Left ventricular non-compaction in paediatrics: a novel semi-automated imaging technique bridging imaging findings and clinical outcomes.

AIMS: We set out to design a reliable, semi-automated, and quantitative imaging tool using cardiac magnetic resonance (CMR) imaging that captures LV trabeculations in relation to the morphologic endocardial and epicardial surface, or perimeter-derived ratios, and assess its diagnostic and prognostic utility. METHODS AND RESULTS: We queried our institutional database between January 2008 and December 2018. Non-compacted (NC)-to-compacted (C) (NC/C) myocardium ratios were calculated and our tool was used to calculate fractal dimension (FD), total mass ratio (TMR), and composite surface ratios (SRcomp). NC/C, FD, TMR, and SRcomp were assessed in relation to LVNC diagnosis and outcomes. Univariate hazard ratios with cut-offs were performed using clinically significant variables to find 'at-risk' patients and imaging parameters were compared in 'at-risk' patients missed by Petersen Index (PI). Ninety-six patients were included. The average time to complete the semi-automated measurements was 3.90 min (SEM: 0.06). TMR, SRcomp, and NC/C were negatively correlated with LV ejection fraction (LVEF) and positively correlated with indexed LV end-systolic volumes (iLVESVs), with TMR showing the strongest correlation with LVEF (-0.287; P = 0.005) and SRcomp with iLVESV (0.260; P = 0.011). We found 29 'at-risk' patients who were classified as non-LVNC by PI and hence, were missed. When compared with non-LVNC and 'low-risk' patients, only SRcomp differentiated between both groups (1.91 SEM 0.03 vs. 1.80 SEM 0.03; P = 0.019). CONCLUSION: This method of semi-automatic calculation of SRcomp captured changes in at-risk patients missed by standard methods, was strongly correlated with LVEF and LV systolic volumes and may better capture outcome events.

Early detection of myocardial changes with and without dexrazoxane using serial magnetic resonance imaging in a pre-clinical mouse model.

BACKGROUND: Cancer therapy-related cardiac dysfunction may occur in pediatric cancer survivors. Identification of early markers of myocardial damage secondary to anthracycline exposure is crucial to develop strategies that may ameliorate this complication. OBJECTIVES: The purpose of this study was to identify early myocardial changes induced by doxorubicin with and without cardioprotection using dexrazoxane detected by serial cardiac magnetic resonance imaging (CMR) in a pre-clinical mouse model. METHODS: Serial CMR examinations were performed in 90 mice distributed in 3 groups: 45 received doxorubicin (DOX group), 30 mice received doxorubicin with dexrazoxane (DOX/DEX group) and 15 mice received saline injections (control group). We obtained the following CMR parameters in all mice: T2, extracellular volume quantification (ECV), myocardial deformation, and functional quantification. RESULTS: Myocardial edema assessed by T2 time was the earliest parameter demonstrating evidence of myocardial injury, most notable in the DOX group at week 4 and 8 compared with DOX/DEX group. Similarly, global longitudinal strain was abnormal in both the DOX and DOX/DEX groups. However, this change persisted only in the DOX group. The ECV was significantly elevated in the DOX group at the final CMR, while only minimally elevated in the DOX/DEX group. The right and left ejection fraction was decreased, along with the mass to volume ratio in the DOX group. The T2 time, ECV, and deformation correlated with ejection fraction and left ventricular volume. CONCLUSIONS: T2 time and deformation by CMR identifies early myocardial injury from anthracyclines. Dexrazoxne did not prevent the initial edema, but the inflammatory changes were not sustained. CMR may be useful for early detection of cardiac dysfunction. Serial CMR demonstrates dexrazoxane minimizes cardiac dysfunction and aids recovery in a mouse model.

Dobutamine stress cardiac MRI is safe and feasible in pediatric patients with anomalous aortic origin of a coronary artery (AAOCA).

