Evolution of Ventricular Energetics in the Different Stages of Palliation of Hypoplastic Left Heart Syndrome: A Retrospective Clinical Study.

Hyperplastic left heart syndrome (HLHS) patients are palliated by creating a Fontan-type circulation passing from different surgical stages. The aim of this work is to describe the evolution of ventricular energetics parameters in HLHS patients during the different stages of palliation including the hybrid, the Norwood, the bidirectional Glenn (BDG), and the Fontan procedures. We conducted a retrospective clinical study enrolling all HLHS patients surgically treated with hybrid procedure and/or Norwood and/or BDG and/or Fontan operation from 2011 to 2016 collecting echocardiographic and hemodynamic data. Measured data were used to calculate energetic variables such as ventricular elastances, external and internal work, ventriculo-arterial coupling and cardiac mechanical efficiency. From 2010 to 2016, a total of 29 HLHS patients undergoing cardiac catheterization after hybrid (n = 7) or Norwood (n = 6) or Glenn (n = 8) or Fontan (n = 8) procedure were retrospectively enrolled. Ventricular volumes were significantly higher in the Norwood circulation than in the hybrid circulation (p = 0.03) with a progressive decrement from the first stage to the Fontan completion. Ventricular elastances were lower in the Norwood circulation than in the hybrid circulation and progressively increased passing from the first stage to the Fontan completion. The arterial elastance and Rtot increased in the Fontan circulation. The ventricular work progressively increased. Finally, the ventricular efficiency improves passing from the first to the last stage of palliation. The use of ventricular energetic parameters could lead to a more complete evaluation of such complex patients to better understand their adaptation to different pathophysiological conditions.

Aortopulmonary window coexisting with tetralogy of Fallot.

Aortopulmonary window is a rare cardiac malformation presenting either in the isolated form, or in association with other cardiac anomalies. The isolated form usually presents an increased pulmonary blood flow as the main clinical feature, but if associated with other cardiac anomalies the clinical findings change according to the additional defect. Only 19 cases of aortopulmonary window associated with tetralogy of Fallot have been reported. Five of them have associated pulmonary atresia. We report two neonatal cases of aortopulmonary window and tetralogy of Fallot, one of them presenting an associated pulmonary atresia.

Treatment of pulmonary artery stenosis after arterial switch operation: stent implantation vs. balloon angioplasty.

The development of pulmonary artery stenosis is a potential complication during the mid- to long-term follow-up after arterial switch operation (ASO) for transposition of the great arteries. Surgical results have been disappointing and conventional balloon dilation yields a fairly important incidence of failures and recurrences. We evaluated our results with implantation of balloon-expandable stents in 5 out of 13 patients with a previously attempted unsuccessful conventional balloon dilation of pulmonary artery branch stenosis after ASO. In two more cases, stents were used as a primary procedure. Balloon angioplasty achieved a 15% increase in mean diameter of the stenosis vs. 124% with the use of stents (P< 0.01), a 10% decrease of the pressure gradient across the stenosis vs. 71% of stents (P<0.01), and a 10% drop in RV/aorta pressure ratio vs. 43% of stents (P<0.01). Compared to conventional balloon angioplasty in our series, stents were more effective in the treatment of patients with peripheral pulmonary artery stenosis after ASO. Balloon dilation should be considered in selected cases unsuitable for treatment with endovascular stents.

Echocardiographic diagnosis of totally anomalous pulmonary venous connection to the azygos vein.

Totally anomalous pulmonary venous connection to the azygos vein is a rare congenital heart malformation in which all the pulmonary venous blood returns anomalously to the azygos vein. Among 111 consecutive patients with totally anomalous pulmonary venous connection undergoing surgical correction at our institution between June 1982 and September 1997, this malformation was present in seven cases. By echocardiography, using a subxyphoid short-axis view at the atrial level and a modified suprasternal sagittal view, the malformation was diagnosed when the pulmonary venous confluence was traced posteriorly and superiorly relative to the right pulmonary artery and right bronchus, finally reaching reach the superior caval vein. Totally anomalous pulmonary venous connection to the azygos vein was misdiagnosed in the first two patients, both by echocardiography and angiocardiography. In the subsequent five patients, a precise diagnosis was obtained by echocardiography. Echocardiography, therefore, can be considered an accurate diagnostic tool permitting recognition of totally anomalous pulmonary venous connection to the azygos vein, and permitting corrective surgery without recourse to catheterization and angiography.

