Importance of gamma-glutamyl transferase elevation in patients with Fontan-associated liver disease.

AIM: In patients with Fontan-associated liver disease (FALD), gamma-glutamyl transferase (GGT) levels are often elevated, however, its clinical importance is unclear. We investigated the relationship between the clinical course of FALD and GGT levels. METHODS: We enrolled 145 patients with FALD who underwent right-heart catheterization (RHC) and visited our department. Ursodeoxycholic acid (UDCA) was administered to 62 of the patients. Patients with GGT levels <50 and ≥50 U/L were compared. Follow-up RHC was undertaken in 76 patients. Cases in which GGT levels decreased by ≥10% or <50 U/L were defined as improved (n = 33). RESULTS: Patients with GGT levels ≥50 U/L had significantly lower levels of albumin and higher levels of alanine transaminase (ALT) but no significant differences in RHC factors. Over a 4.6-year period, 43.4% showed improvement in GGT levels. Improved cases had significantly lower total bilirubin (1.1 vs. 1.6 mg/dL), AST (22 vs. 28 U/L), and ALT (18 vs. 27 U/L) levels than nonimproved cases (n = 29, p < 0.05), and the change in platelet count (-0.5 vs. -3.0 × 10-4/µL) was significantly lower in the latter (p = 0.03). The improvement rate was significantly higher in UDCA-treated cases (55.2%) with GGT levels ≥50 U/L compared to cases not treated with UDCA (18.2%, p = 0.04). CONCLUSION: In cases of FALD with no improvement in GGT level, the platelet count decreased over time, suggesting progression of fibrosis. Physicians should be aware of the importance of a high GGT level in patients with FALD.

α/ß- and ß-Blocker Exposure in Pregnancy and the Risk of Neonatal Hypoglycemia and Small for Gestational Age.

BACKGROUND: α/ß- and ß-blockers are essential in pregnant women's perinatal congenital heart disease management. Nevertheless, data on the effects of α/ß- and ß-blockers on pregnant women and fetuses are limited. We examined the risks of neonatal hypoglycemia and small for gestational age (SGA) associated with maternal exposure to α/ß- and ß-blockers.Methods and Results: All consecutive pregnant women with heart disease admitted to our hospital between January 2014 and October 2020 were included. Of 306 pregnancies (267 women), 32 were in the α/ß-blocker group, 11 were in the ß-blocker group, and 263 were in the control group. All 32 pregnancies in the α/ß-blocker group were treated with carvedilol. In the ß-blocker group, 4 women were treated with bisoprolol, 3 were treated with propranolol, 2 were treated with atenolol, 1 was treated with metoprolol, and 1 was treated nadolol. The incidence of neonatal hypoglycemia was higher in pregnant women taking carvedilol than in the control group (P=0.025). SGA was observed significantly more frequently in pregnant women taking ß-blockers than in the carvedilol and control groups (P<0.001). CONCLUSIONS: Carvedilol administration during pregnancy was associated with neonatal hypoglycemia; however, it did not occur in a time- or dose-dependent manner. Routine monitoring of blood glucose levels in newborns exposed to α/ß- and ß-blockers is essential.

Utility of urinary liver-type fatty acid-binding protein as a prognostic marker in adult congenital heart patients hospitalized for acute heart failure.

