Transcatheter pulmonary valve replacement in congenital heart diseases.

Surgical repair of a variety of congenital heart diseases involves repair of the right ventricular outflow tract (RVOT) with valved or non-valved conduit to connect the right ventricle (RV) to the pulmonary artery (PA) or just patch enlargement of the native RVOT. With time, this RV-PA conduit will degenerate with deterioration of function, either causing pulmonary stenosis or pulmonary regurgitation. This RVOT dysfunction may result in RV dilation, RV dysfunction, and eventual RV failure and arrhythmias. Multiple surgical pulmonary valve replacement (PVR) is often required throughout the patient's lifetime. Patients are subjected to increased risks with each additional cardiac operation. Transcatheter PVR (TPVR) has been developed over the past two decades as a valuable non-surgical alternative to restore the RVOT and RV function, and hence reduce patients' lifetime risks related to surgery. This article will discuss the long-term results of TPVR which are demonstrated to be comparable to surgical results and the latest development of large pulmonary valves which will allow TPVR to be performed on native or larger RVOT.

Comparing the accuracy of obstetric sonography and fetal echocardiography during pediatric cardiology consultation in the prenatal diagnosis of congenital heart disease.

AIM: The diagnostic accuracy of fetal echocardiogram performed by an obstetrician alone and that performed jointly by an obstetrician and pediatric cardiologist for congenital heart disease were compared. MATERIALS AND METHODS: All cases of suspected fetal congenital heart disease (CHD) referred to the Prenatal Diagnostic Clinic at Tsan Yuk Hospital, Hong Kong during 2006-2011 were reviewed. Prenatal fetal echocardiogram findings were compared with postnatal diagnosis. Cases of incorrect prenatal diagnosis with significant difference in prognosis were analyzed qualitatively. RESULTS: One hundred and eleven cases of fetal CHD were analyzed. Complete agreement between prenatal and postnatal diagnosis of CHD was observed in 69.4% of cases by fetal echocardiogram performed by obstetrician and 83.8% by fetal echocardiogram performed during pediatric cardiology consultation (P = 0.001). Collaboration with a pediatric cardiologist also improved detection of ductal-dependent cardiac lesions (77.4% vs. 86%, P = < 0.001). Five cases with an incorrect diagnosis were associated with a different prognosis. Three of the cases involved outflow tract abnormalities with incorrect identification of outflow vessels. CONCLUSION: Collaboration with a pediatric cardiologist can significantly improve the accuracy of prenatal diagnosis of CHD. In particular, joint consultation is associated with significantly better detection of ductal-dependent lesions. Outflow tract abnormalities remain a diagnostic challenge in prenatal diagnosis. Incorrect identification of outflow tract vessels was the major cause of incorrect diagnosis in our series.

NGS identifies TAZ mutation in a family with X-linked dilated cardiomyopathy.

We reported a family with two male siblings affected with infantile dilated cardiomyopathy (DCM). Extensive evaluation failed to identify the underlying cause for the DCM. Next generation sequencing (NGS) with targeted enrichment identified a hemizygous variant c.718G>C (p.Gly240Arg) in the TAZ gene. This variant has been reported in three other families with X linked infantile DCM and is therefore likely pathogenic. NGS allows efficient screening of a large number of uncommon genes in complex disorders like DCM, in which there is substantial genetic and phenotypic heterogeneity. The identification of TAZ mutation has major impact on their medical care as the surveillance needs to be expanded to cover for the Barth syndrome, a severe metabolic phenotype also caused by TAZ mutation, in addition to DCM.

Brain natriuretic peptide as a biomarker of systemic right ventricular function in patients with transposition of great arteries after atrial switch operation.

