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Results for “Ventricular Outflow Obstruction”

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At least 505 records · Page 28Linked to original sources
PubMed1986

Left ventricular outflow tract obstruction due to anomalous mitral valve: successful mitral valve replacement in a four month old infant.

A four month old infant was investigated for heart failure was found to have mitral incompetence and severe subvalvar aortic stenosis. The left ventricular outflow tract obstruction was found to be due to an anatomically anomalous mitral valve. The obstruction could only be relieved by removal of the mitral valve and its replacement with a St Jude's prosthesis. Two years after operation the child is fit and active. There have been no difficulties with anticoagulant treatment.

Aortic Stenosis, Subvalvular↗
PubMed2004

Systole-diastole mismatch in hypertrophic cardiomyopathy is caused by stress induced left ventricular outflow tract obstruction.

BACKGROUND: Pharmacological stress is used to assess the degree of left ventricular (LV) subvalvular gradient in patients with hypertrophic cardiomyopathy (HCM), but there is little information about associated physiological changes. METHODS: Echocardiography-Doppler ultrasound scanning measurements in 23 patients with HCM and 23 control subjects of similar age were studied at rest and at the end point of dobutamine stress. RESULTS: In patients, the systolic time was normal at rest, but increased abnormally with stress. In patients, the total isovolumic contraction time failed to shorten, and the total ejection time increased abnormally. Changes in total ejection time correlated with an increase in peak subvalvular gradient in control subjects and patients (r = 0.52 and r = 0.66, respectively; P <.01 for both). In patients, the diastolic time was normal at rest, but shortened abnormally with stress. In patients, the isovolumic relaxation time fell abnormally, as did the filling time. Mitral E wave acceleration and left atrium size were unchanged with stress in control subjects, but consistently increased in patients with HCM, which indicates an increased early diastolic atrioventricular pressure gradient. CONCLUSION: In HCM, systolic period increases abnormally with stress. This is not because of a loss of inotropy, but is directly related to the degree of LV outflow tract obstruction. As a result, the diastolic period fails to increase, reducing the time available for coronary flow, the LV filling pattern is modified, and the diastolic atrioventricular pressure gradient increases. These changes may contribute to symptom development and suggest why reducing LV outflow tract obstruction per se may be therapeutically useful in HCM.

Cardiomyopathy, Hypertrophic↗
PubMed2006

[Primary biventricular repair for interrupted aortic arch with left ventricular outflow tract obstruction and tricuspid valve regurgitation; report of a case].

An interrupted aortic arch was diagnosed in a 10-day-old girl weighing 3.3 kg, as was perimembranous ventricular septal defect (VSD) and severe tricuspid valve regurgitation (TR). The subaortic diameter was 3.6 mm and the aortic valve (3.7 mm in diameter) was bicuspid. We chose definitive repair, modified Yasui procedure, because of severe TR and no straddling of mitral valve. In primary biventricular repair, we undertook extended aortic arch anastomosis. Left ventricular outflow tract reconstruction consisted of intracardiac rerouting from the VSD to the pulmonary artery by using expanded-polytetrafluoroethylene (ePTFE) and Damus-Kaye-Stansel (DKS) anastomosis. Right ventricular outflow tract reconstruction was performed by the Rastelli procedure with an ePTFE valved conduit. Moreover, we carried out semicircular annuloplasty for severe TR.

Anastomosis, Surgical↗
PubMed1988

Reduction of systolic coronary blood flow in experimental left ventricular outflow tract obstruction.

