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At least 1,117 records · Page 62Linked to original sources
PubMed1992

Long-term results of percutaneous mitral valvuloplasty with the Inoue balloon catheter.

The initial 85 patients who successfully underwent percutaneous mitral valvuloplasty (PMV) with the Inoue balloon catheter at the Guangdong Cardiovascular Institute between November 1985 and November 1988 had a mean follow-up period of 5 +/- 1 year (range 43 to 79 months). Before and after PMV and at follow-up, mean diastolic mitral gradients by the catheter method were 17.5 +/- 6.2, 3.1 +/- 3.3 and 3.3 +/- 3.4 mm Hg, respectively (p < 0.001 before vs after PMV and before vs follow-up; and p > 0.05 after PMV vs follow-up). Mean diastolic mitral gradients by the Doppler method were 18 +/- 6, 8 +/- 5 and 9 +/- 5 mm Hg, respectively (p < 0.001 before vs after PMV and before vs follow-up; and p > 0.05 after PMV vs follow-up). Mean diastolic mitral gradients by the Doppler method were 18 +/- 6, 8 +/- 5 and 9 +/- 5 mm Hg, respectively (p < 0.001 before vs after PMV and before vs follow-up; and p > 0.05 after PMV vs follow-up). Mitral valve areas by the echo-Doppler method were 1.1 +/- 0.3, 2.0 +/- 0.4 and 1.8 +/- 0.5 cm2, respectively (p < 0.001 before vs after PMV and before vs follow-up; and p > 0.05 after PMV vs follow-up). Phonocardiographic and vectorcardiographic studies, and cardiopulmonary exercise testing showed significant improvement after PMV and at follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2006

Significance of 8-hydroxy-2'-deoxyguanosine levels in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: Although oxidative stress mediated by reactive oxygen species plays an important role in the pathogenesis of heart failure (HF), good clinical markers for reactive oxygen species in patients with HF have not been established. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) is formed from deoxyguanosine in DNA by hydroxyl free radicals and might serve as a sensitive biomarker of intracellular oxidative stress in vivo. Thioredoxin (TRX) is known to be induced in cells as a radical scavenger against oxidative stress. The aim of this study is to evaluate the clinical significance of the serum 8-OHdG and TRX of patients with chronic HF with idiopathic dilated cardiomyopathy (DCM). METHODS AND RESULTS: We estimated serum 8-OHdG and TRX levels using enzyme-linked immunosorbent assay in 32 patients with DCM and investigated the impact of these markers to the clinical characteristics of these patients. Serum levels of 8-OHdG, but not TRX were significantly correlated with New York Heart Association functional class, left atrial diameters, left ventricular end-diastolic diameters, left ventricular end-systolic diameters, and plasma levels of brain natriuretic peptide. CONCLUSION: These data suggest oxidative DNA damage is increased in patients with DCM according to the severity of HF. Serum levels of 8-OHdG may represent clinically useful markers of left ventricular remodeling.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1996

Immediate and long-term effect of mitral balloon valvotomy on severe pulmonary hypertension in patients with mitral stenosis.

The pulmonary vascular hemodynamics were studied in 21 patients with severe mitral stenosis and severe pulmonary hypertension. Hemodynamic data were obtained before and immediately after mitral balloon valvotomy (MBV) and at follow-up 7 to 14 months (mean 12 months) later by repeat catheterization. The mean pulmonary capillary wedge pressure (PCW) decreased from 27 +/- 5 to 15 +/- 4 mm Hg (p < 0.001). The mean mitral valve gradient (MVG) decreased from 18 +/- 4 to 6 +/- 2 mm Hg (p < 0.001). Mitral valve area (MVA) increased from 0.6 +/- 0.1 to 1.5 +/- 0.3 cm2 (p < 0.02). Cardiac index increased from 2.2 +/- 0.3 to 2.6 to 0.5 L/min/m2 (p < 0.02). The pulmonary artery systolic pressure decreased from 65 +/- 13 to 50 +/- 13 mm Hg (p < 0.001), and no significant change was seen in pulmonary vascular resistance (PVR) immediately after MBV from 461 +/- 149 to 401 +/- 227 dynes/sec/cm(-5) (p = 0.02). At follow-up the MVA increased from 1.5 +/- 0.3 to 1.7 +/- 0.3 cm2 (p < 0.02). Cardiac index increased further to 3 +/- 0.4 L/min/m2 (p < 0.02). MVG and PCW pressure remained the same. The pulmonary artery systolic pressure decreased further to 38 +/- 9 mm Hg (p < 0.02). PVR decreased significantly to 212 +/- 99 dynes/sec/cm(-5) (p < 0.02). We concluded that the pulmonary artery pressure decreased without normalizing immediately after MBV and normalized in patients with optimal results from mitral balloon valvotomy 7 to 14 months later. Insignificant change in PVR was seen immediately after MBV and markedly decreased or normalized at late follow-up in patients with optimal result from MBV.

