Prediction of Postoperative Left Ventricular Pump Function in Congenital Mitral Regurgitation

In adult patients with severe chronic mitral regurgitation, many predictors for estimating postoperative left ventricular systolic function have been proposed. However, none has been defined in children. We analyzed the relationship between such predictors and postoperative left ventricular fractional shortening in children with isolated congenital mitral regurgitation. Eight patients with isolated congenital mitral regurgitation were examined before and after surgery with echocardiography. Fractional shortening, left ventricular end-diastolic and end-systolic dimension indices, and left ventricular end-systolic wall stress/left ventricular end-systolic dimension index in the preoperative status were poorly correlated with postoperative left ventricular fractional shortening. Predictive wall stress, which was calculated from preoperative data of end-diastolic dimension, end-diastolic wall thickness, and diastolic blood pressure, correlated well with postoperative left ventricular fractional shortening (r=−0.90, p= 0.0024). It is important to consider not only myocardial contractility but also postoperative afterload for estimating postoperative left ventricular performance in chronic severe mitral regurgitation.     

Severity of Mitral Regurgitation Predicts Risk of Death or Cardiac Transplantation in Children With Idiopathic Dilated Cardiomyopathy

Clinical outcomes among children with idiopathic dilated cardiomyopathy (IDC) are diverse, which makes the decision as to when a patient should be listed for a cardiac transplantation challenging. This study aimed to determine echocardiographic and clinical variables that can help clinicians identify those at highest risk for death or cardiac transplantation. The study was a single-center, retrospective chart review of children with IDC. Patients younger than 18 years with a diagnosis of IDC, as defined by a left ventricular end-diastolic dimension (LVEDD) z-score higher than 2, and fractional shortening of less than 28 % on the initial echocardiogram, were included in the study. Echocardiographic parameters including mitral regurgitation (MR) grade and certain clinical parameters at the time of presentation were assessed. A follow-up echocardiogram was similarly studied. The study included 49 children with IDC. Those who died or underwent cardiac transplantation were grouped as “nonsurvivors” (n = 26). The remaining children who either completely recovered or experienced chronic dilated cardiomyopathy were grouped as “survivors” (n = 23). The median age overall was 1.25 years (range 0.1–17 years). The follow-up echocardiograms of the survivors showed significant improvement in left ventricle size, systolic function, left atrial volume, and MR grade, whereas these parameters did not change in the nonsurvivor group. The use of inotropic medications at initial presentation was an independent predictor of death or cardiac transplantation (p < 0.05). The presence of moderate to severe MR at diagnosis also was predictive of a worse outcome.     

Mitral valve replacement in the neonate: A report of two cases

Summary Mitral valve replacement was performed in two critically ill neonates with severe mitral stenosis and regurgitation. Both patients had coexisting severe aortic stenosis previously treated by transventricular aortic valve dilatation. Preoperative echocardiography showed a mitral annulus measuring between 11 and 12 mm in diameter—too small for any of the commercially available free-standing valve prostheses. Accordingly, the porcine valve from a commercially available 12-mm external-valved conduit was removed and sutured into position. The function of the valve was satisfactory in both cases and cardiopulmonary bypass was discontinued easily with a good cardiac output established in both. Both patients died—one at 20 h and one 36 h after surgery. In each case, the immediate cause of death was acute bleeding secondary to preexisting hepatic failure and depletion of coagulation factors. At autopsy, both prostheses had been correctly placed and were competent. Left ventricular outflow tract obstruction secondary to strut imposition was not evident. Both patients were very ill preoperatively. Although neither patient survived mitral valve replacement, we were encouraged by the relative hemodynamic improvement in the immediate postoperative period. We believe that prosthetic valve replacement could become a viable therapy for the neonate with severe mitral valve abnormalities.     

