Simultaneous real-time imaging of four-chamber and left ventricular outflow tract views using xPlane imaging capability of a matrix array probe.

OBJECTIVES: To determine the feasibility and reliability of using xPlane imaging to examine simultaneously the four-chamber and left ventricular outflow tract (LVOT) views in real time, to assess rotation angles from the four-chamber view to the LVOT view, and to investigate factors affecting the angles. METHODS: In 145 fetuses at 11-37 weeks' gestation, we visualized the four-chamber view in one of three cardiac positions: a subcostal view with the apex at the 3 or 9 o'clock position; an apical view with the apex at the 12 or 6 o'clock position; or a view with the fetal heart apex midway between these two positions. We then used the rotation function of xPlane imaging, using the four-chamber view as the reference plane, to visualize the LVOT view simultaneously in real time on the secondary image plane, on the right side of the split screen, by rotating a reference line from 0° with a rotation step of 5°. The rotation angle necessary for the first appearance of LVOT was recorded as the first rotation angle. The reference line was then rotated until the LVOT was just out of view, and this last rotation angle was recorded as the second rotation angle. The difference between these two angles was recorded as the angle span of the LVOT display. Reliability was assessed by intraclass correlation coefficient (ICC). RESULTS: Of the 145 fetuses examined, 29 had cardiac defects. Using xPlane imaging, the LVOT was visualized successfully after 14 weeks in 95.1% of cases. The first and second rotation angles varied significantly with cardiac position (P < 0.001); when the fetal heart was examined using a subcostal approach with the apex at the 3 or 9 o'clock position, the first rotation angle was smaller than that at the apical view for normal hearts (20° vs. 50°, P < 0.001). There was also a significant difference for the second rotation angle and for the angle span, between fetuses with and without normal LVOT (P = 0.038 and 0.006, respectively). Regarding intra- and interobserver reliability for measurement of first and second rotation angles, the ICCs were high (range, 0.847-0.980). CONCLUSION: Using xPlane imaging, it is feasible to examine simultaneously the four-chamber and LVOT views in real time, and measurement of the rotation angles between these two views is reproducible. The rotation angles depend on the position of the fetal heart, and the normality of the LVOT. Proposed algorithms for examination of the fetal heart with three-/four-dimensional ultrasonography may need to be adapted to optimize visualization of the standard planes.

Assessment of left ventricular function long term after arterial switch operation for transposition of the great arteries by dobutamine stress echocardiography.

OBJECTIVES: To use dobutamine stress echocardiography to determine left ventricular (LV) function and wall motion of children long term after arterial switch operation (ASO) for transposition of the great arteries. DESIGN AND PATIENTS: 31 patients (24 boys) with ASO performed at a mean (SD) of 15.5 (4.3) days of life were studied at an age of 9.4 (2.0) years. All had normal coronary angiographic findings. LV echocardiographic indexes, including fractional shortening, ejection fraction, rate corrected velocity of circumferential fibre shortening (VCFc), and wall stress, as well as LV wall motion abnormalities were determined at rest and under dobutamine stress. The results were compared with those of 20 healthy age matched control participants. SETTING: Tertiary paediatric cardiac centre. RESULTS: Fractional shortening, ejection fraction, and VCFc were significantly lower in patients than in controls at rest (all with p < 0.001). Stress-velocity index detected impaired LV contractility in 19 (61%) patients at rest. An older age at operation (p = 0.01), longer bypass (p = 0.01) and circulatory arrest times (p = 0.045), and an unusual coronary artery pattern (p = 0.059) were associated with impaired resting LV contractility. Dobutamine stress echocardiography unmasked wall motion abnormalities in 23 (74%) patients. Exercise myocardial perfusion scan, performed in 22 patients, showed reversible myocardial perfusion defects in 17. These defects corresponded to segments of hypokinesia as detected by dobutamine stress echocardiography. CONCLUSION: A significant proportion of children, albeit asymptomatic, had impaired baseline LV contractility and reversible myocardial perfusion defects and mild wall motion abnormalities on stress after ASO.

