Biomedical subjects

Fabrice Bauer

Publications and source records attributed to Fabrice Bauer.

17 recordsLinked to original sources

PubMed2006

Improvement of peripheral endothelial dysfunction by protein tyrosine phosphatase inhibitors in heart failure.

BACKGROUND: Chronic heart failure (CHF) induces endothelial dysfunction characterized by a decrease in nitric oxide (NO) production in response to flow (flow-mediated dilatation [FMD]). Because activation of endothelial NO synthase (eNOS) by flow requires tyrosine phosphorylation, we tested whether endothelial dysfunction could be corrected by increasing phosphotyrosine levels using protein tyrosine phosphatase (PTP) inhibitors and especially inhibitors of PTP1B. METHODS AND RESULTS: CHF was induced by coronary ligation in mice, and FMD was assessed in isolated and cannulated mesenteric artery segments (2 mm in length and <300 microm in diameter). CHF almost abolished FMD but only moderately affected the response to acetylcholine. In mice with CHF, the PTP1B inhibitors AS279, AS098, and AS713 restored FMD to levels similar to those of normal mice. This restoration was reduced by inhibitors of eNOS and phosphatidylinositol-3 kinase. Polymerase chain reaction and Western blot showed that arteries express PTP1B, and this expression was not affected by CHF. Immunolocalization revealed the presence of PTP1B in the endothelium and the adventitia. Flow induced a transient eNOS phosphorylation that was absent in CHF. PTP1B inhibition stimulated early eNOS phosphorylation and increased phosphorylation of Akt. CONCLUSIONS: Our results demonstrate for the first time that PTP1B inhibitors may be potent treatments for endothelial dysfunction.

Acetylcholine↗

PubMed2006

Treatment of calcific aortic stenosis with the percutaneous heart valve: mid-term follow-up from the initial feasibility studies: the French experience.

OBJECTIVES: The aim of this work was to study the feasibility, safety, efficacy, and durability of percutaneous heart valve (PHV) implantation in the aortic position. BACKGROUND: We developed a PHV (equine pericardium valve in a balloon-expandable, stainless-steel stent) to treat patients with inoperable aortic stenosis (AS). METHODS: Thirty-six patients (aortic valve area < or =0.7 cm2, New York Heart Association [NYHA] functional class IV, and severe comorbidities), formally declined for surgery, were recruited on a compassionate basis. The PHV was implanted by retrograde or antegrade trans-septal approach. Clinical and echocardiographic outcomes were assessed serially. RESULTS: Twenty-seven patients were implanted successfully (23 antegrade, 4 retrograde) in the subcoronary position with improvement in valve area (0.60 +/- 0.11 cm2 to 1.70 +/- 0.10 cm2, p < 0.0001) and transvalvular gradient (37 +/- 13 mm Hg to 9 +/- 2 mm Hg, p < 0.0001). Paravalvular aortic regurgitation was grade 0 to 1 (n = 10), grade 2 (n = 12), and grade 3 (n = 5). One week post-procedure, improvement in left ventricular function (45 +/- 18% to 53 +/- 14%, p = 0.02) was most pronounced in patients with ejection fraction <50% (35 +/- 10% to 50 +/- 16%, p < 0.0001). Thirty-day major adverse events after successful implantation were 26% (pericardial tamponade, stroke, arrhythmia, urosepsis, and one death unexplained at autopsy). Eleven patients are currently alive with follow-up of 9 months (n = 2), 10 months (n = 3), 11 months (n = 1), 12 months (n = 2), 23 months (n = 1), and 26 months (n = 2). All patients experienced amelioration of symptoms (>90% NYHA functional class I to II). Percutaneous heart valve function remained unchanged during follow-up, and no deaths were device-related. CONCLUSIONS: Percutaneous heart valve implantation is feasible in inoperable patients with end-stage AS leading to hemodynamic and clinical improvement. Continued advances and improved patient selection should decrease adverse events in the near future.

Aged↗

PubMed2005

Evaluation of left ventricular outflow tract area after septal reduction in obstructive hypertrophic cardiomyopathy: a real-time 3-dimensional echocardiographic study.