Percutaneous Transvenous Mitral Commissurotomy in Patients with Severe Mitral Stenosis and Acute Rheumatic Fever

There is a concern that percutaneous transvenous mitral commissurotomy (PTMC) performed during acute rheumatic fever (ARF) may result in adverse outcomes. We performed a retrospective study at a tertiary care center. Ten patients (ages 8–12 years) with severe symptomatic mitral stenosis and ARF who underwent PTMC (ARF group) were compared with 10 controls with similar mitral valve area (MVA). The procedure was successful in all patients. The median MVA increased from 0.7 to 1.5 cm² following PTMC in the ARF group and from 0.7 to 1.8 cm² in the control group [p = not significant (NS)]. The median MVA was 1.2 cm² in the study group compared to 1.6 cm² in the control group (p = 0.02) over a mean follow-up of 17.5 ± 11.7 months. Echocardiographic restenosis occurred in 4 patients (40%) in the ARF group compared to 1 patient (10%) in the control group (p = NS). The improvement in the New York Heart Association functional class was maintained in 8 patients of the ARF group and 9 patients of the control group. PTMC can be performed in children with ARF without an increase in procedural complications. However, the restenosis rates appear to be higher.     

QT Dispersion and Diastolic Functions in Differential Diagnosis of Primary Mitral Valve Prolapse and Rheumatic Mitral Valve Prolapse

There is no specific criteria established to guide physicians in the differential diagnosis of primary mitral valve prolapse (MVP) and rheumatic MVP. Previous studies suggested that history and pathology of mitral valve could be helpful in differential diagnosis of MVP. The aim of this study was to evaluate the value of QT interval, QT dispersion, and diastolic function in differential diagnosis of MVP. We examined electrocardiographies and echocardiographies of 24 primary MVP patients, 20 rheumatic MVP patients, and 21 healthy subjects. MVP was defined as superior displacement of the mitral leaflets more than 2 mm into the left atrium during systole. QT dispersion was significantly higher in primary MVP patients (71 ± 13.5 ms, p < 0.01). Maximum QT dispersion value in rheumatic MVP patients was 55 ms. E and A velocity values which show ventricular early and late diastolic filling, were lower in primary MVP patients (p < 0.01). There was no difference in the heart rate corrected QT interval values between the primary MVP patients (397 ± 28.1), rheumatic MVP patients (403 ± 23.8) and healthy children (404 ± 15.8; p > 0.05). Our findings may indicate that QT dispersion can be used as a parameter for differential diagnosis of primary MVP and rheumatic MVP. Further studies are needed to identify a cut-off point of QT dispersion.     

Mitral valve prolapse in children with secundum —Type atrial septal defect (ASD II)

A left ventricular angiocardiogram for evaluation of the mitral valve in patients with uncomplicated secundum type atrial septal defect has been proposed in a recent paper by Victorica et al. (1974). These authors observed 8 children with a ballooning mitral valve and ASD II. They stressed the necessity of performing a left ventricular angiocardiogram in every patient with ASD II. To challange their proposal, the angiocardiograms of 78 children with secundum type ASD were reviewed. Of these 89 angios 34 were performed using the left ventricle (LV) as injection site while 55 times the injection was made in other parts of the heart, e.g. left atrium, pulm. art., right ventricle, right atrium. All 34 LV angios, but only 12 of the others allowed an evaluation of function and morphology of the mitral valve.Of the 46 angiocardiograms 27 (58.7%) revealed an intact, normally closing and opening mitral valve. In the remaining 19 (41.3%) various grades of ballooning or mild prolapsing of one or two leaflets of the mitral valve could be detected. The scallops were minimal in 12, moderate in 4 and pronounced in 3 cases. A mild regurgitation was seen in 1 patient only. No patient had the pronounced ballooning observed by Victorica et al. On auscultation only 1 case had the apical murmur of mitral regurgitation. The ECG of our 19 positive cases did not show signs of left atrial or left ventricular hypertrophy. A left axis deviation was found in 1 patient.During surgery no structural abnormality of the mitral valve was noted. Postoperative reevaluation of the mitral valve (including left ventricular contrast injection) in 10 cases revealed no changes of mitral valve appearance in 8, a decrease of the ballooning in one, and an increase in another patient.It is concluded that prolapses of the mitral valve are seldom of such a degree as to cause dysfunction in children with secundum type ASD. The indications for performing a left ventricular injection of contrast material are the clinical signs of mitral valve regurgitation and/or left axis deviation in the ECG.Partially presented at the 13th Annual General Meeting of the Association of European Paediatric Cardiologists, Marseille, 29 April—3 May, 1975.     