Evolution of the management approach for pulmonary atresia with intact ventricular septum.

OBJECTIVE: To review the evolution of the management approach for pulmonary atresia with intact ventricular septum (PAIVS) in the past two decades and to assess its impact on patient outcomes. DESIGN AND PATIENTS: Retrospective review of the management and outcomes of 94 patients (55 male patients) with PAIVS diagnosed between July 1980 and August 2003. SETTINGS: Tertiary paediatric cardiac centre. RESULTS: Seven patients died before interventions. Of the remaining 87 patients who underwent intervention at a median age of 9 days (from 1 day to 2 years), 12 had right ventricular outflow tract reconstruction (RVOTR), 42 had closed pulmonary valvotomy (CPV), and 15 had laser assisted valvotomy with balloon valvoplasty. A systemic-pulmonary shunt was inserted in 18 patients, six of whom had subsequent RVOTR (n = 4) or laser assisted valvotomy (n = 2). Since 1990, catheter intervention accounted for 38% (17 of 45) of the right ventricular outflow procedures. The mean (SEM) freedom from reintervention was 93 (7)%, 71 (12)%, and 57 (13)% after RVOTR, 75 (7)%, 40 (8)%, and 14 (6)% after CPV, and 54 (13)%, 24 (12)%, and 16 (10)% after laser assisted valvotomy at one month, six months, and one year, respectively (RVOTR versus CPV, p < 0.001; RVOTR versus laser assisted valvotomy, p = 0.001). Low cardiac output syndrome was significantly less common after catheter intervention than after RVOTR (0% v 44%, p = 0.003) or CPV (0% v 29%, p = 0.01). The overall mean (SEM) survival was 77 (5)% and 70 (5)% at one and five years, respectively, and the overall mortality was 33% (29 of 87). There were no significant differences in survival between the three groups. CONCLUSIONS: Multiple interventions are often required in the treatment algorithm of PAIVS. The shift towards increased use of the transcatheter approach has reduced the occurrence of postprocedural low cardiac output syndrome.

Parents' understanding of their child's congenital heart disease.

OBJECTIVES: To assess parents' understanding of their child's congenital heart disease in various knowledge domains and to identify significant determinants of parental knowledge. DESIGN: Cross sectional questionnaire survey SETTING: Tertiary paediatric cardiac centre. PATIENTS: 156 parents of children with relatively simple congenital heart defects were recruited from the outpatient clinic of a tertiary cardiac centre over a three month period. The questionnaire comprised 10 items of knowledge under three domains: nature of heart disease and its treatment; impact of heart disease on exercise capacity; and infective endocarditis and its prevention. The frequency distribution of the parents' knowledge in the different domains was determined. Univariate analyses and logistic regression were performed to identify significant determinants of knowledge in selected items. RESULTS: While 59% of parents correctly named their child's congenital heart disease, only 28.8% correctly indicated the heart lesion(s) diagrammatically. However, more than 80% of parents were aware of the indications and aims of previous surgical and transcatheter interventions. About half of the parents were aware of possible aetiologies and of the hereditary nature and symptoms attributable to underlying heart disease. Disappointingly, of the 56 parents whose children were taking cardiac medications, only 25 (44.6%) and 4 (7.1%) knew correctly the functions and important side effects of the medications, respectively. With regard to exercise capacity, 59% of parents indicated its level appropriate for the heart lesion. While 26.9% of parents had heard of the term "infective endocarditis", slightly more than half of the parents were aware of the need for antibiotics before dental procedures. Significant determinants of knowledge in the nature of heart disease were cardiac diagnosis, occupation of parents, and their educational level. Logistic regression failed to identify any significant determinants of parental knowledge in the other two domains. CONCLUSIONS: Parents of children with congenital heart disease have important knowledge gaps. Our findings suggest that the current educational programme is inadequate and needs to be refined to promote better parental understanding of their child's heart disease, with the ultimate aim of enabling parents to impart such knowledge accurately to their children.

Pericardial effusion after open heart surgery for congenital heart disease.