BACKGROUND: Risk stratification in anomalous aortic origin of a coronary artery (AAOCA) is challenged by the lack of a reliable method to detect myocardial ischemia. We prospectively studied the safety and feasibility of Dobutamine stress-cardiac magnetic resonance (DSCMR), a test with excellent performance in adults, in pediatric patients with AAOCA. METHODS: Consecutive DSCMR from 06/2014-12/2019 in patients≤20 years old with AAOCA were included. Hemodynamic response and major/minor events were recorded. Image quality and spatial/temporal resolution were evaluated. Rest and stress first-pass perfusion and wall motion abnormalities (WMA) were assessed. Inter-observer agreement was assessed using kappa coefficient. RESULTS: A total of 224 DSCMR were performed in 182 patients with AAOCA at a median age of 14 years (IQR 12, 16) and median weight of 58.0 kg (IQR 43.3, 73.0). Examinations were completed in 221/224 (98.9%), all studies were diagnostic. Heart rate and blood pressure increased significantly from baseline (p < 0.001). No patient had major events and 28 (12.5%) had minor events. Inducible hypoperfusion was noted in 31/221 (14%), associated with WMA in 13/31 (42%). Inter-observer agreement for inducible hypoperfusion was very good (Κ = 0.87). Asymptomatic patients with inducible hypoperfusion are considered high-risk and those with a negative test are of standard risk. CONCLUSIONS: DSCMR is feasible in pediatric patients with AAOCA to assess for inducible hypoperfusion and WMA. It can be performed safely with low incidence of major/minor events. Thus, DSCMR is potentially a valuable test for detection of myocardial ischemia and helpful in the management of this patient population.

Decreased Quality of Life in Children With Anomalous Aortic Origin of a Coronary Artery.

BACKGROUND: Anomalous aortic origin of a coronary artery (AAOCA) is associated with sudden death in the young. We sought to determine quality of life (QOL) in patients/families affected by AAOCA. METHODS: Patients with AAOCA (8-18 years) were prospectively included from January 2016 to May 2017. Parent proxy and patient Pediatric Cardiac Quality of Life Inventory (PCQLI) were used to evaluate QOL and Pediatric Quality of Life Inventory (PedsQL) Family Impact Module to assess the impact of AAOCA on families, as primary outcomes. Secondary outcomes included peer relationship, anxiety, and depression assessed using patient-reported outcomes measurement information system. Patients deemed high-risk were offered surgery/exercise restriction. Generalized linear mixed regression models were used to determine significant predictors of outcomes. RESULTS: Fifty-three patients, the majority (n = 31, 59%) unrepaired, and 49 caregivers were included. Using PCQLI, patient and parent proxy QOL scores were similar to published scores for children with long-QT syndrome. Patients' QOL score was associated with exertional symptoms, perceived chronic disease, and altered parent's concentration ability. Likewise, parent proxy QOL scores were associated with mother's living situation, exertional symptoms, parent missing work for ≥1 day, and disturbed parental functioning at work. Family impact scores were associated with lower maternal education, among other measures. Risk categories or surgical status did not impact patient, parent proxy reported, or family impact QOL. CONCLUSION: Anomalous aortic origin of a coronary artery is associated with decreased QOL as perceived by patients and caregiver and is associated with numerous facets of family functioning. These findings are independent of risk categorization or surgical status.

Beta-Blockade in Intraseptal Anomalous Coronary Artery With Reversible Myocardial Ischemia.

Anomalous aortic origin of a left coronary artery (L-AAOCA) with an intraseptal course is a rare anomaly and can be associated with myocardial ischemia and sudden cardiac death. No surgical or medical intervention is known to improve patient outcomes. A 7-year-old boy with intraseptal L-AAOCA presented with nonexertional chest pain, syncope, and had reversible myocardial ischemia on provocative testing. The patient was started on ß-blockade, following which his symptoms improved and resolved over a period of six years. A follow-up dobutamine stress magnetic resonance imaging no longer showed reversible ischemia, and cardiac catheterization with fractional flow reserve did not show coronary flow compromise.

