Impact of Pulmonary Arterial Elastance on Right Ventricular Mechanics and Exercise Capacity in Repaired Tetralogy of Fallot.

BACKGROUND AND OBJECTIVES: Pathophysiological changes of right ventricle (RV) after repair of tetralogy of Fallot (TOF) are coupled with a highly compliant low-pressure pulmonary artery (PA) system. This study aimed to determine whether pulmonary vascular function was associated with RV parameters and exercise capacity, and its impact on RV remodeling after pulmonary valve replacement. METHODS: In a total of 48 patients over 18 years of age with repaired TOF, pulmonary arterial elastance (Ea), RV volume data, and RV-PA coupling ratio were calculated and analyzed in relation to exercise capacity. RESULTS: Patients with a low Ea showed a more severe pulmonary regurgitation volume index, greater RV end-diastolic volume index, and greater effective RV stroke volume (p=0.039, p=0.013, and p=0.011, respectively). Patients with a high Ea had lower exercise capacity than those with a low Ea (peak oxygen consumption [peak VO2] rate: 25.8±7.7 vs. 34.3±5.5 mL/kg/min, respectively, p=0.003), while peak VO2 was inversely correlated with Ea and mean PA pressure (p=0.004 and p=0.004, respectively). In the univariate analysis, a higher preoperative RV end-diastolic volume index and RV end-systolic volume index, left ventricular end-systolic volume index, and higher RV-PA coupling ratio were risk factors for suboptimal outcomes. Preoperative RV volume and RV-PA coupling ratio reflecting the adaptive PA system response are important factors in optimal postoperative results. CONCLUSIONS: We found that PA vascular dysfunction, presenting as elevated Ea in TOF, may contribute to exercise intolerance. However, Ea was inversely correlated with pulmonary regurgitation (PR) severity, which may prevent PR, RV dilatation, and left ventricular dilatation in the absence of significant pulmonary stenosis.

Pregnancy outcomes in patients with structural heart disease: a single center experience.

BACKGROUND: In women, pregnancy is a period of relatively drastic hemodynamic change in a short period of time. Most pregnant women adapt well to these gradual hemodynamic changes. However, in women with congenital heart disease or other structural heart disease, adaptation to theses sudden hemodynamic changes is difficult, and heart failure or arrhythmia can get aggravated. This study shares our experiences on the outcomes of pregnancy in patients with structural heart disease. METHODS: From January 2007 to December 2016, we reviewed the medical records of all pregnant women with structural heart disease who received obstetric care at the Sejong General Hospital. RESULTS: During the study period, 103 pregnancies were observed in 79 women with structural heart disease. Of the 103 pregnancies, 55 were primiparous and 48 were multiparous. Echocardiography performed before pregnancy revealed that 52 patients had moderate to severe valvular regurgitation and 38 patients had moderate to severe valvular stenosis; 22 patients had mechanical valves and 5 patients had pulmonary hypertension. Overall, there were 9 maternal cardiac events, 7 obstetric events and 19 neonatal events. Pulmonary embolic events occurred only in 1 case; 77 deliveries were made, and 26 pregnancies did not last. Among 77 deliveries, 55 patients delivered by cesarean section (C/S) (71.43%). C/S in 16 of 55 patients was performed due to the maternal hemodynamic risk. CONCLUSIONS: Overall complications associated with pregnancy in women with structural heart disease were very high at 28.16%. However, it is hoped that maternal and neonatal outcomes will be improved through careful observation and preparedness for anticipated complications.

Eisenmenger Syndrome in Adults: Treatment Pattern and Prognostic Factors in the Advanced Pulmonary Vasodilator Era.