Total repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals: an integrated approach.

OBJECTIVE: Predicting postrepair right ventricular/left ventricular pressure ratio has prognostic relevance for patients undergoing total repair of pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries. To this purpose, we currently rely on 2 novel parameters: (1) preoperative total neopulmonary arterial index and (2) mean pulmonary artery pressure changes during an intraoperative flow study. METHODS: Since January 1994, 15 consecutive patients (aged 64 +/- 54 months) with pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals were managed according to total neopulmonary arterial index. Seven patients with hypoplastic pulmonary arteries and a total neopulmonary arterial index less than 150 mm(2)/m(2) underwent palliative right ventricular outflow tract reconstruction followed by secondary 1-stage unifocalization and ventricular septal defect closure. The other 8 patients with a preoperative index of more than 150 mm(2)/m(2) underwent primary single-stage unifocalization and repair. The ventricular septal defect was closed in all cases (reopened in 1). In 9, such decision was based on an intraoperative flow study. RESULTS: Patients treated by right ventricular outflow tract reconstruction had a significant increase of pulmonary artery index (P=.006) within 22 +/- 6 months. Repair was successful in 14 cases (postrepair right ventricular/left ventricular pressure ratio = 0.47 +/- 0.1). One hospital death occurred as a result of pulmonary vascular obstructive disease, despite a reassuring intraoperative flow study. Accuracy of this test in predicting the postrepair mean pulmonary artery pressure was 89% (95% CI: 51%-99%). At follow-up (18 +/- 12 months), all patients are free of symptoms, requiring no medications. CONCLUSIONS: The integrated approach to total repair of pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals by preoperative calculation of total neopulmonary arterial index, right ventricular outflow tract reconstruction (when required), and intraoperative flow study may lead to optimal intermediate results.

Amiodarone used alone or in combination with propranolol: a very effective therapy for tachyarrhythmias in infants and children.

The aim of the study was to evaluate the efficacy of amiodarone used alone or in combination with propranolol in infants and children affected by life-threatening or drug-resistant tachyarrhythmias. The study included 27 children (median age 3 months), affected by life-threatening and/or drug-resistant supraventricular or ventricular tachyarrhythmias. The loading dose of amiodarone was 10-20 mg/kg/day and the maintenance dose ranged between 3 and 20 mg/kg/day. When amiodarone was ineffective, propranolol was added at a dosage of 2-4 mg/kg/day. The study population was divided into two groups: group A was composed of patients <1 year and group B of patients >1 year. The effectiveness of the therapy was assessed by clinical evaluation, Holter monitoring, exercise testing, and, in patients with reentry tachycardias, electrophysiological testing. Amiodarone used alone was effective or partially effective in 4/14 (28%) patients in group A and in 11/13 (85%) patients in group B (p < 0.006). Among amiodarone-resistant patients, the combined therapy with propranolol was effective in 8/10 patients in group A and 2/2 patients in group B. Therefore, amiodarone used alone or in combination with propranolol was effective in 25/27 (93%) patients. During the follow-up (20.5 +/- 13 months) there were no arrhythmic effects but side effects were noted in 5/27 (18.5%) patients. Amiodarone seems to be an effective drug in the control of the life-threatening and/or drug-resistant supraventricular and ventricular tachyarrhythmias in children. The addition of propranolol can significantly enhance the success rate of this class III drug, especially in the treatment of reentry tachycardias due to accessory pathways.

Comparison of three different atrial septal defect occlusion devices.

Three different devices were used to close secundum-type atrial septal defects in 28 patients. The "Amplatzer" is associated with an easier and shorter procedure than are the "Sideris Buttoned Device" and the Microvena "Angel Wings" devices.