BACKGROUND: The comparative impact of percutaneous alcohol septal reduction (ASR) and surgical myectomy on the left ventricular outflow tract (LVOT) area in patients with obstructive hypertrophic cardiomyopathy (HC) is not well defined. Real-time 3-dimensional echocardiography (RT3DE) provides accurate information about the LVOT geometry and shape. We aimed to analyze the change in LVOT area after septal reduction interventions in patients with obstructive HC using RT3DE. METHODS: Thirty-one HC patients (mean age 53 +/- 17 years) undergoing ASR (n = 14) or myectomy (n = 17) were studied at baseline and during follow-up with RT3DE. LVOT area was measured after observing the LVOT in the 3D space as the smallest area during midsystole. LVOT pressure gradients were determined by conventional continuous wave Doppler. RESULTS: Overall, LVOT area increased from 0.86 +/- 0.20 to 2.50 +/- 0.88 cm2 (P < .01), and the resting LVOT pressure gradient decreased from 64 +/- 41 to 16 +/- 10 mm Hg (P < .01) after a median follow-up of 3 months after intervention (range 1-24 months). A similar significant decrease in LVOT pressure gradients was seen in myectomy and ASR groups (from 62 +/- 39 to 12 +/- 5 mm Hg and from 67 +/- 43 to 21 +/- 14 mm Hg, respectively, P < .01 in between each group, and P = NS between both groups). However, the increase in LVOT area was greater in myectomy than in ASR group (from 0.81 +/- 0.22 to 2.90 +/- 0.64 cm2 and 0.93 +/- to 0.16 to 2.02 +/- 0.92 cm2, respectively, P < .01 between both groups). CONCLUSION: RT3DE demonstrated an effective increase in LVOT area after both ASR and myectomy. This technique may be useful for assessing the results of septal reduction in patients with obstructive HC.

Adolescent↗

PubMed2005

Quantitative analysis of left atrial function during left ventricular ischemia with and without left atrial ischemia: a real-time 3-dimensional echocardiographic study.

Left atrial (LA) systolic and diastolic function were analyzed in an animal model of acute left ventricular ischemia with LA ischemia by proximal left circumflex coronary artery occlusion or without LA ischemia by midleft anterior descending coronary artery occlusion (7 sheep in each group). LA pressures and LA volumes were simultaneously recorded using a catheter and real-time 3-dimensional echocardiography, respectively. LA stroke volume represented 63% of left ventricular stroke volume during left anterior descending coronary artery occlusion, but only 32% during left circumflex coronary artery occlusion. This animal study with 3-dimensional echocardiographic determination of absolute LA volumes demonstrated dramatic depression of LA function during proximal left circumflex coronary artery occlusion as compared with left anterior descending coronary artery occlusion.

Animals↗

PubMed2005

Left atrial appendage function analyzed by tissue Doppler imaging in mitral stenosis: effect of afterload reduction after mitral valve commissurotomy.

BACKGROUND: This study sought to investigate the relative load dependence of left atrial appendage (LAA) tissue Doppler velocities in patients with mitral stenosis after percutaneous mechanical mitral commissurotomy (PMMC). METHODS: LAA tissue Doppler velocities were obtained in 34 patients with mitral stenosis (20 with sinus rhythm and 14 with atrial fibrillation) before and after PMMC by transesophageal echocardiography. Standard ultrasound studies were also performed for mitral valve orifice area, transmitral pressure gradient, and LAA blood flow velocity measurements. RESULTS: PMMC resulted in a significant increase in mitral valve area (P < .001) and decrease in mean transmitral pressure gradient (P < .001). LAA tissue Doppler velocities consisted of a triphasic velocity profile: SLAA and ELAA occurring during left ventricular contraction and relaxation, respectively, and ALAA occurring after the atrial contraction. After PMMC, ELAA and ALAA velocities consistently increased (4.8 +/- 1.2 to 7.9 +/- 2.6 cm/sec [P < .001] and 6.6 +/- 2.9 to 8.1 +/- 4.2 cm/sec [P < .05], respectively). The mean transmitral pressure gradient was significantly correlated with ALAA before and after PMMC (r = .65). CONCLUSIONS: In mitral stenosis, tissue Doppler velocities illustrated improvement of regional LA function after PMMC, in relation to decreased transmitral pressure gradient.

