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Dobutamine induced dynamic left ventricular outflow tract obstruction in patients with hypertrophic nonobstructive cardiomyopathy.

Some patients with hypertrophic nonobstructive cardiomyopathy (HNCM) suffer symptoms resembling those in obstructive type despite no left ventricular outflow tract (LVOT) gradient could be detected on resting echocardiography. To investigate the value of dobutamine stress echocardiography (DSE) in determining the dynamic left ventricular (LV) obstruction of patients with HNCM. The study was conducted on 31 patients who were diagnosed HNCM on resting echocardiography and 9 healthy person as a control group. Intraventricular flow acceleration of > 3 m/sec on DSE was accepted as dynamic LVOT obstruction. Group 1 and 2 included patients without and with dynamic LVOT obstruction, respectively. The occurrence of chest pain and dyspnea seen during DSE was more frequent in group 2 than group 1 and control group. The frequency of SAM was significantly higher (p < 0.05) and the septal angle was significantly lower (p < 0.001) in Group 2. The presence of SAM significantly correlated with the peak gradient (r = 0.61, p < 0.001). The septal angle had significant negative correlations with the peak gradient (r = -0.77, p < 0.001) reached at DSE. The relative risk for peak gradient was highest when septal angle was < or = 100 degrees, with a sensitivity of 93%, specificity of 80%, positive predictive value of 82%, negative predictive value of 92%, and predictive accuracy of 87%. DSE is a reliable tool for the diagnosis of dynamic LV obstruction in patients with HNCM. The presence of SAM together with a low septal angle is highly predictive for the presence of a dynamic LVOT obstruction detected by DSE.

Adult↗

Failure of disopyramide to improve right ventricular outflow tract obstruction after living-donor lobar lung transplantation.

Right ventricular (RV) outflow tract obstruction (RVOTO) is an uncommon complication of lung transplantation in patients with pulmonary hypertension (PH) and both medical management and surgical intervention are required. A 28-year-old female with primary PH was referred and because she did not respond to medical treatment, living-donor lobar lung transplantation was performed. The operation was successful, but dyspnea and exercise intolerance developed during rehabilitation and transthoracic echocardiography revealed RVOTO. Intravenous disopyramide during cardiac catheterization reduced the pressure gradient from 35 mmHg to 16 mmHg without decreasing RV systolic pressure. However, electrical and hemodynamic parameters were adversely affected by disopyramide and thus, after cardiac catheterization, administration of fluid and a low dose of atenolol was started, and her symptoms improved. Transthoracic echocardiography showed improvement in the RVOTO. This case suggests that disopyramide should be avoided for patients with RVOTO following lung transplantation and that other negative inotropic agents, such as beta-blockers, are more effective for relief of RVOTO.

Adult↗

Late results after operations for left ventricular outflow tract obstruction.

The late results were evaluated of operations for the relief of left ventricular outflow tract obstruction in young patients, 1 to 18 years old, from the National Heart Institute who were followed up for at least 5 years and from recently reported studies with an average follow-up duration of 5 or more years. The operative mortality rate for the combined series was low: 1.9 percent of 522 patients with valvular aortic stenosis, 6.0 percent of 222 patients with fixed subvalvular aortic stenosis and 5.5 percent of 18 patients with hypertrophic subaortic stenosis. From the National Heart Institute series, gradients early postoperatively were decreased to less than 50 mm Hg in 88 percent (30 of 34) of patients with valvular, in 68 percent (15 of 22) of patients with subvalvular and in 88 percent (8 of 9) of patients with hypertrophic subaortic stenosis. Late survival rates for patients in the combined series were 90 percent (472 of 522), 86 percent (190 of 222), and 82 percent (14 of 17) in the three respective groups after mean follow-up periods of 5 to 14.4 years. All late survivors in the current series have had symptomatic improvement; 95 percent (58 of 61) are asymptomatic. However, actuarial analysis in these patients predicts that 50 +/- 8 percent of those with valvular and 44 +/- 10 percent of those with subvalvular aortic stenosis after 10 years will be free from the adverse postoperative events of residual or recurrent left ventricular outflow tract obstruction, clinically significant aortic regurgitation, reoperation, endocarditis or late death. With use of the same adverse postoperative events to determine satisfactory late results from the combined series, it was found that 54 percent (281 of 522) of those operated on for valvular, 54 percent (120 of 222) of those operated on for subvalvular and 78 percent (14 of 18) of those operated on for hypertrophic subaortic stenosis had satisfactory late results 5 to 14 years after operation. Of the patients having unsatisfactory late results, major hemodynamic abnormalities were detected in 55 percent (23 of 42) within 1 year postoperatively. Thus it appears that operations for many children with left ventricular outflow tract obstruction are palliative. These patients should have early postoperative assessment and continuing long-term follow-up evaluation during childhood, adolescence and adulthood.

