Longitudinal ECG changes in tetralogy of Fallot and association with surgical repair.

Background: ECG abnormalities have been linked to adverse changes in right ventricular (RV) morphology and poor clinical outcomes in repaired Tetralogy of Fallot (rTOF). Our aim was to describe how ECG changes progress in early and intermediate follow-up and whether types of surgical strategy at the time of primary repair affected these changes. Methods: We studied patients with rTOF born 2000-2018 operated at our institution. Seven time points in relation to primary repair, follow-up, and pulmonary valve replacement (PVR) were identified. Patients correct with valve sparing repair (VSR), trans-annular patch (TAP) including with a monocusp valve (TAP + M) and with at least 3 ECGs were included. PQ interval, QRS duration, dispersion, and fragmentation, QTc duration and dispersion, JTc as well as presence of a right bundle branch block (RBBB) were analyzed. Medical records were reviewed for demographic and surgical data. Results: Two hundred nineteen patients with 882 ECGs were analyzed with a median follow-up time of 12.3 years (8.4, 17) with 41 (19%) needing PVR during the study period. QRS duration increased at time of primary repair to discharge from 66 msec (IQR 12) to 129 msec (IQR 27) (p < 0.0001) and at 1- and 6- year follow-up but showed only a modest and temporary decrease after PVR. QTc increased at the time of primary repair as well as prior to PVR. PQ interval showed a small increase at the time of primary repair, was at its highest prior to PVR and decreased with PVR. Type of surgical repair affected mainly QTc and JTc and was consistently longer in the TAP + M group until PVR. In VSR, QTc and JTc were prolonged initially compared to TAP but were similar after 1 year. After PVR, there were no differences in adverse ECG changes between surgical groups. Conclusions: PQ interval and QRS duration best correspond to the assumed volume load whereas the relationship with QTc and JTc is more complex, suggesting that these represent more complex remodeling of the myocardium. Before PVR, QTc and JTc are longer in the TAP + M group which may be due to a longer surgical incision.

Impact of prolonged storage time on homograft ultrastructures: an attempt to find optimal guidelines for homograft processing.

According to guidelines, total ischemic time for homografts at processing must be kept short to avoid degeneration. Many homografts are discarded due to practical inability to finish all steps from procurement to cryopreservation within the time limit. Although, several studies have shown that homografts with prolonged ischemic time show adequate quality and performance. Twenty aortic and 12 pulmonary homografts were collected and biopsies were retrieved at preparation (day 0) and after 1, 2, 3, 4, 7, 14, 21, 28, and 60 days in antibiotic decontamination at 4 °C. Biopsies were prepared for light microscopy (LM) and transmission electron microscopy (TEM). Assessment generated scores for cells, elastin, and collagen. Relative differences between times were compared with Wilcoxon signed rank test. Bonferroni corrected p value of 0.0056 was considered significant. LM could only reveal decrease in cell count at 60 days in aortic homografts, no other differences was detected. TEM showed affected cell appearance in day 3 and day 4 and beyond for aortic and pulmonary homografts respectively. Elastin appearance was affected at day 60 for aortic and day 21 for pulmonary homografts. Collagen appearance was affected at day 28 for aortic homografts, with no significant differences in pulmonary homografts. Cell degeneration starts early after homograft procurement, but elastic and collagen fibers are more resistant to degeneration. Overall structure integrity as seen in LM was not affected at all, while TEM could reveal small degeneration signs in individual elastic fibers and collagen bundles at 21 and 28 days respectively.

Impact of storage time prior to cryopreservation on mechanical properties of aortic homografts.

Optimal time spans in homograft procurement are still debatable among tissue banks and needs to be further investigated. Cell viability decreases at longer preparation intervals, but the effect on collagen and elastic fibers has not been investigated to the same extent. These fibers are of importance to the homograft elasticity and strength. The objective of this study was to analyze the mechanical properties of homograft tissue at different time spans in the procurement process. Ten aortic homografts were collected at the Tissue Bank in Lund. Twelve samples were obtained from each homograft, cryopreserved in groups of three after 2-4 days, 7-9 days, 28-30 days, and 60-62 days in antibiotic decontamination. Mechanical testing was performed with uniaxial tensile tests, calculating elastic modulus, yield stress and energy at yield stress. Two randomly selected samples were assessed with light microscopy. Procurement generated a total of 120 samples, with 30 samples in each time group. Elastic modulus and yield stress was significantly higher in samples cryopreserved after 2-4 days (2.7 MPa (2.5-5.0) and 0.78 MPa (0.68-1.0)) compared to 7-9 days (2.2 MPa (2.0-2.6) and 0.53 MPa (0.46-0.69)), p = 0.008 and 0.011 respectively. Light microscopy did not show any difference in collagen and elastin at different time spans. There was a significant decrease in elastic modulus and yield stress after 7 days of decontamination at 4 °C compared to 2-4 days. This could indicate some deterioration of elastin and collagen at longer decontamination intervals. Clinical significance of these findings remains to be clarified.

