Myocardial Perfusion Abnormalities in Patients Occurring More Than 1 Year After Successful Univentricular (Fontan Surgery) and Biventricular Repair (Complete Repair of Tetralogy of Fallot)

The outcome of children born with cyanotic congenital heart disease has markedly improved over the years. Follow up is recommended for most post-operated cases as complications may occur over long term. One of the complications is the development of ventricular dysfunction, often seen after a successful Fontan surgery (or one of its modifications) for single ventricle. The aim of this study was to determine the prevalence of myocardial perfusion abnormalities in the ventricular myocardium of asymptomatic patients, older than 8 years of age, who had earlier undergone either a univentricular palliation (modified Fontan procedure) or a biventricular repair for tetralogy of Fallot, more than a year ago. All eligible patients underwent screening electrocardiogram (to rule out rhythm disturbance) and echocardiography. Patients with ventricular ejection fraction of more than 50 % by echocardiography were included. Enrolled patients were subjected to gated stress–rest myocardial perfusion imaging using Technitium-99m tetrofosmin single photon emission-computerized tomography (SPECT). Ventricular ejection fraction was also calculated from gated rest study. For the Fontan group, we also analyzed data to see if the morphology of the systemic ventricle would make a difference as far as myocardial perfusion was concerned. Twenty-six patients were enrolled (11 had undergone Fontan surgery and 15 had complete repair of tetralogy of Fallot). Seven of 11 patients in the Fontan group had myocardial perfusion defects (63.6 %) as against none in the repaired tetralogy of Fallot group (p < 0.001). The ejection fraction was within normal range in both the groups; it was statistically higher in the post tetralogy of Fallot repair group (p < 0.04). There were two subgroups in the post Fontan group depending on the morphology of systemic ventricle-left (4 patients) and non-left (7 patients). Higher number and larger size of perfusion defects were present in the non-left ventricular systemic ventricle morphology as compared with left ventricular morphology, but this difference did not reach statistical significance. Myocardial perfusion defects are common in patients who have undergone univentricular repair more than one year ago in contrast to patients who had a biventricular repair for tetralogy of Fallot. In the Fontan group, the morphology of the systemic ventricle was not predictive of prevalence of perfusion defect.     

Myocardial Perfusion and Exercise Capacity 12?Years After Arterial Switch Surgery for D-Transposition of the Great Arteries

Peak exercise myocardial perfusion was evaluated in patients with D-transposition of the great arteries 12 years after the arterial switch operation (SWITCH) to evaluate coronary perfusion. Gas-exchange measurements were used to assess cardiac limiting factors to exercise capacity in SWITCH patients when compared to healthy gender-matched controls (CON). Peak myocardial perfusion was evaluated in 42 patients 12 years post-SWITCH, using technetium-99 m (Tetrofosmin). SWITCH exercise data was compared to 42 gender-matched controls (CON). One symptomatic and one asymptomatic SWITCH patient had abnormal exercise myocardial perfusion; both patients had variant coronary anatomy preoperatively. SWITCH patients had lower VO_2peak (p < 0.01), peak heart rates (p = 0.01), percentages of age-predicted peak heart rates (p < 0.01), and peak oxygen pulses indexed to body surface area (p < 0.01) than CON patients. Exercise testing with myocardial perfusion imaging helped to identify the rare SWITCH patient with coronary insufficiencies. This study demonstrates that exercise testing with myocardial perfusion scans can help identify patients at risk for myocardial events. This study also demonstrated that SWITCH patients have a mildly diminished VO_2peak when compared to CON patients.     

