Daniel J. Penny

Ventricular septal defect

Ventricular septal defects account for up to 40% of all congenital cardiac malformations. The diagnosis encompasses a broad range of anomalies, including isolated defects and those associated with other congenital cardiac malformations. Presentation, symptoms, natural history, and management of ventricular septal defects depend on size and anatomical associations of the anomaly, patients age, and local diagnostic and interventional expertise. In this Seminar, we describe the anatomical range of ventricular septal defects and discuss present management of these malformations. Genetic determinants, diagnostic techniques, physiological considerations, and management challenges are examined in detail. Unfortunately, in many circumstances, evidence on which to guide optimum management is scarce. We present some longer term considerations of ventricular septal defects in adolescents and adults, with particular emphasis on patients with raised pulmonary vascular resistance and Eisenmengers syndrome.

Intravenous sildenafil and inhaled nitric oxide: a randomised trial in infants after cardiac surgery

ObjectiveTo investigate the acute effects of intravenous sildenafil on haemodynamics and oxygenation, and its interaction with inhaled nitric oxide (iNO) in infants at risk of pulmonary hypertension early after cardiac surgery.DesignProspective, randomised trial.SettingPaediatric intensive care unit of a children’s hospital.Patients and participantsSixteen ventilated infants early after closure of ventricular or atrioventricular septal defects, were randomly assigned to one of two groups. The study was completed in 15 infants.InterventionsStudies were commenced within 7xa0h of separation from bypass. Seven infants received iNO (20xa0ppm) first, with the addition of intravenous sildenafil (0.35xa0mg/kg over 20xa0min) after 20xa0min. Eight infants received sildenafil first, iNO was added after 20xa0min. Vascular pressures, cardiac output and a blood gas were recorded at 0, 20 and 40xa0min.Measurements and resultsIn infants receiving iNO first, iNO lowered the pulmonary vascular resistance index (PVRI) from 3.45 to 2.95xa0units (p=0.01); sildenafil further reduced PVRI to 2.45xa0units (p<0.05). In those receiving sildenafil first, PVRI was reduced from 2.84 to 2.35xa0units (p<0.05) with sildenafil, and fell to 2.15xa0units (p=0.01) with the addition of iNO. In both groups, sildenafil reduced the systemic blood pressure and systemic vascular resistance (p<0.01) and worsened arterial oxygenation and the alveolar-arterial gradient (p<0.05).ConclusionIntravenous sildenafil augmented the pulmonary vasodilator effects of iNO in infants early after cardiac surgery. However, sildenafil produced systemic hypotension and impaired oxygenation, which was not improved by iNO.

Evaluation of a screening protocol using auscultation and portable echocardiography to detect asymptomatic rheumatic heart disease in Tongan schoolchildren

Background Rheumatic heart disease (RHD) is an important problem in developing countries; however, many cases are detected only when the disease has progressed to cardiac failure. Screening can detect cases earlier, but there are no screening guidelines.Methods We performed a cross-sectional screening study in Tonga among 5,053 primary school children, in whom auscultation followed by echocardiography of those with heart murmurs were used to identify RHD. We also analyzed whether a three-stage screening protocol of auscultation performed by a medical student to detect any heart murmur, second-stage auscultation performed by a local pediatrician to differentiate pathological from innocent murmurs and echocardiography of those with pathological murmurs altered outcomes.Results The prevalence of definite RHD was 33.2 per 1,000. The prevalence of RHD increased significantly with age, peaking at 42.6 per 1,000 in children aged 10–12 years. Most valve lesions (91 [54%] of 169) were mild. Auscultation to detect pathological murmurs was poorly sensitive (46.4%), and the finding of any murmur on auscultation did not affect the likelihood of detecting pathology on echocardiography. The finding of a pathological murmur did significantly increase the likelihood of detecting pathology on echocardiography, but still missed 54% of those with pathology (mainly RHD) detected on echocardiography.Conclusions Screening is a useful method for detecting asymptomatic RHD in regions of high prevalence and we report a high echocardiographically confirmed prevalence. The most appropriate screening strategy remains to be confirmed, however, and implementation will depend on the availability of echocardiography and trained staff.

