Mechanical support for bridge to transplant in an infant with post-cardiotomy end-stage heart failure and complete heart block: report of a case.

The patient was diagnosed with perimembranous ventricular septal defect (VSD). She underwent VSD closure and muscle bundle resection across right ventricular outflow tract at the age of 3 months. Since then, she had suffered from severe heart failure and complete heart block. Permanent pacemaker generator was implanted in the left hypochondrium. She was depended on continuous catecholamine administration, so transferred to our hospital for further management. On arrival, her body weight was 5686 g (- 2.7 SD). She underwent Excor pediatric left ventricular assist device implantation at the age of 9 months. Because the position of the left ventricular assist device cannula interfered with the pacemaker, herein, the pacemaker pocket was newly created in the left thoracic cavity. An 1 mm in thickness of expanded polytetrafluoroethylene sheet was trimmed and sutured under the anterolateral wall of left thoracic cavity as a pacemaker pocket. Bipolar ventricular lead was sutured on left ventricular apex and basal wall to face each other, mimicking cardiac regeneration therapy. Even though she unfortunately required right diaphragmatic plication for iatrogenic phrenic nerve palsy, her respiratory function was well maintained; therefore, secondary right heart failure was not observed. Her cardiopulmonary function was quite stable until post-operative day 275 when the patient was transferred to another hospital for heart transplantation.

Long-Term Influence of Atrial Switch Operation on Hemodynamics After the Rastelli Procedure.

The study aimed to investigate the long-term influence of atrial switch on post-Rastelli hemodynamic condition. Of 112 patients with transposition of the great arteries (TGA) or TGA-type double outlet right ventricle, ventricular septal defect (VSD), and pulmonary stenosis (PS) who underwent intra-cardiac repair between 1979 and 2018, 50 patients with levo-TGA underwent atrial switch and Rastelli as an anatomic repair and 62 patients with dextro-TGA underwent Rastelli. Postoperative outcomes were retrospectively compared. The median follow-up durations were 20.1 years (interquartile range: 4.3, 32.4) in the Rastelli group and 15.3 years (7.1, 23.0) in the atrial switch plus Rastelli group (p = 0.19). Sex, age, and weight at operation were similar in both groups. Overall survival rates at 30 years were 69.8% in the Rastelli group and 80.1% in the atrial switch plus Rastelli group (p = 0.18). The atrial switch plus Rastelli group required more frequent catheter interventions (p < 0.001), mainly for caval obstruction (n = 8) and atrial arrhythmia (n = 6). Medication was more frequent in the atrial switch plus Rastelli group (p = 0.009). Exercise capacity was similarly reduced in two groups. Protein-losing enteropathy (PLE) occurred in three long-term survivors in the atrial switch plus Rastelli group (p = 0.07). Concomitantly performed atrial switch operation did not affect long-term survival and exercise capacity after Rastelli procedure. However, the occurrence of PLE, a frequent need for medication, and catheter interventions after atrial switch plus Rastelli may result from atrial switch under the post-Rastelli condition.

[Post-operative Management After Surgery for Diminutive Branch Pulmonary Arteries].

Congenital severe peripheral pulmonary artery stenosis is usually associated with pulmonary atresia, ventricular septal defect and major aortopulmonary collateral artery. Complications mainly related to respiratory system frequently occur after peripheral pulmonary artery patch augmentation with or without uniforcalization. Pulmonary hemorrhage and airway bleeding can be fatal. Airway compression from surrounding structures such as reconstructed central pulmonary artery, pulmonary hypertension, ventilation/perfusion mismatch, and pulmonary ischemia reperfusion injury are also life-threating complications. Long mechanical ventilator support with positive airway pressure under the deep sedation is a key to success to prevent major complications. Extra corporeal membrane oxygen support should not be hesitated if respiratory and/or hemodynamic conditions are critical. Chylothorax is a risk factor for prolonged intensive care unit stay. Several treatment options are reported, then multidisciplinary treatment with nil per oral and total parenteral nutrition is recommended.

Morphological changes and number of candidates for transcatheter pulmonary valve implantation in conduits involving heterograft and artificial material.