Impaired Myocardial Perfusion on Stress CMR Correlates With Invasive FFR in Children With Coronary Anomalies.

BACKGROUND: Invasive fractional flow reserve (FFR) is considered the gold standard to evaluate coronary artery flow. Stress cardiovascular magnetic resonance (sCMR) is an emerging non-invasive tool to evaluate myocardial perfusion in children. We sought to compare sCMR with FFR to determine impaired intracoronary flow in children with anomalous aortic origin of a coronary artery (AAOCA) and/or myocardial bridge (MB) who presented concern for myocardial ischemia. METHODS: From December 2012 to May 2019, AAOCA and/or MB patients (<20 years old) were prospectively enrolled and underwent sCMR and FFR. Abnormal sCMR included perfusion/regional wall-motion abnormality in the involved coronary distribution. FFR was performed at baseline and with dobutamine/regadenoson and considered abnormal if <0.8 in the affected coronary segment. RESULTS: Of 376 patients evaluated, a total of 19 (age range, 0.2-17 years) underwent 24 sets of sCMR and FFR studies, with 5 repeat studies following intervention. Types of anomalies included 6 isolated MB/normal CA origins, 5 single CAs, 5 left AAOCAs, and 3 right AAOCAs. Seventeen patients (89.5%) had MB/intramyocardial course - 14 involving the left anterior descending coronary artery and 3 with multivessel involvement. sCMR correlated with FFR in 19/24 sets (7 sCMR and FFR positive, 12 sCMR and FFR negative) and it did not correlate in 5/24 sets. The positive percent agreement was 77.8%, negative percent agreement was 80.0%, and overall percent agreement was 79.2%. CONCLUSIONS: Assessment of myocardial perfusion using non-invasive sCMR concurred with FFR, particularly if performed with close proximity in time, and may contribute to risk stratification and decision making in children with AAOCA and/or MB.

Assessing the left atrium of childhood cancer survivors.

Survivors of childhood cancer are at risk of cancer therapy-related cardiac dysfunction (CTRCD) characterized by systolic impairment, with little known about diastolic function. Left atrial strain (LAS) is a surrogate measure of left ventricular filling. We hypothesized that survivors (1) have lower LAS versus controls, and (2) survivors exposed to higher anthracycline dosage have even lower LAS. Cross-sectional study of 45 survivors exposed to anthracyclines ≥ 1 year after chemotherapy and 45 healthy controls. Echo variables included mitral spectral and tissue Doppler, left ventricular ejection fraction (LV EF), LV dimension, LA volume, LV global longitudinal strain (GLS), and LAS. Peak strain (Ɛ) and strain rate (SR) at three phases were obtained: atrial contraction (ac), reservoir (res), and conduit (con). Two sub-analyses of cancer survivors were performed: (1) those with anthracycline dosage ≥ 250 mg/m2, and (2) those with Ɛres in the lowest quartile. On the whole, survivors had lower Ɛres and Ɛcon values. The majority of survivors had relatively normal LAS, while a subset had very low LAS values and were more likely to be older. Survivors exposed to ≥ 250 mg/m2 anthracycline also had lower Ɛres than those < 250 mg/m2. There were no differences in mitral spectral/tissue Doppler, LV dimension, left atrial volume, or GLS. A subset of childhood cancer survivors have lower LAS than their healthy counterparts, while most are essentially normal. Those exposed to higher anthracycline dosage have even lower Ɛres. Longitudinal study of LAS may prove useful in monitoring for CTRCD.

Myocardial Ischemia in Children With Anomalous Aortic Origin of a Coronary Artery With Intraseptal Course.