Actuarial Analysis↗

Responses of plasma norepinephrine and heart rate during exercise in patients after Fontan operation and patients with residual right ventricular outflow tract obstruction after definitive reconstruction.

To determine the exercise responses of patients with congenital heart disease, 20 patients-5 who had undergone a right ventricular outflow tract reconstruction (group R; age, 15 +/- 2 years), eight who had undergone a Fontan operation (group F; age, 13 +/- 2 years), and seven who had a history of Kawasaki disease (group C; age, 15 +/- 1 years)-performed a treadmill exercise test. Patients of group R had a significant residual right ventricular outflow obstruction. Oxygen uptake (VO2), heart rate (HR), and plasma norepinephrine (NE) concentrations were measured at rest, during warm-up, at ventilatory threshold (VT), and at peak exercise. Exercise capacity was determined as a percentage of the predicted normal peak VO2 (%pVO2). The %pVO2 for groups R and F was 65 +/- 10 and 56 +/- 11, respectively. Peak HR for groups R and F was 171 +/- 4 and 155 +/- 5, which were lower than the HR for group C (p < 0.001). Although NE concentrations at rest, during warm-up, and at VT were significantly greater in groups R and F (p < 0.05), there were no significant differences in the NE concentrations at peak exercise. Peak HR correlated with %pVO2 (p < 0.001). The ratio of the increase in HR to NE from rest to VT was significantly lower in groups R and F than in group C (p < 0.001) and correlated with %pVO2 (r = 0.80; p < 0. 001). These data suggest that sympathetic nervous activity in groups R and F is increased at rest and during mild to moderate exercises, and reduced sinus node sensitivity to NE may be partly responsible for the abnormal HR response during exercise of patients with uncorrected congenital heart disease.

Adolescent↗

[Surgical treatment of double-outlet right ventricle with left ventricular outflow tract obstruction].

Three patients with double-outlet right ventricle (DORV) and left ventricular outflow tract obstruction (LVOTO) were described. In each patient, LVOTO was produced by restrictive VSD which resulted from malalignment of the conal musculature and a discrete subaortic membrane. All patients underwent surgical repair with enlargement of the ventricular septal defect and rerouting of the outflow tract from the left ventricle to the aorta. One patient died of congestive heart failure three months postoperatively. Causes of LVOTO and surgical management of DORV with LVOTO were discussed.

Cardiac Surgical Procedures↗

Aortoventriculoplasty: a new technique for the treatment of left ventricular outflow tract obstruction.

Aortoventriculoplasty is a new method of treatment for left ventricular outflow tract obstructions. The concept is based on creating a surgical defect which is patched in such a way as to provide the largest possible outflow to the left ventricle. The incision of the aorta continues down as far as necessary, with the right ventricular wall, the aortic ring, and the septum being cut. Reconstruction with an inner Dacron patch on the septum is completed by replacing the aortic valve with an adequate prosthesis, covering the aortic incision with the same patch, and patching the right venticular opening with an outer patch. This method was used in 4 children with tunnel-like subaortic stenosis, 3 of whom had had unsuccessful previous surgical attempts. Other associated lesions including parachute mitral valve were also corrected during aortoventriculoplasty. Hemodynamic results were excellent following this operation. Two patients died postoperatively, one from advanced myocardial damage and progressive failure and the other from cerebral ischemia caused by insufficient retrograde perfusion through an aortic coarctation that was not repaired earlier. No arrhythmias were observed following the procedure. The other 2 patients are well 7 and 5 months postoperatively with excellent hemodynamic function.