Atrial Function, Left↗

PubMed2004

Acute improvement in global and regional left ventricular systolic function after percutaneous heart valve implantation in patients with symptomatic aortic stenosis.

BACKGROUND: The newly developed percutaneous heart valve (PHV) implantation technique decreases transaortic pressure gradient in patients with aortic stenosis. PHV replacement effects on left ventricular (LV) global and regional systolic function are currently unknown. METHODS AND RESULTS: Eight patients with severe aortic stenosis had 2D echocardiography at baseline and 24 hours after PHV implantation to evaluate changes in LV volume and LV ejection fraction. Regional function, ie, both peak systolic anterior and posterior wall tissue velocity, as well as strain and strain rate imaging, were measured by tissue Doppler imaging from a short-axis view. At 24 hours, a significant reduction in transaortic mean pressure gradient (from 46+/-15 to 8+/-3 mm Hg; P<0.0001) was accompanied by an increase in aortic valve area (from 0.59+/-0.11 to 1.69+/-0.11 cm2; P<0.0001). LV end-diastolic volume remained unchanged (102+/-36 to 101+/-12 mL; P=NS), whereas LV ejection fraction increased (48+/-18% to 57+/-12%; P<0.01). Improvement in posterior wall displacement (posterior wall tissue velocity increased from 2.2+/-0.5 to 4.4+/-1.0 cm/s(-1); P=0.0003) and deformation (strain rate imaging increased from 1.0+/-0.3 to 1.9+/-0.7 s(-1), P=0.009, and strain increased from 11+/-5% to 17+/-9%; P=0.02) were observed. CONCLUSIONS: Immediately after PHV replacement, improvement of LV global and regional systolic function was evidenced by tissue Doppler imaging.

Aged↗

PubMed2004

Early experience with percutaneous transcatheter implantation of heart valve prosthesis for the treatment of end-stage inoperable patients with calcific aortic stenosis.

OBJECTIVES: This study was done to assess the results of percutaneous heart valve (PHV) implantation in non-surgical patients with end-stage calcific aortic stenosis. BACKGROUND: Replacement of PHV has been shown to be feasible in animals and humans. We developed a PHV composed of three pericardial leaflets inserted within a balloon-expandable stainless steel stent. We report the acute and early follow-up results of the initial six PHV implantations. METHODS: An anterograde approach was used in all cases. The PHV, crimped over a 22-mm diameter balloon, was advanced through a 24-F sheath from the femoral vein to the aortic valve and delivered by balloon inflation. Clinical, hemodynamic, and echocardiographic outcomes were assessed serially. RESULTS: All patients were in New York Heart Association functional class IV. The PHV was successfully delivered in five patients. Early migration with subsequent death occurred in one patient who presented with a torn native valve. Acute hemodynamic and angiographic results showed no residual gradient, mild (three patients) or severe (two patients) aortic regurgitation, and patent coronary arteries. On echocardiography, the aortic valve area was increased from 0.5 +/- 0.1 cm(2) to 1.70 +/- 0.03 cm(2) and the aortic regurgitation was paravalvular. Marked and sustained hemodynamic and clinical improvement was observed after successful PHV implants. The first three patients died of a non-cardiac cause at 18, 4, and 2 weeks, respectively, and the other patients are alive at 8 weeks with no signs of heart failure. CONCLUSIONS: Implantation of the PHV can be achieved in patients with end-stage calcific aortic stenosis and might become an important therapeutic option for patients not amenable to surgical valve replacement.

Aged↗

PubMed2004

Determinant of left atrial dilation in patients with hypertrophic cardiomyopathy: a real-time 3-dimensional echocardiographic study.

