Echocardiographic Screening for Postoperative Pericardial Effusion in Children.

Pericardial effusion (PE) after cardiac surgery can be life threatening without timely detection, and the optimal screening method is unknown. We sought to evaluate the role of a surveillance echocardiogram on postoperative day 10 (± 2), determine the incidence of postoperative PE, and identify risk factors. We conducted a retrospective cohort study including all pediatric patients who underwent open heart surgery at a single institution over a 7-month period. To identify risk factors for PE, medical records of patients with PE detected within 6 weeks after surgery (cases) were compared with patients without PE (controls). Of 203 patients, 52 (26%) had PE within 6 weeks; 42 (81%) were trivial-small and 10 (19%) were moderate-large. Twenty-nine (56%) were first detected within 7 days post-operatively, including all cases developing cardiac tamponade (n = 3). An echocardiogram was done 10 (± 2) days post-operatively in 41/52 cases, of which 12/41 (29%) did not have a PE at this time, 24/41 (59%) had a trivial-small PE, and 5/41(12%) had a moderate-large PE; 2 of the latter had no prior detected PE. Closure of an atrial septal defect had the highest incidence of PE (42%). PE cases were associated with postoperative nasopharyngeal detection of a respiratory virus (OR 3.8, p = 0.03). In conclusion, the majority of PE cases were detected within 7 days post-operatively, including all cases subsequently developing cardiac tamponade. Day 10 echocardiography infrequently detected a moderate or large effusion that had previously gone undiagnosed. A positive perioperative nasopharyngeal aspirate for a respiratory virus was associated with postoperative PE.

Optimization of myocardial nulling in pediatric cardiac MRI.

BACKGROUND: Current protocols to determine optimal nulling time in late enhancement imaging using adult techniques may not apply to children. OBJECTIVE: To determine the optimal nulling time in anesthetised children, with the hypothesis that this occurs earlier than in adults. MATERIALS AND METHODS: Sedated cardiac MRI was performed in 12 children (median age: 12 months, range: 1-60 months). After gadolinium administration, scout images at 2, 3, 4 and 10 min and phase sensitive inversion recovery (PSIR) images from 5 to 10 min were obtained. Signal-to-noise ratio (SNR) and inversion time (TI) were determined. Quality of nulling was assessed according to a grading score by three observers. Data was analysed using linear regression, Kruskal-Wallis and quadratic-weighted kappa statistics. RESULTS: One child with a cardiomyopathy had late enhancement. Good agreement in nulling occurred for scout images at 2 (κ = 0.69) and 3 (κ = 0.66) min and moderate agreement at 4 min (κ = 0.57). Agreement of PSIR images was moderate at 7 min (κ = 0.44) and poor-fair at other times. There were significant correlations between TI and scout time (r = 0.61, P < 0.0001), and SNR and kappa (r = 0.22, P = 0.017). CONCLUSION: Scout images at 2-4 min can be used to determine the TI with little variability. Image quality for PSIR images was highest at 7 min and SNR optimal at 7-9 min. TI increases with time and should be adjusted frequently during imaging. Thus, nulling times in children differ from nulling times in adults when using standard adult techniques.

Abnormal flow in the posterior descending artery: an echo Doppler clue to the anomalous origin of left anterior descending coronary artery from the pulmonary trunk.

Anomalous origin of the left anterior descending coronary (LAD) from the pulmonary trunk is a rare lesion. We describe a neonate with anomalous origin of the LAD from the pulmonary artery and the circumflex artery arising normally from the left-facing sinus. The finding of a tortuous and dilated posterior descending coronary artery suggested increased intercoronary collateral flow and provided a clue to the identification of the anomaly in an otherwise asymptomatic neonate. Interrogation of the posterior descending coronary artery should be included in the routine echocardiographic examination of children, as unusual flow patterns may help identify aberrant coronary artery connections.

Late intervention in an asymptomatic pediatric patient with anomalous left coronary artery.

Anomalous left coronary artery from the pulmonary artery (ALCAPA) is most commonly diagnosed within the first year of life with congestive heart failure symptomatology reflecting left ventricle (LV) dysfunction. The late diagnosis of ALCAPA is presented in a 5-year-old without significant LV dysfunction, mild LV dilatation and only mild mitral regurgitation that did not change significantly after surgery. The timing of surgical intervention in the late diagnosis of ALCAPA remains unclear despite risks of significant ongoing myocardial injury secondary to coronary artery hypoperfusion and progressive mitral valve dysfunction. Intervention in this case allows for revascularization which may reverse ventricular and valvular dysfunction.

