Left Ventricular Endocardial Fibroelastosis Research Articles

Evaluation of right ventricular myocardial deformation properties in fetal hypoplastic left heart by two-dimensional speckle tracking echocardiography

PurposeRight ventricular (RV) function influences the outcome of hypoplastic left heart (HLH) patients. This study aimed to confirm the assumption of prenatal RV remodeling and possible influencing factors of myocardial restructuring using two-dimensional speckle tracking echocardiography (2D STE).MethodsThis is a retrospective cross-sectional cohort study including HLH fetuses and gestational age-matched controls. Based on a four-chamber view, cine loops were stored with 60 frames per second. Global longitudinal peak systolic strain (GLPSS) of the RV was retrospectively determined and compared to healthy controls. Furthermore, HLH subgroups were built according to the presence of left ventricular endocardial fibroelastosis (LV-EFE) and restrictive foramen ovale (FO) to investigate the effect of these compromising factors on myocardial deformation.ResultsA total of 41 HLH fetuses and 101 controls were included. Gestational age at fetal assessment was similarly distributed in both groups (controls: 26.0 ± 5.6 weeks vs. HLH: 29.1 ± 5.6 weeks). Relating to RV-GLPSS values, fetuses with HLH demonstrated lower mean values than healthy control fetuses (− 15.65% vs. − 16.80%, p = 0.065). Cases with LV-EFE (n = 11) showed significantly lower mean values compared to such without LV-EFE (n = 30) (RV-GLPSS: − 12.12% vs. − 16.52%, p = 0.003). No significant differences were observed for cases with FO restriction (n = 10).ConclusionsIn HLH the RV undergoes prenatal remodeling, leading to an adaptation of myocardial function to LV conditions. Further explorations by STE should expand knowledge about RV contraction properties in HLH and its impact on surgical outcome.

Outcomes of aortic balloon valvuloplasty in newborns: A single-centre experience

Introduction: Critical or severe aortic stenosis in new-borns is a condition that requires rapid intervention. Aortic balloon valvuloplasty (ABV) is a method of choice that has been successfully performed since 1983. Aims: This study was conducted to explore the experiences of our centre. Study Design: The data of ABV performed on new-borns (n = 52) between 2007 and 2020 were retrospectively analysed to evaluate follow-up of the cases. Materials and Methods: Patients were divided into 4 groups according to procedural immediate results. Results: Left ventricular endocardial fibroelastosis and left ventricular systolic dysfunction were detected in 18 (34.6%) and 19 (36.5%) patients, respectively and there was a significant association between fibroelastosis and left ventricular dysfunction (P < 0.05). The preprocedural echocardiographic mean gradient was significantly lower in the unsuccessful group (P < 0.41). The mean hospital stay day was shorter in the group with optimal results without statistical significance (P = 0.055). Immediate inadequate results after the procedure were detected as a major risk for re-intervention. Re-intervention was required in one-fifth of the patients and the most common cause was aortic stenosis. The risk factors of mortality were found to be associated with the disease itself such as ventricular dysfunction, being critical aortic stenosis instead of procedural reasons. Conclusion: ABV is an effective method and as left ventricular dysfunction and critical aortic stenosis are risk factors of mortality, preprocedural evaluation, and quick intervention are essential.

Paediatric dilated cardiomyopathy with and without endocardial fibroelastosis - a pathological analysis of 89 explants.

Heart failure due to dilated cardiomyopathy is a major indication for paediatric cardiac transplantation. Endocardial fibroelastosis is a recognised pathological finding of unknown prognostic significance in paediatric dilated cardiomyopathy. To evaluate the nature of the association between left ventricular endocardial fibroelastosis and paediatric dilated cardiomyopathy, we reviewed surgical pathology reports of dilated cardiomyopathy explants (1986-2016) in order to characterise the pathological findings and to compare and contrast their frequency among four age groups: less than 1 year; 1-5 years; 6-10 years; and greater than 11 years. The 89 explants (47 males and 42 females) were all characterised by increased weight and left ventricular chamber dilatation without increased wall thickness. Ninety-five per cent of the specimens in the two youngest subsets had left ventricular endocardial fibroelastosis. Compared to the oldest age group, recipients aged 1-5 years had a 6-fold increase and those younger than 1 year a 19-fold increase in the odds of observing left ventricular endocardial fibroelastosis. Explants with and without endocardial fibroelastosis were otherwise phenotypically similar. In paediatric dilated cardiomyopathy endocardial fibroelastosis is a very common pathological finding, especially in infants and young children. We propose that the descriptive, clinico-pathological designation "Dilated Cardiomyopathy with Endocardial Fibroelastosis" should be adopted to facilitate future investigation into the potential prognostic/therapeutic significance of left ventricular endocardial fibroelastosis.

