, left atrial enlargement, left ventricular dysfunction and verrucous valvular thickening, global valvular thickening with dysfunction, and mitral and aortic regurgitation. Among these abnormalities, antiphospholipid antibodies were significantly associated with isolated left ventricular (global or segmental) dysfunction (four of five positive; p less than 0.05), verrucous valvular (mitral or aortic) thickening (seven of nine positive; p less than 0.005), global valvular (mitral or aortic) thickening and dysfunction (five of six positive; p less than 0.02), as well as mitral regurgitation (16 of 19 positive; p less than 0.001) and aortic regurgitation (five of six positive; p less than 0.02). CONCLUSION: Valvular lesions and myocardial dysfunction are associated with elevated antiphospholipid antibodies. This study has important implications for the pathogenic role of anti-phospholipid antibodies in relation to these cardiac abnormalities.

Correlation of quantitative angiographic parameters with changes in left ventricular diastolic function after angioplasty of the left anterior descending coronary artery.

This study evaluates the changes in left ventricular (LV) diastolic filling after percutaneous transluminal coronary angioplasty and the relation of such changes to quantitative angiographic measurements of the severity of coronary narrowings. Pulsed Doppler echocardiographic measurements were performed in 40 patients with single left anterior descending artery narrowing before, and 10 and 30 days after angioplasty. Minimal luminal diameter and percent diameter stenosis of coronary lesions were measured by computer-assisted quantitation. The ratio of early to late diastolic flow velocities (E/A ratio), time velocity integral of early diastolic filling period (Ei) and the ratio of early and late diastolic filling periods (Ei/Ai ratio) increased gradually after angioplasty. Minimal luminal diameter correlated significantly with the percent changes in E/A ratio (r = 0.59 at 10 days, r = 0.57 at 30 days), Ei (r = 0.53 at 10 days, r = 0.55 at 30 days) and Ei/Ai ratio (r = 0.41 at 10 days, r = 0.49 at 30 days). Percent diameter stenosis showed overall weaker correlations than minimal diameter with the percent changes in E/A ratio (r = 0.39 at 10 days, r = 0.32 at 30 days) and Ei (r = 0.38 at 10 days, r = 0.31 at 30 days). Thus, LV diastolic filling improves serially after coronary angioplasty in patients with 1-vessel disease. The magnitude of improvement in diastolic filling correlates better with minimal luminal diameter than percent diameter stenosis. Therefore, minimal luminal diameter is a better predictor of changes in Doppler transmitral flow parameters after angioplasty than percent diameter stenosis.

Usefulness of labetalol in chronic atrial fibrillation.

Beta-adrenergic blocking agents are useful in controlling excessive ventricular rate in chronic atrial fibrillation (AF) but often reduce exercise capacity. To investigate the advantage of labetalol--a unique beta blocker with alpha-blocking property--in chronic AF, 10 patients without underlying structural heart disease were studied with treadmill test, 12-minute walk and 24-hour ambulatory electrocardiographic monitoring. Patients were randomized and crossed over to receive 4 phases of treatment (placebo, digoxin, digoxin with half-dose labetalol, and full-dose labetalol). Exercise durations were 14.1 +/- 1.5, 14.2 +/- 1.5, 16.1 +/- 1.1 and 15.6 +/- 1.1 minutes, respectively, indicating that labetalol did not reduce exercise tolerance. Although digoxin had no advantage over placebo in controlling maximal heart rate (177 +/- 2 vs 175 +/- 3 beats/min), labetalol, both as monotherapy or as an adjunct to digoxin, was advantageous (156 +/- 4 vs 177 +/- 2 beats/min, p less than 0.01, and 154 +/- 4 vs 177 +/- 2 beats/min, p less than 0.01, respectively). The rate-pressure product was consistently lowered by labetalol at rest and during exercise. At peak exercise, the addition of labetalol to digoxin reduced the maximal rate-pressure product achieved from 30,900 +/- 1300 to 24,100 +/- 2,000 mm Hg/min (p less than 0.01) and the maximal rate-pressure product was lowest with full-dose labetalol (22,300 +/- 1,600 mm Hg/min). During submaximal exercise on treadmill or during the 12-minute walk, the combination of labetalol and digoxin produced the best heart rate control, whereas labetalol monotherapy was comparable to digoxin therapy.(ABSTRACT TRUNCATED AT 250 WORDS)