Improved early ventricular performance with a right ventricle to pulmonary artery conduit in stage 1 palliation for hypoplastic left heart syndrome: evidence from strain Doppler echocardiography

Objective: To quantify non-invasively right ventricular (RV) performance in infants after stage 1 palliation for hypoplastic left heart syndrome (HLHS). Design: Prospective, observational study with two dimensional and strain Doppler echocardiography. Setting: Single tertiary paediatric cardiology centre. Patients: Convenience sample of nine consecutive infants with HLHS. Four whose surgery involved a systemic to pulmonary artery (S-PA) shunt were compared with five whose surgery incorporated a right ventricle to pulmonary artery (RV-PA) conduit. Methods: Basal RV free wall longitudinal strain rate, systolic strain (ϵ), and RV percentage area change were calculated during a single assessment between 27–50 days after surgery. Results: Cardiopulmonary bypass time was longer in patients who underwent RV-PA (226 (30) minutes v 181 (18) minutes, p u200a=u200a 0.03), but cross clamp time, duration of ventilation, and inotrope use did not differ. Two patients in the S-PA group died, on days 29 and 60 after surgery. Peak systolic strain rate (−1.24 (0.19)/s v −0.91 (0.21)/s, p u200a=u200a 0.048), peak ϵ (−17.8 (1.8)% v –13.4 (2.0)%, p u200a=u200a 0.01), and RV percentage area change (56 (6)% v 25 (6)%, p < 0.01) were all greater among RV-PA patients. These indices also tended to be greater in survivors as a group. Ventricular loading conditions (oxygen saturations, diuretic treatment, and blood pressure) were similar in both groups. Conclusion: Strain Doppler echocardiography shows improved RV longitudinal systolic contractility in patients during convalescence after the RV-PA modification of stage 1 palliation for HLHS compared with those with an S-PA shunt.

Pulmonary Atresia with Intact Ventricular Septum: Surgical Management Based on Right Ventricular Infundibulum

Abstract The optimal management of infants with pulmonary atresia with intact ventricular septum (PA.IVS) remains a controversy. Attempts have been made to base the surgical approach on various geometrical or morphological characteristics of the right ventricle (RV). However, the overall results remain poor when compared to other complex congenital heart defects. Forty‐eight neonates with PA.IVS were admitted to our unit between 1980 and 1992. The management plan has evolved to be based entirely on the echocardiographic assessment of the state of development of the infundibulum of the RV. In neonates with a well‐formed infundibulum (n = 31), the initial palliation consisted mainly of pulmonary valvotomy (without cardiopulmonary bypass) and PTFE shunt from the left subclavian artery to the main pulmonary artery. There was one death from initial palliation in this subgroup. If necessary, the RV cavity was later enlarged by excision of the hypertrophic muscle of both the trabecular and infundibular portions, before finally attempting biventricular repair. The actuarial probability of achieving a biventricular repair at 40 months of age was 60% (95% CL = 39.5% to 71.3%). Thirteen patients have undergone biventricular repairs with one late death over a total follow‐up of 1,720 patient months. In one patient, the RV failed to grow satisfactorily, necessitating a Fontan procedure. Seventeen patients without a well‐formed infundibulum were approached with a Fontan procedure in mind. The initial palliation in these patients consisted of a modified Blalock‐Taussig shunt only. Ten have undergone a Fontan procedure so far and five are awaiting such repairs. In this group there were four operative deaths: two after initial palliation, and two after Fontan procedures. In patients with a well‐developed infundibulum, the actuarial survival probability was 93% (95% CL = 74% to 98%) at 8 months with no further late deaths over 120 months follow‐up, whereas in patients without a well‐formed infundibulum it was 75% at 40 months (95% CL = 46% to 89%). The overall survival probability at 104 months was 77% (95% CL = 51% to 90%).

Surgical intervention for infective endocarditis in infancy and childhood.

BACKGROUNDnInfective endocarditis is an uncommon but serious disease in children. Optimal treatment strategy, especially surgical indications, continues to evolve.nnnMETHODSnRetrospective review of 98 patients treated for infective endocarditis during the past 13 years at the Royal Childrens Hospital, including medically and surgically treated patients.nnnRESULTSnThirty of 98 patients had surgical intervention with 6.7% hospital mortality, and 76% survival probability at 45 months. The remaining patients were treated medically, with 10% hospital mortality and 52% 5-year survival probability. The incidence of structural heart disease, congestive heart failure, and spectrum of organisms was similar in the two groups.nnnCONCLUSIONSnDespite advances in antibiotic therapy, early surgical intervention is required in a significant subset. Concurrent intracardiac repair may be appropriate.

Management of the univentricular connection: are we improving?