Heterograft and artificial materials have been used for extracardiac conduit implantation to create right ventricular (RV) to pulmonary artery (PA) continuity for biventricular repair in Japan because of the limited availability of homograft valves. However, few studies have examined morphological changes and number of candidates for transcatheter pulmonary valve implantation (TPVI) in which the conduit includes more than one type of material. Overall, 88 patients who underwent biventricular repair with an external conduit were included in this evaluation. Based on catheterization data and surgical records, we estimated morphological change in the RV outflow tract for each material and the number of candidates for Melody valve implantation based on premarket approval application criteria established by the U.S. Food and Drug Administration. There were 63 candidates for TPVI (72%, 63/88). Median anteroposterior and lateral diameter of the RV outflow tract was 20.4 mm (range 9.0-41.5) and 17.8 mm (range 9.5-34.9), respectively. Bovine pericardium tended to dilate by 11.2%. Polytetrafluoroethylene (ePTFE), homograft, and Dacron polyethylene terephthalate (PET) tended to become stenotic by 11.1%, 28.0%, and 13.4%, respectively. While ePTFE (27/33, 82%) and Dacron PET (2/2, 100%) were highly suitable for TPVI, bovine pericardium (32/48, 67%) was less suitable. In Japan, many patients with hemodynamic indications for TPVI following extracardiac conduit implantation to create RV to PA continuity may also meet the morphological indications.

Renal replacement therapy with a cytokine-adsorbing hemofilter after neonatal open-heart surgery.

Two neonates with right atrial isomerism, single right ventricle, common atrioventricular valve regurgitation, and obstructive extra-cardiac total anomalous pulmonary venous connection underwent emergent total anomalous pulmonary venous connection repair combined with adjustment of pulmonary blood flow soon after birth. After the operation, both patients developed serious capillary leak syndrome, acute kidney injury, and lethal lactic acidosis with hemodynamic instability. Continuous renal replacement therapy was initiated with a cytokine-adsorbing hemofilter of polymethyl methacrylate membrane and a double lumen dialysis catheter inserted directly into the atrium. Elevated serum lactate levels were successfully decreased, and blood pressure was immediately increased.

Long-Term Outcomes After Fenestration Closure in High-Risk Fontan Candidates.

The study aimed to assess the long-term outcomes after fenestration closure in patients at risk for Fontan failure. Of 119 patients who underwent Fontan operation between 1995 and 2004, fenestration was not created in 89 patients (NF group) and created in 30 patients with hypoplastic left heart syndrome, heterotaxy syndrome, high pulmonary arterial pressure, high systemic ventricular end-diastolic pressure, low ventricular ejection fraction, or atrioventricular valve regurgitation. All fenestrations were closed spontaneously or by catheter/surgical interventions, excepting two patients, and therefore, they were excluded. In fenestration group, patients with pre-Fontan mean pulmonary arterial pressure ≥ 15 mmHg or systemic atrioventricular valve regurgitation ≥ moderate were classified as high-risk Fontan candidates (F-HR group, n = 16), and the remaining patients were as standard-risk (F-SR group, n = 12). Protein-losing enteropathy-free survival rates did not differ among the three groups (p = 0.72). Serial follow-up catheter examinations after Fontan operation were completed in 69 patients in NF group and 11 patients in both F-SR and F-HR groups. Cardiac index and pulmonary vascular resistance significantly and similarly decreased over time in all groups, though the F-HR group showed lowest arterial oxygen saturation, lowest cardiac index, and highest pulmonary vascular resistance. The F-HR group also showed much veno-venous collaterals (p = 0.049), low peak oxygen consumption (p = 0.019), and low anaerobic threshold (p = 0.023) as compared to those in the F-SR group. In F-HR group, cyanosis remained after fenestration closure due to transformation from fenestration to veno-venous collaterals, which resulted in elevation of pulmonary vascular resistance, low cardiac index, and deterioration of exercise tolerance.

The Impact of Post-Graduate Year of Primary Surgeon on Technical Performance Score in Tetralogy of Fallot Repair.

BACKGROUND: The aim of this study was to assess the impact of surgeon years of experience on clinical outcomes of tetralogy of Fallot (TOF) repair using technical performance score (TPS), and to investigate the possibility of safe operations by surgical trainees.Methods and Results:We assessed the cases of 159 consecutive patients who underwent TOF repair between 2001 and 2015. Thirteen different primary surgeons performed operations with 41 different first assistants. The primary surgeon and first assistant mean postgraduate years were 19.1±5.1 years (range, 5.7-31.6 years) and 11.2±6.3 years (range, 3.2-36.3 years), respectively. TPS was assigned using pre-discharge echocardiography based on original criteria. Logistic regression analysis was used to examine the factors associated with TPS. TPS could be scored for all patients, 16 of whom were graded as having optimal (10%), 119 as adequate (75%), and 24 as having inadequate (15%) TPS. None of the preoperative and perioperative variables affected TPS. Although neither the primary surgeon nor the first assistant postgraduate years was associated with TPS independently, total primary surgeon and first assistant postgraduate years correlated with TPS (OR, 1.07; 95% CI: 1.01-1.13, P=0.031). CONCLUSIONS: Primary surgeon postgraduate years was not associated with TPS for TOF repair. TOF repair can be performed adequately and safely by surgical trainees under the support of highly experienced supervisors.