Patients with Eisenmenger syndrome (ES) have a higher mortality rate than patients with simple congenital heart disease (CHD). To determine factors associated with death in the era of advanced pulmonary vasodilator treatment, we analyzed the characteristics of adult ES patients depending on underlying CHD. Simple septal defects and patent ductus arteriosus were classified as simple CHD, and other conditions were classified as complex CHD. Sixty-seven adult ES patients (50.7% women) were reviewed retrospectively. CHD was diagnosed at a median of 10.0 years of age and ES was diagnosed at 18.6 years. Thirteen patients (19.4%) died; the median age was 38.6 years (IQR 32.2-47.8). In a multivariate analysis, patients with SpO2 < 85% had a higher mortality rate than others [hazard ratio (HR) 9.7; 95% confidence interval (CI) 1.002-95.2, p = 0.05]. In simple CHD patients, those with a low platelet count (< 100 × 109/L) or low SpO2 (< 85%) were at a higher risk of death than those without (HR 16.32, 95% CI 1.25-2266.31, p = 0.032; and HR 38.91, 95% CI 3.44-5219.41, p = 0.001, respectively). Advanced pulmonary vasodilators were used more in survivors than in non-survivors (48.1% vs. 15.4%, p = 0.032). Low SpO2 and platelet count were related to mortality in adult ES, especially in those with simple CHD. Therefore, careful attention should be paid to the care of adult ES patients with this tendency; active pulmonary vasodilator treatment should be considered.

A new surgical strategy for medically uncontrolled protein-losing enteropathy after Fontan surgery.

Managing protein-losing enteropathy after Fontan surgery is challenging. We report a case of protein-losing enteropathy associated with Fontan circulation in a 14-year-old boy. He was treated medically for 2 years, without improvement until Fontan takedown and pulsatile bidirectional cavopulmonary shunting were performed.

The Complexity of Pediatric Multifocal Atrial Tachycardia and Its Prognostic Factors.

BACKGROUND AND OBJECTIVES: Multifocal atrial tachycardia (MAT), in general, has a favorable outcome. However, there are insufficient data regarding MAT in a pediatric population. This study sought to determine the clinical course of MAT and identify potential prognostic factors. METHODS: The medical records of MAT patients from 1997-2015 were reviewed. The arrhythmia control rate and factors for unfavorable outcomes were assessed and compared to those in the literature. RESULTS: Of the 33 included patients (19 boys and 14 girls), 27 were infants less than 1 year of age. The median age at diagnosis was 1.7 months (range, 0 day to 14 years). Fourteen (42%) patients had structural heart disease. Eight (24%) patients had lung disease and 6 (18%) had a syndromic diagnosis belonging to RASopathy. Two patients developed polymorphic ventricular tachycardia, in whom genetic analysis confirmed the presence of the RyR2 mutation several years later. MAT was controlled in 26 patients (84%) within 3.9 months (median; range, 16 days-18.4 years) using an average of 2.4 medications. There were 3 cases of cardiopulmonary mortality. The arrhythmia control rate was higher in the infant group (85%) than in the non-infant group (67%), although this trend was not statistically significant. There was a significantly lower rate of unfavorable outcomes in the idiopathic infant group (n=11) than in the other groups (p=0.008). Considering the findings of previous studies, the mortality rate was significantly higher in patients with structural heart disease than in patients without (21% vs. 5%, p=0.01). CONCLUSIONS: MAT usually affects infants and has a favorable prognosis, particularly in the idiopathic infant group. However, in the presence of other comorbidities, MAT may have a variable clinical course.

Clinical Characteristics and Independent Factors Related to Long-Term Outcomes in Patients with Left Isomerism.