Evaluation and comparison of patch materials used for pulmonary arterioplasty in pediatric congenital heart surgery.

Objective: To evaluate the long-term performance of the patch materials we have used to augment the pulmonary arterial tree across a wide spectrum of diagnoses and anatomical locations. Methods: Retrospective, single-center review of 217 consecutive pediatric patients at a tertiary referral center from 1993 to 2020 who underwent patch arterioplasty of the pulmonary arterial tree from the pulmonary bifurcation to the distal pulmonary arterial branches. Reintervention data were collected and analyzed. Lesion-specific anatomy and other variables were analyzed as risk factors for reintervention. Results: There were 280 total operations performed (217 initial operations and 63 reoperations) and 313 patches used. The patches used were autologous pericardium (166, 53.0%), pulmonary homograft (126, 40.3%), and a heterogeneous group of other materials (21, 6.7%). Overall patient survival was 86.2%, freedom from reoperation was 81.0% and freedom from reintervention (FFR) was 70.6%, with a median follow-up of 13.8 years (interquartile range, 6.3-17.9 years). For all patches, 10-, 20-, and 27-year FFR was 76.6%, 70.6%, and 70.6%, respectively. FFR was similar among all 3 patch type groups (P = .29). Multivariable Cox regression analysis showed that diagnoses of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries and hypoplastic left heart syndrome, patches placed at initial cardiac operation, and increasing number of cardiac operations were risk factors for reintervention. Conclusions: Autologous pericardium and pulmonary homograft patches performed similarly. Although patch type conferred no difference in need for reintervention, other risk factors did exist. Namely, diagnoses of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries and hypoplastic left heart syndrome, patch placement at a patient's first cardiac operation, and increasing number of cardiac operations were risk factors for reintervention.

Long-Term Follow-Up of Right Ventricle to Pulmonary Artery Biologic Valved Conduits Used in Pediatric Congenital Heart Surgery.

Valved conduit reconstruction between the right ventricle (RV) and the pulmonary circulation is often necessary in the surgical treatment of complex congenital heart defects. The aim of this study is to evaluate the long-term performance of the three types of conduits we have used and assess risk factors for conduit failure. Retrospective, single-center review of 455 consecutive pediatric patients with 625 conduits from 1990 to 2019 undergoing RV-to-pulmonary artery (PA) reconstruction with a valved conduit. The three conduit types investigated were pulmonary homograft, aorta homograft, and bovine jugular vein (BJV) graft. Overall patient survival was 91.4%, freedom from conduit replacement (FCR) was 47.4%, and freedom from reintervention (FFR) was 37.8% with a median follow-up of 8.7 years (interquartile range 4.3-13.3 years). For pulmonary homografts, 10-, 20-, and 28-year FCR was 79.6%, 68.6%, and 66.0%, respectively. For aortic homografts, 10-, 20-, and 30-year FCR was 49.8%, 31.5%, and 23.0%, respectively. For BJV grafts, 10- and 19-year FCR was 68.1% and 46.0%, respectively. When controlling for baseline variables, FCR was similar for pulmonary homografts and BJV grafts. Overall patient survival was excellent. Risk factors for conduit failure in patients operated with reconstruction of the RV-PA outflow tract included low age, low weight, small conduit size, and certain cardiac diagnoses. There was no evidence for a shorter life span of the second graft. Pulmonary homografts and BJV grafts performed similarly but the risk of endocarditis was greater in the BJV group.

Outcomes following surgical repair of absent pulmonary valve syndrome: 30 years of experience from a Swedish tertiary referral centre.