Discrepancy Between Pre- and Postnatal Diagnoses of Congenital Heart Disease and Impact on Neonatal Clinical Course　- A Retrospective Study at a Japanese Tertiary Institution.

BACKGROUND: Congenital heart disease (CHD) is often diagnosed prenatally using fetal echocardiography, but few studies have evaluated the accuracy of these fetal cardiac diagnoses in detail. We investigated the discrepancy between pre- and postnatal diagnoses of CHD and the impact of discrepant diagnoses.Methods and Results:This retrospective study at a tertiary institution included data from the medical records of 207 neonates with prenatally diagnosed CHD admitted to the cardiac neonatal intensive care unit between January 2011 and December 2016. Pre- and postnatal diagnoses of CHD differed in 12% of neonates. Coarctation of the aorta and ventricular septal defects were the most frequent causes of discrepant diagnosis. Unexpected treatments were added to 38% of discrepant diagnostic cases. However, discrepant diagnoses did not adversely affect the clinical course. The 9% of the 207 neonates who required invasive intervention within 24 h of delivery were accurately diagnosed prenatally. CONCLUSIONS: Pre- and postnatal diagnoses differed in only a few neonates, with differences not adversely affecting the clinical course. Neonates who required invasive intervention immediately after delivery were accurately diagnosed prenatally. Prenatal diagnosis thus seems to contribute to improved prognosis in neonates with CHD.

Evaluating the response to cardiac resynchronization therapy performed with a new ventricular morphology-based strategy for congenital heart disease.

BACKGROUND: In cardiac resynchronization therapy (CRT) for patients with congenital heart disease (CHD) and a ventricular morphology other than a systemic left ventricle (LV), we previously proposed pacing sites that are different from those used for a systemic LV. The leads should be placed laterally on opposite sides of both ventricles in patients with short-axis dyssynchrony and a single ventricular physiology with two ventricles, whereas they should be placed at the farthest sites along the longitudinal direction in the right ventricle (RV) in patients with long-axis dyssynchrony of the RV. Moreover, in patients with interventricular dyssynchrony and a biventricular physiology with a systemic RV, they should be placed at sites that both ventricles can contract simultaneously. We retrospectively investigated 27 consecutive procedures in 24 patients with CHD who underwent CRT to evaluate the effectiveness of a new ventricular morphology-based CRT strategy. The responder rate was 63% (17/27). The reasons for a non-response to CRT in 10 cases were as follows: non-optimal lead positions during CRT, 4; no systemic ventricular conduction delay or heart failure symptoms before the CRT, 5; short follow-up periods after the CRT, 2; and an extremely dilated systemic RV, 1. The responder rate became 88% (14/16), after excluding the procedures without a ventricular conduction delay or heart failure symptoms and those with non-optimal lead positions. This new strategy for CRT can provide favorable results for CHD patients with a systemic ventricular conduction delay and heart failure.

Retraction Note to: Primary Draining Vein Stenting for Obstructive Total Anomalous Pulmonary Venous Connection in Neonates with Right Atrial Isomerism and Functional Single Ventricle Improves Outcome.

The authors have retracted this article [1] because, contrary to the statement in the article, this research did not obtain ethics approval from the National Cerebral and Cardiovascular Center Institutional Review Board prior to submission of the manuscript to Pediatric Cardiology. All authors agree to this retraction.

Current Surgical Outcomes of Congenital Heart Surgery for Patients With Down Syndrome in Japan.