BACKGROUND: Intraseptal anomalous aortic origin of a coronary artery is considered a benign condition. However, there have been case reports of patients with myocardial ischemia, arrhythmia, and sudden cardiac death. The purpose of this study was to determine the clinical presentation, myocardial perfusion on provocative stress testing, and management of children with anomalous aortic origin of a coronary artery with an intraseptal course in a prospective cohort. METHODS: Patients with anomalous aortic origin of a coronary artery and intraseptal course were prospectively enrolled from December 2012 to May 2019, evaluated, and managed following a standardized algorithm. Myocardial perfusion was assessed using stress imaging. Fractional flow reserve was performed in patients with myocardial hypoperfusion on noninvasive testing. Exercise restriction, ß-blockers, and surgical intervention were discussed with the families. RESULTS: Eighteen patients (female 6, 33.3%), who presented with no symptoms (10, 55.6%), nonexertional (4, 22.2%), and exertional symptoms (4, 22.2%), were enrolled at a median age of 12.4 years (0.3-15.9). Perfusion imaging was performed in 14/18 (77.8%) and was abnormal in 7/14 (50%); fractional flow reserve was positive in 5/8 (62.5%). All 4 patients with exertional symptoms and 3/10 (30%) with no or nonexertional symptoms had myocardial hypoperfusion. Coronary artery bypass grafting was performed in a 4-year-old patient; ß-blocker and exercise restriction were recommended in 4 patients not suitable for surgery. One patient had nonexertional chest pain and 17 were symptom-free at median follow-up of 2.5 years (0.2-7.1). CONCLUSIONS: Up to 50% of patients with intraseptal anomalous aortic origin of a coronary artery had inducible myocardial hypoperfusion during noninvasive provocative testing. Long-term follow-up is necessary to understand the natural history of this rare anomaly.

Outcomes in Anomalous Aortic Origin of a Coronary Artery Following a Prospective Standardized Approach.

BACKGROUND: Anomalous aortic origin of a coronary artery (CA) is the second leading cause of sudden cardiac death in young athletes. Management is controversial and longitudinal follow-up data are sparse. We aim to evaluate outcomes in a prospective study of anomalous aortic origin of CA patients following a standardized algorithm. METHODS: Patients with anomalous aortic origin of a CA were followed prospectively from December 2012 to April 2017. All patients were evaluated following a standardized algorithm, and data were reviewed by a dedicated multidisciplinary team. Assessment of myocardial perfusion was performed using stress imaging. High-risk patients (high-risk anatomy-anomalous left CA from the opposite sinus, presence of intramurality, abnormal ostium-and symptoms or evidence of myocardial ischemia) were offered surgery or exercise restriction (if deemed high risk for surgical intervention). Univariate and multivariable analyses were used to determine predictors of high risk. RESULTS: Of 201 patients evaluated, 163 met inclusion criteria: 116 anomalous right CA (71%), 25 anomalous left CA (15%), 17 single CA (10%), and 5 anomalous circumflex CA (3%). Patients presented as an incidental finding (n=80, 49%), with exertional (n=31, 21%) and nonexertional (n=32, 20%) symptoms and following sudden cardiac arrest/shock (n=5, 3%). Eighty-two patients (50.3%) were considered high risk. Predictors of high risk were older age at diagnosis, black race, intramural course, and exertional syncope. Most patients (82%) are allowed unrestrictive sports activities. Forty-seven patients had surgery (11 anomalous left CA and 36 anomalous right CA), 3 (6.4%) remained restricted from sports activities. All patients are alive at a median follow-up of 1.6 (interquartile range, 0.7-2.8) years. CONCLUSIONS: In this prospective cohort of patients with anomalous aortic origin of a CA, most have remained free of exercise restrictions. Development of a multidisciplinary team has allowed a consistent approach and may have implications in risk stratification and long-term prognosis.

Regadenoson Stress Perfusion Cardiac Magnetic Resonance Imaging in Children With Kawasaki Disease and Coronary Artery Disease.