OBJECTIVES: Absent pulmonary valve syndrome is a rare congenital heart defect with pulmonary artery dilatation and secondary airway compression. Although preoperative respiratory support and early surgical repair with pulmonary arterioplasty are often required in patients with airway compromise, the need for extensive plasty in these patients and for plasty in general in those with no or mild respiratory issues remains debatable. METHODS: We performed a retrospective survey of patients with this diagnosis and repair from 1988 to 2018. RESULTS: Twenty patients were identified. The median age and weight at repair were 0.8 (0.1-2.4) years and 7.0 (2.5-13.8) kg and included a valved conduit in 17 (85%) patients and a transannular patch in 3 patients. Five (29%) patients were ventilator-dependent prior to repair at the age of 0.3 (0.1-0.4) years. Pulmonary arterioplasty was performed in 7 patients (35%), including all 5 with ventilator dependency and 2 with respiratory symptoms due to recurrent infections. Two patients (10%) with preoperative ventilator dependency underwent extensive intrahilar arterioplasty. Preoperative ventilator dependency was associated with earlier repair and reinterventions (P < 0.05). There were 3 late deaths among cases with repair after 2000 (n = 14), none with preoperative ventilator dependency. CONCLUSIONS: The long-term outcomes of patients with this rare defect are good, comparable to those of other previous studies. Reduction pulmonary arterioplasty, which in this study was used only in patients with respiratory distress and ventilator dependency, is associated with excellent survival. Reinterventions are common in these patients.

Does microbiological contamination of homografts prior to decontamination affect the outcome after right ventricular outflow tract reconstruction?

OBJECTIVES: Homografts are often in short supply. Today, European guidelines recommend that all tissues contaminated by any of 18 different bacteria and fungi be discarded before antibiotic decontamination has been conducted. The tissue bank in Lund uses more liberal protocols: It accepts all microbes prior to decontamination except multiresistant microbes and Pseudomonas species. The aim of this study was to analyse the effect of contamination on the long-term outcome and occurrence of endocarditis in recipients. METHODS: Data were collected on homografts and on recipients of homografts in the right ventricular (RV) outflow tract who were operated on between 1995 and 2018 in Lund. The long-term outcome of recipients was analysed in relation to different types of contamination using Cox proportional hazard regression. The proportion of patients with endocarditis was analysed with the χ2 test. RESULTS: The study included 509 implanted homografts. Follow-up was a maximum of 24 years and 99% complete. A total of 156 (31%) homografts were contaminated prior to antibiotic decontamination. Homografts contaminated with low-risk microbes had the lowest reintervention rate, but there was no significant difference compared to no contamination [hazard ratio (HR) 1.1, 95% confidence interval (CI) 0.73-1.7] or contamination with high-risk microbes (HR 1.6, 95% CI 0.87-2.8) in the multivariable analysis. There was no significant difference in the proportion of cases of endocarditis during the follow-up period between recipients of homografts contaminated prior to decontamination and recipients of homografts with no contamination (P = 0.83). CONCLUSIONS: Contamination of homograft tissue prior to decontamination did not show any significant effect on the long-term outcome or the occurrence of endocarditis after implantation in the RV outflow tract. Most contaminated homografts can be used safely after approved decontamination.

Impact of valve fenestrations and structural changes in homografts on the long-term outcome in the recipient.

Homografts have long been used for right ventricular outflow tract (RVOT) reconstruction. Tissue banks struggle to meet the clinical demand of tissue, with insufficient donor availability and strict recommendations on tissue quality with high proportions of discards. This study analyzes the long-term outcome of patients receiving a homograft with small fenestrations of the cusps or other structural changes, to evaluate if minor impairment of the homograft affects the durability. Homograft characteristics and patient outcome were described. Follow-up was maximum 24 years. Structural changes of the homografts were analyzed in relation to patient outcome, using univariable and multivariable Cox proportional hazard regression. Between 1995 and 2018, 468 patients received 535 homografts in the RVOT in Lund. Median recipient age was 13 years. There were 137 (26.9%) reinterventions. Freedom from reintervention was 75.8% (95% CI 71.3-79.7%) at 10 years and 57.4% (95% CI 50.0-64.0%) at 20 years. Small fenestrations of the cusps, fibrosis of the cusps and minor atheromatosis of the vessel did not show any statistically significant impact on long-term outcome, hazard ratio = 0.46 (95% CI 0.11-1.87, p = 0.276) and hazard ratio = 0.80 (95% CI 0.25-2.56, p = 0.704). Minor structural changes of the homografts seem to be acceptable without affecting the long-term durability.

Long-term results of aortic arch reconstruction with branch pulmonary artery homograft patches.