BACKGROUND: Current surgical outcomes of congenital heart surgery for patients with Down syndrome are unclear.Methods and Results:Of 29,087 operations between 2008 and 2012 registered in the Japan Congenital Cardiovascular Surgery Database (JCCVSD), 2,651 were carried out for patients with Down syndrome (9%). Of those, 5 major biventricular repair procedures [ventricular septal defect repair (n=752), atrioventricular septal defect repair (n=452), patent ductus arteriosus closure (n=184), atrial septal defect repair (n=167), tetralogy of Fallot (TOF) repair (n=108)], as well as 2 major single ventricular palliations [bidirectional Glenn (n=21) and Fontan operation (n=25)] were selected and their outcomes were compared. The 90-day and in-hospital mortality rates for all 5 major biventricular repair procedures and bidirectional Glenn were similarly low in patients with Down syndrome compared with patients without Down syndrome. On the other hand, mortality after Fontan operation in patients with Down syndrome was significantly higher than in patients without Down syndrome (42/1,558=2.7% vs. 3/25=12.0%, P=0.005). CONCLUSIONS: Although intensive management of pulmonary hypertension is essential, analysis of the JCCVSD revealed favorable early prognostic outcomes after 5 major biventricular procedures and bidirectional Glenn in patients with Down syndrome. Indication of the Fontan operation for patients with Down syndrome should be carefully decided.

Primary Draining Vein Stenting for Obstructive Total Anomalous Pulmonary Venous Connection in Neonates with Right Atrial Isomerism and Functional Single Ventricle Improves Outcome.

For neonates with right atrial isomerism (RAI), functional single ventricle (f-SV), and obstructive total anomalous pulmonary venous connection (TAPVC), primary TAPVC repair (TAPVCR) has a poor outcome. At our hospital, the survival rate at 1 year of such neonates undergoing primary TAPVCR between 1999 and 2010 (TAPVCR group) was 30% (3/10). Most deceased cases suffered from capillary leak syndrome and unstable pulmonary resistance after the surgeries. We sought to determine whether less invasive primary draining vein stenting (DVS) improved the outcome of these neonates. We investigated outcomes in consecutive nine such neonates (median gestational age 38 weeks, birth weight 2.8 kg, females 4) who underwent primary DVS with 6-mm-diameter Palmaz® Genesis® stents at our hospital between 2007 and 2017 (DVS group). Eight patients underwent subsequent surgeries to adjust the pulmonary flow after decreased pulmonary resistance. The survival rate at 1 year after the first interventions in the DVS group improved to 77% (7/9), although there was a difference between the interventional eras of the two groups. Of the seven patients who underwent multiple stent redilations with a larger balloon or additional stenting in other sites until the next stage of surgery at a median age of 8 months, four received a bidirectional Glenn (BDG) shunt and TAPVCR and three underwent TAPVCR, with two of those cases reaching BDG. Less invasive primary DVS improved the outcome of neonates with RAI, f-SV, and obstructive TAPVC, with many reaching BDG. Patient selection to advance toward Fontan is thought to further improve the outcome.

Impact of Hybrid Stage 1 Palliation for Hypoplastic Left Heart Syndrome: Histopathological Findings.

The purpose of the study is to analyze the impact of hybrid stage 1 palliation on right ventricular myocardial pathology in hypoplastic left heart syndrome. Sufficient amount of right ventricular biopsies could be obtained from 16 of 32 patients who underwent Norwood operation between 2007 and 2013. Histopathological findings of right ventricle in patients who underwent primary Norwood operation (primary group, n = 5), patients with aortic atresia (HS1P AA group, n = 6) or aortic stenosis (HS1P AS group, n = 5) who underwent staged Norwood palliation following hybrid stage 1 palliation were compared. To eliminate the influence of right ventricular pressure afterload, right ventricular biopsies were obtained from patients with truncus arteriosus communis (TAC group, n = 6) at total correction. The percentage of myocardial fibrosis was significantly higher in both HS1P groups than in TAC group; moreover, it was significantly higher in HS1P AA group than in primary group. Capillary vascular density was significantly lower in all hypoplastic left heart syndrome groups than in TAC group. At the sub-endocardial layer, collagen type I/III ratios were higher in HS1P AA group than in other hypoplastic left heart syndrome groups. The proportions of N-cadherin immunolocalized to myocyte termini were lower in all hypoplastic left heart syndrome groups than in TAC group. Right ventricle in hypoplastic left heart syndrome showed more significant ischemic change and myocardial immaturity than that in truncus arteriosus communis. Hybrid stage 1 palliation for aortic atresia would be a risk factor for further right ventricular myocardial ischemia.

Optimal pacing sites for cardiac resynchronization therapy for patients with a systemic right ventricle with or without a rudimentary left ventricle.