Progression to acute kidney injury (AKI) under treatment in adult congenital heart disease (ACHD) patients with heart failure is associated with poor prognosis, early detection and interventions are necessary. We aimed to explore the utility of urinary liver-type fatty acid binding protein (L-FABP) in ACHD patients hospitalized for acute decompensated heart failure (ADHF). We prospectively evaluated hemodynamic, biochemical data, and urinary biomarkers including urinary L-FABP in ACHD patients hospitalized in our institution from June 2019 to March 2022. The primary outcomes were the development of AKI and death. AKI was defined as serum creatinine level increased by 0.3 mg/dl or more within 5 days after hospitalization. A total of 104 ADHF patients aged 31 (36-51) years were enrolled. 26 cases (25% of ADHF patients) developed AKI during hospitalization and 4 died after hospital discharge. Serum creatinine (sCr), serum total bilirubin, brain natriuretic peptide (BNP), and urinary L-FABP in AKI patients were significantly higher than in non-AKI patients, whereas systemic oxygen saturation of the peripheral artery (SpO2) and estimated glomerular filtration ratio in AKI patients were lower than non-AKI patients. There was no difference in the intravenous diuretic dose on admission and during hospitalization between the two groups. In the receiver operating characteristic (ROC) analysis, the maximum area under the curve (AUC) of urinary biomarkers in AKI patients was urinary L-FABP (AUC = 0.769, p < 0.001) with a cutoff value of 4.86 µg/gCr. Urinary L-FABP level on admission was associated with a predictor for AKI development during hospitalization after adjusting for sCr, BNP and SpO2. Urinary L-FABP was a useful predictor for the development of AKI in ACHD patients hospitalized for ADHF. Monitoring of urinary L-FABP allows us to detect a high-risk patient earlier than the conventional biomarkers.

Abdominal lymphatic pathway in Fontan circulation using non-invasive magnetic resonance lymphangiography.

Lymphatic congestion is known to play an important role in the development of late Fontan complications. This study aimed to (1) develop a gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) contrast three-dimensional heavily T2-weighed MR technique that can detect abnormal lymphatic pathway in the abdomen while simultaneously evaluating hepatocellular carcinoma (HCC) and to (2) propose a new classification of abnormal abdominal lymphatic pathway using a non-invasive method in adults with Fontan circulation. Twenty-seven adults with Fontan circulation who underwent Gd-EOB-DTPA abdominal MR imaging were prospectively enrolled in this study. We proposed MR lymphangiography that suppresses the vascular signal on heavily T2-weighted imaging after EOB contrast. The patients were classified as follows: grade 1 with almost no lymphatic pathway, grade 2 with a lymphatic pathway mainly around the bile duct and liver surface, and grade 3 with a lymphatic pathway mainly around the vertebral body and inferior vena cava. The grade 3 group showed the lowest oxygen saturation level, highest central venous pressure, highest incidence of massive ascites, HCC, and focal nodular hyperplasia. This group also tended to have patients with the oldest age and highest cardiac index; however, the difference was not statistically significant. As for the blood test, the grade 3 group showed the lowest platelet count and serum albumin level and the highest fibrosis-4 index. A novel technique, Gd-EOB-DTPA MR lymphangiography, can detect abnormal abdominal lymphatic pathways in Fontan circulation, which can reflect the severity of failing Fontan.

Predictors of long-term mortality among perioperative survivors of Fontan operation.

AIMS: The criteria for 'good' Fontan haemodynamics have been poorly defined in relation to long-term outcomes. The aim of this study was to identify the risk factors for mortality among haemodynamic parameters obtained early after the Fontan operation. METHODS AND RESULTS: Clinical data of all perioperative survivors of the Fontan operation performed before 2011, from nine institutions, were collected through a retrospective chart review. In total, 1260 patients were included. The median age at the time of Fontan operation was 3.6 years. Post-operative cardiac catheterization was conducted in 1117 patients at a median period of 1.0 years after the operation. During the median follow-up period of 10.2 years, 107 patients died. The mortality rates at 10, 20, and 25 years after the operation were 5%, 12%, and 22%, respectively. On multivariable analysis, older age at the time of the operation {≥15 years, hazard ratio (HR) [95% confidence interval (CI)]: 3.2 (1.7-5.9)} and haemodynamic parameters obtained at post-operative catheterization, such as low ejection fraction [<30%, HR (95% CI): 7.5 (3.2-18)], low systemic oxygen saturation [<80%, HR (95% CI): 3.8 (1.6-9.1)], high central venous pressure [≥16 mmHg, HR (95% CI): 2.3 (1.3-3.9)], and low mean systemic arterial pressure [<60 mmHg, HR (95% CI): 3.0 (1.4-6.2)] were identified as independent predictors of mortality. The predictive model based on these parameters had a c-index of 0.75 at 10 years. CONCLUSIONS: Haemodynamic parameters obtained at a median period of 1.0 years, post-operatively, can accurately identify patients with a high mortality risk, who may need intensive management to improve long-term outcomes.