Coronary artery (CA) stenosis and occlusion in convalescent Kawasaki disease (KD) is progressive and may result in myocardial infarction. The use of regadenoson, a strong selective CA vasodilator with low side effect profile, for stress cardiac magnetic resonance (CMR) imaging has not been studied in children with KD. The safety, feasibility, and diagnostic utility of regadenoson stress CMR was assessed in children with KD and CA abnormalities. A retrospective review of regadenoson stress CMR in children with convalescent KD was performed. Hemodynamics changes after regadenoson administration and adverse effects were recorded. First-pass perfusion was evaluated at rest and during pharmacologic stress. The results were compared with anatomic CA imaging. Forty-one stress CMR (18 sedated examinations, 44%) were performed successfully in 32 patients. Median age was 11.2 years (range 2.2 to 18.6) and weight 41 kg (range 13 to 93.4). Heart rate increased 66 ± 25% (p <0.005) after regadenoson. Minor adverse events occurred in 6 sedated and 1 unsedated patients. Hypoperfusion during stress occurred in 16 of 41 (39%), including 5 inducible, 9 inducible and fixed, and 2 fixed lesions. Late gadolinium enhancement was present in 10 of 16 with hypoperfusion and in 1 without hypoperfusion. Stress CMR had 100% positive agreement and >90% negative and overall agreement with moderate-to-severe CA stenoses. Four patients with hypoperfusion underwent revascularization for severe CA stenoses. In conclusion, regadenoson stress CMR is hemodynamically safe and feasible in children with KD and CA disease. It has excellent agreement with CA angiography and aided decision-making to proceed with revascularization.

Free-breathing Cardiorespiratory Synchronized Cine MRI for Assessment of Left and Right Ventricular Volume and Function in Sedated Children and Adolescents with Impaired Breath-holding Capacity.

PURPOSE: To prospectively compare left ventricular and right ventricular volume, function, and image quality of a free-breathing (FB) cardiorespiratory synchronized balanced steady-state free precession cine MRI sequence with that of a standard of reference breath-hold (BH) technique in sedated children and adolescents who are unable to perform BHs. MATERIALS AND METHODS: Cohort 1 included 30 patients able to perform BHs (mean age, 19 years; age range, 9-69 years). Cohort 1 underwent both BH and FB cine short-axis imaging with identical acquisition parameters. Cohort 2 included 63 patients unable to perform BHs (50 sedated patients [mean age, 9 years; age range, 4 months to 28 years], 13 unsedated patients [mean age, 21 years; age range, 8-58 years]). Cohort 2 underwent FB cine imaging in multiple views with spatiotemporal resolution equivalent to BH imaging. Comparative quantitative analysis was performed for left ventricular and right ventricular volumes in cohort 1 and for qualitative image quality scores in all patients. RESULTS: Global left ventricular and right ventricular volumetric indexes and image quality scores were comparable between BH and FB sequences in cohort 1. FB image quality was graded as excellent (37 sequences), good (197 sequences), adequate (26 sequences), and suboptimal (three sequences) for 263 cine sequences in cohort 2. In cohort 1, de facto image acquisition time for FB (6.1 minutes ± 1.9 [standard deviation]) was comparable to the equivalent for BH (6.1 minutes ± 2.6) for a stack of 14 sections. CONCLUSION: In cohorts of sedated children, adolescents, and young adults unable to perform BHs consistently, left ventricular and right ventricular volumes and function were comparable and image quality was noninferior between FB and standard of reference BH techniques.© RSNA, 2019.

Myocardial Stress Perfusion MRI Using Regadenoson: A Weight-based Approach in Infants and Young Children.