AIMS: This study aims to assess the impact of pacing sites on the effectiveness of cardiac resynchronization therapy (CRT) in systemic right ventricle (sRV) patients with/without a rudimentary left ventricle (rLV). METHODS AND RESULTS: We evaluated 13 procedures in 11 sRV patients with a wide QRS (>150 ms). Based on the digitalization results of ventriculography, long-axis dyssynchrony (LD) was defined as extremely delayed right ventricular (RV) outflow tract movement: ≥100 ms delay from the RV apical contraction, and short-axis dyssynchrony (SD) was defined as a paradoxical contraction between the rLV and sRV caused by a conduction delay between the two ventricles. During the follow-up period (2.1 ± 1.9 years), the response rates were 71% (5/7) and 33% (2/6) in the sRV patients with and without an rLV, respectively (P = ns). Following the CRT, the QRS duration remained similar between the responders and nonresponders. Among five responders with an rLV, the leads were placed in the longitudinal RV direction in two with LD, longitudinal RV direction with fusion of the intrinsic QRS in two with LD + SD, and laterally on opposite sides of both ventricles in one with SD. Among two responders without an rLV, the leads were placed in the longitudinal RV direction in those two with LD. CONCLUSIONS: In sRV patients with LD with/without an rLV, the leads should be placed at furthest sites in the longitudinal RV direction. In patients with an rLV and SD, the leads should be placed laterally on opposite sides of both ventricles.

Early Single Institutional Experience of Berlin Heart EXCOR® Pediatric Ventricular Assist Device in Japan.

BACKGROUND: Since August 2015, the pediatric ventricular assist device (VAD), Berlin Heart EXCOR®, has been accepted for use in Japan.Methods and Results:Between August 2015 and July 2016, 4 pediatric patients with endstage heart failure underwent LVAD implantation with the EXCOR®device. The median age and body weight at operation were 8 months and 4.8 kg. During a median follow-up of 7.3 months (range, 5.0-10.3), all patients survived. Two patients went on to heart transplantation and the remaining 2 are on a waiting list with stable hemodynamics. CONCLUSIONS: The early outcomes of the Berlin Heart EXCOR®pediatric VAD were satisfactory. (Circ J 2016; 80: 2552-2554).

Efficacy of "Awake ECMO" for critical respiratory failure after pediatric open-heart surgery.

A 4-year-old boy with atrioventricular discordance, double-outlet right ventricle, pulmonary stenosis, and mitral regurgitation, was undergoing anatomical repair consisting of Senning, Rastelli, Damus-Kaye-Stansel procedures, and a mitral valve repair, complained of post-operative excessive airway tract secretion, which ultimately developed into acute respiratory distress syndrome (ARDS) 28 days after the operation. The cause of the ARDS was thought to be frequent manual positive pressure recruitment and prolonged inhalation of pure oxygen. At 45 days after the operation, hypercapnia and respiratory acidosis turned out to be irreversible, and therefore, veno-arterial extracorporeal membrane oxygenation (ECMO) was established utilizing the Endumo(®)4000 system. Pulmonic interstitial inflammation gradually improved while resting the lung under ECMO support; however, effective ventilation volume decreased critically because a massive pulmonary hemorrhage occurred at 2 and 9 days after the initiation of ECMO. To maximize the effectiveness of respiratory physical therapy, "Awake ECMO" was started and tidal volume dramatically increased with a regained cough reflex. Five days later, he was successfully weaned off from ECMO, and discharged 7 months after the operation without any neurological and physiological sequelae.

Early clinical outcomes of right ventricular outflow tract reconstruction with small caliber bovine jugular vein conduit (Contegra®) in small children.

This study reviewed early clinical outcomes of right ventricular outflow tract reconstruction with Contegra® valved conduits in pediatric patients. Between April 2013 and July 2014, thirteen pediatric patients underwent right ventricular outflow tract reconstruction with Contegra valved conduits. The size of the implanted conduits were 12 mm in 5 patients, 14 mm in 3, 16 mm in 3, and then 2 patients were implanted with bicuspidized conduits for downsizing the conduit to 9 and 10 mm in each. Follow-ups were completed in all patients. One conduit was explanted 7 days after a neonatal biventricular repair for Ebstein's anomaly and pulmonary atresia, timed to be at the point of conversion to a single ventricular palliation. Among the 5 patients who developed significant pulmonary insufficiency and/or conduit stenosis, 3 patients exhibited persistent pulmonary hypertension. Both the bicuspidized conduits resulted in early pulmonary insufficiency. One patient implanted with a ring-supported conduit developed coronary artery stenosis, caused by suppression between the ring of the implanted conduit and the annulus of the mechanical vale. Although the small caliber Contegra valved conduit might be an alternative to RVOT reconstruction, the indication should be carefully considered. More than mild pulmonary hypertension, and low body weight at operation of less than 3.0 kg caused early conduit dysfunction.