Platelet volume indices correlate to severity of heart failure and have prognostic value for both cardiac and thrombotic events in patients with congenital heart disease.

Patients with heart failure (HF) reportedly have activated platelets with increased platelet distribution width (PDW) and mean platelet volume (MPV), which lead to thrombotic events. These platelet indices are easily measured by routine blood tests and have been proposed as potential markers of cardiac events. We performed the present study to clarify whether platelet indices correlate to the severity of HF and to the prognosis of patients with congenital heart disease (CHD). We performed a retrospective single-center study including 400 patients with CHD [median age, 34 years (range 12-76); 49% males] hospitalized between 2014 and 2017. We assessed their clinical data, correlation between platelet indices and severity of HF, and prognosis of HF-related hospitalization and thrombus formation. In multivariate analysis, a significant correlation was found between PDW and logBNP (log-transformed brain natriuretic peptide; r = 0.30, p < 0.001), as well as between MPV and logBNP (r = 0.24, p < 0.001). After treatment for heart failure, a significant reduction was found in PDW (average value before treatment: 14.2; after: 13.2, p = 0.017). In multivariate logistic regression analysis, PDW [hazard ratio (HR) 1.365; 95% confidence interval (CI) 1.005-1.768] and MPV (HR 1.472; 95% CI 1.055-2.052) were predictors of HF-related hospitalization. Similarly, PDW (HR 1.998; 95% CI 1.461-2.630) and MPV (HR 1.792; 95% CI 1.155-2.781) were predictors of thrombus formation. Platelet volume indices correlate to severity of heart failure and have prognostic value for both cardiac and thrombotic events in patients with CHD.

Management of pregnancy and delivery in women with transposition of the great arteries after atrial switch operation: A 16-year single-center experience.

AIM: This study aimed to summarize cases of successful pregnancy and delivery in patients with transposition of the great arteries (TGA) after atrial switch operation (ASO), to provide management, clinical experience, and maternal and fetal outcomes. METHODS: During a 16-year period (2004-2019), we experienced 30 pregnancies in 15 patients after ASO at our institution. We retrospectively reviewed the medical records of the patients. RESULTS: In 30 pregnancies, there were 21 (70%) live births, five (17%) miscarriages, and four (13%) artificial abortions. There were no maternal or neonatal deaths. Cardiac complications occurred in nine (43%) patients: deterioration of right ventricular (RV) function in one, symptomatic heart failure (HF) in three, supraventricular tachyarrhythmia requiring electrical cardioversion in two, sick sinus syndrome that required pacemaker implantation in two, and hemoptysis in one. Obstetric complications occurred in five (24%). Neonatal complications were premature births (delivery at <37 weeks of gestation) in 15 (71%), and birthweight <2500 g in 18 (86%). The mode of delivery consisted of vaginal delivery (VD) in five (24%), and cesarean section (CS) in 16 (76%). CONCLUSION: A high incidence of preterm CS and cardiac complications including deterioration of RV function was observed in patients who had undergone ASO for TGA.

Predictors of neo-aortic valve regurgitation in the long term after arterial switch operation.