To identify the determinants of left atrial (LA) dilation for patients with hypertrophic obstructive cardiomyopathy (HOCM), first we validated LA volume determination by real-time 3-dimensional echocardiography using magnetic resonance imaging in patients. Subsequently, real-time 3-dimensional echocardiography and 2-dimensional Doppler echocardiography were performed in 60 patients with HOCM and in 17 age-matched control subjects. LA volumes and left ventricular (LV) filling pressures were higher for patients with HOCM than in control subjects. By stepwise multilinear regression analysis, LV end-diastolic pressure, resting LV outflow tract pressure gradient, and LV wall thickness were significant determinants of LA dilation. However, tau, -dP/dt, LV stiffness, provokable pressure gradient, and mitral regurgitation did not have any independent relationship with LA volumes. Therefore, it is concluded that LA volume can be accurately determined by real-time 3-dimensional echocardiography; and LA dilation in patients with HOCM is related to LV filling pressure, LV outflow tract pressure gradient, and LV wall thickness.

Atrial Function, Left↗

PubMed2004

Combination of pulsed-wave Doppler and real-time three-dimensional color Doppler echocardiography for quantifying the stroke volume in the left ventricular outflow tract.

Real-time three-dimensional (3-D) color Doppler echocardiography (RT3D) is capable of quantifying flow. However, low temporal resolution limits its application to stroke volume (SV) measurements. The aim of the present study was, therefore, to develop a reliable method to quantify SV. In animal experiments, cross-sectional images of the LV outflow tract were selected from the RT3D data to calculate peak flow rates (Q(p3D)). Conventional pulsed-wave (PW) Doppler was performed to measure the velocity-time integral (VTI) and the peak velocity (V(p)). By assuming that the flow is proportional to the velocity temporal waveform, SV was calculated as alpha x Q(p3D) x VTI/V(p), where alpha is a temporal correction factor. There was an excellent correlation between the reference flow meter and RT3D SV (mean difference = -1. 3 mL, y = 1. 05 x -2. 5, r = 0. 94, p < 0. 01). The new method allowed accurate SV estimations without any geometric assumptions of the spatial velocity distributions.

Animals↗

PubMed2004

Management of maternal cor triatriatum during pregnancy.

BACKGROUND: Cor triatriatum is a rare congenital cardiac abnormality, usually diagnosed in childhood. We describe the first case of atrial fibrillation secondary to maternal cor triatriatum diagnosed during the first trimester of pregnancy and its successful management until postpartum (MEDLINE [1966 to 2003] and Embase [1988 to 2003], using MeSH terms for "cor triatriatum" and "pregnancy"). CASE: A 31-year-old gravida 1 complained of progressive dyspnea on exertion and palpitations, which occurred at the end of the first trimester of the pregnancy. Atrial fibrillation was observed on electrocardiogram. A transesophageal echocardiography examination revealed a cor triatriatum that was responsible for the arrhythmia. beta-adrenergic blocking agents and digitalis glycosides were used to control supraventricular arrhythmia, while low-molecular-weight heparin was administered to prevent thromboembolic events. Low-molecular-weight heparin was discontinued at 37 weeks of gestation, and subcutaneous unfractionated heparin was administered instead. Pregnancy continued a normal course until full-term vaginal delivery with epidural anesthesia and close hemodynamic monitoring. CONCLUSION: A standard treatment for atrial fibrillation could be effective in preventing maternal hemodynamic complications secondary to cor triatriatum during pregnancy. Moreover, this case illustrates the American consensus in neuraxial anesthesia and anticoagulation, which supports the opinion that there is a limited risk associated with the use of epidural and spinal anesthesia in the presence of subcutaneous heparin treatment.

Adrenergic beta-Antagonists↗

PubMed2003

Role of reactive oxygen species in cocaine-induced cardiac dysfunction.