In aortic valvular stenosis, coronary reserve has been shown to be markedly diminished despite normal coronary arteries. To gain further insight into this phenomenon, we examined the effects of an acute subaortic valvular obstruction on coronary blood flow (CBF) in seven open-chest anesthetized dogs. Transient subaortic obstruction was produced by inflating a catheter-tip balloon in the left ventricular (LV) outflow tract. The degree of obstruction, a 26 +/- 3 mm Hg gradient across the aortic valve, was adjusted to achieve an elevation of LV pressure while maintaining a constant aortic pressure (coronary perfusion pressure). In seven dogs with intact coronary vasomotor tone, systolic left anterior descending CBF decreased from 20 +/- 9 ml/min during the control period to 13 +/- 3 ml/min during subaortic obstruction (p less than 0.001). Diastolic CBF increased from 52 +/- 9 to 58 +/- 10 ml/min (p less than 0.05), and total CBF remained unchanged. In three dogs with maximal coronary vasodilation, systolic CBF decreased during subaortic obstruction, diastolic CBF remained unchanged, and total CBF decreased. The present data suggest that elevation of LV intracavitary pressure above coronary perfusion pressure can reduce systolic CBF and lead to an autoregulatory compensation that taxes coronary flow reserve.

Animals↗
PubMed2006

Hypertrophic cardiomyopathy is predominantly a disease of left ventricular outflow tract obstruction.

BACKGROUND: Nonobstructive hypertrophic cardiomyopathy (HCM) has been regarded as the predominant hemodynamic form of the disease on the basis of assessment of outflow gradient under resting conditions. We sought to prospectively define the prevalence, clinical profile, and significance of left ventricular (LV) outflow tract obstruction under resting conditions and with physiological exercise in a large HCM cohort. METHODS AND RESULTS: We prospectively analyzed 320 consecutive HCM patients (age, 47+/-17 years), measuring LV outflow gradient at rest, with Valsalva maneuver, and with exercise echocardiography. LV outflow obstruction was present at rest and/or with exercise in 225 patients (70%); 119 had rest gradients > or = 50 mm Hg and were not exercised. Of the other 201 patients with gradients < 50 mm Hg at rest (average, 4+/-9 mm Hg), 106 developed mechanical obstruction to LV outflow resulting from mitral valve-septal contact after exercise (80+/-43 mm Hg), including 76 with marked gradients > or = 50 mm Hg and 46 with heart failure symptoms. The remaining 95 patients (30%) had no or small gradients (< 30 mm Hg) both at rest and with exercise. Valsalva maneuver underestimated the presence and magnitude of exercise-induced obstruction. CONCLUSIONS: Among those patients who come to clinical evaluation, HCM is a predominantly obstructive disease in which LV outflow gradients, frequently associated with heart failure symptoms and often identified only with exercise, are evident in most patients (ie, 70%). Identification of LV outflow obstruction with exercise echocardiography may broaden management options in HCM by identifying symptomatic patients not otherwise regarded as potential candidates for septal reduction therapy. Assessment of subaortic gradients with exercise should be a routine component of the evaluation of HCM patients without outflow obstruction under resting conditions.

Adult↗
PubMed1986

Left ventricular outflow tract obstruction following mitral valve replacement: effect of strut height and orientation.

The influence of strut position and strut height of Ionescu-Shiley bovine pericardial valves on the degree of left ventricular outflow tract (LVOT) obstruction was studied following mitral valve replacement (MVR) in hypertrophied left ventricles. Left ventricular hypertrophy was created in 6 lambs by constrictive banding of the descending thoracic aorta at 2 weeks of age. MVR was accomplished seven months later utilizing cardiopulmonary bypass and hypothermic cardioplegic arrest. Each animal underwent three consecutive valve replacements with 25-mm bovine pericardial valves randomly inserted in each of the following manners: (1) standard-profile valve with orientation of the struts out of the LVOT; (2) standard-profile valve with a strut oriented into the LVOT; and (3) low-strut profile investigational valve with a strut oriented into the LVOT. Gradients across the LVOT were measured after MVR and then following administration of isoproterenol hydrochloride (0.05 micrograms per kilogram of body weight per minute). No gradient was created with the struts oriented out of the LVOT with or without isoproterenol administration. When a strut was oriented into the LVOT without isoproterenol, the gradients were comparable with the standard- and low-profile valves (7 +/- 2 mm Hg versus 6 +/- 4 mm Hg, respectively). With isoproterenol, however, a significant difference in gradients between the standard- and low-profile valves (65 +/- 20 mm Hg versus 22 +/- 14 mm Hg, respectively) was observed when a strut was oriented into the LVOT. The results show that LVOT obstruction following MVR was related to the orientation of the strut of the bioprosthetic valve, and this obstruction was diminished with a decreased strut height of the Ionescu-Shiley prosthesis.