Although arterial switch operations (ASOs) have been performed globally to repair d-transposition of the great arteries (d-TGA) in neonates and infants, few studies have been reported regarding the influence of the hemodynamics of patients with d-TGA who have undergone ASO on the development of neo-aortic valve regurgitation (AR). We aimed to investigate the relationship between the hemodynamics and development of AR after ASO in patients with d-TGA by catheter evaluation. This observational study screened 114 consecutive patients who underwent ASO for d-TGA or Taussig-Bing anomaly and who subsequently underwent catheter evaluations in our institution. We reviewed their records for the past 20 years and collected their first catheterization data post-ASO in early childhood. Thirty-six post-ASO patients who underwent catheter evaluations in both the early surgical and long-term phases were finally analyzed. Patients were divided into the following groups according to the presence of significant AR in the long-term phase: the AR group (n = 9 with AR ≥ grade II by the Sellers classification) and the non-AR group (n = 27 with AR < grade II). In the long-term phase, the diastolic blood pressure was significantly lower and the ascending aortic diameter was significantly larger in the AR group than in the non-AR group (p = 0.004 and p = 0.006, respectively). The systolic blood pressure (SBP) and pulse pressure (PP) were similar in both groups. Meanwhile, in the early surgical phase, SBP and PP were significantly higher in the AR group than in the non-AR group (p = 0.029 and p = 0.002, respectively). The receiver operating characteristic curve for late AR showed that the area under the curve for SBP and PP in the early surgical phase were 0.746 and 0.853, respectively. Even though sensitivity analysis was performed, SBP or PP greater than the cutoff value in the early surgical phase was identified as predictors for late AR. Our results suggested that high SBP or PP in the early surgical phase could influence the development of AR in the long term after ASO.

Pregnancy and Delivery in Patients With Repaired Congenital Heart Disease　- A Retrospective Japanese Multicenter Study.

BACKGROUND: Although advances in cardiac surgery have led to an increased number of survivors with congenital heart disease (CHD), epidemiological data regarding the pregnancies and deliveries of patients with repaired CHD are scarce.Methods and Results:In this study, we retrospectively reviewed the clinical outcomes of pregnancies and deliveries of women with repaired CHD. Overall, 131 women with repaired CHD were enrolled and there were 269 gestations. All patients were classified as New York Heart Association (NYHA) Class I or II. The prevalence of cesarean sections was higher in patients with (CyCHD) than without (AcyCHD) a past history of cyanosis (51% vs. 19%, respectively; P<0.01). There were 228 offspring from 269 gestations and the most prevalent neonatal complication was premature birth (10%), which was more frequent in the CyCHD than AcyCHD group (15.7% vs. 5.6%, respectively; P<0.01). Five maternal cardiac complications during delivery were observed only in the CyCHD group (8%); these were classified as NYHA Class II and none was fatal. CONCLUSIONS: Delivery was successful in most women with repaired CHD who were classified as NYHA Class I or II, although some with CyCHD and NYHA Class II required more attention. Cesarean sections were more common in the CyCHD than AcyCHD group, and CyCHD may be a potential risk for preterm deliveries.

Clinical Significance of Central Venous Pressure During Exercise After Fontan Procedure.

Various late complications are associated with the Fontan procedure. In patients who undergo the Fontan procedure, the central venous pressure (CVP) tends to be higher than normal. However, the relationship between CVP (at rest and during exercise) and late complications associated with the Fontan procedure is unknown. Thirty-four patients who underwent the Fontan procedure were enrolled in this study. The median age was 19.3 years, and the median time after the Fontan procedure was 12.7 years. With exercise, the CVP increased from a median of 11 to 19 mmHg, and the cardiac index increased from a median of 2.1 to 4.4 l/min/m2. In 38% of the patients, CVP measured at the resting condition and during exercise differed. Laboratory results indicated no significant difference between the patients in the high-CVP group and low-CVP group at rest. In contrast, during exercise, brain natriuretic peptide (67 ± 38 vs. 147 ± 122 pg/ml, p < 0.05), gamma-glutamyl transpeptidase (63 ± 33 vs. 114 ± 30 IU/l, p < 0.05), type IV collagen 7S (6.7 ± 1.3 vs. 8.1 ± 1.3 ng/ml, p < 0.05), and creatinine (0.72 ± 3.14 vs. 0.83 ± 3.16 mg/dl, p < 0.05) levels were significantly higher in the high-CVP group than in the low-CVP group. Elevated CVP during exercise may be associated with long-term complications after the Fontan procedure; hence, CVP should be measured during exercise in patients who underwent the Fontan procedure to accurately predict the risk of developing such complications.