Exercise Performance in Patients with D-Loop Transposition of the Great Arteries After Arterial Switch Operation: Long-Term Outcomes and Longitudinal Assessment

The first patients to undergo a successful arterial switch operation (ASO) for d-transposition of the great arteries (D-TGA) are now entering their fourth decade of life. Past studies of ASO survivors’ exercise function have yielded conflicting results. We therefore undertook this study to describe the current function of ASO survivors, to identify factors related to inferior exercise performance and to determine whether their exercise function tends to deteriorate over time. A retrospective cohort study was designed examining all patients with D-TGA after the ASO who underwent comprehensive cardiopulmonary exercise testing (CPET). Patients with palliative surgery prior to ASO, ventricular hypoplasia or severe valvar dysfunction were excluded from the study. Data from CPETs in which the peak respiratory exchange ratio was <1.09 were also excluded. We identified 113 patients who met entry criteria and had 186 CPX at our institution between 1/2002 and 1/2013; 41 patients had at least 2 qualifying CPX. Mean age at the time of the initial test was 17 ± 1 year. Peak oxygen consumption (VO2) averaged 84 ± 2 % predicted. Peak VO2 was lower among patients with repaired ventricular septal defects (82 ± 4 vs. 86 ± 3 % predicted; p < 0.05) and among patients with ≥ moderate right-sided obstructive lesions (77 ± 5 vs. 87 ± 3 % predicted; p < 0.05). Surgery prior to 1991 was also associated with a lower peak VO2 (81 ± 3 vs. 87 ± 3 % predicted; p < 0.01). The mean % predicted peak heart rate was 92 ± 1 %, with no significant difference between any of the subgroups. Non-diagnostic exercise-induced STT changes developed in 10 patients (12 studies). In the subgroup with at least 2 exercise tests, the annual decline in % predicted peak VO2 was quite slow (?0.3 % points/year; p < 0.01 vs. expected normal age-related decline). The exercise capacity of ASO survivors is well preserved and is only mildly reduced compared to normal subjects. Moreover, there is only a slight deterioration in exercise capacity over time. VSD repair, residual right-sided obstructive lesions, and earlier surgical era are associated with worse exercise performance. Peak heart rate was preserved with no significant change in follow up testing.     

Anomalous Left Coronary Artery Connected to the Pulmonary Artery Associated With Other Cardiac Defects: A Difficult Joint Diagnosis

Anomalous left coronary artery connected to the pulmonary artery (ALCAPA) can be associated rarely with other congenital heart defects. The preoperative joint diagnosis is challenging. From 1987 to 2012, a retrospective bicentric assessment of 12 patients with ALCAPA related to other cardiac defects focused on the associated heart defect, the moment of complete diagnosis related to surgery, and outcome. Coarctation was the most frequently associated heart defect (n = 5) followed by tetralogy of Fallot with or without pulmonary atresia (n = 3). The study group comprised one case of hypoplastic left heart syndrome, one right aortic arch, one congenital mitral malformation, and one infant with divided left atrium and anomalous pulmonary venous return. Only four patients had a complete diagnosis of both the cardiac defect and the coronary abnormality before surgery. In two cases, the coronary anomaly was discovered during surgery performed for another cardiac defect and treated at the same time. The diagnosis of the six remaining patients was determined after cardiac repair. Of the 12 patients, 7 (58 %) died after surgery. Half of these patients died within the first 30 days after repair. At this writing, the remaining patients are in good health after a median follow-up period of 5.4 years (range, 2.1–8.5 years). This study confirmed that ALCAPA associated with other cardiac defects often is misdiagnosed before surgery, mostly due to specific hemodynamics masking myocardial ischemia preoperatively. Survival was compromised due to the unrecognized diagnosis of an associated coronary abnormality but also because of midterm complications related to the other cardiac defects.     