Angiocardiography↗

Surgical experience with left ventricular outflow tract obstruction in patients with complete transposition of the great arteries and essentially intact ventricular septum undergoing the Mustard operation.

During a 24-year period (1963-1987), 46 infants and children with complete transposition of the great arteries (CTGA) and an essentially intact ventricular septum (IVS) have undergone surgical relief of left ventricular outflow tract obstruction (LVOTO) concurrently with the Mustard operation (MO). The obstruction was valvar in 2 patients, subvalvar in 43 and combined valvar and subvalvar in 1; the ventricular septum was intact in 42, and 4 patients had a small VSD at the time of repair. Neonatal and pre-Mustard cardiac catheterization (CC) data were analyzed to obtain LV to right ventricular peak systolic pressure ratio (LV/RVPSP) and LVOT peak systolic gradient (PSG). The mean neonatal LV/RVPSP (n = 31) was 0.79 +/- 0.04; pre-Mustard LV/RVPSP (n = 44) was 0.75 +/- 0.05; pre-Mustard LVOT PSG (n = 34) was 46.5 +/- 3.5 mmHg. Neonatal (n = 29) and pre-Mustard (n = 30) cardiac angiograms were retrospectively reviewed to analyse morphologic substrates of LVOTO. In the neonatal period, LVOTO was present in 7 patients (anatomic, n = 4; dynamic, n = 2; combined, n = 1). Immediately prior to the MO, LVOTO was present in 29 (anatomic, n = 20; dynamic n = 2; combined, n = 7). Techniques to correct LVOTO at the initial MO included pulmonary valvotomy (n = 3), ventriculomyectomy (n = 41), resection of an windsock aneurysm (n = 1), LV to pulmonary artery valved conduit (VC) (n = 1). Two patients underwent VC early postoperatively (PO) for severe residual LVOTO (both died).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗

Dynamic left ventricular outflow tract obstruction. Diagnosis by transesophageal echocardiography in a critically ill patient.

Dynamic left ventricular outflow tract obstruction (DLVOTO) can be present in critically ill patients with congestive heart failure. Diagnosis by transthoracic two-dimensional echocardiography may be technically difficult in the critically ill patient or patients who are obese. This report describes the diagnosis of DLVOTO by transesophageal echocardiography and subsequent management.

Atrial Fibrillation↗

Dynamic left ventricular outflow tract obstruction in critically ill patients.

OBJECTIVE: To review patients managed in an intensive care unit diagnosed with dynamic left ventricular outflow tract obstruction without hypertrophic cardiomyopathy. PATIENTS AND METHODS: Dynamic left ventricular outflow tract obstruction (DLVOTO) is characteristically associated with hypertrophic cardiomyopathy, although it has also been described in patients without this disorder. We reviewed patients managed in two intensive care units over a one year period who were hypotensive and/or resistant to catecholamine infusions. RESULTS: During the one year period nine critically ill patients were found on echocardiography to have DLVOTO. None of the patients had a prior history of hypertrophic cardiomyopathy (HOCM) or echocardiographic evidence of asymmetrical septal hypertrophy and in three patients HOCM was specifically excluded by prior or convalescent echocardiography or by post mortem analysis. We found the risk factors for DLVOTO included left ventricular hypertrophy, hypovolaemia and use of positive inotropic agents. All patients responded to an increase in intravascular volume, reduction in infused inotropic agents with one requiring metaraminol to maintain blood pressure. CONCLUSIONS: Dynamic left ventricular outflow tract obstruction without hypertrophic cardiomyopathy is not an uncommon cause of hypotension resistant to catecholamines in critically ill patients. The diagnosis is important because management which includes fluid loading, vasopressors and reducing catecholamine infusions, differs from the management of other causes of shock.