The Ross-Konno procedure in neonates and infants less than 3 months of age.

Patients with severe left ventricular outflow tract obstruction often suffer from impaired left ventricular function, endocardial fibroelastosis and borderline-sized structures. The early Ross-Konno operation can offer complete repair due to outflow tract stenosis and enable the functional recovery and growth of small structures. Between 2008 and March 2017, 44 early Ross-Konno procedures were performed at our centre. Thirty-five patients were neonates, and 9 were infants less than 3 months of age. A retrospective single-centre investigation was carried out analysing early and late deaths, postoperative complications and reoperations during the follow-up period. Potential prognostic influence factors as previous fetal intervention, associated lesions as presence of a VSD or hypoplastic aortic arch or severe endocardial fibroelastosis were examined. The in-hospital mortality rate was 7% (3 of 44), and the late mortality rate was 2%. There were no deaths in the group with ventricular septal defects (9 cases), and there was 1 death in the group with critical aortic stenosis without arch repair (1 of 24; 4%). The most deaths occurred in patients with critical aortic stenosis and aortic arch repair (3 of 11; 27%) (P = 0.012). Fifteen patients with foetal intervention had a mid-term survival rate of 87%. Reoperations were necessary in 19 of 40 surviving patients during a mean follow-up period of 5.9 years. The early Ross-Konno procedure can enable biventricular repair even in borderline left ventricles with good long-term outcome. Thus far, there were no reoperations at the level of the autograft or the left ventricular outflow tract in our cohort. The highest operative risk was observed in patients with critical aortic stenosis and aortic arch hypoplasia.

Echocardiographic Diagnosis, Surgical Treatment, and Outcomes of Anomalous Left Coronary Artery from the Pulmonary Artery

Anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare condition that can be difficult to diagnose by echocardiography alone. The purpose of this study was to describe the clinical and echocardiographic presentation of ALCAPA, create a set of critical echocardiographic diagnostic criteria, and report outcomes. A retrospective review was conducted of all patients diagnosed with isolated ALCAPA at two major cardiac centers between 1990 and2015. Of the 37 patients identified, only 54% presented in infancy. The anomalous coronary artery (CA) origin was clearly imaged in only 54% of echocardiographic examinations. However, other consistently identified echocardiographic markers were found, including left CA flow reversal (91%), collateral CA flow (85%), right CA dilation (81%), abnormal pulmonary artery flow (79%), mitral regurgitation (74%), left ventricular dysfunction (66%) and endocardial fibroelastosis (57%). Presenting echocardiograms had five of seven markers in 85% of patients. Left ventricular dysfunction was the most common marker in infants (89% vs 38%, P=.005); older children were more likely to have collateral formation visualized by color Doppler (100% vs 75%, P=.04). Following surgery, there were no early surgical deaths. The median follow-up duration was 10.3years. At last follow-up, 92% had normal left ventricular function, 3% hadmoderate or worse mitral regurgitation, and 17% had required reintervention. Echocardiographic markers can reliably identify ALCAPA; these markers vary with the age of presentation. Surgical outcomes are excellent, and most patients will recover left ventricular and mitral valve function.

Ethical considerations of transparency, informed consent, and nudging in a patient with paediatric aortic stenosis and symptomatic left ventricular endocardial fibroelastosis.