Influence of pregnancy on cardiac function and hemodynamics in women with Ebstein's anomaly.

INTRODUCTION: We examined the perinatal outcomes and right ventricular function before pregnancy, during pregnancy, and after delivery in women with Ebstein's anomaly. MATERIAL AND METHODS: We retrospectively investigated the clinical course and mode of delivery and monitored hemodynamic parameters throughout pregnancy in 17 women with Ebstein's anomaly who delivered at our institution during the period of 1995-2015. RESULTS: Eight women, including nine pregnancies, underwent elective cesarean section, and nine women, including 14 pregnancies, underwent vaginal delivery. Elective cesarean section was performed in cases with significant heart failure or arrhythmias and in the presence of more than two of the following: cardiothoracic ratio ≥60%, moderate or severe tricuspid valve regurgitation, tricuspid valve regurgitation pressure gradient ≥35 mmHg during pregnancy. The cardiothoracic ratio and tricuspid valve regurgitation pressure gradient significantly increased during pregnancy compared with prepregnancy values. The New York Heart Association classification deteriorated from class I to class II or III in five cases during pregnancy. CONCLUSIONS: Although pregnancy was relatively safe among women with Ebstein's anomaly, some women developed cyanosis, arrhythmia, and heart failure, leading to elective cesarean section. Monitoring clinical and hemodynamic changes throughout pregnancy is advised to minimize maternal cardiac risk and select the appropriate mode of delivery.

Pregnancy and delivery outcomes from patients with repaired anomalous origin of the left coronary artery from the pulmonary artery.

AIM: We investigated the clinical courses before and during pregnancy and after delivery in patients with repaired anomalous origin of the left coronary artery from the pulmonary artery to determine the impact of the hemodynamic changes and cardiac function on the selection of the appropriate mode of delivery. METHODS: Six patients who underwent coronary artery reimplantation delivered 10 infants. We scrutinized the patients' hemodynamic changes on echocardiographs and the plasma brain natriuretic peptide levels before and during pregnancy and after delivery, the perinatal outcomes and maternal and fetal events. RESULTS: All patients were asymptomatic and categorized as having New York Heart Association functional class I before pregnancy. In 8 of 10 pregnancies, vaginal deliveries were performed; two elective cesarean sections were performed because of symptomatic heart failure. The hemodynamic parameters were stable throughout pregnancy and postdelivery, and no maternal or fetal events occurred in the patients who underwent vaginal deliveries. One cesarean section patient developed significant heart failure during the late second and third trimesters, which was accompanied by hemodynamic changes, including increased brain natriuretic peptide levels, left ventricular diastolic dysfunction and worsening arrhythmias, and thrombosis and post-partum hemorrhage occurred postdelivery. The baby had intrauterine growth retardation and small for gestational age. None of the babies had congenital anomalies. CONCLUSION: Pregnancy was safe in most of the asymptomatic patients long after anomalous origin of the left coronary artery from the pulmonary artery was repaired. Symptomatic heart failure might occur during pregnancy in patients with persisting myocardial damage. Pregnancy and delivery should be carefully managed.

Prognostic predictive value of gene mutations in Japanese patients with hypertrophic cardiomyopathy.

Although some studies have attempted to find useful prognostic factors in hypertrophic cardiomyopathy (HCM), those results are not fully helpful for use in actual clinical practice. Furthermore, several genetic abnormalities associated with HCM have been identified. However, the genotype-phenotype correlation in HCM remains to be elucidated. Here, we attempted to assess patients with different types of gene mutations causing HCM and investigate the prognosis. A total of 140 patients with HCM underwent a screening test for myofilament gene mutations by direct sequencing of eight sarcomeric genes. Patients with a single mutation in cardiac troponin T, cardiac troponin I, α-tropomyosin, and regulatory and essential light chains were excluded from the study because the number of cases was too small. The clinical presentations and outcomes of the remaining 127 patients with HCM, 31 ß-myosin heavy chain (MYH7) mutation carriers, 19 cardiac myosin-binding protein C (MYBPC3) mutation carriers, and 77 mutation non-carriers were analyzed retrospectively. MYBPC3 mutation carriers had a high frequency of ventricular arrhythmia and syncope. Kaplan-Meier curves revealed no significant difference in prognosis among the three groups, but a lack of family history of sudden death (SD) and a past history of syncope were significantly related to poor prognosis. An absence of family history of SD and past history of syncope are useful prognostic factors in patients with HCM. MYH7 and MYBPC3 mutations did not significantly influence prognosis compared to non-carriers. However, patients with the MYBPC3 mutation should be closely followed for the possibility of SD.