Displacement of the anterior leaflet of the tricuspid valve: Rare variant of Ebstein's anomaly.

In Ebstein's anomaly, the points of attachment, or hinges, of the septal and mural leaflets in the right ventricle are displaced away from the atrioventricular junction. In contrast, the junctional hinge of the anterior leaflet usually retains a normal position. Here, we report a case of giant right atrial aneurysm due to isolated displacement of the anterior leaflet of the tricuspid valve in an infant, a rare variant of Ebstein's anomaly. Enlargement of the right atrium, which was initially diagnosed during the fetal period, progressively and markedly dilated after birth and was successfully treated with surgical resection. Isolated displacement of the anterior leaflet should be recognized as a variant of Ebstein's anomaly.

Clinical Features and Surgical Outcomes of Coronary Sinus Orifice Atresia.

This study aimed to review clinical features and surgical outcomes of coronary sinus orifice atresia (CSOA). From 2003 to 2015, 6 patients were diagnosed with CSOA. Median age at diagnosis was 2 years (range 0.2-73). CSOA was preoperatively diagnosed in 2 patients, intraoperatively in 3, and postoperatively in 1. Coronary venous blood flow drained into innominate vein through the left superior vena cava (LSVC) in 2, into the atrium through Thebesian veins in 2, and into both in 2. Three patients required surgical treatment. The first patient with a congenitally corrected transposition of great arteries had undergone ligation of the LSVC and a cutback of the proximal LSVC into the functional right atrium during the double-switch operation. The second patient with tricuspid atresia gradually developed hypoxia after the Fontan operation due to the increase in veno-venous shunt blood flow from the Fontan pathway to the right atrium through the LSVC and Thebesian veins, so that the LSVC was ligated and the coronary sinus was unroofed 6 years after Fontan operation. The other functional single ventricle patient had undergone ligation of the LSVC and a cutback of the proximal LSVC into the left atrium during the Fontan operation. There were no mortalities at the median follow-up of 9 years (1-11). CSOA should be suspected when the LSVC and usual-sized innominate vein were presented. Surgical treatment is required if the postoperative hemodynamics would affect coronary venous perfusion, like single ventricular palliation (244 words).

Acute rupture of chordae tendineae of the mitral valve in infants: a nationwide survey in Japan exploring a new syndrome.

BACKGROUND: Recently, infant cases of acute heart failure attributable to rupture of the mitral chordae tendineae have been reported. However, little is known about the pathogenesis and clinical course of this condition. METHODS AND RESULTS: Ninety-five children with rupture of mitral chordae tendineae were identified in nationwide surveys of Japan diagnosed from 1995 to 2013. The clinical manifestations, management strategies, and prognosis were investigated. Eighty-one (85%) patients were between 4 and 6 months (median, 5 months) of age. In 63 (66%) patients, rupture occurred during the spring or summer. The underlying conditions before rupture included Kawasaki disease (10 cases), maternally derived anti-SSA antibodies (2 cases), and infective endocarditis (1 case). Surgery was performed in 80 patients (94 operations), and the final operations included plasty of mitral chordae in 52 cases and mechanical valve replacement in 26 cases. The histopathologic examinations of the mitral valves and chordae (n=28) revealed inflammatory reactions with predominant mononuclear cell infiltration in 18 cases (64%) and increased fibrous and myxoid tissue in 11 cases (39%), suggesting that nonbacterial infectious or autoimmune endocarditis and myxoid changes are involved in the pathogenesis. Eight patients (8.4%) died before (n=6) and shortly after (n=2) the operation, and significant neurological complications persisted in 10 cases (11%). CONCLUSIONS: Acute heart failure attributable to rupture of the mitral chordae tendineae in infants is a unique disease resulting from diverse causes. This condition should be recognized as a significant cardiovascular disorder that may cause sudden onset of cardiogenic shock and death in infants.