Comparison of the Occlutech<Superscript>®</Superscript> Figulla<Superscript>®</Superscript> Septal Occluder and Amplatzer<Superscript>®</Superscript> Septal Occluder for Atrial Septal Defect Device Closure

The Occlutech^® Figulla^® septal occluder (OFSO) is a later-generation double-disk device with few reports of its success rates and complications compared with the Amplatzer^® septal occluder (ASO), which is the worldwide standard device in percutaneous atrial septal defect (ASD) closure. We recruited and compared the results in 149 patients (76.5 % female) who underwent ASD device closure in our center between January 2003 and June 2012. The patients ranged in age from 2.3 to 77.2 years. There were no statistically significant differences between the two groups regarding patient baseline characteristics and procedure variables. The success rate using either device was excellent (ASO 94.4 % and OFSO 97.4 %; p = 0.43). Although the diameter of the ASD and the pulmonary arterial pressure in the OFSO group were slightly higher than in the ASO group, the median fluoroscopic time in the OFSO group was significantly shorter (ASO 13.7 min; OFSO 9.0 min; p < 0.001). The overall median follow-up time was 3.6 years (interquartile range 2.1–9.0 years). There were no significant differences between the major and minor complications when comparing the two devices. Both devices were safe and effective for percutaneous ASD closures. The OFSO had the benefit of a shorter fluoroscopic time.     

Altered Right Ventricular Function in the Long-Term Follow-up Evaluation of Patients After Delayed Aortic Reimplantation of the Anomalous Left Coronary Artery From the Pulmonary Artery

This study aimed to evaluate regional and global ventricular functions in the long term after aortic reimplantation of the anomalous left coronary artery from the pulmonary artery (ALCAPA) and to assess whether the time of surgical repair influences ventricular performance.The study examined 20 patients with a median age of 15 years (range 3–37 years) who had a corrected ALCAPA and 20 age-matched control subjects using echocardiography and tissue Doppler imaging (TDI). The median follow-up period after corrective surgery was 6 years (range 2.6–15 years). Seven patients underwent surgery before the age of 3 years (early-surgery group), whereas 13 patients had surgery after that age (late-surgery group). The TDI-derived myocardial strain of the interventricular septum (IVS), lateral wall of the left ventricle (LV), and lateral wall of the right ventricle (RV) in the basal and mid regions were examined, and a mean was calculated. The pulsed Doppler-derived Tei index was used to assess global left ventricular function. No significant differences were found between the early-surgery group and the control group regarding the regional myocardial strain or the Tei index. Compared with the early-surgery group, the late-surgery group had a significantly higher Tei index (mean 0.37; range 0.31–0.42 vs. mean 0.52; range 0.39–0.69; p < 0.005), a lower strain percentage of the lateral wall of the LV (mean 29; range 17–30 vs. mean 9; range 7–23), IVS (mean 23; range 21–31 vs. mean 19; range 13–25), and lateral wall of the RV (mean 23; range 21–31 vs. mean 19; range 13–25). The age at operation correlated significantly with the Tei index (r = 0.84, p < 0.001) and inversely with the mean strain of the lateral wall of the LV (r = ?0.53, p = 0.028), IVS (r = ?0.68, p = 0.003), and lateral wall of the RV (r = ?0.68, p = 0.003). At the midterm follow-up evaluation after corrective surgery of ALCAPA, not only the left but also the right ventricular function seemed to be affected in patients with delayed diagnosis and late surgical repair but preserved among the younger patients with early diagnosis and corrective surgery.     

Continuous Cerebral and Myocardial Perfusion During One-Stage Repair for Aortic Coarctation With Ventricular Septal Defect