BACKGROUND: Homograft tissue is an important reconstructive material used in the surgical correction of a variety of congenital heart defects. The aim of this study is to evaluate the long-term outcome of pulmonary artery (PA) branch patches used in the reconstruction of the thoracic aorta in children. METHODS: Retrospective review of 124 consecutive pediatric patients undergoing corrective surgery for their congenital heart defects between 2001 and 2016. Survival, reoperation, and reintervention data were collected, as well as imaging data to assess for presence of recoarctation, dilation, or aneurysm formation in the area of patch reconstruction. RESULTS: Overall 15-year survival was 83.9% and 15-year freedom from reintervention in the area of patch reconstruction was 89.2%. Rates of mortality (0%), cardiac transplantation (0%), and reoperation (0.8%) attributable to the area of patch reconstruction were low. The frequency of catheter-based intervention in the area of patch reconstruction was 9.7%; such interventions were successful in all but one patient, who ultimately underwent successful surgical aortoplasty. CONCLUSIONS: Homograft patches harvested from PA branches are an effective reconstructive material used for reconstruction of the aorta in small children. Long-term results show no risk of aneurysm formation and low rates of stenosis formation.

Transplantation-free survival after Norwood surgery for hypoplastic left heart syndrome with aortic atresia: A Swedish national cohort study.

BACKGROUND: Norwood surgery has been available in Sweden since 1993. In this national cohort study, we analysed transplantation-free survival after Norwood surgery for hypoplastic left heart syndrome with aortic atresia. METHODS: Patients were identified from the complete national cohort of live-born with hypoplastic left heart syndrome/aortic atresia 1993-2010. Analysis of survival after surgery was performed using Cox proportional hazards models for the total cohort and for birth period and gender separately. Thirty-day mortality and inter-stage mortality were analysed. Patients were followed until September 2016. RESULTS: The 1993-2010 cohort consisted of 208 live-born infants. Norwood surgery was performed in 121/208 (58%). The overall transplantation-free survival was 61/121 (50%). The survival was higher in the late period (10-year survival 63%) than in the early period (10-year survival 40%) (p = 0.010) and lower for female (10-year survival 34%) than for male patients (10-year survival 59%) (p = 0.002). Inter-stage mortality between stages I and II decreased from 23 to 8% (p = 0.008). For male patients, low birthweight in relation to gestational age was a factor associated with poor outcome. CONCLUSION: The survival after Norwood surgery for hypoplastic left heart syndrome/aortic atresia improved by era of surgery, mainly explained by improved survival between stages I and II. Female gender was a significant risk factor for death or transplantation. For male patients, there was an increased risk of death when birthweight was lower than expected in relation to gestational age.

Surgical Age and Morbidity After Arterial Switch for Transposition of the Great Arteries.

BACKGROUND: Transposition of the great arteries (TGA) is a complex congenital heart disease that requires early diagnosis as well as advanced surgical repair and postoperative support. This study sought to investigate the impact of surgical timing on early postoperative morbidity. METHODS: This study reviewed all patients with TGA repaired at a single institution (Skåne University Hospital, Lund, Sweden) by arterial switch operation (ASO) between June 2001 and June 2017. Major postoperative morbidity (MPM) and death within 30 days after ASOs were documented. Patients with double-outlet right ventricle, chromosomal abnormalities, and noncardiac diseases were excluded. MPM was defined as the presence of at least 1 of the following: delayed sternum closure, reoperation, prolonged mechanical ventilation, noninvasive ventilation after extubation, peritoneal dialysis, extracorporeal membrane oxygenation, and readmission. RESULTS: A total of 241 patients were included, with medians for birth weight, gestational week, and age at surgery of 3.5 kg, 39 weeks, and 5 days, respectively. MPM was encountered in 32.3% of patients. Prematurity (P = .001) and need for aortic arch repair at the time of ASO (P = .04) were associated with a significant increase in MPM. Non-A coronary anatomy, associated ventricular septal defect requiring surgical closure, and fetal diagnosis of TGA had no significant impact on MPM (P = .35, .08, and .21, respectively). There was no significant difference in MPM among the surgical groups (P = .49). CONCLUSIONS: Early complications after ASO do occur and are mostly associated with prematurity and the need for aortic arch repair. Timing of surgical repair does not seem to influence the rate of these complications.

[Important contribution to tissue donation and transplantation by departments of forensic medicine (DFM) in Sweden 2011-16]. / Rättsmedicins viktiga bidrag till vävnadsdonation och transplantations­verksamheten.