Real Time Three-Dimensional Echocardiographic Evaluations of Fetal Left Ventricular Stroke Volume, Mass, and Myocardial Strain: In Vitro and In Vivo Experimental Study.

BACKGROUND: Left ventricular stroke volume, mass, and myocardial strain are valuable indicators of fetal heart function. This study investigated the feasibility of nongated real time three-dimensional echocardiography (RT3DE) to determine fetal stroke volume (SV), left ventricular mass (LVM), and myocardial strain under different conditions. METHODS: To evaluate fetal hearts, fetal-sized rabbit hearts were used in this study. The in vitro portion of this study was carried out using a balloon inserted into the LV of eight fresh rabbit hearts and driven by a calibrated pulsatile pump. RT3DE volumes were obtained at various pump-set SVs. The in vivo experiments in this study were performed on open-chest rabbits. RT3DE volumes were acquired at the following conditions: baseline, simulated hypervolemia, inferior vena cava (IVC) ligation, and ascending aorta (AAO) ligation. Displacement values and sonomicrometry data were used as references for RT3DE-derived SV, LVM, longitudinal strain (LS), and circumferential strain (CS). RESULTS: Excellent correlations between RT3DE-derived values and reference values were demonstrated and accompanied by high coefficients of determination (R(2) ) for both in vitro and in vivo studies for SV, LVM, LS, and CS (in vitro: SV: R(2)  = 0.98; LVM: R(2)  = 0.97; LS: R(2)  = 0.87, CS: R(2)  = 0.80; in vivo: SV: R(2)  = 0.92; LVM: R(2)  = 0.98; LS: in vivo: R(2)  = 0.84; CS: in vivo: R(2)  = 0.76; all P < 0.05). CONCLUSIONS: RT3DE is capable of quantifying the SV, LVM, and myocardial strain of fetal-sized hearts under different conditions. This nongated RT3DE may aid the evaluation of fetal cardiac function, providing a superior understanding of the progress of fetal heart disorders.

Quantitative assessment of mitral inflow and aortic outflow stroke volumes by 3-dimensional real-time full-volume color flow doppler transthoracic echocardiography: an in vivo study.

OBJECTIVES: Noninvasive quantification of left ventricular (LV) stroke volumes has an important clinical role in assessing circulation and monitoring therapeutic interventions for cardiac disease. This study validated the accuracy of a real-time 3-dimensional (3D) color flow Doppler method performed during transthoracic echocardiography (TTE) for quantifying volume flows through the mitral and aortic valves using a dedicated offline 3D flow computation program compared to LV sonomicrometry in an open-chest animal model. METHODS: Forty-six different hemodynamic states in 5 open-chest pigs were studied. Three-dimensional color flow Doppler TTE and 2-dimensional (2D) TTE were performed by epicardial scanning. The dedicated software was used to compute flow volumes at the mitral annulus and the left ventricular outflow tract (LVOT) with the 3D color flow Doppler method. Stroke volumes by 2D TTE were computed in the conventional manner. Stroke volumes derived from sonomicrometry were used as reference values. RESULTS: Mitral inflow and LVOT outflow derived from the 3D color flow Doppler method correlated well with stroke volumes by sonomicrometry (R = 0.96 and 0.96, respectively), whereas correlation coefficients for mitral inflow and LVOT outflow computed by 2D TTE and stroke volumes by sonomicrometry were R = 0.84 and 0.86. Compared to 2D TTE, the 3D method showed a smaller bias and narrower limits of agreement in both mitral inflow (mean ± SD: 3D, 2.36 ± 2.86 mL; 2D, 10.22 ± 8.46 mL) and LVOT outflow (3D, 1.99 ± 2.95 mL; 2D, 4.12 ± 6.32 mL). CONCLUSIONS: Real-time 3D color flow Doppler quantification is feasible and accurate for measurement of mitral inflow and LVOT outflow stroke volumes over a range of hemodynamic conditions.