Controversy still exists concerning the use of deep hypothermic circulatory arrest (DHCA) and selective antegrade cerebral perfusion (SACP) for repair of aortic coarctation (CoA) with ventricular septal defect (VSD). This report therefore describes outcomes of patients undergoing continuous cerebral and myocardial perfusion (CCMP) under mild hypothermia compared with DHCA and SACP. Retrospective analysis was performed for 110 consecutive patients undergoing anatomic reconstruction of CoA with VSD closure between 1999 and 2011. Patients repaired under CCMP with mild hypothermia (32 °C) (group A, n = 60) were compared with those repaired under DHCA (18 °C) and SACP (group B, n = 50). In group A, the single arterial cannula perfusion technique was used for 15 patients (25 %), and the dual arterial cannula perfusion technique was used for 45 patients (75 %). The preoperative data were similar in the two groups. Group A had no hospital mortalities, compared with two mortalities (4 %) in group B. Group A had shorter myocardial ischemic and cardiopulmonary times, fewer delayed sternal closures, a shorter time to extubation, lower postoperative lactate levels, and fewer patients with low cardiac output requiring extracorporeal membrane oxygenation or with multiorgan failure than group B. During the postoperative course, no clinical or electrical neurologic events occurred in either group. The mean follow-up period was 5.2 ± 3.2 years for group A and 7.5 ± 3.1 years for group B (P = 0.048). One late death occurred in group B and no late deaths in group A. The actuarial survival for the two groups was similar (100 % for group A vs 96 % for group B; P = 0.264). The freedom from all types of cardiac reintervention was 96.7 % in group A and 89.6 % in group B (P = 0.688). All the patients were free of neurologic symptoms. The authors’ perfusion strategy using CCMP with mild hypothermia for repair of CoA with VSD is feasible, safe, and associated with improved postoperative recovery and should be the method of choice.     

Reference Values of Aortic Flow Velocity Integral in 1193 Healthy Infants, Children, and Adolescents to Quickly Estimate Cardiac Stroke Volume

The aortic velocity time integral (VTI) is an echocardiographic tool used to estimate cardiac output (CO) by multiplying it with the aortic valve (AV) area and heart rate (HR). Inaccurate measurement of AV diameter will lead to squared miscalculation of CO. The aortic VTI itself can serve as a left-ventricular (LV) output parameter. The normal range of aortic VTI in adulthood is relatively stable, compared with childhood, but reference data are lacking. The aim of this study was to establish reference values of VTI in infants, children, and adolescents. A retrospective analysis of 1223 echocardiographic examinations of healthy children (age 0–20 years, body surface area [BSA] 0.11–2.23 m²) was performed. Data were correlated with age, BSA, and HR, and age subgroups with normal distribution were determined. Interobserver and intraobserver variability was calculated. Aortic VTI ranged from mean 13.8 cm (10.0–18.4 cm 5–95th percentile) in neonates to 25.1 cm (19.6–32.8 cm 5–95th percentile) in children >17 years of age and had a positive correlation with age (r = 0.685, p < 0.001), BSA (r = 0.645, p < 0.001) and a negative correlation with HR (r = ?0.710, p < 0.001). Interobserver and intraobserver variability were excellent (3.9 ± 3.1 and 4.6 ± 3.7 %, respectively). Calculated mean values and percentile charts for the different age groups can serve as reference data to easily judge LV output in patients with or without congenital heart disease without enlargement or dysfunction of the AV.     

Attention Deficit Hyperactivity Disorder Screening Electrocardiograms: A Community-Based Perspective

Screening electrocardiograms (EKGs) for attention deficit hyperactivity disorder (ADHD) medication administration is controversial. We reviewed our experience as a community-based cardiology group. We reviewed all ADHD screening EKGs during a 2-year period. We evaluated whether screening EKGs resulted in further consultation and if management was altered. We also evaluated differences between patients on ADHD medications and those starting ADHD medications and further stratified the patients into stimulant versus nonstimulant groups. A total of 691 screening EKGs met our criteria. Forty-two patients (6.1 %) were recommended for further consultation. EKG findings requiring consultation included the following: left-ventricular hypertrophy, right atrial enlargement, arrhythmia, prolonged QT, and axis deviation. Studies performed during consultation included 39 echocardiograms, 2 stress tests, 2 Holter monitors, and 1 heart card. Five patients (0.72 %) were identified to have cardiac disease, one of whom decided against starting ADHD medications due to an arrhythmia, resulting in a change in management (0.14 %). Results comparing mean age, heart rate, and corrected QT interval between patients on medication and patients starting medications were as follows: 10.06 years, 82.87, bpm and 405.24 ms compared with 9.99 years, 80.05 bpm, and 405.82 ms, respectively (p = not significant [NS], p = 0.013 [NS], respectively). Results comparing mean age, heart rate, and corrected QT interval between patients on stimulant versus nonstimulant medications were as follows: 9.68 years, 83.10 bpm, and 403.04 ms compared with 9.81 years, 80.10 bpm, and 407.08 ms, respectively (p = NS for all). In our population, screening EKGs rarely resulted in management changes for patients taking or starting ADHD medications.     