Adolescent↗
PubMed1998

Role of transesophageal echocardiography in the evaluation of patients with clinical pacemaker syndrome.

OBJECTIVES: The goal of this study was to investigate the possible role of transesophageal echocardiography in the evaluation of patients with clinical pacemaker syndrome. BACKGROUND: Several reports on transthoracic echocardiographic features of ventricular pacing were described; however, no previous study of transesophageal echocardiography has been undertaken in patients at the severe end of pacemaker syndrome who need reprogramming of dual-chamber pacing for symptom relief. METHODS: Twelve patients with ventricular-inhibited pacemakers (VVI) with clinical symptomatic pacemaker syndrome (group I) and 10 patients with VVI without pacemaker syndrome (group II) were prospectively studied. The two groups were pacemaker dependent and had persistent ventriculoatrial conduction. Transesophageal echocardiographic parameters were assessed in group II and within 6 hours before reprogramming to the DDD mode in group I. Follow-up transesophageal echocardiographic study was performed 28+/-5 days after reprogramming in group I. RESULTS: All patients in group I had subjective improvements of symptoms after DDD reprogramming. The atrial reverse flow velocities of pulmonary veins in group I before reprogramming were significantly higher in group II (39.3+/-11.4 versus 15.7+/-13.5 cm/sec, p < 0.0001). Spontaneous echo contrast in the descending aorta was detected in all patients from group I before reprogramming. The prevalence of significant mitral regurgitation (> or = moderate) was significantly higher in group I before reprogramming than in group II (67% versus 8%, p = 0.01). Significant mitral regurgitation and spontaneous echo contrast in the descending aorta in group I disappeared after reprogramming to the DDD mode. CONCLUSIONS: Transesophageal echocardiography provides physiologic, pacemaker-related hemodynamic changes in paced patients. Significantly higher atrial reverse flow velocities of pulmonary veins, increased frequency of spontaneous echo contrast in the descending aorta, and significant mitral regurgitation are peculiar echocardiographic findings in patients with VVI with clinical pacemaker syndrome.

Adult↗
PubMed2003

Surgical outcome of the maze procedure for atrial fibrillation in mitral valve disease: rheumatic versus degenerative.

BACKGROUND: The results of the maze procedure are known to be less satisfactory in rheumatic mitral disease than in nonrheumatic mitral valve disease. The aim of this study was to determine whether the etiology of mitral valve disease affected surgical outcome. METHODS: From July 1997 to January 2001, 129 consecutive patients with chronic atrial fibrillation associated with mitral valve disease had mitral valve operations with the maze procedure. The underlying mitral pathology was rheumatic in 86 patients (group R) and degenerative in 43 (group D). Echocardiograms and electrocardiograms were performed immediately and then repeated 3 months and 6 months postoperatively. RESULTS: The mean age, duration of atrial fibrillation, and preoperative left atrial size were similar between the groups. There was no operative mortality and no significant difference in cardiopulmonary bypass and aortic cross-clamp times. The sinus conversion rate at 7 days postoperatively was 86% in both groups, and at 6 months it was 95.3% in group R and 97.7% in group D (p > 0.05). The transmitral A wave detection rates in groups R and D at 7 days and 6 months postoperatively were, respectively, 63.1% versus 67.4% and 90.4% versus 91.9% (p > 0.05). The transmitral A wave velocity (cm/second) at the same times (7 days and 6 months postoperatively) was 41.9 +/- 41.6 versus 45.5 +/- 37.7 and 67.8 +/- 38.2 versus 69.8 +/- 35.8 in groups R and D, respectively (p > 0.05). CONCLUSIONS: The maze procedure is equally effective in treating chronic atrial fibrillation in patients with either rheumatic or nonrheumatic mitral valve disease in terms of sinus conversion rate and left atrial transport function.

Atrial Fibrillation↗
PubMed2000

Acetazolamide reduces hypoxic pulmonary vasoconstriction in isolated perfused rabbit lungs.

Carbonic anhydrase (CA) may modulate regional blood flow by mediating changes in extra- and intracellular pH. We hypothesized that CA inhibition with acetazolamide would inhibit the kinetics and magnitude of hypoxic pulmonary vasoconstriction (HPV). Isolated rabbit lungs were ventilated and perfused in situ at constant flow, with buffer containing red blood cells. Preparations were sequentially challenged with hypoxic (FI(O(2)) 0.05) and/or hypercapnic (FI(CO(2)) 0.10) gas mixtures for 5 or 10 min. In the experimental groups, acetazolamide (33 microM) was added to the perfusate after establishing baseline responses, and gas challenges were repeated; control groups were studied without acetazolamide. Acetazolamide reduced the increase in pulmonary artery pressure (DeltaPAP) and the rate of pressure rise by approximately 30-50% during hypoxia and combined hypoxia/hypercapnia. The reduction in DeltaPAP occurred for both 5 and 10 min challenges. Acetazolamide did not affect expired nitric oxide concentrations. We conclude that acetazolamide reduces both the magnitude and kinetics of HPV by a mechanism that does not involve nitric oxide.