Mitral and aortic regurgitation in 84 patients with mucopolysaccharidoses

In echocardiographic and necropsy studies nodular thickening of the mitral valve and, less frequently, of the aortic valve has been found in 60%–90% of patients with mucopolysaccharidoses (MPS). Little is known about the haemodynamic consequences of these morphological changes. In this study 84 unselected patients with different enzymatically proven MPS and 84 age and sex matched, healthy persons were studied prospectively by colour Doppler flow mapping. The patients' age ranged from 1 to 47 years (median 8.1 years). Mitral and aortic regurgitation were defined as a holosystolic or holodiastolic jet originating from the valve into the left atrium or the left ventricular outflow tract, respectively, with peak velocities exceeding 2.5 m/s. Of the 84 patients with satisfactory studies, mitral regurgitation was detected in 64.3% and aortic regurgitation in 40.5%, respectively. Regurgitation was severe in 4.8% of mitral valves and 8.3% of aortic valves. The frequency of aortic and/or mitral regurgitation was 75% in all patients, 89% in MPS I, 94% in MPS II, 66% in MPS III, 33% in MPS IV, and 100% in MPS VI. Combined mitral and aortic regurgitation was present in 29% of our patients. None of the control persons showed mitral or aortic regurgitation.     

Incidence and Risk Factors for Mitral Valve Prolapse in Severe Adolescent Idiopathic Scoliosis

Mitral valve prolapse (MVP) is known to be associated with thoracic skeletal anomalies. To determine the incidence and risk factors for mitral valve prolapse in the adolescent population with severe idiopathic scoliosis (IS), a prospective follow-up study on 139 adolescent patients with IS from the Pediatric Orthopedic Service was undertaken. Data collected included age, sex, medical and family history, physical exam, electrocardiogram and echocardiogram, spinal x-rays, and pulmonary function tests. MVP was detected by echocardiogram in 13.6% (19/139) of patients with IS as compared with 3.2% in 154 age- and weight-matched controls (p < 0.006). All patients with MVP were asymptomatic and a systolic click or murmur was detected on the single preoperative exam only in 37% (7/19) of them. Patients with MVP and IS weighed less (45.1 ± 2.0 vs 51.8 ± 0.1 kg, p < 0.002) as compared with those IS patients without MVP. The electrocardiogram was abnormal in 21% (4/19) of patients with MVP as compared with only 1.6% (2/120) of patients with IS but no MVP. The two groups did not differ with respect to age at diagnosis, severity of scoliosis, positive family history of scoliosis, or the presence of restrictive lung disease. Though IS was more prevalent in females (79%), the presence of MVP was not related to gender. MVP was persistent in 10 of the 19 patients reevaluated by echocardiogram 2–4 years after spinal surgery. We conclude that MVP is four times more common in patients with severe IS than in the normal adolescent population, and is associated with a lower body weight in IS patients with MVP than in IS patients without MVP. The persistent nature of MVP, even after corrective spinal surgery, may be related to factors other than geometric changes of the heart caused by abnormal thoracic curvature.     

Mitral valve replacement for severe mitral regurgitation in infants with anomalous left coronary artery from the pulmonary artery

Infants with anomalous left coronary artery from the pulmonary artery (ALCAPA) may present with heart failure, mitral regurgitation, and dilated cardiomyopathy. Reestablishment of a two coronary artery system markedly improves the morbidity and mortality. However, the mitral regurgitation may continue to deteriorate despite surgical correction of the ALCAPA because of previous ischemic damage to the papillary muscles and chordae. Surgical intervention, including mitral valve replacement, may be required even during infancy. We present two infants with ALCAPA who required early mitral valve replacement for severe mitral regurgitation and have done well subsequently.     