The number of organ donors in Sweden is not enough to cover the need of tissues for transplant purposes. Other sources have to be defined. Young and healthy potential donors can be identified within DFM. Without precise written agreements and a well-educated and trained organization those donations will not be realized. With the purpose to evaluate national efforts to establish close cooperation between tissue establishments and DFM, two surveys were conducted at two time periods, 2011-13 and 2014-16. A total of 2118 pieces of tissue were retrieved within 6 years, 1799 for transplant purposes and 319 for research or education. Most common tissues were heart valves and cornea but also skin and ear bones were collected. 23% of all retrieved tissue from deceased donors in Sweden came from DFM. In the first period 19 % of all transplanted tissue came from DFM and in the latter period it had increased to 26%. Education and national courses for employees in DFM as well as logistic and economical support from national authorities are important factors for building a stable organization and for sustainable progress.

Comprehensive echocardiographic imaging of atrioventricular valves in children with atrioventricular septal defect: Accuracy of 2D and 3D imaging and reasons for disagreement.

OBJECTIVE: To compare the accuracy and reasons for disagreement of two-dimensional (2D) and three-dimensional (3D) echocardiography findings in the assessment of the atrioventricular valve complex in patients with atrioventricular septal defect. METHODS: A total of 20 children (mean age 8 months) with atrioventricular septal defect were enrolled prospectively into this study. The accuracy of and the reasons for disagreement in the assessment of the atrioventricular valve features were analyzed between 2D and 3D echocardiography and surgical findings. RESULTS: We found that in assessing the Rastelli type and the extension of the inferior leaflet into the right ventricle, 3D echocardiography was more accurate compared to 2D echocardiography. In all other features, 2D and 3D echocardiography showed similar accuracy. A significant reason for inaccuracy by both echo modalities was that the technique itself could not visualize the feature, although the image quality was considered to be adequate. In most cases, where it was not possible to visualize the atrioventricular feature by 2D, it was possible by 3D, and vice versa. CONCLUSION: The accuracy of 2D and 3D echocardiography and understanding the potential reasons for disagreements in assessing the atrioventricular valve complex with 2D and 3D can guide the use of those two techniques when combining them in the clinical practice.

Changing Epidemiology of Hypoplastic Left Heart Syndrome: Results of a National Swedish Cohort Study.

Background Norwood surgery provides a palliative surgical option for hypoplastic left heart syndrome and has been available in Sweden since 1993. The practice of prenatal ultrasound screening was gradually implemented in the same era, resulting in an increased prenatal detection rate. Our primary aims were to study changes in the incidence of live births, prenatal detection rate, and the termination of pregnancies over time. The secondary aims were to study the proportion of live-borns undergoing surgery and to identify factors that influenced whether surgery was or was not performed. Methods and Results Neonates with hypoplastic left heart syndrome with aortic atresia born 1990-2010 were identified through national databases, surgical files, and medical records. The fetal incidence was estimated from the period when prenatal screening was rudimentary. The study period was divided into the presurgical, early surgical, and late surgical periods. The incidence was calculated as the overall yearly incidence for each time period and sex separately. Factors influencing whether surgery was performed were analyzed using Cox-logistic regression. The incidence at live birth decreased from 15.4 to 8.4 per 100 000. The prenatal detection rate increased from 27% to 63%, and terminations increased from 19% to 56%. The odds of having surgery was higher in the late period and higher in the group with prenatal diagnosis. Conclusions We observed a decrease in incidence of live-borns with hypoplastic left heart syndrome aortic atresia. There was in increase in prenatal detection rate and an increase in termination of pregnancy. The proportion of live-borns who underwent surgery increased between time periods.

Preoperative Coronary Anatomy Assessment with Echocardiography and Morbidity After Arterial Switch Operation of Transposition of the Great Arteries.