OBJECTIVE: Contractility alterations and LV hypertrophy after chronic cocaine administration have been shown to be accompanied by an increase in oxidative stress. This study was carried out to investigate whether the production of reactive oxygen species is an early event of primary importance in cocaine-induced myocardial injury or simply occurs as a consequence of the ventricular dysfunction itself. METHODS AND RESULTS: After 2 days of cocaine administration to rats, no differences were observed in echocardiographic parameters between the cocaine-treated group and the control group. However, an increase in oxidative stress in the myocardium was indicated by an increase in lipid peroxidation (+35%, cocaine vs. control), an increase in antioxidant enzymes (catalase +110%, glutathione peroxidase +40% and superoxide dismutase +38%) and of NADPH-driven superoxide production (assessed by chemiluminescence). Furthermore, higher gp91phox and p22phox mRNA expression, measured by quantitative real-time RT-PCR, was found in the cocaine group. On day 8, cocaine administration induced a cardiac dysfunction, characterized by a decrease in cardiac index (-30%, cocaine vs. controls) and left ventricular (LV) fractional shortening (-23%, cocaine vs. controls). This LV dysfunction was prevented by antioxidant treatment (100 mg/kg/day vitamin C and 100 U/kg/day vitamin E). Moreover, in these animals, antioxidant treatment decreased lipid peroxides and decreased the activity of NADPH oxidase, associated with the downregulation of gp91phox. CONCLUSION: These data indicate that cocaine administration induces early NADPH-driven O2-. release which may play an important role in the development and progression of the LV dysfunction observed after chronic cocaine abuse.

Animals↗

PubMed2003

Comparison of left ventricular diastolic function in obstructive hypertrophic cardiomyopathy in patients undergoing percutaneous septal alcohol ablation versus surgical myotomy/myectomy.

Both percutaneous transcoronary alcohol septal reduction (ASR) and surgical myectomy are effective treatments to relieve left ventricular (LV) outflow tract obstruction in obstructive hypertrophic cardiomyopathy (HC). LV diastolic function was assessed by echocardiography in 57 patients with obstructive HC at baseline and 5 +/- 4 months after ASR (n = 37) or surgical myectomy (n = 20). LV outflow tract pressure gradient decreased from 65 +/- 40 to 23 +/- 21 mm Hg (p <0.01) after treatment. The ratio of the early-to-late peak diastolic LV inflow velocities, and the ratio of the early peak diastolic LV inflow velocity to the lateral mitral annulus early diastolic velocity determined by tissue Doppler imaging significantly decreased after the procedures (1.6 +/- 1.7 vs 1.0 +/- 0.7 and 15 +/- 8 vs 11 +/- 5, respectively), whereas LV inflow propagation velocity significantly increased (60 +/- 24 vs 71 +/- 36 cm/s). Left atrial size decreased from 29 +/- 7 to 25 +/- 6 cm(2) (p <0.05). Patients had a significant improvement in New York Heart Association functional class and in exercise performance. When comparing ASR with myectomy, no difference was found in the degree of change in any parameter of diastolic function. Thus, diastolic function indexes obtained by echocardiography changed after septal reduction interventions in patients with obstructive HC; this change was similar to that after surgical myectomy and ASR.

Adolescent↗

PubMed2003

Real-time three-dimensional color doppler evaluation of the flow convergence zone for quantification of mitral regurgitation: Validation experimental animal study and initial clinical experience.

BACKGROUND: Pitfalls of the flow convergence (FC) method, including 2-dimensional imaging of the 3-dimensional (3D) geometry of the FC surface, can lead to erroneous quantification of mitral regurgitation (MR). This limitation may be mitigated by the use of real-time 3D color Doppler echocardiography (CE). Our objective was to validate a real-time 3D navigation method for MR quantification. METHODS: In 12 sheep with surgically induced chronic MR, 37 different hemodynamic conditions were studied with real-time 3DCE. Using real-time 3D navigation, the radius of the largest hemispherical FC zone was located and measured. MR volume was quantified according to the FC method after observing the shape of FC in 3D space. Aortic and mitral electromagnetic flow probes and meters were balanced against each other to determine reference MR volume. As an initial clinical application study, 22 patients with chronic MR were also studied with this real-time 3DCE-FC method. Left ventricular (LV) outflow tract automated cardiac flow measurement (Toshiba Corp, Tokyo, Japan) and real-time 3D LV stroke volume were used to quantify the reference MR volume (MR volume = 3DLV stroke volume - automated cardiac flow measurement). RESULTS: In the sheep model, a good correlation and agreement was seen between MR volume by real-time 3DCE and electromagnetic (y = 0.77x + 1.48, r = 0.87, P <.001, delta = -0.91 +/- 2.65 mL). In patients, real-time 3DCE-derived MR volume also showed a good correlation and agreement with the reference method (y = 0.89x - 0.38, r = 0.93, P <.001, delta = -4.8 +/- 7.6 mL). CONCLUSIONS: real-time 3DCE can capture the entire FC image, permitting geometrical recognition of the FC zone geometry and reliable MR quantification.