Prevalence and Long-Term Predictors of Left Ventricular Hypertrophy, Late Hypertension, and Hypertensive Response to Exercise After Successful Aortic Coarctation Repair

Controversial data exist about the long-term results of aortic coarctation (AC) repair. This study explored the prevalence and predictors of left ventricular (LV) hypertrophy, late hypertension, and hypertensive response to exercise in 48 subjects (age, 15.1 ± 9.7 years) currently followed in the authors’ tertiary care hospital after successful AC repair. Data on medical history, clinical examination, rest and exercise echocardiography, and ambulatory blood pressure monitoring were collected. The time from AC repair to follow-up evaluation was 12.9 ± 9.2 years. The prevalence of LV hypertrophy ranged from 23 to 38 %, based on the criteria used to identify LV hypertrophy, and that of concentric geometry was 17 %. One sixth of the patients without residual hypertension experienced late-onset hypertension. One fourth of those who remained normotensive without medication showed a hypertensive response to exercise. Age at AC repair was the strongest independent predictor of LV hypertrophy, defined using indexation either for body surface area (odds ratio [OR], 1.03; p = 0.0090) or for height^2.7 (OR 1.02; p = 0.029), and it was the only predictor of late hypertension (OR 1.06; p = 0.0023) and hypertensive response to exercise (OR 1.09; p = 0.029). The risk of LV hypertrophy was 25 % for repair at the age of 3.4 years but rose to 50 and 75 % for repair at the ages of 5.9 and 8.4 years, respectively. Similar increases were found for the risk of late-onset hypertension and hypertensive response to exercise. A considerable risk of LV hypertrophy, late hypertension, and hypertensive response to exercise exists after successful AC repair. Older age at intervention is the most important predictor of these complications.     

川崎病冠状动脉管壁非扩张性病变及其功能改变的研究

目的 探讨川崎病冠状动脉管壁非扩张性病变及其对心肌灌注的影响。方法 应用多普勒组织成像(Doppler tissue imaging,DTI)技术对43例二维超声心动图(two-dimensionalechocardiogaphy,2DE)显示冠状动脉管壁异常(内膜粗糙,管壁反射增强或增厚,管周反射模糊)而管径正常的川崎病患儿室壁运动功能进行动态观察,对亚急性期和恢复期持续存在管壁异常和节段性室壁运动功能异常的患儿,配合铊201亚极量负荷心肌灌注成像(single photon emitting computerizedtomography,SPECT)检测。结果 43例合并冠状动脉管壁非扩张性病变的川崎病患儿,亚急性期和恢复期复检冠状动脉管壁有非扩张性病变的分别为36例(84%)和32例(74％),同期DTI检查有节段性室壁运动功能减弱的分别为34例(79％)和31例(72％),两种检测结果之间的关联性非常显著(xc2分别为9.64和7.14,P<0.01);31例经铊201亚极量负荷SPECT检查,17例阳性,其22处核素充填缺损或稀疏区在DTI上表现有相应节段性室壁运动功能减弱的有18处,吻合率82％(18/22),室间隔,左室前壁上核素充填异常与DTI室壁运动减弱的一致性显著(xc2值分别为5.07,7.48,P分别<0.05和0.01)。结论 非扩张性冠状动脉管壁异常是川崎病冠状动脉损害的重要表现之一,该病变可降低心肌的灌注能力,应引起临床上     