NT-proBNP as a Marker for Persistent Cardiac Disease in Children with History of Dilated Cardiomyopathy and Myocarditis

Children with myocarditis and dilated cardiomyopathy may recover clinically and echocardiographically. Plasma levels of the N-terminal segment of B-type natriuretic peptide prohormone (NT-proBNP), a sensitive marker for cardiac dysfunction, may reflect residual cardiac damage in these patients. The purpose of this study was to evaluate NT-proBNP status in pediatric patients with a history of myocarditis and dilated cardiomyopathy. Cardiac evaluation was performed and the levels of NT-proBNP were measured in 23 children who had a history of myocarditis or dilated cardiomyopathy. NT-proBNP levels were also measured in 56 age-matched control children. Nine of the 23 patients had evidence of left ventricular dysfunction (DCM group), whereas 14 had none (recovery). NT-proBNP levels were higher in the DCM group (3154 ± 2858 pg/ml) than in the recovery group (122 ± 75 pg/ml, p < 0.001) and the control group (113 ± 96 pg/ml, p < 0.001). There was no difference between the recovery and the control groups (p = 0.45), and none of the recovered patients had a NT-proBNP level higher than the upper limit of normal. The area under the receiver operating characteristics curve for the diagnosis of persistent left ventricular dysfunction was 0.984. NT-proBNP levels correlated with echocardiographically derived shortening fraction and with clinical score. NT-proBNP is a good marker for persistent left ventricular dysfunction in children who have had myocarditis or cardiomyopathy. In this group of patients, NT-proBNP levels are normal in children who recover echocardiographically, suggesting no residual hemodynamic abnormalities.     

应用自体心包二尖瓣成形术治疗小儿二尖瓣关闭不全

目的探讨应用自体心包的改良二尖瓣成形术治疗小儿二尖瓣关闭不全的手术经验及临床效果。方法回顾性分析2005年1月至2012年1月我们收治的32例二尖瓣关闭不全患儿临床资料,年龄1～17岁,平均年龄（8．12±7．05）岁;单纯二尖瓣关闭不全14例,合并其他心血管畸形18例。其中中度二尖瓣关闭不全15例,重度17例。二尖瓣脱垂2例,瓣叶裂24例,二尖瓣环扩大32例。患儿均在全麻中低温体外循环下采用自体心包行改良二尖瓣成形术,同时矫正合并心血管畸形;术中均采用经左心室注水试验、心脏复跳后再次检查及停体外循环后测左房压等一系列方法评价成形效果。结果全组无一例手术死亡;术后早期死亡1例,于术后第2天死于低心排出量综合征。31例痊愈出院,完整随访28例,时间6～72个月,平均（42．10±9．50）个月。术后6个月超声心动图复查提示二尖瓣中度反流2例,心功能Ⅱ级,于术后1年再次行二尖瓣成形术。随访期间无死亡病例。除2例再次手术患儿外,其余获访患儿NYHA心功能评级均保持在I级,5年生存率96．8％,再手术率6．25％。结论应用自体心包的改良二尖瓣成形术治疗小儿尖瓣关闭不全具有预防后瓣环扩张和保留前瓣叶及其瓣环部分生长潜力的优点,同时能够保证二尖瓣开口的柔软性,再手术率相对较低,可获得良好疗效。     

Severe mitral insufficiency in mucopolysaccharidosis type III-B (Sanfilippo syndrome)

Summary A 6-year-old girl with mucopolysaccharidosis (MPS) III-B (Sanfilippo syndrome) who developed severe mitral regurgitation and congestive heart failure requiring surgery (valvuloplasty) is reported. One year after surgery the patient remains well, with marked improvement in her physical activity, and without signs of heart failure. This is only the second report of severe mitral regurgitation in MPS III, and is the first report of a successful repair (valvuloplasty) of a dysplastic mitral valve in the MPS. Mitral valvuloplasty should be considered instead of valve replacement in any MPS patient with mitral valve regurgitation requiring surgery.     