Permanent overdrive atrial pacing in the chronic management of recurrent postoperative atrial reentrant tachycardia in patients with complex congenital heart disease.

This study investigated the value of permanent atrial pacing as an adjunct to the current therapy in the chronic management of recurrent postoperative atrial reentrant tachycardia in patients with complex congenital heart disease. We studied the postpacing clinical course in 18 patients with recurrent atrial reentrant tachycardias unresponsive to conventional therapy who had an implanted atrial pacemaker. The pacemaker was programmed at a lower pacing rate 20% faster than the spontaneous mean daily rate previously determined with 24-hour Holter monitoring. Serial Holter recordings and pacemaker programming sessions were subsequently performed trying to maintain a paced atrial rhythm overdriving the spontaneous rhythm as long as possible. Twenty-four hour Holter monitoring documented a prevalent (> 80%) paced rhythm during the daily hours in all patients during the follow-up; all patients, however, required at least once a variation in programmed mode and pacing rate. Antiarrhythmic medications were discontinued after 6 months if the patient remained arrhythmia free while on pacing. Recurrences of atrial reentrant tachycardia occurred in five patients (29%) during the initial 6 months interval after the pacemaker implantation, while late recurrences occurred in only two patients (11%). One patient died suddenly 10 months after the pacemaker implant. At the end of the follow-up, 15 patients (83%) were arrhythmia-free and only 2 of them were still on antiarrhythmic drugs. We conclude that permanent atrial overdrive pacing can be an important tool in the management of patients with atrial reentrant tachycardia following repair of congenital heart disease.

Difference in QT interval measurement on ambulatory ECG compared with standard ECG.

Measurement of the QT interval on standard ECG has diagnostic importance in the congenital long QT syndrome, in pharmacological therapy of arrhythmias, as well as in ischemic heart disease. It has been suggested that QT prolongation on ambulatory ECG (Holter) may have similar importance. To assess agreement between methods, QT interval measurement on standard ECG was compared to that on Holter. Simultaneously obtained ECG and Holter tracings (25 mm/s) of the same complexes in leads V1 and V5 were studied in 14 patients (age range 4-36 years). ECG pairs (n = 100, 49 V1 and 51 V5) were compared over a range of QT interval from 300-620 ms, as determined with the use of calipers by two observers blinded to pairing relationship. Correlation between methods was high for both observers (observer 1:r[V1] = 0.872, r[V5] = 0.973; observer 2: r[V1] = 0.972, r[V5] = 0.988), and interobserver variability was small (> 85% of measurements within 20 ms). As compared to ECG, Holter underestimated QT interval in V1, mean difference (QT [Holter]-QT [ECG]) observer 1 (-23 ms, P < 0.001), observer 2 (-7 ms, P < 0.05), and overestimated QT in V5, mean difference observer 1 (+13 ms, P < 0.001), observer 2 (+ 13 ms, P < 0.001). However, individual variation between methods was wide, as expressed by the difference between individual measurements (95% confidence interval [V1]: observer 1 [-99 to +53 ms] observer 2 [-47 to +33 ms]; [V5]: observer 1 [-33 to +59 ms] observer 2 [-17 to +43 ms]). Furthermore, when using the QTA (interval from onset of Q wave to apex of T wave) similar variability was observed. In the assessment of QT interval, potential sources of error of this magnitude could limit the clinical utility of ambulatory monitoring in detecting prolongation of the QT interval for diagnostic purposes.

[Idiopathic recurrent ventricular tachycardia in children: characteristics and long-term prognosis]. / La tachicardia ventricolare idiopatica incessante nel bambino: sue caratteristiche e prognosi a distanza.