Journal Article↗

Different effects of propranolol, phenylephrine, and saline volume loading on catecholamine-induced left ventricular outflow tract obstruction in acute coronary syndrome.

Hemodynamic deterioration due to left ventricular outflow tract (LVOT) obstruction can occur during catecholamine infusion in patients with acute coronary syndrome (ACS). The purpose of the present study was to compare the utility of propranolol, phenylephrine infusion, and rapid saline loading for reversal of dobutamine-induced LVOT obstruction in a canine model of ACS. ACS was induced via left anterior descending artery ligation in 21 open-chest anesthetized dogs, and LVOT obstruction, defined as an LVOT gradient > 30 mmHg, was induced by dobutamine infusion (20 to 40 microg/kg/min). Subsequently, the effects of propranolol infusion (0.7 to 1.0 microg/kg/min, n = 8), phenylephrine infusion (10 to 200 microg/kg/min, n = 7), and saline loading (200 to 400 mL/hr, n = 6) were assessed by serial hemodynamic measurements. All interventions produced significant and comparable improvements in the LVOT pressure gradient (propranolol: 60 +/- 16 to 15 +/- 12; phenylephrine: 68 +/- 15 to 12 +/- 10; saline loading: 58 +/- 18 to 22 +/- 10 mmHg; P < 0.001 for baseline versus postintervention; P = NS for comparison between interventions). Phenylephrine produced the greatest elevation in aortic pressure (propranolol: +15 +/- 13; phenylephrine: +51 +/- 36; saline loading: +15 +/- 15 mmHg; P < 0.05), while saline loading produced the greatest increase in cardiac output (propranolol: +0.05 +/- 0.12; phenylephrine: +0.28 +/- 0.37; saline loading: +0.73 +/- 0.48 L/min; P < 0.05). Propranolol was the only intervention that produced a significant decrease in diastolic pulmonary artery pressure (16 +/- 5 to 11 +/- 3 mmHg, P < 0.05). Propranolol, phenylephrine infusion, and saline volume loading were similarly effective in reversing dobutamine-induced LVOT obstruction in this canine model of ACS. However, each intervention produced different hemodynamic effects with potentially different clinical indications.

Adrenergic beta-Antagonists↗

Non-Hodgkins lymphoma presenting with evidence of right ventricular outflow tract obstruction.

Anterior mediastinal tumours have been reported that initially presented with signs suggestive of cardiac disease. The widespread availability of two-dimensional echocardiography has demonstrated that, in the majority of cases, right ventricular compression is the major cardiac complication of such masses. We report two cases of mediastinal lymphoma that presented with chest pain and signs of right ventricular outflow obstruction.

Adult↗

[A case of left ventricular outflow tract obstruction after repair of ostium primum defect].

We report a 3-year-old girl with left ventricular outflow tract obstruction after repair of ostium primum defect. The girl had closure of an ostium primum defect performed at the age of 1 year. Two years later, she developed left ventricular hypertrophy with systolic ejection murmur. Echocardiography showed discrete stenosis of the left ventricular outflow tract. Cardiac catheterization showed a peak systolic gradient of 63 mmHg across the left ventricular outflow tract. At the reoperation, the fibrous tissue was excised and myectomy was done. After the operation the peak systolic gradient across the left ventricular outflow tract disappeared. Since there is a possibility of occurrence of the left ventricular outflow tract obstruction after repair of atrioventricular septal defect, long term follow up is mandatory.

Child, Preschool↗

Left ventricular outflow tract obstruction and sudden death risk in patients with hypertrophic cardiomyopathy.