BACKGROUND AND OBJECTIVES: We studied the results of patient management for left isomerism (LI) and sought to determine factors that may influence survival and prognosis. SUBJECTS AND METHODS: We reviewed the medical records of 76 patients who were compatible with LI criteria between 1982 and 2014. RESULTS: Of the total study population, 29 patients (38.1%) had functional univentricular heart disease, 43 patients (56.5%) had cardiac anomalies suitable for biventricular hearts, and four patients (5.2%) had normal heart structure. Extracardiac anomalies were noted in 38.1% of the study population, including biliary atresia in 7.8% of all patients. Of the 25 patients who underwent Kawashima procedures, 24.0% developed pulmonary arteriovenous fistulas (PAVFs). During the median follow-up period of 11.4 years (range: 1 day to 32 years), 14 patients died. The 10-year, 20-year, and 30-year survival rates were 87%, 84%, and 76%, respectively. Preoperative dysrhythmia and uncorrected atrioventricular valve regurgitation were significantly associated with late death. There was no significant difference in the number of surgical procedures and in survival expectancy between patients in the functional single-ventricle group and in the biventricular group. However, late mortality was higher in functional single-ventricle patients after 18 years of age. CONCLUSION: Patients with LI need to be carefully followed, not only for late cardiovascular problems such as dysrhythmia, valve regurgitation, and the development of PAVFs, but also for noncardiac systemic manifestations.

Long-Term Prognosis for Patients with Kawasaki Disease Complicated by Large Coronary Aneurysm (diameter ≥6 mm).

BACKGROUND AND OBJECTIVES: Some patients with Kawasaki disease (KD) develop large coronary aneurysms and subsequent coronary stenosis or obstruction, leading to ischemic heart disease. This study examined the long-term outcomes of patients with KD complicated by large coronary aneurysms. SUBJECTS AND METHODS: The medical records of 71 patients (53 men and 18 women) diagnosed with large coronary aneurysms (diameter ≥6 mm) between December 1986 and December 2013 were retrospectively reviewed from our institutional database. RESULTS: The mean age at onset was 4.6±3.3 years, and the mean follow-up duration was 12.5±6.9 years. Maximum coronary artery internal diameter ranged from 6.1 to 25 mm. Giant coronary aneurysms occurred in 48 patients and coronary aneurysms 6-8 mm in diameter developed in 23 patients. Coronary stenosis and/or complete occlusion occurred in 30 patients (42.3%). Catheter and/or surgical interventions (mean: 1.5 interventions, range: 1-5 interventions) were performed in 20 patients (28.2%), 9 months to 18 years after KD onset, resulting in 33.7% cumulative coronary intervention rates at 20 years after onset. There were no differences in cumulative coronary intervention rates between two coronary aneurysm groups (6-8 mm vs. ≥8 mm). Myocardial infarction occurred in 7 patients with a giant aneurysm and there was one death. CONCLUSIONS: Long-term survival of patients with KD complicated by large coronary aneurysm was good even though 28.2% of patients underwent multiple catheter or surgical interventions. Careful follow-up is also necessary in KD patients with coronary aneurysms 6-8 mm in diameter, such as those with giant aneurysms.

Prophylactic Pulmonary Artery Reduction in a Young Female with Severe Pulmonary Hypertension from Complete Atrioventricular Septal Defect.

Management of severely dilated pulmonary artery (PA) associated with severe pulmonary hypertension from congenital heart disease remains controversial, primarily due to its rare nature and concern for perioperative unpredictable complications. Herein, we report a 25 year-old female with a severely dilated PA (up to 73 mm), who was successfully treated by a PA graft replacement by creating a Y-shaped conduit using a 28 mm hemashield tube in the main PA and a 20 mm hemashield tube in both proximal parts of the branch PA.

Congenital heart disease at Laos Children's Hospital: Two year experience.