A 9-year-old boy who was born with bicuspid aortic stenosis underwent two unsuccessful aortic valvuloplasty interventions, and by 2 years of age he developed restrictive cardiomyopathy caused by left ventricular endocardial fibroelastosis and diastolic dysfunction. The attending cardiologist referred the patient to a high-volume, high-profile congenital cardiac surgical programme 1000 miles away that has a team with considerable experience with left ventricular endocardial fibroelastosis resection and a reputation of achieving good results. Owing to problems with insurance coverage, the parents sought other options for the care of their child in their home state. Dr George Miller is a well-respected local congenital and paediatric cardiac surgeon with considerable experience with the Ross operation as well as with right ventricular endocardial fibroelastosis resection. When talking with Dr Miller, he implied that there is little difference between right ventricular endocardial fibroelastosis and left ventricular endocardial fibroelastosis resection, and stated that he would perform the operation with low mortality based on his overall experience. Dr Miller stated that the local institution could provide an equivalent surgical procedure with comparable outcomes, without the patient and family having to travel out of state. A fundamental dilemma that often arises in clinical surgical practice concerns the conduct of assessing and performing new procedures, especially in rare cases, for which the collective global experience is scant. Although Dr Miller has performed right ventricular endocardial fibroelastosis resection, this procedure differs from left ventricular endocardial fibroelastosis resection, and he cannot be sure that he will indeed be able to perform the procedure better than the high-volume surgeon. This ethical situation is best understood in terms of the principles of respect for patient autonomy, beneficence, non-maleficence, and justice. The tension between the imperatives of beneficence and the obligation to respect the autonomy of the patient by acting only with the patient's best interest in mind is discussed.

Right Ventricular Mechanics in the Fetus with Hypoplastic Left Heart Syndrome

Right ventricular mechanics influence outcomes in patients with hypoplastic left heart syndrome (HLHS). The aim of this study was to determine whether differences in right ventricular performance have their origins in fetal life and if the architectural character of the hypoplastic left ventricle affects right ventricular mechanics. The first complete fetal echocardiograms after 17 weeks' gestation were reviewed in 84 fetuses withHLHS and in 115 gestational age-matched normal controls. Inflow, outflow, and myocardial tissue Dopplervelocities were measured. E/A and E/e' ratios and right ventricular myocardial performance index were calculated. In fetuses with HLHS, there were lower tricuspid E/A ratios (mean, 0.6 ± 0.1 vs 0.7 ± 0.1; P < .001), higher E/e' ratios (mean, 8.1 ± 2.6 vs 7.0 ± 1.3; P= .006), and higher right ventricular myocardial performance indices (mean, 0.47 ± 0.14 vs 0.40 ± 0.10; P < .001) compared with controls. Among fetuses with HLHS grouped according to left ventricular architecture, those with left ventricular endocardial fibroelastosis had the most striking differences in right ventricular mechanics. Right ventricular mechanics are different from normal in fetuses with HLHS and are influenced by the presence of left ventricular endocardial fibroelastosis. These differences precede the imposition of undue loading conditions as a consequence of surgical palliation and may offer clues to the development of later right ventricular failure.

Assessment of Left Ventricular Endocardial Fibroelastosis in Fetuses With Aortic Stenosis and Evolving Hypoplastic Left Heart Syndrome

Assessment of Left Ventricular Endocardial Fibroelastosis in Fetuses With Aortic Stenosis and Evolving Hypoplastic Left Heart Syndrome

Assessment of Left Ventricular Endocardial Fibroelastosis in Fetuses With Aortic Stenosis and Evolving Hypoplastic Left Heart Syndrome

Systematic evaluation of left ventricular (LV) endocardial fibroelastosis (EFE) in the fetus has not been reported. The role of EFE in the pre- and postnatal evolution of hypoplastic left heart disease, and the implications of EFE for outcomes after prenatal intervention for fetal aortic stenosis with evolving hypoplastic left heart syndrome have also not been determined. A 4-point grading system (0-3) was devised for the assessment of fetal LV echogenicity, which was presumed to be due to EFE. Two reviewers independently graded EFE on the preintervention echocardiograms of fetuses treated with in utero aortic valvuloplasty for evolving hypoplastic left heart syndrome from 2000 to 2008. Intra- and interobserver reproducibility was determined for the EFE grade and characterization of related echocardiographic features. The relations among EFE severity, other left heart anatomic and physiologic variables, and postintervention outcomes were analyzed. The assessment and grading of EFE was possible for both observers in all 74 fetuses studied. By consensus, the EFE severity was grade 1 in 31 patients, grade 2 in 32, and grade 3 in 11. Fetuses with mild (grade 1) EFE had significantly greater maximum instantaneous aortic stenosis gradients (e.g., higher LV pressures) and less globular LV geometry than patients with grade 2 or 3 EFE on preintervention echocardiogram. The severity of EFE was not associated with the size of the aortic valve or LV. From preintervention to late gestation, the time-indexed change in LV end-diastolic volume was significantly greater in fetuses with grade 1 EFE than those with more severe EFE. Incorporation of EFE severity into our previously published threshold score improved the sensitivity and positive predictive value for the postnatal biventricular outcomes. In conclusion, echocardiographic grading of EFE is possible, with reasonable intra- and interobserver reliability in midgestation fetuses with evolving hypoplastic left heart syndrome. EFE severity corresponded to some indexes of left heart size, geometry, and function and with the probability of a biventricular outcome postnatally. Additional experience and external validation of the EFE grading scoring system are necessary.