AIMS: Left ventricular outflow tract obstruction (LVOTO) is associated with reduced survival in patients with hypertrophic cardiomyopathy (HCM). The influence of LVOTO on survival from SD in relation to other recognized clinical risk markers is unknown. METHODS AND RESULTS: A total of 917 patients with HCM (554 males, 43+/-15 years) were studied; 288 (31.4%) had LVOTO at rest (> or =30 mmHg). During follow-up [median 61 (30;99) months], 54 (5.9%) patients died suddenly (SD), survived ventricular fibrillation, or had an appropriate ICD discharge; 25 (2.7%) died from heart failure or were transplanted; 17 (1.8%) died from other cardiovascular causes. Five-year survival from all-cause death or cardiac transplantation was lower in patients with LVOTO [86.5% (95% CI: 81.7-91.2) vs. 90.1% (95% CI: 87.3-92.8), P=0.006], with a trend towards higher all-cause death and transplantation with increasing LVOTO [(RR per 20 mmHg=1.24 (95% CI: 1.08-1.42), P=0.003)]. In patients with obstruction, there was a significant relation between 5-year survival from all-cause death and functional limitation (NYHA class I: 91.0%; NYHA class II: 83.3%; NYHA class III/IV: 82.6%, P=0.002). LVOTO was associated with reduced survival from SD and ICD discharge (SD/ICD) [91.4% (95% CI: 87.4-95.3) vs. 95.7% (95% CI: 93.8-97.6), P=0.0004]. Magnitude of LVOTO was related to a higher occurrence of SD/ICD [RR per 20 mmHg=1.36 (95% CI: 1.12-1.65), P=0.001]. There was no relation between survival from SD/ICD, LVOTO, and NYHA class. The annual rate of SD/ICD in patients with LVOTO and no risk factors was 0.37% (95%CI: 0.05-1.35). There was a trend towards lower survival from SD/ICD, with increasing numbers of risk factors in patients with and without LVOTO (P=0.002 and P=0.002, respectively). Multivariable analysis demonstrated that LVOTO was an independent predictor of SD/ICD, with a 2.4-fold (P=0.003) increase in the risk of SD/ICD. CONCLUSION: LVOTO is associated with an increased risk of SD/ICD that is related to the severity of obstruction and the presence of other recognized risk factors for SD. The low sudden death mortality in asymptomatic patients with LVOTO and no other SD risk markers suggests that aggressive interventions to reduce LVOTO are unwarranted in this group. Further studies are required to determine the most appropriate treatment strategies (ICD or gradient reduction) in patients with additional risk factors.

Adolescent↗

Central pulmonary artery anatomy in right ventricular outflow tract obstructions.

We reviewed the cine-angiograms of 190 patients with right ventricular outflow tract (RVOT) obstructions for size and anatomy of pulmonary arteries, patent ductus arteriosus (PDA) and major aorto pulmonary collateral arteries (MAPCAs). Patients were grouped into three, Tetralogy of Fallot (TOF) with pulmonary atresia (group 1, N=86), TOF with pulmonary stenosis (group 2, N=97) and 7 cases of pulmonary atresia with intact interventricular septum (group 3). Out of 86 patients in group 1, 49 had PDA alone, 30 had MAPCAs alone, six had both and one had none. In group 2, 31 patients had persistent PDA and one patient had MAPCAS and PDA. A discrete stenosis (DS) of pulmonary artery was seen significantly more in patients with RVOT obstructions associated with PDA compared to patients without PDA (67/84 vs. 5/96). Out of the 84 cases with ducti, 53 had stenosis of the pulmonary artery at the site of ductus insertion. Thus presence of PDA was an important factor in the development of DS. The likely cause of pulmonary artery stenosis in TOF with PDA may be the opposing flows through RVOT and PDA producing a watershed effect at the ductus-pulmonary artery junction. Diffuse hypoplasia of pulmonary arteries (DH) was seen more significantly in RVOT obstructions associated with MAPCAs, compared to other patient groups (19/36 vs. 14/87). These small pulmonary arteries had no discrete stenosis and this diffuse hypoplasia might be the result of inadequate blood flow during intrauterine life [Harikrishnan S, Tharakan J, Titus T, Bhat A, Sivasankaran S, Bimal F, Syam Sunder KR, James, KJ. Central pulmonary artery anatomy in right ventricular outflow tract obstructions. Indian Heart Journal 1997;49:624 (Abstract)[18]].