Positron Emission Tomography Myocardial Perfusion Imaging in Children with Suspected Coronary Abnormalities

Positron emission tomography (PET) myocardial perfusion imaging has higher spatial resolution than conventional single photon emission computed tomography (SPECT) imaging and allows accurate and reproducible quantification of myocardial blood flow (MBF). In this article, we describe the role of PET myocardial perfusion imaging in clinical decision making in children with suspected coronary abnormalities. We performed a PET myocardial perfusion study using N-13 ammonia in 10 children (median age, 14 years; range, 1–17 years). The indications included exercise-induced chest pain and ST segment changes during exercise testing, coronary artery ectasia, hypertrophic cardiomyopathy with myocardial bridging of the left anterior descending coronary artery, and suspected left coronary stenosis in an infant with William's syndrome. MBF was assessed at baseline and during adenosine hyperemia in all 10 patients and postexercise in 8 patients. Myocardial perfusion was homogeneous at baseline in all 10 patients, during adenosine perfusion in 9 of 10 patients, and postexercise in all 8 patients. Three patients with homogeneous rest and stress perfusion had impaired myocardial flow reserve. The infant with William's syndrome developed a large, reversible perfusion defect in the left coronary territory during adenosine stress and underwent surgical repair. Myocardial flow reserve findings were valuable for clinical decision making in individual patients. We conclude that MBF quantification with N-13 ammonia and PET provides supplemental perfusion information and is helpful in clinical decision making in children with suspected coronary abnormalities.     

Effect of Inhaled Nitric Oxide on Blood Flow Dynamics in Patients After the Fontan Procedure Using Cardiovascular Magnetic Resonance Flow Measurements

Invasive hemodynamic studies have shown that nitric oxide (NO), a selective pulmonary vasodilator, can lower pulmonary vascular resistance in Fontan patients. Because oximetry-derived flow quantification may be unreliable, we sought to detect changes in blood flow within the Fontan circulation after inhalation of NO using cardiovascular magnetic resonance (CMR). Thirty-three patients (mean age 12.8 ± 7.0 years) after the Fontan procedure underwent CMR as part of their routine clinical assessment. Standard two-dimensional blood flow measurements were performed in the Fontan tunnel, superior vena cava (SVC) and ascending aorta (AAO) before and after inhalation of 40 ppm NO for 8–10 min. Systemic-to-pulmonary collateral (SPC) flow was calculated as AAO ? (SVC + tunnel). Heart rate (82 ± 18 to 81 ± 18 bpm; p = 0.31) and transcutaneous oxygen saturations (93 ± 4 to 94 ± 3 %; p = 0.13) did not change under NO inhalation. AAO flow (3.23 ± 0.72 to 3.12 ± 0.79 l/min/m²; p = 0.08) decreased, tunnel flow (1.58 ± 0.40 to 1.65 ± 0.46 l/min/m²; p = 0.032) increased, and SVC flow (1.01 ± 0.39 to 1.02 ± 0.40 l/min/m²; p = 0.50) remained unchanged resulting in higher total caval flow (Qs) (2.59 ± 0.58 to 2.67 ± 0.68 l/min/m²; p = 0.038). SPC flow decreased significantly from 0.64 ± 0.52 to 0.45 ± 0.51 l/min/m² (p = 0.002) and resulted in a significant decrement of the Qp/Qs ratio (1.23 ± 0.23 to 1.15 ± 0.23; p = 0.001). Inhalation of NO in Fontan patients results in significant changes in pulmonary and systemic blood flow. The reduction in SPC flow is accompanied by a net increase in effective systemic blood flow suggesting beneficial effects of pulmonary vasodilators on cardiac output, tissue perfusion and exercise capacity.     

