D. Schranz

Primary Noncompaction of the Ventricular Myocardium from the Morphogenetic Standpoint

This review compiles the current knowledge of normal and abnormal myocardial morphogenesis to facilitate an unambiguous diagnosis of primary myocardial noncompaction. During the early stages of development, the formation of trabeculae with the resulting increase in myocardial surface is a adaptation of the rapidly growing heart to improve nourishment by exchange diffusion from the cardiac lumen. Once the coronary vasculature has developed, the switch to cardiac nutrient supply through active circulation from the subepicardial space is paralleled by gradual compaction of the myocardial trabeculae. This results in a decrease of the inner, trabeculated myocardial layer with a parallel increase in thickness of the outer, compact myocardial layer. Similar to the direction of coronary arterial development, this process proceeds from the epicardium toward the endocardium and from the base of the heart to the apex. Based on developmental data, congenital myocardial noncompaction represents a failure of normal embryonic myocardial maturation. The time of arrest of this process will determine the extension of myocardial noncompaction within the ventricle. Whereas disturbances of myocardial microcirculation are frequent in these hearts, direct communications between the myocardial cavity and the coronary arteries (sinusoids) do not belong to this morphogenetic entity.

Impact of residual right ventricular outflow tract obstruction on biventricular strain and synchrony in patients after repair of tetralogy of Fallot: a cardiac magnetic resonance feature tracking study

OBJECTIVES Residual right ventricular outflow tract (RVOT) obstruction (RVOTO) is considered beneficial in patients after repair of tetralogy of Fallot (TOF) although underlying mechanisms are unknown. We sought to elucidate differences in myocardial strain and dyssynchrony parameters in patients after TOF repair with and without residual RVOTO using cardiovascular magnetic resonance (CMR) feature-tracking (CMR-FT) analysis. METHODS Fifty-four patients (mean age 16.4 ± 8.4 years) were assessed by CMR 14.2 ± 7.3 years after repair of TOF. Residual RVOTO on echocardiography was defined as a peak systolic RVOT gradient >25 mmHg and was present in 27 patients (no RVOTO in n = 27 patients). Right ventricular (RV) and left ventricular (LV) strain measurements were performed using CMR-FT software. RESULTS The two groups were well matched for age at CMR scan, time and type of surgical repair. There was no difference in the degree of pulmonary regurgitation (PR) and RV end-diastolic volume. Patients with RVOTO showed significant higher RV circumferential strain (CS) (P = 0.02) and RV radial strain (RS) (P = 0.02) values, whereas RV longitudinal strain (LS) did not differ between the two groups (P = 0.39). The degree of RVOTO showed a significant correlation with RV-CS (r = 0.37; P = 0.006) and RV-RS (r = 0.30; P = 0.03) while RV-LS was unrelated to RVOTO (r = 0.06; P = 0.68). Significant relationships between RV and LV strain parameters were only found in the RVOTO group. Interventricular dyssynchrony was significantly higher in the group without RVOTO (P = 0.03) while LV-LS (P = 0.03) and LV intraventricular synchrony (P = 0.05) were impaired in the RVOTO group. CONCLUSIONS In patients after TOF repair, residual RVOTO seems to preserve RV strain and results in stronger RV-LV interactions and less interventricular dyssynchrony and may therefore possess an early protective effect on RV remodelling. However, the potential negative impact of residual pulmonary stenosis on LV strain and intraventricular synchrony needs further investigation.

Impaired cardiac growth and function in children and adolescents after heart transplantation assessed by cardiac magnetic resonance

Methods Seventy-five pediatric HTx patients (mean age 14.0 ± 4.2 years, 26 females) were assessed by CMR 11.2 ± 5.4 years after HTx (time interval between HTx and CMR at least 1 year). Right (RV) and left ventricular (LV) volumes and LV mass were derived from short-axis cine images. The results were compared with a healthy reference population of 79 patients (mean age 13.7 ± 3.7 years, 29 females, p = 0.30) from the German Competence Network for Congenital Heart Defects. LV strain measurements were performed using CMR feature tracking (FT) software (TomTec, Germany) and were compared with a group of 46 healthy controls (mean age 13.3 ± 3.5 years, 21 females).

Transcatheter creation of a de novo communication across an extracardiac Fontan conduit for catheter ablation of a “left-sided” accessory pathway