Correcting human mitochondrial mutations with targeted RNA import.

Mutations in the human mitochondrial genome are implicated in neuromuscular diseases, metabolic defects, and aging. An efficient and simple mechanism for neutralizing deleterious mitochondrial DNA (mtDNA) alterations has unfortunately remained elusive. Here, we report that a 20-ribonucleotide stem-loop sequence from the H1 RNA, the RNA component of the human RNase P enzyme, appended to a nonimported RNA directs the import of the resultant RNA fusion transcript into human mitochondria. The methodology is effective for both noncoding RNAs, such as tRNAs, and mRNAs. The RNA import component, polynucleotide phosphorylase (PNPASE), facilitates transfer of this hybrid RNA into the mitochondrial matrix. In addition, nucleus-encoded mRNAs for mitochondrial proteins, such as the mRNA of human mitochondrial ribosomal protein S12 (MRPS12), contain regulatory sequences in their 3'-untranslated region (UTR) that confers localization to the mitochondrial outer membrane, which is postulated to aid in protein translocation after translation. We show that for some mitochondrial-encoded transcripts, such as COX2, a 3'-UTR localization sequence is not required for mRNA import, whereas for corrective mitochondrial-encoded tRNAs, appending the 3'-UTR localization sequence was essential for efficient fusion-transcript translocation into mitochondria. In vivo, functional defects in mitochondrial RNA (mtRNA) translation and cell respiration were reversed in two human disease lines. Thus, this study indicates that a wide range of RNAs can be targeted to mitochondria by appending a targeting sequence that interacts with PNPASE, with or without a mitochondrial localization sequence, providing an exciting, general approach for overcoming mitochondrial genetic disorders.

Evaluation of a new 3-dimensional color Doppler flow method to quantify flow across the mitral valve and in the left ventricular outflow tract: an in vitro study.

OBJECTIVES: The aim of this study was to assess the accuracy, feasibility, and reproducibility of determining stroke volume from a novel 3-dimensional (3D) color Doppler flow quantification method for mitral valve (MV) inflow and left ventricular outflow tract (LVOT) outflow at different stroke volumes when compared with the actual flow rate in a pumped porcine cardiac model. METHODS: Thirteen freshly harvested pig hearts were studied in a water tank. We inserted a latex balloon into each left ventricle from the MV annulus to the LVOT, which were passively pumped at different stroke volumes (30-80 mL) using a calibrated piston pump at increments of 10 mL. Four-dimensional flow volumes were obtained without electrocardiographic gating. The digital imaging data were analyzed offline using prototype software. Two hemispheric flow-sampling planes for color Doppler velocity measurements were placed at the MV annulus and LVOT. The software computed the flow volumes at the MV annulus and LVOT within the user-defined volume and cardiac cycle. RESULTS: This novel 3D Doppler flow quantification method detected incremental increases in MV inflow and LVOT outflow in close agreement with pumped stroke volumes (MV inflow, r = 0.96; LVOT outflow, r = 0.96; P < .01). Bland-Altman analysis demonstrated overestimation of both (MV inflow, 5.42 mL; LVOT outflow, 4.46 mL) with 95% of points within 95% limits of agreement. Interobserver variability values showed good agreement for all stroke volumes at both the MV annulus and LVOT. CONCLUSIONS: This study has shown that the 3D color Doppler flow quantification method we used is able to compute stroke volumes accurately at the MV annulus and LVOT in the same cardiac cycle without electrocardiographic gating. This method may be valuable for assessment of cardiac output in clinical studies.