PURPOSE: To determine the safety and feasibility of stress cardiac MRI by using weight-based dosing of regadenoson in patients less than 40 kg and whether stress cardiac MRI affects patient management. MATERIALS AND METHODS: All patients less than 40 kg undergoing stress cardiac MRI by using weight-based dosing (8 µg/kg) of regadenoson were included in this retrospective single-center study. Hemodynamic response, adverse events, and cardiac MRI abnormalities in myocardial perfusion, wall motion, and delayed enhancement were evaluated. Patient management based on the results of the stress cardiac MRI were evaluated. RESULTS: Forty-six consecutive stress cardiac MRI examinations were performed in 36 patients (median age, 9.0 years; age range, 2 months to 13.9 years) with congenital and acquired heart disease. Thirty-one of 46 (67.4%) studies were performed with the use of sedation. A myocardial perfusion defect was present in 20 of 46 (43.5%) studies, five with inducible defects only, and the remaining 15 with fixed or irreversible defects. In the 46 total studies, there were no major adverse events and nine (19.6%) minor adverse events including emesis (n = 1) and transient hypotension requiring pharmacologic intervention in eight patients who were all sedated. Sedation was an independent predictor for hypotension (P =.040). Twenty-six negative studies had no coronary interventions performed, and of the 20 positive studies, 15 were referred for catheterization, eight of which underwent coronary interventions. CONCLUSION: Weight-based dosing of regadenoson for stress cardiac MRI was safe and feasible in infants and young children and played an integral role in the outcome and treatment decisions for children with coronary artery disease.© RSNA, 2019.

Myocardial Stress Perfusion MRI: Experience in Pediatric and Young-Adult Patients Following Arterial Switch Operation Utilizing Regadenoson.

Dextro-transposition of the great arteries (D-TGA) is one of the most common cyanotic heart lesions. The arterial switch operation (ASO) is the preferred surgical palliation for D-TGA. One of the primary concerns following the ASO is complications arising from the coronary artery transfer. There is a need for myocardial perfusion assessment within ASO patients. There is no report on the utility of regadenoson as a stress agent in children following ASO. Our objective was to observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric and young-adult patients who have undergone ASO. We reviewed our initial experience with regadenoson stress cardiac MR in 36 pediatric and young-adult patients 15.1 ± 4.5 years (range 0.2-22 years) with history of ASO. The weight was 61.6 ± 21.5 kg (range 3.8-93 kg). All patients underwent cardiac MR because of concern for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. All stress cardiac MR examinations were completed without adverse events. Resting heart rate was 72 ± 13 beats per minute (bpm) and rose to peak of 120 ± 17 bpm (95 ± 50% increase, p < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. A total of 11/36 (31%) patients had a perfusion defect on the stress FPP images. 14 of the 36 patients (39%) underwent cardiac catheterization within 6 months of the CMR and the findings showed excellent agreement. Regadenoson may be a useful coronary hyperemia agent to utilize for pediatric patients following arterial switch procedure when there is concern for ischemia. The ability to administer as a single bolus with one IV makes it advantageous in pediatrics. In a limited number of cases, regadenoson stress perfusion showed excellent agreement with cardiac catheterization.

Post-operative Assessment of the Arterial Switch Operation: A Comparison of Magnetic Resonance Imaging and Echocardiography.

After an arterial switch operation (ASO), serial imaging is necessary to monitor for maladaptive changes. We compared cardiac magnetic resonance imaging (CMR) to 2-D transthoracic echocardiography (TTE) in assessing post-operative ASO patients. We performed a retrospective review of patients at a single tertiary care center who underwent an ASO and subsequently had a CMR performed from 7/2010 to 7/2016. Those with single ventricle anatomy, congenitally corrected transposition of the great arteries, or previous atrial switch operation were excluded. TTE obtained within 6 months of the CMR was used for comparison. Parameters compared included ventricular size and systolic function, semilunar valve regurgitation, neo-aortic root dimension, and the presence of branch pulmonary artery (PA) stenosis (on CMR by the Nakata index or right/left flow differential; on TTE by peak velocity > 2 m/s or PA diameter Z score < - 2). Forty-seven patients with 90 CMR and 86 TTE studies met inclusion criteria. CMR and TTE assessment of right ventricular (RV) and left ventricular function did not statistically differ. RV dilation was overdetected by TTE (p = 0.046). Right pulmonary artery and left pulmonary artery (LPA) visualization by TTE was worse than CMR (p < 0.01). There was no statistically significant difference between CMR and TTE assessment of branch PA stenosis; however, there was poor agreement between the use of Z score and velocity when determining branch PA stenosis by TTE (κ < 0). Assessment of neo-pulmonary regurgitation (PR) and neo-aortic regurgitation (AR) was significantly different between CMR and TTE (p < 0.05). Assessment for delayed enhancement was performed in 18% of CMR studies (n = 16), with perfusion defects appreciated in three patients. Substantial differences between CMR and TTE exist when examining the post-operative ASO patient. CMR was superior for evaluation of the branch PAs, which commonly require re-intervention. TTE failed to recognize altered ventricular function in several cases. Differences between TTE and CMR could alter management is some cases. Incorporation of CMR into the routine surveillance of patients who received an ASO is warranted.