Extracardiac polytetrafluoroethylene (PTFE) conduits are often used in modified Fontan procedures for separating systemic and pulmonary circulations in morphological and functional single ventricles [1]. However, most arrhythmia substrates of congenital and acquired supraventricular tachycardias will then be located ‘‘left-sided’’ across the extracardiac conduit. Remote magnetic navigation not only may facilitate a retrograde approach, but may also fail to reach the arrhythmia substrate [2]. Hybrid intervention consisting of transcatheter ablation via a sternotomy approach and atriotomy incision [3] as well as catheter ablation via direct transthoracic percutaneous access [4] have been described, but appear to be associated with frequent complications. An antegrade approach via femoral access requires special techniques for traversing the stiff PTFE material, the pericardial space and the atrial muscular wall. This is the first report that describes a modified transseptal puncture technique using no more than mechanical force [5] for successful catheter ablation across an extracardiac PTFE Fontan conduit. A 23-year-old male patient with double-outlet right ventricle, mitral atresia, severe left ventricular hypoplasia, subpulmonary ventricular septal defect, valvular pulmonary stenosis and D-transposition of the great arteries after modified Fontan anastomosis presented with a 15-year history of recurrent supraventricular tachycardia. Bidirectional superior cavopulmonary anastomosis (Glenn) had been performed at the age of 6 years, modified Fontan anastomosis with an extracardiac non-fenestrated 19 mm PTFE conduit connecting the inferior vena cava and the pulmonary arteries 2 years later. Tricuspid valve (TV) repair employing an anuloplasty ring was carried out for tricuspid regurgitation at the age of 17 years. Despite various oral antiarrhythmic medications [propafenone (up to 600 mg per day, 13 mg/kg per day); propafenone (up to 600 mg per day, 13 mg/kg per day) plus bisoprolol (2,5 mg per day) plus digoxin (aiming at serum levels of 1–2 ng/ ml); sotalol (up to 320 mg per day, 5 mg/kg per day); sotalol (160 mg per day) plus digoxin (aiming at serum levels of 1–2 ng/ml)], the patient continued to experience recurrent adenosine-sensitive supraventricular tachycardias (cycle length 340 ms). After discontinuation of antiarrhythmic medication, electrophysiology testing was performed with one steerable quadripolar catheter placed retrograde across the aortic valve in a right ventricular (RV) position and with one steerable decapolar catheter at the junction of the left pulmonary artery and the calcified extracardiac conduit where atrial sensing and pacing was possible. A supraventricular tachycardia (cycle length 350 ms) characteristic for orthodromic atrioventricular reciprocating tachycardia (AVRT) was easily induced by programmed ventricular pacing (Fig. 1a, b). Electroanatomical mapping of earliest retrograde atrial activation during tachycardia was performed using the EnSite Velocity Cardiac Mapping System (EnSite NavX, St. Jude Medical, St. Paul, MN, USA). Using the steerable quadripolar catheter placed retrograde across the aortic valve, the G. Kerst (&) D. Schranz M. B. Gonzalez y Gonzalez Department of Pediatric Cardiology, Pediatric Heart Center Giessen, University Children’s Hospital, Feulgenstr. 10-12, 35392 Giessen, Germany e-mail: gunter.kerst@paediat.med.uni-giessen.de

Heart Rate Variability is Related to Disease Severity in Children and Young Adults with Pulmonary Hypertension.

Background Pulmonary hypertension (PH) is frequently associated with an increase in sympathetic tone. This may adversely affect cardiac autonomic control. Knowledge about the clinical impact of autonomic dysfunction in patients with PH is limited. We aimed to assess whether parameters of heart rate variability (HRV) are related to disease severity in children with PH. Methods Parameters of HRV [SDNN, standard deviation of normal-to-normal intervals and SDANN, standard deviation of mean values for normal-to-normal intervals over 5 min] were determined from Holter electrocardiograms of 17 patients with PH without active intracardial shunt (10 female, mean age 12.8 ± 8.7 years). Patients were allocated to two groups according to their disease severity: patients with moderate PH [ratio of pulmonary to systemic arterial pressure (PAP/SAP ratio) < 0.75] (n = 11), patients with severe PH (PAP/SAP ratio > 0.75) (n = 6). An additional group of five adolescents with Eisenmenger syndrome (PAP/SAP ratio 1.13 ± 0.36) was included. Results Children with severe PH had significantly lower values of HRV [SDNN (73.8 ± 21.1 vs. 164.9 ± 38.1 ms), SDANN (62.2 ± 19.0 vs. 139.5 ± 33.3 ms)] compared to patients with moderate PH (p = 0.0001 for all). SDNN inversely correlated with ratio of PAP/SAP of PH patients without shunt (r = −0.82; p = 0.0002). Eisenmenger patients showed no significant difference of HRV [SDNN 157.6 ± 43.2 ms, SDANN 141.2 ± 45.3 ms] compared to patients with moderate PH without shunt (p > 0.05 for all). Conclusion According to our results, children with severe PH may have alterations in HRV. Since HRV appears to be related to disease severity, it may therefore serve as an additional diagnostic marker of PH. Remarkably, although Eisenmenger patients have systemic pulmonary arterial pressures, they seem to have preserved HRV, which might reflect a more favorable autonomic adaptation.