Assessing ST Segment Changes and Ischemia During Exercise Stress Testing in Patients with Hypoplastic Left Heart Syndrome and Fontan Palliation

While exercise stress testing (EST) is an important tool, little is known about its use for determining ischemia in patients with hypoplastic left heart syndrome (HLHS) and Fontan palliation. We sought to determine the frequency of ST segment changes during EST in HLHS patients after Fontan and examine results of further testing performed in response to ST changes. A single-center chart review of HLHS patients post-Fontan from January 1995 to December 2012 was performed. Data collected included demographics, indications for EST, resting electrocardiogram findings, EST and echocardiogram results and outcomes. ESTs were evaluated for ST segment changes concerning for ischemia. Results of additional testing performed based on concerning EST findings were collected. Twenty-seven patients underwent 64 ESTs (mean 2.4 ESTs/patient). Median age at first EST was 9.6 years (range 6.2–16.4). EST was concerning for ischemia in 13 patients (48 %) on 25 (39 %) ESTs. Based on EST results, two patients had stress sestamibi testing, two underwent coronary angiography, and one had both. No reversible perfusion defects or coronary artery obstructions were demonstrated. No patient who underwent EST has died. ST segment depression was not associated with ventricular dysfunction prior to EST or at the end of follow-up (p > 0.05). In patients with HLHS post-Fontan palliation, ST segment depression on EST is common. In patients who underwent further testing, no evidence of ischemia or coronary abnormalities was found. Additional testing may not be necessary in all patients.     

Effect of Tadalafil on Myocardial and Endothelial Function and Exercise Performance After Modified Fontan Operation

Better postoperative management of patients who have undergone single ventricle (SV) Fontan procedure could potentially reduce long-term complications and improve the quality of life for patients. The present study determined the effect of tadalafil on myocardial and endothelial function and exercise performance after modified Fontan operation. Patients who had undergone SV modified Fontan operation were enrolled in this clinical trial. The demographic characteristics of the patients were recorded. Before administration of tadalafil and after the trial, ventricular function (MPI, EF, FS, E/A, VTI), exercise performance, and endothelial function were evaluated for sonographic and biochemical markers (FMD, IMT, ICAM, VCAM, NO) using echocardiography, exercise testing, vascular ultrasonography, and biochemical measurements, respectively. A single dose of tadalafil of 1 mg/kg was administered daily for 6 weeks, and the functional class of the patients before and after tadalafil was determined. A total of 15 patients completed this clinical trial. Tadalafil was shown to have a significant effect on myocardial function, exercise performance, and improvement in NYHA functional class (p < 0.05) of study population. It had no significant effect on the biochemical variables and endothelial function except for IMT (p > 0.05), which decreased significantly after tadalafil administration (p < 0.05). The findings indicate that tadalafil is a safe, well-tolerated agent for the use after modified Fontan operation to improve myocardial function and exercise performance and possibly reduce long-term morbidity and mortality of patients. More conclusive results could be obtained from further study with a larger sample size and long-term follow-up.     

Usefulness of Percutaneous Transluminal Coronary Balloon Angioplasty for the Left Coronary Artery Stenosis 10 Years More Than After Arterial Switch Operation

Proximal stenosis adjacent to the orifice of one or both coronary arteries may occur after the arterial switch operation (ASO) for d-transposition of the great arteries (d-TGA). Coronary artery stenosis (CAS) often progresses within the first 6 months postoperatively and may result in myocardial ischemia and infarction. Although percutaneous transluminal coronary balloon angioplasty (PCBA) for CAS within 15 months after ASO for d-TGA has been reported, there is no report of PCBA for CAS in the late period after ASO. We present the results of PCBA for CAS of the left coronary artery performed more than 10 years after ASO in an 11-year-old boy and a 14-year-old boy without complication. The stenosis degree improved in both patients from 81 to 45 and 80 to 54 %, respectively. Restenosis did not occur, and the stenosis degree improved to about 25 % late after PCBA. Although the initial effect of PCBA may not be dramatic, it can improve late after PCBA. It was considered that the optimal balloon–reference vessel ratio was about 1.0, to obtain the minimal effective lumen diameter. PCBA for CAS even if performed many years after ASO is feasible without complication. PCBA can also provide delayed improvement late after the procedure.     