Acetazolamide↗
PubMed1997

The mechanism of blood flow in cardiopulmonary resuscitation--introducing the lung pump.

The mechanism of blood flow in cardiopulmonary resuscitation remains controversial. Inconsistencies in the cardiac pump model necessitated the development of the thoracic pump. Neither hypothesis alone can account for blood flow during external massage. Using the postulates that a cyclical pump has three components, an inlet valve, a compression chamber and an outlet valve, we propose the lung pump hypothesis where these components are represented by the pulmonary valve; the lung vasculature/left atrium/left ventricle; and the aortic valve. We explore the mechanism and effect of this hypothesis and match it to previous observations. The implications to cardiopulmonary resuscitation are addressed.

Animals↗
PubMed2002

Action potential duration restitution kinetics in human atrial fibrillation.

OBJECTIVES: We undertook this study to determine whether human atrial fibrillation (AF) relates to steeply sloped action potential duration restitution (APDR) kinetics and whether the spatial nonuniformity of APDR promotes persistence of AF. BACKGROUND: A steeply sloped APDR curve is known to be an important determinant of the induction of more complex action potential duration (APD) dynamics and fibrillation. METHODS: Patients with chronic atrial fibrillation (CAF) (n = 18), paroxysmal atrial fibrillation (PAF) (n = 14) and normal control subjects (n = 9) were studied. The monophasic action potential duration at 90% repolarization (APD(90)) and the effective refractory period (ERP) were measured at six sites in the right atrium. After AF was electrically converted, APDR was assessed by delivering a single extrastimulus after a train of stimuli at a cycle length of 600 ms (S(1)S(2)) at six different sites of the right atrium, as well as rapid pacing at cycle lengths that induced APD alternans. RESULTS: The APD(90) and ERP in patients with CAF were shorter than those in patients with PAF and control subjects (p < 0.05); however, the dispersions of APD(90) and ERP in each group were similar. The maximal slopes of APDR by S(1)S(2) and rapid pacing in patients with CAF (1.2 +/- 0.4 and 1.7 +/- 0.2) and PAF (1.1 +/- 0.4 and 1.3 +/- 0.4) were higher than those in control subjects (0.5 +/- 0.3 and 0.8 +/- 0.2, respectively; p < 0.01). The maximal slope obtained by S(1)S(2) did not differ from that obtained by rapid pacing in any group. The inter-regional difference of the maximal slope in patients with CAF (1.6 +/- 0.4, p < 0.05) was greater than that in patients with PAF (1.2 +/- 0.3, p = NS vs. control) and control subjects (0.4 +/- 0.2). CONCLUSIONS: Atrial fibrillation was related to steeply sloped (>1) APDR kinetics. The spatial dispersion of APDR in patients with chronic AF was greater than that of patients with paroxysmal AF and control subjects, indicating that the heterogeneity of APDR of the atrium plays an important role in the persistence of AF.

Action Potentials↗
PubMed2003

Pulmonary venous flow by doppler echocardiography: revisited 12 years later.

In 2003, pulmonary venous flow (PVF) evaluation by Doppler echocardiography is being used daily in clinical practice. Twelve years ago, we reviewed the potential uses of PVF in various conditions. Some of its important uses in cardiology have materialized, while others have not and have been supplanted by newer approaches. Current applications of measuring PVF have included: differentiating constrictive pericarditis from restriction, estimation of left ventricular (LV) filling pressures, evaluation of LV diastolic dysfunction and left atrial (LA) function, and grading the severity of mitral regurgitation (MR). However, there have been a number of controversies raised in the use of PVF profiles. Using transthoracic echocardiography, there may be technical issues in measuring the atrial reversal flow velocity. The use of PVF in the evaluation of the severity of MR is not always specific and can be affected by atrial fibrillation (AF) and elevated mean LA pressure. Mitral valvuloplasty and radiofrequency ablation for AF, which are the newer applications of PVF in monitoring invasive procedures, are mentioned. This article reviews the important clinical role of Doppler evaluation of PVF, discusses its limitations and pitfalls, and highlights its newer applications.

Catheter Ablation↗
PubMed1985

M-mode echocardiography in constrictive pericarditis.

M-mode echocardiograms from 40 patients with proven constrictive pericarditis and 40 subjects without evidence of cardiac disease were reviewed for features previously described in constrictive pericarditis. In this large series, no single feature of the M-mode echocardiogram could be considered diagnostic, although a pattern of normal left ventricular size and systolic function, mild left atrial dilation, flattened diastolic left ventricular posterior wall motion and abnormal septal motion was found in most patients. It is concluded that the M-mode echocardiogram can provide findings suggestive of constrictive pericarditis but must be used in conjunction with hemodynamic and other studies to establish the diagnosis.

Echocardiography↗