Branch Pulmonary Artery Valve Implantation Reduces Pulmonary Regurgitation and Improves Right Ventricular Size/Function in Patients With Large Right Ventricular Outflow Tracts.

OBJECTIVES: The authors sought to assess the intermediate-term effects of percutaneous placed valves in the branch pulmonary artery (PA) position. BACKGROUND: Most patients with large right ventricular outflow tracts (RVOTs) are excluded from available percutaneous pulmonary valve options. In some of these patients, percutaneous branch PA valve implantation may be feasible. The longer-term effects of valves in the branch PA position is unknown. METHODS: Retrospective data were collected on patients with significant pulmonary regurgitation who had a percutaneous branch PA valve attempted. RESULTS: Percutaneous branch PA valve implantation was attempted in 34 patients (18 bilateral and 16 unilateral). One-half of the patients were in New York Heart Association (NHYA) functional class III or IV pre-implantation. There were 2 failed attempts and 6 procedural complications. At follow-up, only 1 patient had more than mild valvar regurgitation. The right ventricular end-diastolic volume index decreased from 147 (range: 103 to 478) ml/m2 to 101 (range: 76 to 429) ml/m2, p < 0.01 (n = 16), and the right ventricular end-systolic volume index decreased from 88.5 (range: 41 to 387) ml/m2 to 55.5 (range: 40.2 to 347) ml/m2, p < 0.01 (n = 13). There were 5 late deaths. At a median follow-up of 2 years, all other patients were in NYHA functional class I or II. CONCLUSIONS: Percutaneous branch PA valve implantation results in a reduction in right ventricular volume with clinical benefit in the intermediate term. Until percutaneous valve technology for large RVOTs is refined and more widely available, branch PA valve implantation remains an option for select patients.

State of the art review: Chemotherapy-induced cardiotoxicity in children.

Chemotherapy-induced cardiotoxicity in adults and children is a topic with a growing interest in the cardiology literature. The ability to detect cardiac dysfunction in a timely manner is essential in order to begin adequate treatment and prevent further deterioration. This article aims to provide a review on the myocardial injury process, chemotherapeutic agents that lead to cardiotoxicity, the definition of cardiotoxicity, and the methods of timely detection and treatment.

Cardiac stress MRI evaluation of anomalous aortic origin of a coronary artery.

Myocardial ischemia is an insult that is primarily thought of in an adult population. However, there are several congenital and acquired cardiac lesions that may lead to myocardial ischemia in a pediatric population. One of the prominent congenital lesions is anomalous aortic origin of a coronary artery (AAOCA). Anomalous aortic origin of a coronary artery is one of the leading causes sudden cardiac death in pediatric and young adult patients, and thus the assessment of myocardial perfusion is of the utmost importance. Over the past decade, pharmacologic stress MRI has proven to be a highly sensitive and accurate diagnostic examination for qualifying myocardial perfusion in adults with coronary artery disease. This noninvasive imaging modality may be a useful tool in assessing the function impact of AAOCA on myocardial perfusion.

Imaging of the pulmonary valve in the adults.