4D flow MRI-derived energy loss and RV workload in adults with tetralogy of Fallot.

PURPOSE: To assess flow energy loss (EL) pattern inside the pulmonary circulation in adult patients with repaired tetralogy of Fallot (TOF), particularly in TOF with pulmonary stenosis (PS) and pulmonary regurgitation (PR), as a cardiac workload parameter and its relationship to symptoms and major adverse cardiovascular events (MACE). METHODS: Prospectively, 51 consecutive TOF adults after intracardiac repair, who underwent four-dimensional flow magnetic resonance imaging, were enrolled. All of them had significant PR (PR regurgitant fraction >25 %). TOF patients who had already reached the conventional criteria were excluded. We defined MACE as the following: 1) fatal arrhythmias, 2) sudden cardiac death, 3) surgical pulmonary valvular repair (PVR), 4) right heart failure (HF) needing diuretics and/or hospitalization within 2 years. RESULTS: A total of 15 patients had MACE; 1) 10 patients underwent PVR within 2 years, 2) 2 patients had ventricular tachycardia, and 3) 6 patients developed right HF (overlapped). Right ventricular (RV) end diastolic volume index (EDVI), RV end systolic volume index (ESVI), average EL/cardiac output (CO), and diastolic EL/CO in patients with MACE were greater than ones without MACE. On a multivariate logistic analysis, the diastolic EL/CO ratio and RVEDVI had the highest odds with MACE in all TOF (odds ratio, 40.7 and 1.15. 95%CI, 1.83-905 and 1.02-13.0; p-value, 0.02 and 0.03). In sub-analysis within 29 patients with moderate PS with PR, and 10 patients with MACE showed higher diastolic EL/CO. Average and diastolic EL/CO negatively correlated with RV ejection fraction (EF) in this sub-analysis. CONCLUSIONS: High EL, particularly, high diastolic EL/CO, were the important factors for MACE in adult TOF. Higher diastolic EL/CO was also related to lower RV EF and deteriorated RV function in adult TOF with PS and PR. Right-sided EL can be a sensitive marker of excessive cardiac workload which integrates both afterload and preload in adult patients with TOF, beyond the RV size.

Increased Diastolic Energy Loss Associated with Cardiac Events in Adults with Pulmonary Atresia Suffering from Intact Ventricular Septum.

PURPOSE: To assess right heart diastolic energy loss (EL) as a cardiac workload and evaluate its association with major cardiac events (MACE) in adult patients with pulmonary atresia with an intact ventricular septum (PAIVS). METHODS: We retrospectively enrolled and compared 30 consecutive adult patients (18 with PAIVS and 12 with pulmonary stenosis [PS] as controls) who underwent right ventricular (RV) outflow tract reconstruction and 4D flow MRI. EL, conventional parameters on MRI, and the severity of tricuspid regurgitation (TR) on echocardiography were assessed. We also evaluated the association between MACE including arrhythmias, heart failure, surgical intervention, and imaging parameters in adults with PAIVS. RESULTS: Patients with PAIVS were younger, had a higher diastolic EL/cardiac output (CO) ratio, and had a more significant TR than those with PS (controls). However, RV volume, ejection fraction (EF), and pulmonary regurgitation (PR) severity did not differ between the two groups. Higher RV end-diastolic pressure (EDP) and lower cardiac index (CI) correlated with the diastolic EL/CO in patients with PAIVS. Univariate logistic analysis demonstrated that older age and a higher diastolic EL/CO ratio were important factors for MACE in adults with PAIVS (P = 0.048, 0.049). CONCLUSION: A higher diastolic EL/CO ratio was associated with a higher RV EDP and lower CI. A high diastolic EL/CO ratio is also associated with MACE in adults with PAIVS. Even in adults with normal RV volume and EF, the right heart EL was elevated, suggesting an excessive right-sided cardiac workload that integrated both afterload and preload beyond the RV size in adult patients with PAIVS.