Cineangiography↗

Apicoaortic conduit for left ventricular outflow tract obstruction: revisited.

BACKGROUND: We have used a variety of techniques to correct left ventricular outflow tract obstructions, including, in the past, placement of an apicoaortic valved conduit to bypass the outflow tract. Because the operation was technically difficult, it had fallen into disuse. Recently, we used a simplified transthoracic approach to implant apicoaortic conduits in 7 patients with complex lesions of the left ventricular outflow tract. METHODS: The thoracic cavity was entered through the fifth intercostal space in all 7 patients. The distal end of the valve-containing conduit was attached to the aorta with continuous 3-0 or 4-0 polypropylene sutures after incising the pleura over the distal descending aorta. The pericardium was opened to expose the left ventricular apex, which was cored so that the proximal end of the conduit could be inserted into the left ventricular cavity. RESULTS: Five of the patients recovered completely. The 2 patients who died had severe heart disease and multiple comorbidities. CONCLUSIONS: The transthoracic approach gives direct access to the descending aorta and avoids a redo sternotomy. The technique, which is simple to perform, does not compromise major coronary arteries, the conduction system, or other valves; and may be useful in patients who are not good candidates for other, more conventional procedures.

Adult↗

Hypertrophic cardiomyopathy during corticotropin therapy for infantile spasms. A clinical and echocardiographic study.

OBJECTIVE: To evaluate the incidence and clinical features of abnormal cardiac hypertrophy during treatment of infantile spasms with corticotropin. DESIGN: A prospective, echocardiographic study. PARTICIPANTS: Eighteen children treated for infantile spasms with high-dose corticotropin at a large tertiary children's hospital. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Abnormal cardiac hypertrophy was seen in 13 (72%) of 18 patients. Five of 18 patients (group 1) developed hypertrophic cardiomyopathy with asymmetric septal hypertrophy; none developed significant left ventricular outflow obstruction. Concentric left ventricular hypertrophy was seen in eight patients (group 2), whereas no changes were observed in five (group 3). CONCLUSION: Abnormal ventricular hypertrophy occurs in the majority of patients treated with corticotropin for infantile spasms. In our study, many of these patients developed hypertrophic cardiomyopathy with dramatic asymmetric septal hypertrophy; however, none developed significant obstruction to left ventricular outflow. All changes were reversible, and did not require premature discontinuation of therapy.

Adrenocorticotropic Hormone↗

Two-dimensional echocardiographic evaluation of right ventricular size and function in newborns with severe right ventricular outflow tract obstruction.

Critical pulmonary stenosis or atresia with intact ventricular septum represents a congenital cardiac lesion for which the long-term prognosis appears to depend partly on the size of the right ventricle. Thus, the capability of noninvasive assessment of right ventricular size to predict operative outcome was examined in 15 infants (aged 1 to 30 days, mean 5.6) with severe right ventricular outflow tract obstruction (either critical pulmonary stenosis [7 patients] or pulmonary atresia with intact ventricular septum [8 patients]). Using echocardiography in two orthogonal subxiphoid views, right ventricular volume, wall thickness, area change fraction, ejection fraction and tricuspid anulus dimension were measured. All patients with a normalized right ventricular enddiastolic volume of less than 5 ml/m2 and a normalized tricuspid anulus dimension of less than 1.0 cm/m2/3 required a shunt operation. Only one patient with a volume of more than 6 ml/m2 and a normalized tricuspid anulus dimension of more than 1.4 cm/m2/3 required more than relief of right ventricular outflow tract obstruction. In this patient, residual severe pulmonary stenosis necessitated the shunt procedure. One patient with a volume of more than 6 ml/m2 had an anulus diameter of less than 1.4 cm/m2/3 and one patient with an anulus diameter of more than 1.4 cm/m2/3 had a volume of less than 6 ml/m2; both required shunt procedures. It therefore appears that if either the ventricular volume or tricuspid anulus size is excessively small, a shunt procedure is necessary. Wall thickness, area change fraction and ejection fraction measurements were not significantly correlated with right ventricular volume or postoperative outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Volume↗