BACKGROUND: Management of congenital heart disease (CHD) in developing countries is challenging because of limited access to health-care facilities and socioeconomic limitations. The aim of this study was to describe the recent experience with CHD at Children's Hospital, Vientiane, Laos, the only pediatric referral hospital in the country. METHODS: From July 2013 to November 2015, 1009 echocardiograms were carried out in 797 individuals who visited Children's Hospital, in whom CHD was identified in 213. Demographic characteristics, echocardiography and age at first CHD diagnosis on echocardiogram were compared by residential area. RESULTS: Among the 213 patients, the most frequent anomalies, in descending order, were ventricular septal defect, atrial septal defect, patent ductus arteriosus, and tetralogy of Fallot. Moderate or severe CHD requiring surgery or intervention was detected in 137 patients; median age at initial diagnosis was 6.0 months (IQR, 1.5-29.8). Among those with moderate or severe CHD, 89 patients were from rural areas and 48 from the capital area. The proportion of patients from rural areas older than 1 and 3 years at diagnosis was 46.1% and 32.6%, respectively. In contrast, patients from the capital area were diagnosed at a significantly earlier age: 16.7% at age >1 year and 6.2% at age >3 years (both P < 0.001 vs rural areas). CONCLUSIONS: Diagnosis of CHD requiring surgery is delayed in Laos, especially in rural areas. Better education and training of local medical staff, and greater access to medical advice are required to improve CHD care in Laos.

Impaired Vascular Function of the Aorta in Adolescents with Turner Syndrome.

To investigate intrinsic vascular abnormalities of the ascending aorta before adulthood in Turner syndrome patients (TS), we compared 25 adolescent TS patients (mean age 14.6 ± 3.4 years) and 16 healthy controls from a university hospital. Blood pressure and other vascular indices were evaluated using echocardiography such as aortic strain, stiffness index, distensibility, and pulse wave velocity. Aortic strain (0.1237 vs. 0.1865, respectively; P = 0.003) and aortic distensibility (0.0049 vs. 0.0081, P = 0.002) were significantly lower in the TS group than in the controls. The fractional area change on velocity vector imaging was also lower in TS patients (29.05 vs. 36.19, P = 0.002). These findings were still observed after adjustment for age, body mass index, and systolic blood pressure. The aortic stiffness index was greater in the TS patients than in the control group (6.79 vs. 3.34, P = 0.02). The pulse wave velocity and ascending aorta diameter did not significantly differ between the TS and control groups. Blood pressures were significantly higher in the TS patients than in the controls (systolic, 120.4 vs. 108.4 mmHg, P = 0.001; diastolic 71.5 vs. 61.7 mmHg, P < 0.001). Although the dimensional changes in the aorta were not clearly observed in adolescents with TS, the elastic properties of the aorta were significantly decreased in TS patients as compared to control subjects.

Idiopathic midaortic syndrome with malignant hypertension in 3-year-old boy.

Midaortic syndrome (MAS) is a rare vascular disease that commonly causes renovascular hypertension. The lumen of the abdominal aorta narrows and the ostia of the branches show stenosis. MAS is associated with diminished pulses in the lower extremities compared with the upper extremities, severe hypertension with higher blood pressure in the upper rather than lower extremities, and an abdominal bruit. The clinical symptoms are variable, and recognition in children with hypertension can aid early diagnosis and optimal treatment. Hypertension with MAS is malignant and often refractory to several antihypertensive drugs. Recently, radiologic modalities have been developed and have led to numerous interventional procedures. We describe the case of a 3-year-old boy presenting with left ventricular hypertrophy whose severely elevated blood pressure led to the diagnosis of idiopathic MAS. This case highlights the importance of measuring blood pressure and conducting a detailed physical examination to diagnose MAS. This is the first reported case of idiopathic MAS diagnosed in childhood in Korea.

Long-Term Outcomes of Pulmonary Hypertension in Preterm Infants with Bronchopulmonary Dysplasia.