Cardiovascular changes in children with mucopolysaccharide storage diseases and related disorders – clinical and echocardiographic findings in 64 patients

Cardiovascular abnormalities were evaluated in 64 children aged between 1 year 9 months and 25 years with mucopolysaccharidoses (MPS) and related disorders. A heart murmur was heard in 18 patients, but in only 6 was it characteristic for specific valvular lesions. Echocardiography was performed in 63 children. In one girl cardiac lesions were diagnosed on autopsy. In 46 patients (72%), valvular lesions and/or different types of cardiomyopathy were detected. There were no characteristic changes for different types of MPS. In the majority of children in whom dermatan sulphate accumulated, cardiac involvement was the most frequent (88%) and severe. The most common lesion, regardless of MPS type, was thickening of the mitral valve (66%), with regurgitation or stenosis in 28 (44%). Aortic valve thickening was detected in 17 patients (27%), asymmetric septal hypertrophy or hypertrophic cardiomyopathy in 18, congestive cardiomyopathy in 1 and endocardial thickening in 13 patients. Cardiac involvement was less frequent in children with Sanfilippo disease. Two or more echocardiographic examinations were performed in 23 patients. In 19 of them (83%) cardiac changes were more severe during the second examination. One 7-year-old boy with Hunter disease underwent successful mitral valve replacement. Conclusions Cardiac involvement is present in most patients with MPS although there are few clinical signs and symptoms. The most common and severe changes are in Hurler, Hunter, Maroteaux-Lamy and I-cell disease, rarely in Sanfilippo disease. Mitral valve deformation is most frequent in all patients. The cardiac lesions are progressive. Received: 15 March 1997 / Accepted: 20 January 1998     

Abnormal Mitral Valve Anatomy in d-Transposition of the Great Arteries: Anatomic Characterization and Surgical Outcomes

Mitral valve anomalies can occur with S,D,D-transposition of the great arteries (d-TGA). Their influence on surgical technique and outcome after an arterial switch operation (ASO) has not been well described. Patients with d-TGA who underwent ASO from February 1990 to January 2011 were identified. Echocardiograms, operative reports, hospital course, and latest follow-up evaluation were reviewed. A total of 218 infants underwent ASO at a median age of 15.8 days. Survival was 95 % during a mean follow-up period of 60 months. Nine patients (4 %) were found to have similar mitral valve anomalies including anterior malalignment conoventricular septal defect, anterior displacement of the mitral valve toward the left ventricular outflow tract (LVOT), malpositioning of the posteromedial papillary muscle, unusual rotation of the mitral valve leaflets orienting the commissure toward the anterior ventricular septum, and redundant mitral valve tissue extending into the LVOT. Coarctation was more frequent in this subgroup (33 vs. 10 %; p = 0.05). Preoperative echocardiography consistently indicated suspicion of a cleft mitral valve with chordal attachments to the ventricular septum causing potential LVOT obstruction. Operative inspection did not identify a cleft or anomalous attachments in any patient, and no valvuloplasty or chordal manipulation was performed. The average hospital length of stay were similar (30.7 vs. 25.3 days; p = 0.54). One patient died late due to progressive LVOT obstruction, and one required heart transplantation. No patient had significant mitral valve regurgitation. We conclude that mitral valve anomalies associated with d-TGA are rare but present with consistent anatomic features and higher risk of coarctation. Unusual mitral valve apparatus positioning and chordal redundancy can suggest the need for valvuloplasty and chordal resection preoperatively, but this is rarely needed.     