Ventricular function and vascular dimensions after Norwood and hybrid palliation of hypoplastic left heart syndrome

Objective Norwood and hybrid procedure are two options available for initial palliation of patients with hypoplastic left heart syndrome (HLHS). Our study aimed to assess potential differences in right ventricular (RV) function and pulmonary artery dimensions using cardiac magnetic resonance (CMR) in survivors with HLHS. Methods 42 Norwood (mean age 2.4±0.8) and 44 hybrid (mean age 2.0±1.0 years) patients were evaluated by CMR after stage II palliation prior to planned Fontan completion. Initial stage I Norwood procedure was performed using a modified Blalock-Taussig shunt, while the hybrid procedure consisted of bilateral pulmonary artery banding and arterial duct stenting. Need for reinterventions and subsequent outcomes were also assessed. Results Norwood patients had larger RV end-diastolic dimensions (91±23 vs 80±31 mL/m2, p=0.004) and lower heart rate (90±15 vs 102±13, p<0.001) than hybrid patients. Both Norwood and hybrid patients showed preserved global RV pump function (59±9 vs 59%±10%, p=0.91), while RV strain, strain rate and intraventricular synchrony were superior in the Norwood group. Pulmonary artery size was reduced (lower lobe index 135±74 vs 161±62 mm2/m2, p=0.02), and reintervention rate was significantly higher in the hybrid group whereas subsequent outcome did not differ significantly (p=0.24). Conclusions Norwood and hybrid strategy were associated with equivalent and preserved global RV pump function while development of the pulmonary arteries and reintervention rate were superior using the Norwood approach. Impaired RV myocardial deformation as a potential marker of early RV dysfunction in the hybrid group may have a negative long-term impact in this population.

Long-Term Outcome of Renal Function with Everolimus Treatment in a Pediatric Center

Purpose Survival after heart transplantation (HTX) has improved and therefore major morbidities like renal dysfunction are increasing and affecting the long-term outcome over time. One reason for renal dysfunction is the use of calcineurin-inhibitors. Treatment changes to mTOR-inhibitors like everolimus have shown to stabilize renal function. We previously showed an increase in renal function after 1 year of everolimus treatment. The purpose of this study was to evaluate how patients (pts) did after 5 years and if renal function could be preserved. Methods and Materials We followed renal function in 28 pts that were initially switched to everolimus when calculated GFR (cGFR) was less than 75 ml/min/1.73m. Serum creatinine and cGFR were determined before and after 1 and 5 years of everolimus treatment. Creatinine Clearance was also followed by 24-hour-urine samples when available and proteinuria was detected with spot urine or 24-hour-urine sample. Results Median serum creatinine stayed stable with 1.2(range 0.7-3.7) mg/dl before everolimus to 1.0(range 0.5-1.9) mg/dl and 1.1(range 0.5-2) mg/dl after 1 and 5 years. Median cGFR was 47.81(range 18.3-72.6) ml/min/1.73 m 2 before everolimus and 64.8 (range 37.7-106.6) ml/min/1.73m 2 after 1 and 72.27 (range 39.2-113.6) ml/min/1.73 m 2 after 5 years. Median age at switch was 11.93 (range 6.8-32.8) with 10.51 (range 3.3-16) years after HTX, 5 pts were older than 18 years at time of switch. Everolimus treatment was stopped in 7 pts due to side effects: infection (n=2), lymph edema (n=1), acne (n=1), elevated liver enzymes (n=1) and compliance (n=2). Median treatment duration in these pts was 2.41 (range 0.3-4.9) years. Conclusions Renal dysfunction can be stabilized by conversion to everolimus-treatment. Short term results could be confirmed by the results after 5 years. Treatment was generally tolerated well. Everolimus treatment should be considered in pts with developing renal dysfunction to preserve function and therefore reduced morbidities.

Transcatheter closure of a perimembranous ventricular septal defect in isolated dextrocardia

Priv.-Doz. Dr. Ulrike Bartram ()) Ina Michel-Behnke · Dietmar Schranz Department of Pediatric Cardiology University Children’s Hospital Gießen Feulgenstr. 12 35385 Gießen, Germany Tel.: +49-6 41 / 9 94 34 61 Fax: +49-6 41 / 9 94 34 69 E-Mail: ulrike.bartram@paediat.med.uni-giessen.de Sirs: In a 6-year-old boy, closure of a perimembranous ventricular septal defect (VSD) was indicated because of progressive tricuspid regurgitation secondary to the chronic left-to-right shunt. In addition, the boy had isolated dextrocardia – the heart being located in the right side of the chest, the situs of the other viscera being solitus. Right-left orientation within the heart was normal. Percutaneous closure of the defect was performed using a modification of the standard technique [6]. A left ventricular angiogram profiled the small VSD (Fig. 1 a). Despite the dextrocardia it was possible to cross the VSD from the left ventricle with a right Judkins catheter and establish an arteriovenous circuit using a Terumo wire and a goose neck snare. Following the advancement via the VSD into the ascending aorta, the guiding sheath was brought in stable position in the left ventricular outflow tract in kissing position with the arterially advanced pigtail catheter. When the Terumo wire was removed, the released pigtail catheter delineated the membranous septum (Fig. 1 b). In succession, the leftand rightsided discs of a 4 mm Amplatzer membranous VSD occluder were deployed. Final transthoracic echocardiographic and angiographic evaluation (Fig. 1 b) demonstrated complete occlusion of the VSD without compromise to the cardiac valves. The patient was discharged on aspirin. Echocardiographic follow-up at 6 months documented improvement of tricuspid regurgitation.