In transposition of the great arteries (TGA), certain coronary patterns have been associated with major adverse events early after the arterial switch operation (ASO). We sought to determine the impact of preoperative echocardiographic (ECHO) diagnosis on the intra- and postoperative morbidity. All patients with TGA born between June 2001 and June 2017 and who underwent ASO were reviewed. Data on presumed coronary anatomy (CA) preoperatively were obtained from the preoperative ECHO report. Intraoperative CA was categorized according to Yacoub classification. Major postoperative morbidity included at least one of the following: delayed sternal closure (DSC), prolonged (> 72 h) mechanical ventilation, reintubation, peritoneal dialysis (PD), ECMO, reoperation, and readmission within 30 days after surgery. 240 patients with median age of 5 days (range 1-614) and mean weight at surgery was 3.6 kg (1.8-8.4) were included. Preoperative ECHO assessment of CA was available in 228 patients. Intraoperatively, 181 patients (75%) were found to have type A, 25 patients had type B or C or intramural (B-C-IM; 10%), and 34 patients had type D or E (D-E; 14%). Patients with types B, C, and intramural coronary (B-C-IM) had increased risk for delayed sternum closure (9/25 vs. 20/181 in type A and 8/34 in type D-E; p = 0.04), peritoneal dialysis (4/25 vs. 8/181 and 1/34; p = 0.04), and ECMO (2/25 vs. 1/131 and 1/34; p = 0.02). Within the B-C-IM group, preoperative ECHO raised suspicion of type A in 13 patients (i.e., incorrect diagnosis, ID; 52%), whereas non-A CA was suspected in 12 patients (i.e., correct diagnosis, CD; 48%). With the exception of reoperation, which was seen only in the ID subgroup (4/12 vs. 0/10 in the CD subgroup; p = 0.04), the intraoperative (cardiopulmonary bypass time and cross-clamp time) and postoperative morbidity indices were comparable in both ID and CD subgroups (p > 0.1). Although there is a significant risk for early postoperative morbidity in TGA patients with single, interarterial, and intramural CA, there seems to be relatively limited influence of preoperative ECHO assessment of coronary anatomy on this morbidity burden.

Long-Term Outcome of Homograft Implants Related to Donor and Tissue Characteristics.

BACKGROUND: Cardiovascular homografts are used for right ventricular outflow tract reconstruction. The procedure has excellent survival rates, but many homografts degenerate and require reintervention. Studies analyzing risk factors for reintervention most often focus on recipient and homograft characteristics, with identification of risk factors such as young recipient age and the use of aortic homografts. This study focuses on less known variables, including donor characteristics and homograft management and its effect on long-term outcome of homograft implantation. METHODS: A retrospective study was conducted of 304 patients undergoing right ventricular outflow tract reconstruction at University Hospital Lund, Sweden, between 1995 and 2008. Follow-up was up to 22 years. Donor, homograft, and recipient characteristics were analyzed. Statistical analyses included the Kaplan-Meier method with log-rank test and Cox proportional hazard regression. RESULTS: Follow-up was 98% complete. There were 12 deaths, and 115 reinterventions were required. Younger donor age was identified as a risk factor. Homografts from multiorgan donors with no ischemic time produced the longest homograft survival. In non-heart-beating donors, long-term results did not differ between 1 and 24 hours of ischemic time and more than 24 hours of ischemic time. Longer retrieval to cryopreservation times seemed to be better compared with shorter time intervals. Long-term outcome was superior in homografts from middle-aged donors. CONCLUSIONS: The best long-term outcome was found when homografts were retrieved from organ donors and middle-aged donors. There is no harm extending the ischemic time in non-heart-beating donors to 48 hours to increase the number of possible donors.

Decreased Diastolic Ventricular Kinetic Energy in Young Patients with Fontan Circulation Demonstrated by Four-Dimensional Cardiac Magnetic Resonance Imaging.

Four-dimensional (4D) flow magnetic resonance imaging (MRI) enables quantification of kinetic energy (KE) in intraventricular blood flow. This provides a novel way to understand the cardiovascular physiology of the Fontan circulation. In this study, we aimed to quantify the KE in functional single ventricles. 4D flow MRI was acquired in eleven patients with Fontan circulation (median age 12 years, range 3-29) and eight healthy volunteers (median age 26 years, range 23-36). Follow-up MRI after surgical or percutaneous intervention was performed in 3 patients. Intraventricular KE was calculated throughout the cardiac cycle and indexed to stroke volume (SV). The systolic/diastolic ratio of KE in Fontan patients was similar to the ratio of the controls' left ventricle (LV) or right ventricle (RV) depending on the patients' ventricular morphology (Cohen´s κ = 1.0). Peak systolic KE/SV did not differ in patients compared to the LV in controls (0.016 ± 0.006 mJ/ml vs 0.020 ± 0.004 mJ/ml, p = 0.09). Peak diastolic KE/SV in Fontan patients was lower than in the LV of the control group (0.028 ± 0.010 mJ/ml vs 0.057 ± 0.011 mJ/ml, p < 0.0001). The KE during diastole showed a plateau in patients with aortopulmonary collaterals. This is to our knowledge the first study that quantifies the intraventricular KE of Fontan patients. KE is dependent on the morphology of the ventricle, and diastolic KE indexed to SV in patients is decreased compared to controls. The lower KE in Fontan patients may be a result of impaired ventricular filling.