BACKGROUND: Assessment of systemic right ventricular (RV) function is inherently difficult. In adults, plasma brain natriuretic peptide (BNP) level has been shown to reflect systemic ventricular dysfunction. We sought to test the hypothesis that plasma BNP is a biomarker of systemic RV function in patients after atrial switch operation. METHODS: We determined the RV function in 44 patients, 35 after Senning and 9 after Mustard operation, aged 19.7+/-4.0 years, by tissue Doppler echocardiography and determination of myocardial performance index (MPI). The results were compared to the left ventricular function of 14 age-matched controls. Their plasma BNP levels were correlated with indices of systemic ventricular function. RESULTS: Compared with controls, the patients had greater MPI (p<0.001), lower systemic ventricular free wall-annular early diastolic (p<0.001), late diastolic (p<0.001), and systolic velocities (p=0.001), lower septal-annular early diastolic (p<0.001), late diastolic (p<0.001), and systolic velocities (p<0.001), and higher BNP levels (p=0.03). Plasma BNP levels correlated positively with MPI (r=0.43, p=0.001) and negatively with the free wall- and septal-annular myocardial velocities (r=-0.32 to -0.47, p<0.05). The area under the receiver operating characteristic curve for BNP to detect ventricular dysfunction (MPI >0.45) in patients was 0.67 (p=0.04). A BNP level of 36 pg/ml had a sensitivity of 55%, specificity of 86%, positive predictive value 80%, negative predictive value of 64%, and an accuracy of 70% for detecting systemic ventricular dysfunction. CONCLUSIONS: Plasma BNP has modest accuracy in the detection of systemic RV dysfunction in patients after atrial switch operation.

Cardiac rhythm and symptomatic arrhythmia in right atrial isomerism.

BACKGROUND: The conduction system in right atrial isomerism may be complicated by the presence of paired sinus nodes and twin atrioventricular nodes. With a large cohort of infants and children with right atrial isomerism, we sought to investigate the nature of atrial rhythm, its prevalence, factors predisposing patients to symptomatic cardiac arrhythmia, and the relation of arrhythmia to long-term morbidity and mortality. METHODS: Standard 12-lead baseline electrocardiograms were performed in 110 infants and children with right atrial isomerism at a median age of 1 day, and their clinical records were reviewed. The type, timing, and precipitating factors of symptomatic cardiac arrhythmia that occurred in 15 patients, among a cohort of 85 patients who had or were awaiting surgical interventions, were noted. RESULTS: All patients except 1 had a sinus rhythm with intact atrioventricular conduction. Of these, 87% (95/109) had single P-wave morphology, whereas 13% (14/109) had multiple P-wave morphologies. For patients with a single P-wave morphology, the frontal P-wave axis was between 0 degrees and 90 degrees in 62% (59/95), 90 degrees and 180 degrees in 23% (22/95), and superior in 15% (14/95). There was no relation between either P-wave axis or morphology and cardiac anatomy. Symptomatic cardiac arrhythmia occurred in 15 of 85 patients (18%); 11 of the 15 patients had supraventricular tachycardia, and 1 patient each had atrial tachycardia, atrial flutter, ventricular tachycardia, and congenital complete heart block. The arrhythmias occurred before surgery in 4 patients, early after surgery in 5 patients, and late after surgery in 6 patients. Although 3 of the 7 patients who died suddenly had a history of symptomatic arrhythmia, arrhythmia was the documented cause of mortality in only 1 of the 32 fatalities (3.1%). Freedom from arrhythmia at 1, 5, 10, 15, and 20 years was 93% +/- 3%, 86% +/- 4%, 80% +/- 6%, 73% +/- 9%, and 48% +/- 15% (mean +/- SE), respectively. No risk factors for symptomatic arrhythmia were identified by means of logistic regression. CONCLUSIONS: The atrial pacemaker varies in location within and between patients with right atrial isomerism. Although symptomatic cardiac arrhythmias are not uncommon, they do not seem to relate to the overall high mortality rate and occurrence of sudden death in this patient group. Nonetheless, detailed assessment and aggressive management of cardiac arrhythmias once they occur are warranted because of the precarious single ventricular hemodynamics.