Ross and Yasui operations for complex biventricular repair in infants with critical left ventricular outflow tract obstruction☆

To define the outcomes following Ross and Yasui procedures for complex biventricular repair of critical left ventricular outflow tract obstruction (LVOTO). Of 1217 neonates presenting with critical LVOTO enrolled in the Congenital Heart Surgeons Society studies (1994-2008), 52 underwent the Ross or Yasui procedure and their outcomes were investigated using univariate and multivariable parametric models. ROSS (N=39): The Ross procedure (median age 87 days) was rarely the primary intervention (5/39, 13%). A significant number of cases were performed to treat iatrogenic aortic regurgitation after other previous interventions (25/39, 64%). Co-existing functional morphological defects were also common: 72% had preoperative evidence of mitral dysfunction, moderate-to-severe left ventricular dysfunction or endocardial fibroelastosis. Emergency iatrogenic aortic regurgitation (P=0.005) and co-existing abnormalities (mitral stenosis, P=0.02; mitral regurgitation, P=0.05; LV dysfunction, P=0.03) were strong determinants of death. Severe postoperative ventricular dysfunction or need for extracorporeal membrane oxygenation (ECMO) conferred negligible survival. Younger age was associated with disproportionately worse late outcome (5-year survival 44+/-10% for neonates vs 76+/-8% for age >3 months, P=0.0013). However, mitral and left ventricular dysfunction and emergency presentation were significantly more common in the younger age groups. Infants less than 3 months of age without co-existing abnormalities had acceptable late survival ( approximately 75+/-20%). YASUI (N=13): Yasui repair (median age 22 days) was usually the primary intervention (nine of 13) but occasionally followed Norwood palliation (four of 13). None was an emergency. All had a ventricular septal defect. Survival was 69+/-13% at 10 years, which is not significantly different from other biventricular repair strategies in neonates. Aortic atresia was associated with better survival than stenosis (90+/-12% vs 30+/-14% at 3 years, P=0.039). None reverted to univentricular physiology later. Case selection is key for complex biventricular repair and the importance of appropriate case selection is exaggerated at young ages. All available options should be considered before pursuing the Ross operation in the presence of co-existing functional morphological abnormalities or emergent iatrogenic aortic regurgitation. However, both the Ross and Yasui operations in children (including neonates and young infants) with favourable functional morphology offer good survival, at least matching that of other biventricular repair strategies.

Outcome and Growth Potential of Left Heart Structures After Neonatal Intervention for Aortic Valve Stenosis

The purpose of this study was to determine trends of growth of left heart structures after intervention for neonatal aortic valve stenosis. The growth potential of left heart structures in neonatal aortic valve stenosis after relief of obstruction might influence risk for subsequent outcomes. From 1994 to 2004, 53 patients underwent neonatal (< or =30 days old) balloon aortic valve dilation. Factors associated with time-related outcomes (death, reintervention, aortic valve replacement) and longitudinal changes in normalized left heart dimensions were sought. The median age at intervention was 3.5 days (range 1 to 30 days). During a median follow-up of 3.2 years ranging up to 10.9 years, there were 31 reinterventions on the aortic valve in 21 (40%) patients and 7 deaths (13%). The presence of moderate or severe left ventricular (LV) endocardial fibroelastosis was the only independent predictor for time-related mortality (hazard ratio 22.1; p = 0.004), and a smaller initial aortic valve annulus z-score was a significant independent predictor for aortic valve replacement (hazard ratio 0.63 per 1-U change; p = 0.007). Aortic valve annulus, aortic sinus, and LV dimension z-scores significantly increased over time, whereas mitral valve z-scores remained below normal. The structure's initial z-score and concomitant size of other left heart structures were significant independent factors associated with subsequent z-scores. There is potential catch-up growth of the aortic valve and LV over time for neonates after intervention for aortic valve stenosis. However, the continued hypoplasia of the mitral valve warrants further consideration in the long-term management of these patients.