Mitral Valve Replacement with the Pulmonary Autograft in Children: A Word of Caution

A 4½-month-old patient who underwent mitral valve replacement for congenital mitral stenosis using a pulmonary autograft is reported. Failure of the autograft resulted in pulmonary hypertension, leading to pulmonary regurgitation in the reconstructed right ventricular outflow tract, then tricuspid regurgitation, refractory right heart failure, and death. Caution should be exercised in applying this procedure with children, particularly those at risk for pulmonary hypertension.     

A comparison of left ventricular volumes and regurgitant fraction by Doppler echocardiography and angiography in children

Regurgitant fraction calculations by echocardiography were compared to angiocardiography in 11 patients with mitral regurgitation. Although there was a very good correlation when compared with angiocardiography (r = 0.99, SEE: 6.26, P< 0.001), two-dimensional echocardiography underestimated left ventricular end-diastolic volumes (P < 0.05). The mean regurgitant fraction was 36.2 ± 13.5% by echocardiography and 43.6 ± 15.7% (P< 0.05) by angiography. Most of the variability in measuring the regurgitant fraction is attributed to the left ventricular volume measurements. In conclusion, regurgitant fraction calculations of mitral regurgitation by echocardiography compares favorably to angiography. Since the severity of mitral regurgitation is an important determinant of prognosis, quantification of the regurgitant fraction may be useful in the long term follow-up of those patients.     

M-mode echocardiographic findings in children with idiopathic restrictive cardiomyopathy

Summary The M-mode echocardiographic findings in five pediatric patients, ages 4–15 years, with primary idiopathic restrictive cardiomyopathy, diagnosed by cardiac catheterization, and of 12 normal children (control group) are presented. The M-mode echocardiographic findings in patients with restrictive cardiomyopathy were (1) normal left and right ventricular end-diastolic dimension, (2) normal left ventricular posterior wall and interventricular septal thickness (three patients) or mild concentric hypertrophy (two patients), (3) normal opening and closing velocity of the mitral valve, (4) consistently enlarged left atrium (more than 40 mm) in all, and (5) right ventricular systolic time intervals compatible with pulmonary artery hypertension. The left ventricular ejection phase parameters (systolic time intervals, shortening fraction, and mean velocity of circumferential fiber shortening) were normal. Left ventricular relaxation phase parameters (diastolic function) were abnormal. The isovolumic relaxation time index was prolonged, 68±40 ms (±SD), in the study group as compared with 11±6 ms (±SD) in the control group (P<0.001). Percent relaxation of left ventricular posterior wall endocardium at 50% of diastole was decreased, 58±4% (±SD), in the study group as compared with 85±6% (±SD) in the control group (P<0.005). We conclude that M-mode echocardiography provides arelatively useful and specific noninvasive method for the diagnosis of primary restrictive cardiomyopathy in pediatric patients. This work was supported in part by NHLBI grant HL07436.     

Fetal Echocardiographic Measurements and the Need for Neonatal Surgical Intervention in Tetralogy of Fallot

Background

This study aimed to evaluate fetal echocardiographic measurements at the time of the first fetal echocardiogram as predictors of neonatal outcome for tetralogy of Fallot (TOF).

Methods

The study reviewed all infants with a prenatal diagnosis of TOF from January 2004 to June 2011. Aortic valve (AoV), pulmonary valve (PV), main pulmonary artery (MPA), left and right pulmonary artery diameters, and ductus arteriosus flow were evaluated on fetal echocardiograms, and associations between the fetal echocardiogram and the neonatal echocardiogram measurements and outcomes were assessed.

Results

The study identified 67 TOF patients who had an initial fetal echocardiogram at a mean gestational age of 25.0 ± 5.2 weeks. Patients with absent PV syndrome or major aortopulmonary collaterals were excluded from the study, as were those without anterograde pulmonary blood flow at the first fetal echocardiogram. Of the remaining 44 patients, 10 were ductal dependent and required neonatal surgery. Infants who were ductal dependent had lower fetal PV (?5.38 ± 2.95 vs. ?3.51 ± 1.66; p < 0.05) and MPA (?3.94 ± 1.66 vs. ?2.87 ± 1.04; p < 0.05) z-scores. A fetal PV z-score of ?5 predicted ductal dependence with 78 % sensitivity and 87 % specificity, and a PV z-score of ?3 showed 100 % sensitivity and 34 % specificity (p < 0.001). Fetuses with a reversed left-to-right flow across the ductus arteriosus (DA) were more likely to be ductal dependent (odds ratio, 25; p < 0.001) than those who had normal ductal flow.