Adult↗

PubMed2002

Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description.

BACKGROUND: The design of a percutaneous implantable prosthetic heart valve has become an important area for investigation. A percutaneously implanted heart valve (PHV) composed of 3 bovine pericardial leaflets mounted within a balloon-expandable stent was developed. After ex vivo testing and animal implantation studies, the first human implantation was performed in a 57-year-old man with calcific aortic stenosis, cardiogenic shock, subacute leg ischemia, and other associated noncardiac diseases. Valve replacement had been declined for this patient, and balloon valvuloplasty had been performed with nonsustained results. METHODS AND RESULTS: With the use of an antegrade transseptal approach, the PHV was successfully implanted within the diseased native aortic valve, with accurate and stable PHV positioning, no impairment of the coronary artery blood flow or of the mitral valve function, and a mild paravalvular aortic regurgitation. Immediately and at 48 hours after implantation, valve function was excellent, resulting in marked hemodynamic improvement. Over a follow-up period of 4 months, the valvular function remained satisfactory as assessed by sequential transesophageal echocardiography, and there was no recurrence of heart failure. However, severe noncardiac complications occurred, including a progressive worsening of the leg ischemia, leading to leg amputation with lack of healing, infection, and death 17 weeks after PHV implantation. CONCLUSIONS: Nonsurgical implantation of a prosthetic heart valve can be successfully achieved with immediate and midterm hemodynamic and clinical improvement. After further device modifications, additional durability tests, and confirmatory clinical implantations, PHV might become an important therapeutic alternative for the treatment of selected patients with nonsurgical aortic stenosis.

Amputation, Surgical↗

PubMed2002

Left ventricular outflow tract mean systolic acceleration as a surrogate for the slope of the left ventricular end-systolic pressure-volume relationship.

OBJECTIVE: The goal of this study was to analyze left ventricular outflow tract systolic acceleration (LVOT(Acc)) during alterations in left ventricular (LV) contractility and LV filling. BACKGROUND: Most indexes described to quantify LV systolic function, such as LV ejection fraction and cardiac output, are dependent on loading conditions. METHODS: In 18 sheep (4 normal, 6 with aortic regurgitation, and 8 with old myocardial infarction), blood flow velocities through the LVOT were recorded using conventional pulsed Doppler. The LVOT(Acc) was calculated as the aortic peak velocity divided by the time to peak flow; LVOT(Acc) was compared with LV maximal elastance (E(m)) acquired by conductance catheter under different loading conditions, including volume and pressure overload during an acute coronary occlusion (n = 10). In addition, a clinically validated lumped-parameter numerical model of the cardiovascular system was used to support our findings. RESULTS: Left ventricular E(m) and LVOT(Acc) decreased during ischemia (1.67 +/- 0.67 mm Hg.ml(-1) before vs. 0.93 +/- 0.41 mm Hg.ml(-1) during acute coronary occlusion [p < 0.05] and 7.9 +/- 3.1 m.s(-2) before vs. 4.4 +/- 1.0 m.s(-2) during coronary occlusion [p < 0.05], respectively). Left ventricular outflow tract systolic acceleration showed a strong linear correlation with LV E(m) (y = 3.84x + 1.87, r = 0.85, p < 0.001). Similar findings were obtained with the numerical modeling, which demonstrated a strong correlation between predicted and actual LV E(m) (predicted = 0.98 [actual] -0.01, r = 0.86). By analysis of variance, there was no statistically significant difference in LVOT(Acc) under different loading conditions. CONCLUSIONS: For a variety of hemodynamic conditions, LVOT(Acc) was linearly related to the LV contractility index LV E(m) and was independent of loading conditions. These findings were consistent with numerical modeling. Thus, this Doppler index may serve as a good noninvasive index of LV contractility.