Revisiting Animal Models of Aortic Stenosis in the Early Gestation Fetus

Mechanisms leading to left ventricular hypoplasia and endocardial fibroelastosis in the fetus remain unknown. Prevailing theory is that obstruction to blood flow through the left ventricle leads to elevated end-diastolic pressures, compromised myocardial perfusion, and endocardial ischemia. Fetal interventions are now being performed, based on the presumption that they would prevent such pathogenic mechanisms. Forty first-trimester fetal sheep (mean gestational age, 53 days) were studied. Severe fetal left ventricular outflow obstruction was created by banding the ascending aorta in 25 fetuses; 15 control fetuses underwent "sham" surgery with thoracotomy. Serial fetal echocardiography was used to assess left ventricular growth and fetal hemodynamics. Findings were correlated to morphologic and histopathologic changes, and intracardiac pressure measurements obtained from fetal cardiac catheterization. Surviving banded fetuses (n = 13) had one of two phenotypes: compensatory left ventricular hypertrophy (n = 7) or noncompensatory left ventricular dilatation (n = 6) with hydrops and severe left ventricular dysfunction. All fetuses had elevated left ventricular end-diastolic pressures (mean, 21 mm Hg; range, 14 to 28 mm Hg), which correlated to the gradient across the ascending aorta (mean, 41 mm Hg; range, 28 to 73 mm Hg). In vivo echocardiography findings were incongruous with those at autopsy, and demonstrated preservation of left ventricular growth indices in all fetuses. Endocardial fibroelastosis and myocardial fibrosis were not observed in any banded fetus. While early gestational obstruction to flow can compromise left ventricular function in the fetus, it does not retard normal growth. Similarly, an elevated left ventricular end-diastolic pressure is not sufficient to cause myocardial fibrosis or endocardial fibroelastosis in the fetus.

Usefulness of Magnetic Resonance Imaging of Left Ventricular Endocardial Fibroelastosis in Infants After Fetal Intervention for Aortic Valve Stenosis

Usefulness of Magnetic Resonance Imaging of Left Ventricular Endocardial Fibroelastosis in Infants After Fetal Intervention for Aortic Valve Stenosis

Usefulness of Magnetic Resonance Imaging of Left Ventricular Endocardial Fibroelastosis in Infants After Fetal Intervention for Aortic Valve Stenosis

This report describes the use of myocardial delayed-enhancement magnetic resonance imaging to delineate the extent of endocardial fibroelastosis (EFE) in 4 infants after fetal balloon aortic valvuloplasty. The preoperative mapping of EFE followed by extensive resection led to biventricular physiology in 2 patients.

Ross-Konno Operation With Resection of Endocardial Fibroelastosis for Critical Aortic Stenosis With Borderline-Sized Left Ventricle in Neonates

Background. Critical aortic stenosis with severe concentric left ventricular hypertrophy and endocardial fibroelastosis has a substantial mortality rate when the conventional therapeutic strategy, ie, open surgical or balloon valvuloplasty, is applied. During the last decade, univentricular repair (Norwood operation) and heart transplantation have evolved as the only viable therapeutic options. An alternative in patients with borderline hypoplastic left heart syndrome consists of performance of a Ross-Konno operation with surgical enlargement of the left ventricular cavity, a procedure that has the advantage of achieving a two-ventricle repair. Methods. Two neonates and 2 young infants with critical aortic stenosis, concentric left ventricular hypertrophy, and severe endocardial fibroelastosis, with echocardiographically documented antegrade flow in the ascending aorta, underwent a Ross-Konno operation combined with extensive endocardial and myocardial resection of the left ventricular septum and free wall. The incision in the ventricular septum was closed with a wide cuff of infundibular muscle that was harvested in continuity with the pulmonary autograft. Results. In all 4 patients, the operation resulted in normal aortic valve function, marked reductions of width of the left ventricular septum (median, 6.5 mm, versus 11 mm preoperatively) and the left ventricular posterior free wall (median, 8.5 mm, versus 15.5 mm preoperatively), and enlargement of the left ventricular end-diastolic volume (median, 12.5 cm 3, versus 6.5 cm 3 preoperatively). Three patients had an uneventful recovery, with gradual improvement of left ventricular diastolic and systolic function during the first postoperative week; 1 neonate with associated mitral regurgitation died of left ventricular failure. Conclusions. The Ross-Konno procedure with resection of endocardial fibroelastosis may be a valuable adjunct for achieving a two-ventricle repair in borderline hypoplastic left heart syndrome. The operation results in enlargement of the left ventricular stroke volume and improvement of left ventricular diastolic function; in addition, resection of endocardial fibroelastosis relieves the mechanical impairment of myocardial function and therefore may promote the potential for left ventricular growth. (Ann Thorac Surg 1997;63:112–6)

Left ventricular dysfunction in the fetus: relation to aortic valve anomalies and endocardial fibroelastosis.