OBJECTIVEnTo assess the impact of the bidirectional cavopulmonary shunt, total cavopulmonary connection, and baffle fenestration on outcome of the Fontan operation in our unit.nnnMETHODnWe reviewed 123 bidirectional cavopulmonary shunts and 264 Fontan operations performed from 1980 to 1995. Analysis of pulmonary artery size (right and left main and lower lobe branches) before and after bidirectional cavopulmonary shunt was performed. Outcome of the Fontan operation was analysed in various time periods to assess the effect of prior bidirectional cavopulmonary shunt, use of the lateral tunnel, and fenestration.nnnRESULTSnOperative risk for the bidirectional cavopulmonary shunt was 4% (CI = 2-10%) with a survival of 89% (CI = 83-95%) at 36 months. Probability of conversion to Fontan operation at 36 months was 49% (CI = 38-61%). Pulmonary artery size (Nakata and lower lobe indices) fell after bidirectional cavopulmonary shunt (P = 0.0006). Fontan risk dropped from 8.5% (1980-1987) to 1.8% (1988-1995) (P = 0.02), coinciding with the use of the bidirectional cavopulmonary shunt. There was no further risk reduction after introduction of the lateral tunnel and baffle fenestration, although these comparisons are limited by relatively small numbers. Duration of hospital stay related to pleural effusions was lowest for patients with a fenestrated lateral tunnel operation (P < 0.05).nnnCONCLUSIONnThe bidirectional cavopulmonary shunt is a suboptimal stimulus for pulmonary artery enlargement, but may reduce the risk of Fontan operation in selected children. Fenestrated lateral tunnel operations have reduced the duration of postoperative pleural effusions.

Impact of antenatal screening on the presentation of infants with congenital heart disease to a cardiology unit.

Aim:u2003 Antenatal diagnosis of congenital heart disease (CHD) facilitates prenatal treatment and optimal perinatal care. This has been demonstrated to improve perinatal mortality and morbidity in neonates with CHD. Thus, antenatal diagnosis of CHD is most likely to benefit patients who require surgery in early infancy. We aimed to examine the frequency of antenatal diagnosis in neonates presenting to The Royal Children’s Hospital severe CHD.

Unnatural history of the right ventricle in patients with congenitally malformed hearts.

The long-term outcome of patients with congenitally malformed hearts involving abnormal right ventricular morphology and haemodynamics is variable. In most instances, the patients are at risk for right ventricular failure, in part due to morphological differences between the right and left ventricles and their response to chronic volume and pressure overload. In patients after repair of tetralogy of Fallot, and after balloon valvotomy for valvar pulmonary stenosis, pulmonary regurgitation is the most significant risk factor for right ventricular dysfunction. In patients with a dominant right ventricle after Fontan palliation, and in those with systemic right ventricles in association with surgically or congenitally corrected transposition, the right ventricle is not morphologically capable of dealing with chronic exposure to the high afterload of the systemic circulation. In patients with Ebsteins malformation of the tricuspid valve, the degree of atrialisation of the right ventricle determines how well the right ventricle will function as the pump for the pulmonary vascular bed.

Validity of the LaFarge equation for estimation of oxygen consumption in ventilated children with congenital heart disease younger than 3 years—A revisit

Background The LaFarge equation is the most commonly used equation to estimate oxygen consumption (Vo2) in patients of all ages with congenital heart disease, although it was generated in patients older than 3 years. We sought to determine the validity of the LaFarge equation in estimating Vo2 in children younger than 3 years undergoing cardiac catheterization with general anesthesia. Methods Vo2 was measured directly using respiratory mass spectrometry in 75 sedated, paralyzed, and mechanically ventilated children in the pediatric cardiac catheterization laboratory. Age ranged from 0.13 to 24 years; 40 children being younger than 3 years. Estimated values for Vo2 were calculated using the LaFarge equation for all patients. The agreement between measured and estimated Vo2 was evaluated by the bias and limits of agreement in the 2 age groups. Regression analysis was used to analyze the influence of age on the agreement. Results A failure of agreement between measured and estimated Vo2 was noted in both groups of children. As compared to the older group of patients, the agreement was significantly poorer in children younger than 3 years, with a significantly greater overestimation introduced by the LaFarge equation (11% ± 21% vs 53% ± 52%, P < .0001). Conclusion The LaFarge equation introduces significant error in the estimation of Vo2 in ventilated patients with congenital heart disease of all ages, particularly in children younger than 3 years.