Conclusions

In TOF, fetal PV and MPA z-scores and direction of the DA blood flow predict neonatal ductal dependence. Patients with fetal PV z-scores lower than ?3 or any left-to-right flow at the level of the DA should be admitted to a center where prostaglandin is available.     

Clinical and Echocardiographic Outcome in Patients Receiving Carvedilol for Treatment of Dilated Cardiomyopathy

Objective

To determine outcome of children receiving carvedilol in addition to other standard drug therapy for treatment of dilated cardiomyopathy.

Methods

Children receiving carvedilol for treatment of dilated cardiomyopathy with moderate to severe ventricular dysfunction were included into the study. Data on history, clinical examination and investigations were obtained and detailed echocardiography findings were recorded for the initial and all subsequent visits.

Results

Thirty-three children, mean age 26?±?30 mo (range 7 mo to 138 mo) were enrolled. Carvedilol was initiated at a mean dose of 0.14?±?0.03 mg/kg/d and the maintenance dose was 0.46?±?0.14 mg/kg/d. At a follow up of 6–90 mo (mean of 28?±?23 mo), functional class using Ross classification for pediatric heart failure improved from 2.7 to 1.3. The left ventricular ejection fraction rose from a basal value of 22 %?±?7 % (10–40 %) to 42 %?±?15 % (15–65 %) (p?<?0.0001). Similarly, left ventricular fractional shortening increased significantly from 16?±?6 % (8–34 %) to 21?±?7 % (10–44 %) (p?<?0.0001). One patient deteriorated and died of refractory heart failure. Carvedilol was discontinued in two more patients temporarily due to bronchospasm during respiratory infection.

Conclusions

The present study suggests that improvement in ventricular function and clinical symptoms is seen on oral carvedilol added to standard drug therapy in pediatric patients with dilated cardiomyopathy and moderate to severe ventricular dysfunction. The drug is well tolerated with minimal side effects but close monitoring is required as it may worsen heart failure and bronchospasm.     

Acute loads applied to the right ventricle: Effect on left ventricular filling dynamics in the presence of an open pericardium

To determine whether diastolic ventricular interdependence mechanisms would act in the presence of an open pericardial sac, as during cardiac surgery, moderate acute right ventricle afterload increases were applied to eight dogs with the chest and pericardium open while left ventricular filling dynamics were being assessed by Doppler echocardiography. Dogs were studied under basal conditions and after acute banding of the main pulmonary artery tightened to produce a 100% increase in right ventricular systolic pressure. With banding, the left ventricular filling velocity ratio (E/A), as assessed by Doppler echocardiography of mitral inflow, changed from a baseline value of 1.32 ± 0.05 to 1.16 ± 0.03 (p < 0.02), suggesting a restrictive pattern to early left ventricular filling, which is differed to that during the second half of diastole. Isovolumic relaxation time, measured as the time interval between aortic valve closure and mitral valve opening, assessed by M-mode echocardiography of both valves, was prolonged, though not significantly, from 63.3 ± 2.5 ms to 69.4 ± 2.9 ms, by banding of the pulmonary artery. E wave deceleration time, a filling variable influenced by chamber pressure/volume relations, was shortened by pulmonary artery banding, changing from 75.1 ± 1.7 ms to 68.0 ± 1.8 ms (p < 0.01). It was concluded that pressure loads applied to the right ventricle restricted early left ventricular filling. Prolonged relaxation and altered pressure–volume chamber relations were the diastolic interdependence mechanisms involved that proved to be acting even under open pericardium conditions.