To examine the relation between a characteristic form of left ventricular dysfunction in the fetus and abnormalities of the aortic valve and endocardial fibroelastosis of the left ventricle. A retrospective study to examine the correlation between echocardiographic findings in the fetus and postnatal or necropsy findings. Tertiary referral centre for fetal echocardiography. Thirty fetuses showing a characteristic echocardiographic picture of left ventricular dysfunction. The relation between the prenatal echocardiographic features and the postnatal and necropsy findings. At presentation the size of the left ventricular cavity was normal or enlarged in all cases. The measurements of the orifice of the aortic root and mitral valve were either normal or small for the gestational age. The echocardiographic diagnosis made at presentation was critical aortic stenosis in all cases. At necropsy or postnatal examination the aortic valve was dysplastic and stenotic in 15 cases and the left ventricle had become hypoplastic in one of these. Aortic atresia was present in seven patients, three of whom had a hypoplastic left ventricle. In six patients the aortic valve was bicuspid although not obstructive. One of these patients had hypoplasia of the aortic arch and one had a hypoplastic left ventricle but in the remaining four patients endocardial fibroelastosis of the left ventricle was the only abnormality found. No follow up information was available in two. Of 26 patients for whom there was postmortem information, 24 had evidence of some degree of endocardial fibroelastosis of the left ventricle. Sequential observations showed that five cases developed into the hypoplastic left heart syndrome. This type of left ventricular dysfunction in the fetus is the result of an overlap of diseases, including primary left ventricular endocardial fibroelastosis, critical aortic stenosis, and the hypoplastic left heart syndrome.

Anatomic evidence of spontaneous intrauterine closure of a ventricular septal defect

An infant, born to a mother on carbamazepine monotherapy, had a complex cardiac anomaly, consisting of double-outlet right ventricle (DORV), right-sided aorta, pulmonary artery hypoplasia, left ventricular endocardial fibroelastosis, and anatomic evidence of a spontaneously closed muscular ventricular septal defect (VSD). The last finding is one which, to the best of our knowledge, has never been illustrated before.

Dilated and contracted forms of primary endocardial fibroelastosis: a single fetal disease with two stages of development.

Left ventricular endocardial fibroelastosis was diagnosed by echocardiographic scanning in a fetus at 20 weeks' gestation. Repeated prenatal examination over the next 20 weeks' gestation showed the development of the left ventricle from a chamber with a dilated cavity to a small cavity with a very thick wall. These findings were confirmed at necropsy and by the absence of other morphological anomalies. The contracted form of primary fibroelastosis in the fetus must have followed an insult that prevented any further increase in the size of the left ventricular cavity.

Endokardfibroelastose des linken Ventrikels bei einem Patienten mit Alagille-Syndrom

We present a case of a 6 week old infant with Alagille syndrome. Cardiological evaluation revealed peripheral pulmonary arterial stenosis and left ventricular endocardial fibroelastosis. While peripheral pulmonary arterial stenosis are typical for the syndrome this is the first case reported with endocardial fibroelastosis. Complex cardiac malformations may worsen the prognosis in Alagille syndrome. They require early diagnosis and therapy.

Reduced left ventricular size and endocardial fibroelastosis as correlates of mortality in newborns and young infants with severe aortic valve stenosis.

30 patients with severe aortic valve stenosis presented in severe congestive heart failure within the first 2 months of life. In 25 of them, left ventricular volume and contractility were assessed; five of them had a left ventricle of normal size, in 11 left ventricular size was diminished, and in nine patients it was enlarged. Eleven of the infants had extensive endocardial fibroelastosis (EFE) evidenced angiographically by myocardial sinusoids in ten of them and established at autopsy in six. The presence of EFE correlated with the size of the left ventricle; eight of 11 with a small left ventricle, two of five with a normal-sized left ventricle, and one of nine with an enlarged left ventricle displayed EFE. The severe depression of left ventricular function associated with EFE was documented by left ventricular volume determinations on exclusion of the myocardial sinusoids. Of 30 patients, 12 (including eight of 26 who underwent surgery) did not survive. Mortality, severity, and early onset of symptoms were associated mainly with small size of the left ventricle and with the severe left ventricular dysfunction associated with EFE.