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.

     

Asymptomatic myocardial infarction in Kawasaki disease: Long-term prognosis

Summary Eight patients with Kawasaki disease who had sustained asymptomatic myocardial infarction 8–15 years ago (mean, 13.1 years) were reexamined by various noninvasive cardiac function tests to assess long-term prognosis.At present, electrocardiograms (ECGs) are normal in six patients. However, all eight patients had a prolonged preejection period (PEP) to left ventricular ejection time (LVET) ratio 30 s after amylnitrate (AN) inhalation. Six patients had perfusion defects by exercise thallium-201 myocardial scintigraphy, and two patients developed ST segment depression in treadmill exercise testing.These patients are symptom-free even though their physical activity has not been restricted. Yet they proved to have serious abnormalities suggesting sequelae of myocardial infarction or existing myocardial ischemia. Judging from the results of noninvasive cardiac function tests and recently performed coronary angiography, five of the eight patients require coronary bypass surgery.     

Right- and Left-Ventricular Strain Evaluation in Repaired Pediatric Tetralogy of Fallot Patients Using Magnetic Resonance Tagging

Residual pulmonary insufficiency in post-repair Tetralogy of Fallot (rToF) patients often mediates biventricular dysfunction which is associated with long-term adverse clinical outcomes. The objective of this study was to demonstrate the presence of impaired left ventricle (LV) circumferential strain (CS) in pediatric rToF patients as compared to controls using cardiac magnetic resonance imaging (CMRI). Additionally, bivariate analysis between right ventricle (RV) and LV functional measures in rToF patients was performed to further characterize the interventricular interactions thought to mediate LV dysfunction secondary to RV volume overload. The medical records of 12 rToF patients (mean age 13.3 years) and 9 controls (mean age 10.9 years) were analyzed. LV global CS was significantly decreased in rToF patients versus controls (p = 0.04). This impairment was differentially distributed within the LV, with only the LV anterior and anterior lateral walls significantly decreased versus controls (p = 0.04, p = 0.03). Bivariate analysis revealed a significant correlation between RV mean CS and LV EF (r = 0.71, p = 0.01), RV infundibulum CS and LV EF (r = 0.70, p = 0.01), RV infundibulum CS and LV anterolateral wall CS (r = 0.59, p = 0.04), and RV infundibulum CS and pulmonary regurgitation fraction (r = ?0.63, p = 0.03). These findings support existing research implicating interventricular interactions in the development of LV dysfunction. Furthermore, the segment specific CS impairment in the LV suggests a possible spatial component to these interactions. The success of this study in identifying regional myocardial strain impairment indicates CMRI based techniques may be useful in localizing otherwise undetectable myocardial dysfunction.     

Calcified occlusion of the right coronary artery in Kawasaki disease: evidence of myocardial ischaemia using cardiac technetium-99m-tetrofosmin perfusion single-photon emission computed tomography.

We report the case of a 14-year-old boy who developed Kawasaki disease at 5 months of age. The patient developed severe aneurysmal disease of both the left and right coronary arteries. He eventually developed total calcified occlusion of the right coronary artery despite long-term treatment with aspirin. Catheterisation showed no antegrade flow into the right coronary artery, with retrograde flow from the left coronary system into the right coronary. At the most recent follow-up he was asymptomatic, with normal exercise tolerance and a negative exercise stress test. Single-photon emission computed tomography (SPECT) myocardial perfusion imaging was carried out during stress and at rest using intravenous persantine (dipyridamole) and technetium-99m tetrofosmin. During stress, there were prominent left ventricular apical and anteroseptal defects, which normalised at rest. SPECT during stress and at rest may detect subclinical ischaemia and influence further management options in such patients.