BACKGROUND: The aim of this study was to assess the prognosis and the clinical course of incessant idiopathic ventricular tachycardia (VT) with left bundle branch morphology, in a group of 14 children consecutively evaluated in our institutions between 1983 and 1994. METHODS: Mean age of these patients was 8 +/- 2 years, and they were followed for 56 +/- 32 months. In all the children, VT was present for more than 80% of the day, in non sustained runs. The mean rate of VT was of 142 +/- 30 beats/min. Four children were symptomatic. The evaluation of these children was obtained by treadmill stress test (12/14), cardiac catheterization (13/14), electrophysiologic study (10/14), nuclear magnetic resonance (7/14), and serial echocardiographic and Holter examinations. RESULTS: Right ventricular dysplasia was suspected in 2 cases on the basis of nuclear magnetic resonance and angiographic data. In both these cases VT was not suppressed by exercise. Medical treatment was started in 9/14 patients (69%), it was completely effective in 4 (44%) and partially effective in 2 further cases (22%). Thirteen out of fourteen patients had a regular follow-up. No patient died. All patients remained asymptomatic and in 6 (46%) VT disappeared. In 4 of these last 6 patients therapy has been previously effective. Two children, one with right ventricle dysplasia, continue antiarrhythmic treatment. CONCLUSIONS: Incessant VT is well tolerated in pediatric age. The frequency of spontaneous remissions is relatively high (46% of cases). In few patients this arrhythmia is associated with evident cardiac abnormalities. In our opinion, medical treatment is necessary in symptomatic patients and in those with heart abnormalities.

[Transesophageal atrial stimulation in the oral treatment of supraventricular reciprocal paroxysmal tachycardia in infants]. / La stimolazione atriale transesofagea nel trattamento orale della tachicardia parossistica reciprocante sopraventricolare del lattante.

INTRODUCTION: The aim of the study was the evaluation of the usefulness of transesophageal atrial pacing in predicting chronic oral treatment efficacy of symptomatic reciprocating supraventricular tachycardia in infants and in avoiding the risk of very dangerous recurrences at home. METHODS: We studied 13 infants (11 males, 2 females, mean age 43 +/- 31 days) with symptomatic reciprocating supraventricular tachycardia and no structural heart disease. All patients had chronic oral therapy, using the drug effective in acute i.v. somministration. Each patient was discharged when supraventricular tachycardia was not inducible with transesophageal atrial pacing after 5 half-lives of the drug used in chronic oral treatment. All patients, every 6 months, were retested with transesophageal atrial pacing alternatively during chronic oral therapy and after complete wash out. Oral therapy was stopped in each patient when supraventricular tachycardia was not inducible after the wash out. RESULTS: The number of oral treatments tested for each patient were 2 +/- 1 (range 1-5). The number of transesophageal studies performed for each patient were 4 +/- 2 (range 3-7). No patient had symptomatic episodes of supraventricular tachycardia or needed to change therapy during the follow-up. The oral treatment was stopped after the twelfth month of life in 8 patients and after the twenty-fourth in 2 others without recurrences. CONCLUSION: Transesophageal atrial pacing seems to be useful in predicting accurately and rapidly the oral treatment efficacy of supraventricular tachycardia in infants. Our protocol seems to be effective to avoid dangerous recurrences of tachycardia and to decide when we can stop therapy without risk.

New antiarrhythmic drugs in pediatric use: amiodarone.

Amiodarone, a class III antiarrhythmic agent, prolongs action potential duration and refractoriness of all cardiac structures. The drug is more rapidly metabolized in pediatric patients than in adults, but its kinetics are still unique compared with other drugs. Due to the unusual pharmacokinetic characteristics of amiodarone, treatment has to be started by administering loading doses, and there is a significant delay both in the achievement of the full anti-arrhythmic effect and in the development of side effects. Amiodarone is a highly effective agent in pediatric patients with automatic and reentrant supraventricular tachycardia as well as in refractory atrial flutter. Efficacy in ventricular tachycardia has been shown to be variable depending on the underlying anatomical substrate. The incidence of side effects is lower than that observed in adult studies with similar duration of therapy but their incidence is still significant. Amiodarone treatment is associated with a significant risk of proarrhythmic effects, requiring hospitalization of the patient during the loading period.