BACKGROUND: The long-term cardiovascular outcomes of pulmonary hypertension (PH) in preterm infants with bronchopulmonary dysplasia (BPD) are uncertain. OBJECTIVES: The purpose of this study was to assess outcomes of PH in prematurely born children diagnosed with moderate to severe BPD. METHODS: We retrospectively reviewed the medical records of patients born before 32 weeks of gestation and diagnosed with moderate to severe BPD from June 2004 to April 2008. Patients were recruited for a cross-sectional study from August to October 2014 and underwent echocardiography. RESULTS: Forty-two children were enrolled. Their mean gestational age and birth weight were 26.2 ± 1.7 weeks and 753.1 ± 172.5 g, respectively. Sixteen patients (38%) were diagnosed with PH at a mean age of 3.3 ± 1.6 months, and the PH improved after a median of 12.3 months (range 0.7-46.6). Cardiovascular function was reassessed at a mean age of 7.7 ± 0.9 years, at which time 1 patient was taking a medication for recurrent PH, and 12 (28.6%) patients exhibited elevated blood pressure. Conventional 2-dimensional and Doppler echocardiography indicated normal ventricular function in all children. However, right ventricular longitudinal strains were decreased in children with previous PH. CONCLUSIONS: Subclinical ventricular dysfunction was detectable using sensitive echocardiographic techniques in children with previous BPD-associated PH. Long-term follow-up and meticulous cardiovascular function assessment are required in this population.

Infantile Marfan syndrome in a Korean tertiary referral center.

PURPOSE: Infantile Marfan syndrome (MFS) is a rare congenital inheritable connective tissue disorder with poor prognosis. This study aimed to evaluate the cardiovascular manifestations and overall prognosis of infantile MFS diagnosed in a tertiary referral center in Korea. METHODS: Eight patients diagnosed with infantile MFS between 2004 and 2014 were retrospectively evaluated. RESULTS: Their median age at the time of diagnosis was 2.5 months (range, 0-20 months). The median follow-up period was 25.5 months (range, 0-94 months). The median length at birth was 50.0 cm (range, 48-53 cm); however, height became more prominent over time, and the patients were taller than the 97th percentile at the time of the study. None of the patients had any relevant family history. Four of the 5 patients who underwent DNA sequencing had a fibrillin 1 gene mutation. All the patients with echocardiographic data of the aortic root had a z score of >2. All had mitral and tricuspid valve prolapse, and various degrees of mitral and tricuspid regurgitation. Five patients underwent open-heart surgery, including mitral valve replacement, of whom two required multiple operations. The median age at mitral valve replacement was 28.5 months (range, 5-69 months). Seven patients showed congestive heart failure before surgery or during follow-up, and required multiple anti-heart failure medications. Four patients died of heart failure at a median age of 12 months. CONCLUSION: The prognosis of infantile MFS is poor; thus, early diagnosis and timely cautious treatment are essential to prevent further morbidity and mortality.

Complications of Cardiac Catheterization in Structural Heart Disease.

BACKGROUND AND OBJECTIVES: Cardiac catheterization is used to diagnose structural heart disease (SHD) and perform transcatheter treatment. This study aimed to evaluate complications of cardiac catheterization and the associated risk factors in a tertiary center over 10 years. SUBJECTS AND METHODS: Total 2071 cardiac catheterizations performed at the Seoul National University Children's Hospital from January 2004 to December 2013 were included in this retrospective study. RESULTS: The overall complication, severe complication, and mortality rates were 16.2%, 1.15%, and 0.19%, respectively. The factors that significantly increased the risk of overall and severe complications were anticoagulant use before procedure (odds ratio [OR] 1.83, p=0.012 and OR 6.45, p<0.001, respectively), prothrombin time (OR 2.30, p<0.001 and OR 5.99, p<0.001, respectively), general anesthesia use during procedure (OR 1.84, p=0.014 and OR 5.31, p=0.015, respectively), and total procedure time (OR 1.01, p<0.001 and OR 1.02, p<0.001, respectively). Low body weight (OR 0.99, p=0.003), severe SHD (OR 1.37, p=0.012), repetitive procedures (OR 1.7, p=0.009), and total fluoroscopy time (OR 1.01, p=0.005) significantly increased the overall complication risk. High activated partial thromboplastin time (OR 1.04, p=0.001), intensive care unit admission state (OR 14.03, p<0.001), and concomitant electrophysiological study during procedure (OR 3.41, p=0.016) significantly increased severe complication risk. CONCLUSION: Currently, the use of cardiac catheterization in SHD is increasing and becoming more complex; this could cause complications despite the preventive efforts. Careful patient selection for therapeutic catheterization and improved technique and management during the peri-procedural period are required to reduce complications.