OBJECTIVES: To determine the prevalence and time course of pericardial effusion after open heart surgery for congenital heart diseases and to identify predisposing risk factors. DESIGN AND PATIENTS: Prospective assessment of development of pericardial effusion in 336 patients (163 males) undergoing open heart surgery for congenital heart disease by serial echocardiography on days 5, 7, 14, 21, and 28 postoperatively. SETTING: Tertiary paediatric cardiac centre. RESULTS: The prevalence of pericardial effusion was 23% (77 of 336). Of the 77 patients who developed effusion, 43 (56%) had moderate to large effusions and 18 (23%) were symptomatic. Patients who had a large amount of effusion were more likely to be symptomatic than those with only a small to moderate amount (47.4% v 15.5%, p = 0.01). The mean (SD) onset of pericardial effusion was 11 (7) days after surgery, with 97% (75 of 77) of cases being diagnosed on or before day 28 after surgery. The prevalence of effusion after Fontan-type procedures (60%, 6 of 10) was significantly higher than that after other types of cardiac surgery: repair of left to right shunts (22.1%, 43 of 195), repair of lesions with right ventricular outflow tract obstruction (22.6%, 19 of 84), arterial switch operation (6.7%, 1 of 15), and miscellaneous procedures (25%, 8 of 32) (p = 0.037). Univariate analyses showed that female patients (p = 0.009) and those receiving warfarin (p = 0.002) had increased risk of postoperative pericardial effusion. A greater pericardial drain output in the first four hours after surgery also tended to be significant (p = 0.056). Multivariate logistic regression similarly identified warfarin treatment (beta = 1.73, p = 0.009) and female sex (beta for male = -0.63, p = 0.037) as significant determinants. CONCLUSIONS: Pericardial effusion occurs commonly after open heart surgery for congenital heart disease. Serial echocardiographic monitoring up to 28 days postoperatively is indicated in selected high risk patients such as those with symptoms of postpericardiotomy syndrome and those given warfarin.

Tracheobronchography and angiocardiography of paediatric cardiac patients with airway disorders.

OBJECTIVE: We report our experience in combining tracheobronchography and angiocardiography in the assessment of a selected cohort of paediatric cardiac patients with problematic airway disorders. METHODOLOGY: The clinical records of 11 patients who underwent 17 studies at a median age of 5.5 months (range 3 months to 10.8 years) were reviewed. Tracheobronchography and angiocardiography were performed under general anaesthesia using a non-ionic contrast agent. The findings were compared with those of flexible bronchoscopy and magnetic resonance imaging (MRI). RESULTS: Seven patients had cardiac lesions associated with vascular anomalies potentially compressing the airway, while four had no identifiable aberrant or enlarged vessels. All examinations but one were performed without complications. Tracheobronchography demonstrated extrinsic vascular compression with secondary airway malacia in three (27%), intrinsic tracheobronchial stenosis in five (45%), and airway malacia in three patients (27%). Precise measurement of the airway calibre and real-time fluoroscopic monitoring facilitated transcatheter tracheobronchial interventions (six balloon dilations, three stent implantations) in four patients. In conjunction with angiocardiography, cine-tracheobronchography provided detailed information on the spatial relationship between vascular and airway structures in all patients; allowed dynamic assessment of airway malacia; and facilitated preoperative planning in six patients. In contrast, bronchoscopy failed to differentiate malacia from extrinsic compression in four patients (36%), while MRI, performed in six patients, was unsatisfactory in one due to a motion artefact and failed to diagnose airway malacia and extrinsic compression in three patients. CONCLUSIONS: Tracheobronchography is relatively safe in paediatric cardiac patients. Combined tracheobronchography and angiocardiography, a less operator-dependent imaging modality compared to bronchoscopy and MRI, delineated the airway and vascular anatomy in detail; facilitated preoperative planning; and permitted transcatheter tracheo-bronchial interventions. The dynamic capability of tracheobronchography supplements that of flexible bronchoscopy and MRI in the diagnosis of airway malacia.