Animals↗
PubMed1996

Quantitative lung perfusion scintigraphy in postoperative evaluation of congenital right ventricular outflow tract obstructive lesions.

Improved methods to relieve pulmonary artery stenosis have emphasized the need for an accurate noninvasive method to quantify the pulmonary blood flow. The aim of this study was to compare the roles of Tc-99m MAA perfusion lung imaging, chest x-ray, MRI, and cine-angiography for postoperative evaluation of pulmonary blood flow in patients with congenital right ventricular outflow tract (RVOT) obstructive lesions. Eleven patients underwent chest x-ray, MRI, perfusion lung imaging, and cine-angiography after corrective surgery of RVOT obstruction. The perfusion ratio on lung scans was calculated on the posterior views. The correlation coefficient of the left to right perfusion ratio measured by lung scans obtained with that by visual assessment of chest x-rays, with the most stenotic diameter ratio on MRI and on angiography being 0.57, 0.88 (P < 0.001), and 0.87 (P < 0.001), respectively. Follow-up perfusion lung scans in seven patients, before and after pulmonary artery intervention showed significantly improved perfusion ratios (0.30 +/- 0.11 to 0.70 +/- 0.22; P < 0.001), which were concordant with the clinical findings. The authors conclude that the quantitative perfusion lung scan is the noninvasive method of choice for postoperative evaluation of the pulmonary artery in congenital RVOT obstruction.

Adolescent↗
PubMed1990

Left ventricular-to-aortic conduit as a variant of surgical treatment of left ventricular outflow tract obstructions. An experimental study.

In 76 experiments on mongrel dogs the authors tried to solve principal problems interfering with a broader clinical application of extracardiac conduit for left ventricular-aortic shunting. They present an original conduit design whose prolonged trials in chronic experiments on dogs yielded favourable results. A new, relatively atraumatic and easy-to-perform method was used for conduit implantation. Functional condition of conduits and systemic and intraventricular haemodynamics were investigated shortly after operation and in the late postoperative period. At various intervals after surgery the conduits corresponded haemodynamically and functionally to systemic blood flow. Use of conduit to construct a new left ventricular outflow tract proved to be an effective alternative in surgical treatment of many hitherto inoperable aortic root defects.

Animals↗
PubMed1980

Recognition of developing left ventricular outflow tract obstruction in complete transposition of the great arteries.

In the months following balloon atrial septostomy for complete transposition of the great arteries (TGA), clinical deterioration is often ascribed to closure of the septostomy. Of 16 neonates with TGA, 5 showed early clinical deterioration. Each had an adequate septostomy at operation. Deterioration was characterized clinically by increasing cyanosis and radiographically by progressive diminution in pulmonary vascularity. Subsequent catheterization and axial cineangiography demonstrated that pulmonary flow had decreased, probably secondary to a progressive form of left ventricular outflow tract obstruction (LVOTO) characterized by bulging of the ventricular septum with mitral valve apposition. It is important to recognize this phenomenon as an aid in predicting which children will need early surgical intervention.

Cardiomyopathy, Hypertrophic↗
PubMed1996

[Doppler ultrasonography diagnosis of right ventricular outflow tract obstruction caused by mediastinal tumor and its reversibility after treatment].

Doppler-echocardiography has proved useful in the assessment of mediastinal masses. We present the case of a young man with fever and new systolic murmur. Echocardiographic examination revealed a paracardiac mass compressing the right ventricular outflow tract and Doppler flow study detected marked acceleration in luminal narrowing. Complete remission of the tumour was obtained with subtotal resection and chemotherapy. Histological diagnosis was of embryonary carcinoma with areas of endodermic sinus. A new Doppler-echocardiography study showed disappearance of both the mass and the compression and showed normal right ventricular outflow tract flow.

Adult↗