Alagille syndrome and a JAG1 mutation: 41 cases of experience at a single center.

PURPOSE: Alagille syndrome is a complex hereditary disorder that is associated with cardiac, hepatic, skeletal, ocular, and facial abnormalities. Mutations in the Notch signaling pathway, such as in JAG1 and NOTCH2, play a key role in embryonic development. A cardiac or hepatic presentation is a critical factor for determining the prognosis. METHODS: We conducted a retrospective study of 41 patients with Alagille syndrome or a JAG1 mutation between 1983 and 2013. RESULTS: The first presentations were jaundice, murmur, cyanosis, and small bowel obstruction at a median age of 1.0 months (range, 0-24 months). The JAG1 mutation was found in 27 of the 28 genetically-tested patients. Cardiovascular anomalies were identified in 36 patients, chronic cholestasis was identified in 34, and liver transplantation was performed in 9. There was no significant correlation between the severity of the liver and cardiac diseases. The most common cardiovascular anomaly was peripheral pulmonary stenosis (83.3%), with 13 patients having significant hemodynamic derangement and 12 undergoing surgical repair. A total bilirubin level of >15 mg/dL with a complex surgical procedure increased the surgical mortality (P=0.022). Eight patients died after a median period of 2.67 years (range, 0.33-15 years). The groups with fetal presentation and with combined severe liver and heart disease had the poorest survival (P<0.001). CONCLUSION: The group with combined severe liver and heart disease had the poorest survival, and a multidisciplinary approach is necessary to improve the outcome.

Ruptured Tricuspid Valve Papillary Muscle in a Neonate with Intractable Persistent Fetal Circulation.

Unguarded tricuspid regurgitation (TR) due to a flail tricuspid leaflet is a rare condition of newborn cyanosis. A high perinatal mortality has been associated with this fatal condition. But, there are feasible surgical repairs to improve survival. We report the case of a male full-term neonate with intractable hypoxia. He had profound tricuspid insufficiency and leaflet prolapse caused by a ruptured papillary muscle supporting the anterior leaflet of the tricuspid valve. He presented with severe cyanosis and respiratory distress immediately after birth. Despite medical management, the pulmonary vascular resistance was not decreased and a low cardiac output persisted. Initial stabilization was accomplished with nitric oxide and extracorporeal membrane oxygenation. The tricuspid valve repair surgery was successfully performed subsequently. TR resulting from papillary muscle rupture is a potentially lethal condition. Timely diagnosis and proper surgical treatment can be lifesaving.

The strong association of left-side heart anomalies with Kabuki syndrome.

PURPOSE: Kabuki syndrome is a multiple congenital malformation syndrome, with characteristic facial features, mental retardation, and skeletal and congenital heart anomalies. However, the cardiac anomalies are not well described in the Korean population. We analyzed the cardiac anomalies and clinical features of Kabuki syndrome in a single tertiary center. METHODS: A retrospective analysis was conducted for a total of 13 patients with Kabuki syndrome. RESULTS: The median age at diagnosis of was 5.9 years (range, 9 days to 11 years and 8 months). All patients showed the characteristic facial dysmorphisms and congenital anomalies in multiple organs, and the diagnosis was delayed by 5.9 years (range, 9 days to 11 years and 5 months) after the first visit. Noncardiac anomalies were found in 84% of patients, and congenital heart diseases were found in 9 patients (69%). All 9 patients exhibited left-side heart anomalies, including hypoplastic left heart syndrome in 3, coarctation of the aorta in 4, aortic valve stenosis in 1, and mitral valve stenosis in 1. None had right-side heart disease or isolated septal defects. Genetic testing in 10 patients revealed 9 novel MLL2 mutations. All 11 patients who were available for follow-up exhibited developmental delays during the median 4 years (range, 9 days to 11 years 11 months) of follow-up. The leading cause of death was hypoplastic left heart syndrome. CONCLUSION: Pediatric cardiologist should recognize Kabuki syndrome and the high prevalence of left heart anomalies with Kabuki syndrome. Genetic testing can be helpful for early diagnosis and counseling.