Insights into the evolution of myocardial dysfunction in the functionally single right ventricle between staged palliations using speckle-tracking echocardiography.

BACKGROUND: The long-term prognosis of hypoplastic left heart syndrome is limited by progressive right ventricular dysfunction. The aim of this study was to determine the trends in single right ventricular systolic function between staged palliative surgeries using speckle-tracking and conventional echocardiography. METHODS: There were 76 patients with functionally single right ventricles at the (1) pre-Norwood (n = 26), (2) pre-bidirectional cavopulmonary anastomosis (BCPA; n = 19), (3) pre-Fontan (n = 16), and (4) post-Fontan (n = 15) stages, compared with 30 controls of similar ages. Speckle-tracking-derived longitudinal and circumferential strain and strain rate, postsystolic strain index, and mechanical dyssynchrony index were compared with conventional measures of ventricular function. Differences between stages were analyzed using analysis of variance (P < .05). RESULTS: Strain rate was highest at the pre-Norwood stage and decreased at the other stages (longitudinal P < .0001, circumferential P = .0002), as opposed to controls, in whom strain rate was maintained. Longitudinal strain was significantly decreased at the pre-BCPA stage compared with the pre-Norwood stage (P = .004), but circumferential strain was maintained, resulting in a corresponding decrease in the ratio of longitudinal to circumferential strain, which failed to resemble that of controls. Longitudinal (P = .003) and circumferential (P = .002) postsystolic strain indices were greatest at the pre-BCPA stage. CONCLUSIONS: A decline in contractility occurred at the pre-BCPA stage. Although there was evidence of adaptation of the single right ventricle, this failed to resemble the normal left ventricle and may be insufficient to handle the chronic volume load or insult from previous surgery. These findings suggest an intrinsic inability of the single right ventricular myocardium to fully adapt to chronic systemic pressures.

Noninvasive assessment of vascular function and hydraulic power and efficiency in pediatric Fontan patients.

BACKGROUND: Invasive studies have shown that children with Fontan palliation have abnormal arterial stiffness, impedance, and hydraulic power and efficiency. The aim of this study was to assess these indexes noninvasively in a cohort of children with Fontan circulation using Doppler echocardiography and compare their results with those of healthy peers. METHODS: This was a case-control study of 22 Fontan patients and 31 healthy control children. Using standard two-dimensional, M-mode, and Doppler echocardiographic imaging and carotid artery applanation tonometry, aortic flows, dimensions, and pulse-wave velocity were measured, and vascular impedance and arterial stiffness were calculated. Hydraulic power and efficiency were calculated from standard fluid dynamics formulae. RESULTS: The median age was similar between groups. Stroke volume index (39 vs 39 mL/min/m(2)) and cardiac index (2.6 vs 2.5 L/min/m(2)) were similar. Aortic cross-sectional area (3.3 vs 2.8 cm(2)), peak aortic flow (302 vs 261 cm(3)/sec), and myocardial performance index (0.47 vs 0.25) were higher and ejection fraction (50% vs 66%) was lower in Fontan patients. Input impedance (61 vs 83 dyne · sec/cm(5)/m(2)) was lower in Fontan patients. Pulse-wave velocity (488 vs 364 cm/sec), elastic pressure-strain modulus (305 vs 263 torr), and stiffness index (4.15 vs 3.04) were higher in Fontan patients. Total arterial compliance (1.29 vs 1.32 mL/torr/m(2)) and mean power (606 vs 527 mW/m(2)) were similar and total hydraulic power (716 vs 627 mW/m(2)) was higher in Fontan patients. Efficiency and the power cost per unit of forward flow were similar. CONCLUSIONS: Despite stiffer aortas, Fontan patients generate more hydraulic power associated with decreased ventricular function to achieve a similar hydraulic efficiency. In Fontan patients, therapy that is given to improve ventricular function may need to target vascular stiffness as well. This technique may be used to monitor the efficacy of therapeutic interventions.

Benign cardiac tumours, malignant arrhythmias.

Four cases of pediatric cardiac tumours (PCTs) associated with ventricular arrhythmias are reported. Sudden cardiac death attributable to the tumour occurred in two children. A third child received an implantable cardioverter defibrillator and the fourth had persistent ventricular arrhythmia despite medical therapy. Most PCTs are considered benign; however, the development of malignant arrhythmias may complicate the management of these tumours in some patients. The literature regarding the arrhythmogenic potential of PCTs and the use of implantable cardioverter defibrillators in these patients is reviewed. The series highlights the deficiency of prognostic information for this cohort.