Efficacy and safety of ventricular rate responsive pacing in children with complete atrioventricular block.

Single chamber rate responsive pacing offers many potential advantages over the more complex dual chamber atrial tracking pacing mode in children, and the preservation of atrioventricular synchrony could be unnecessary in selected groups of pediatric patients. Twenty-two pediatric patients (age range 9 months to 12 years; mean 6.5 years) had implantation of ventricular rate responsive (VVIR) pacemakers over a 2-year period. All patients had chronic third-degree atrioventricular block, and a normal ventricular function at rest. During the follow-up each patient underwent a 24-hour Holter monitoring, and ten performed a graded treadmill test in both ventricular fixed rate (VVI) and rate responsive (VVIR) pacing mode. Paced ventricular rates were found to be normal for age in all 22 patients; maximum rate did not reach the higher programmed rate during daily activities in any patient. Comparing the mean paced ventricular rate to the mean rates of blocked P waves, six patients showed a difference of more than 20 beats/min, which induced the pacemaker parameters to be reprogrammed. In all patients a significant correlation was found between variations of paced ventricular rate and variations of spontaneous blocked atrial rhythm (P < 0.05); this correlation persisted in the subsequent Holter controls in the ten patients with longer follow-up. Exercise tolerance resulted normal in the ten patients who performed a treadmill test either in VVIR or VVI mode, with increased maximal heart rates and maximal systolic blood pressure in VVIR mode (P < 0.0013). Rate responsive ventricular pacemakers seem to adequately respond to the physiological needs of daily life of this selected group of children requiring permanent pacing.

[Central cyanosis in a newborn infant due to a prominence of the eustachian valve]. / Cianosi centrale in un neonato dovuta a prominenza della valvola della vena cava inferiore.

A 3-day-old neonate with severe central cyanosis was found to have a right to left shunt across a secundum atrial septal defect, due to prominence of the Eustachian valve. Two-dimensional echocardiography with Doppler and color Doppler allowed a precise morphological and pathophysiological diagnosis. Cardiac catheterization and angiocardiography confirmed the diagnosis. The patient is asymptomatic 12 months after surgical excision of the Eustachian valve and closure of the atrial septal defect, performed at two months of age.

Cardiac catheterization through the internal jugular vein in pediatric patients. An alternative to the usual femoral vein access.

The percutaneous femoral vein approach is used routinely for cardiac catheterization in the pediatric age but in some children, it may be impossible as in the case of iliac vein or inferior vena cava thrombosis due to previous cardiac catheterization, or inconvenient as for right ventricular endomyocardial biopsies. In the period between 1982 and 1990, 160 cardiac catheterizations or right ventricular endomyocardial biopsies were performed in 102 children. Patients ranged in age between 2 months and 17 years (mean, 3.8 years) and in weight from 3.2 to 57.3 kg (mean, 14.4 kg). Indications for the internal jugular vein approach were as follows: (1) thrombosis of the inferior vena cava due to previous cardiac catheterization in 42 patients (41 percent); (2) right ventricular endomyocardial biopsy after cardiac transplant in 19 patients (19 percent); (3) control catheterization of the pulmonary arteries following classic or bidirectional cavopulmonary anastomosis in 16 patients (16 percent); (4) superior vena cava obstruction following Mustard's procedure in 14 patients (14 percent); (5) failed percutaneous femoral venous approach in six patients (6 percent); and (6) absence of the hepatic segment of the inferior vena cava in four patients (4 percent). The right or left internal jugular vein could be entered in all but three procedures (98 percent). Seventeen patients had more than one procedure through the same internal jugular vein and the vein was found patent in all. A complete right heart cardiac catheterization was performed using this route. Right ventricular endomyocardial biopsy and interventional procedure were performed through this route. Two major complications occurred. A patient developed a central transient ischemic attack and another patient developed a persistent Horner syndrome. Accidental carotid puncture occurred in five patients without consequences. Our data indicate that cardiac catheterization in infants and children can be performed safely through the internal jugular vein, with a high success rate and a low incidence of major complications.