Acceleration↗

PubMed2002

Tissue Doppler imaging differentiates physiological from pathological pressure-overload left ventricular hypertrophy in rats.

BACKGROUND: The myocardial velocity gradient (MVG) is a recent index of regional myocardial function derived from endocardial and epicardial velocities obtained by tissue Doppler imaging (TDI). This index might be useful for discriminating between physiological and pathological left ventricular hypertrophy (LVH) and for documenting the early transition from compensated LVH to heart failure. We sought to compare MVG measured across the left ventricular posterior wall between normal rats and rats with physiological (exercise) and pathological (pressure-overload) LVH. METHODS AND RESULTS: Wistar rats were assigned to one of the following groups: sedentary, exercise (swimming), and 2-month or 9-month abdominal aortic banding. Compared with sedentary rats, exercise and 2-month banding led to similar and significant LVH. After 2-month banding, conventional parameters of systolic function (left ventricular fractional shortening and dP/dt(max)) were not affected. However, systolic and diastolic MVG were similar in exercise and sedentary rats but were significantly lower in rats with aortic banding. Aortic debanding after 2 months led to a full recovery of MVG, whereas MVG remained decreased when debanding was performed after 9 months. CONCLUSIONS: Myocardial contraction and relaxation assessed by TDI were impaired in pressure-overload LVH but not in exercise LVH. Therefore, TDI is more sensitive than conventional echocardiography for assessing myocardial dysfunction in pressure-overload LVH and for predicting early recovery in myocardial function after loading conditions normalization.

Animals↗

PubMed2002

Impact of left ventricular outflow tract area on systolic outflow velocity in hypertrophic cardiomyopathy: a real-time three-dimensional echocardiographic study.

OBJECTIVES: The aim of this study was to use real-time three-dimensional echocardiography (3DE) to investigate the quantitative relation between minimal left ventricular (LV) outflow tract area (A(LVOT)) and maximal LV outflow tract (LVOT) velocity in patients with hypertrophic obstructive cardiomyopathy (HCM). BACKGROUND: In patients with HCM, LVOT velocity should change inversely with minimal A(LVOT) unless LVOT obstruction reduces the pumping capacity of the ventricle. METHODS: A total of 25 patients with HCM with systolic anterior motion (SAM) of the mitral valve leaflets underwent real-time 3DE. The smallest A(LVOT) during systole was measured using anatomically oriented two-dimensional "C-planes" within the pyramidal 3DE volume. Maximal velocity across LVOT was evaluated by two-dimensional Doppler echocardiography (2DE). For comparison with 3DE A(LVOT), the SAM-septal distance was determined by 2DE. RESULTS: Real-time 3DE provided unique information about the dynamic SAM-septal relation during systole, with A(LVOT) ranging from 0.6 to 5.2 cm(2) (mean: 2.2 +/- 1.4 cm(2)). Maximal velocity (v) correlated inversely with A(LVOT) (v = 496 A(LVOT)(-0.80), r = -0.95, p < 0.001), but the exponent (-0.80) was significantly different from -1.0 (95% confidence interval: -0.67 to -0.92), indicating a significant impact of small A(LVOT) on the peak LVOT flow rate. By comparison, the best correlation between velocity and 2DE SAM-septal distance was significantly (p < 0.01) poorer at -0.83, indicating the superiority of 3DE for assessing A(LVOT). CONCLUSIONS: Three-dimensional echocardiography-measured A(LVOT) provides an assessment of HCM geometry that is superior to 2DE methods. These data indicate that the peak LVOT flow rate appears to be significantly decreased by reduced A(LVOT). Real-time 3DE is a potentially valuable clinical tool for assessing patients with HCM.

Adult↗