Intra-atrial reentrant tachycardia in adult patients after Fontan operation.

BACKGROUND: Atrial tachyarrhythmia is a major late complication in adult Fontan patients. This study examined the clinical features and risk factors of late intra-atrial reentrant tachyarrhythmia (IART) in adult patients after Fontan surgery and the mid-term outcome of Fontan conversion with or without antiarrhythmic surgery in these patients. METHODS: We conducted a retrospective study on adult patients who were born before 1994 and survived at least 3 months after a Fontan operation at Seoul National University Children's Hospital. RESULTS: We followed 160 patients over 20.9 ± 4.1 years. Sustained atrial tachycardia was identified in 51 patients, and IART was found in 41, appearing a mean 13.6 years after surgery. By the 25 year follow-up, 40% had developed IART. The incidence of IART significantly increased over time. Patients with an atriopulmonary connection (APC) (n=65) had significantly longer follow-up duration and higher incidence of IART than patients with a lateral tunnel (n=86) or extracardiac conduit Fontan (n=9). On multivariate analysis, APC, sinus node dysfunction, and nonsustained atrial tachycardia were found to be significantly associated with IART. Twenty-four patients with IART underwent Fontan conversion. Over the follow-up period, IART severity scores in the 22 patients who survived after Fontan conversion decreased significantly, and New York Heart Association functional class significantly improved. On multivariate analysis, protein losing enteropathy and ventricular dysfunction were found to be significant risk factors for mortality. CONCLUSIONS: IART was common in adult Fontan patients, and Fontan conversion with or without antiarrhythmic surgery and pacemaker placement helped to control it.

Safety and efficacy of the off-label use of milrinone in pediatric patients with heart diseases.

BACKGROUND AND OBJECTIVES: Milrinone is often used in children to treat acute heart failure and prevent low cardiac output syndrome after cardiac surgery. Due to the lack of studies on the long-term milrinone use in children, the objective of this study was to assess the safety and efficacy of the current patterns of milrinone use for ≥3 days in infants and children with heart diseases. SUBJECTS AND METHODS: We retrospectively reviewed the medical records of patients aged <13 years who received milrinone for ≥3 days from January 2005 to December 2012. Patients' characteristics including age, sex, height, weight, and body surface area were recorded. The following parameters were analyzed to identify the clinical application of milrinone: initial infusion rate, maintenance continuous infusion rate, total duration of milrinone therapy, and concomitantly infused inotropes. The safety of milrinone was determined based on the occurrence of adverse events such as hypotension, arrhythmia, chest pain, headache, hypokalemia, and thrombocytopenia. RESULTS: We assessed 730 admissions (684 patients) during this period. Ventricular septal defects were the most common diagnosis (42.4%) in these patients. Milrinone was primarily used after cardiac surgery in 715 admissions (97.9%). The duration of milrinone treatment varied from 3 to 64.4 days (≥7 days in 149 admissions). Ejection fraction and fractional shortening of the left ventricle improved in patients receiving milrinone after cardiac surgery. Dose reduction of milrinone due to hypotension occurred in only 4 admissions (0.5%). Although diverse arrhythmias occurred in 75 admissions (10.3%), modification of milrinone infusion to manage arrhythmia occurred in only 3 admissions (0.4%). Multivariate analysis indicated that the development of arrhythmia was not influenced by the pattern of milrinone use. CONCLUSION: Milrinone was generally administered for ≥3 days in children with heart diseases. The use of milrinone for ≥3 days was effective in preventing low cardiac output after cardiac surgery when combined with other inotropes, suggesting that milrinone could be safely employed in pediatric patients with heart diseases.