PURPOSE OF REVIEW: Pulmonary valve is the least imaged of the cardiac valves in adults. This review will address the strengths and the limitations of various imaging modalities that are commonly used for evaluation of pulmonary valve diseases in the adults. RECENT FINDINGS: Valvular pulmonary stenosis is mostly congenital and pulmonary regurgitation is usually an acquired pulmonary valve disease. Combined pulmonary stenosis and pulmonary regurgitation as sequel to previous surgeries for congenital heart diseases is the most common form of pulmonary valve disease in the adults. Transthoracic echocardiography (TTE) is the first-line imaging for the pulmonary valve, however, TTE pose considerable technical limitations in adults secondary to the body habitus, previous surgeries, and imaging artifacts by the interposed foreign tissue. Transesophageal echocardiography is infrequently used because of farther location of the imaging probe from the pulmonary valve precluding optimal imaging. Cardiac computerized tomography (CT) and cardiac MRI are fast emerging as the most preferred imaging modalities for pulmonary valve diseases in the adults.CT is used to obtain precise anatomic information about the pulmonary valve and the contiguous anatomy such as the right ventricular outflow tract, the distal pulmonary arteries including the coronary arteries. MRI by virtue of its high temporal resolution has the unique advantage of obtaining hemodynamic information related to the pulmonary valve; such as quantification of the pulmonary regurgitation, the right ventricle volumes, mass, and the systolic function. Combined imaging with CT and MRI provide anatomic and hemodynamic information in a variety of pulmonary valve diseases; is useful for understanding of the right ventricle adaptive mechanism and remodeling process, for preprocedure planning during percutaneous pulmonary valve implantation and for surveillance of different pulmonary valve diseases. SUMMARY: Multimodality imaging involving a combination of TTE, CT, and (or) MRI are useful to delineate the anatomic and hemodynamic abnormalities associated with different pulmonary valve diseases in the adults.

Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson.

BACKGROUND: Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children. OBJECTIVE: To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease. MATERIALS AND METHODS: We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. RESULTS: One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement. CONCLUSION: Regadenoson might be a safe and feasible pharmacologic stress agent for use in cardiac MR in older pediatric patients with congenital heart disease and acquired heart disease. The ease of use as a bolus and the advantage of a prolonged hyperemia make its use appealing in pediatrics. In a limited number of cases, regadenoson stress perfusion showed excellent agreement with cardiac catheterization. Regadenoson might be a viable pharmacologic stress agent in this population.

Association of Late Gadolinium Enhancement and Degree of Left Ventricular Hypertrophy Assessed on Cardiac Magnetic Resonance Imaging With Ventricular Tachycardia in Children With Hypertrophic Cardiomyopathy.

There are limited data on the clinical significance of left ventricular (LV) mass and late gadolinium enhancement (LGE) in pediatric hypertrophic cardiomyopathy (HC). We reviewed cardiovascular magnetic resonance (CMR) studies of children with HC to investigate the associations between the extent and distribution of LGE and LV mass with ventricular tachycardia (VT) in children with HC. A blinded observer reviewed CMR studies for the presence and distribution of LV hypertrophy and LGE using a 17-segment model. The primary outcome was VT. LGE was present 17 of 33 subjects (52%). VT was present on outpatient Holter monitor or exercise stress test in 7 patients, of which 5 patients (71%) had LGE. Each additional segment of LGE was associated with an increase in the odds of VT (odds ratio [OR] 1.4, 95% CI 1.1 to 1.9) and fewer than 5 segments with LGE had 93% specificity for the presence or absence of VT (OR 0.06, 95% CI 0.01 to 0.5). VT was more common in patients with LGE in the apical septal (p = 0.03), basal inferoseptal (p <0.01), and basal inferior (p = 0.04) segments, whereas LGE in more commonly involved segments (midanteroseptal and midinferoseptal) was not associated with VT (p = 0.13, 0.26). Patients with VT had greater LV mass index (76.4 ± 40.4 g/m(2.7) vs 50.9 ± 24.3 g/m(2.7); p = 0.03). Each centimeter of increased maximum LV thickness was associated with increased likelihood of VT (OR 2.9, 95% CI 1.2 to 6.8). In conclusion, in pediatric HC, CMR to evaluate the extent and pattern of LGE, LV mass index, and maximum LV thickness may help to identify children with HC at risk of VT.