Overlapping and Distinct Features of Cardiac Pathology in Inherited Human and Murine Ether Lipid Deficiency.

Inherited deficiency in ether lipids, a subgroup of glycerophospholipids with unique biochemical and biophysical properties, evokes severe symptoms in humans resulting in a multi-organ syndrome. Mouse models with defects in ether lipid biosynthesis have widely been used to understand the pathophysiology of human disease and to study the roles of ether lipids in various cell types and tissues. However, little is known about the function of these lipids in cardiac tissue. Previous studies included case reports of cardiac defects in ether-lipid-deficient patients, but a systematic analysis of the impact of ether lipid deficiency on the mammalian heart is still missing. Here, we utilize a mouse model of complete ether lipid deficiency (Gnpat KO) to accomplish this task. Similar to a subgroup of human patients with rhizomelic chondrodysplasia punctata (RCDP), a fraction of Gnpat KO fetuses present with defects in ventricular septation, presumably evoked by a developmental delay. We did not detect any signs of cardiomyopathy but identified increased left ventricular end-systolic and end-diastolic pressure in middle-aged ether-lipid-deficient mice. By comprehensive electrocardiographic characterization, we consistently found reduced ventricular conduction velocity, as indicated by a prolonged QRS complex, as well as increased QRS and QT dispersion in the Gnpat KO group. Furthermore, a shift of the Wenckebach point to longer cycle lengths indicated depressed atrioventricular nodal function. To complement our findings in mice, we analyzed medical records and performed electrocardiography in ether-lipid-deficient human patients, which, in contrast to the murine phenotype, indicated a trend towards shortened QT intervals. Taken together, our findings demonstrate that the cardiac phenotype upon ether lipid deficiency is highly heterogeneous, and although the manifestations in the mouse model only partially match the abnormalities in human patients, the results add to our understanding of the physiological role of ether lipids and emphasize their importance for proper cardiac development and function.

Rationale and Design of the FREQUENCY Study: The Fetal Cardiac Registry of Québec to Improve Resource Utilization in Fetal Cardiology.

OBJECTIVE: Prenatal detection of congenital heart diseases (CHD) decreases morbidity and cost. To improve detections rates, most physicians refer pregnant women with high-risk pregnancies to fetal cardiologists even when there is no suspicion of CHD at the second trimester screening. This paper presents the rationale and detailed method of the Fetal Cardiac Registry of Québec to Improve Resource Utilization in Fetal Cardiology (FREQUENCY) study. The overall objective is to assess the impact of second trimester ultrasound screening (U/S) and referral pattern in fetal cardiology on detection rates, health care costs, and resource utilization, as well as perinatal morbidity and mortality. METHODS: This multicentre retrospective population-based cohort study will link fetal echocardiography data from all centres performing fetal echocardiography in Québec with administrative health care data. This data linking will allow the determination of a true denominator (all women in Québec who underwent second trimester U/S) with complete follow-up of up to 2 years for offspring. This protocol meets Canadian Task Force Classification II-2. RESULTS: The study investigators have collected and cleaned fetal echocardiography data for 24 259 eligible pregnancies referred to fetal cardiology. These data will be matched to approximately 860 000 pregnancies between 2007 and 2015. CONCLUSION: The results of the FREQUENCY study will shed light on the impact of the current prenatal CHD screening strategy in Canada.

Intrapericardial Ectopic Hepatic Tissue Masquerading as a Fetal Pericardial Tumor.

Prenatal diagnosis of pericardial mass, with associated large pericardial effusion, resected postnatally and diagnosed to be ectopic hepatic tissue on pathology.

Severe Antenatal Hypertrophic Cardiomyopathy Secondary to ACAD9-Related Mitochondrial Complex I Deficiency.

Introduction: Antenatal presentation of hypertrophic cardiomyopathy (HCM) is rare. We describe familial recurrence of antenatal HCM associated with intrauterine growth restriction and the diagnostic process undertaken. Methods: Two pregnancies with antenatal HCM were followed up. Biological assessment including metabolic analyses, genetic analyses, and respiratory chain study was performed. We describe the clinical course of these two pregnancies, antenatal manifestations as well as specific histopathological findings, and review the literature. Results: The assessment revealed a deficiency in complex I of the respiratory chain and two likely pathogenic variations in the ACAD9 gene. Discussion and Conclusion: Antenatal HCM is rare and a diagnosis is not always made. In pregnancies presenting with cardiomyopathy and intrauterine growth restriction, ACAD9 deficiency should be considered as one of the potential underlying diagnoses, and ACAD9 molecular testing should be included among other prenatal investigations.

The utility of echocardiography and pulmonary function testing in the preoperative evaluation of pectus excavatum.

PURPOSE: Echocardiography (ECHO) and pulmonary function testing (PFT) are routinely performed during the preoperative evaluation of pectus excavatum (PE). We hypothesized that these investigations may be performed selectively based on patient symptoms and pectus severity. METHODS: A retrospective review of all PE patients who underwent a Nuss procedure during a 15-year period (2004-2018) was conducted. Symptoms, clinical characteristics, ECHO, and PFT results were extracted from the medical chart. PE severity on computed tomography was measured using the Haller Index (HI) and Correction Index (CI), and reported as mean ± SEM. Logistic and linear regression assessed the ability of symptoms and indices to predict abnormal cardiopulmonary test results. RESULTS: Of 119 patients, 116 patients had symptom documentation, and 74 (64%) had one or more symptoms. HI and CI were 3.8 ± 1.0 and 31.6 ± 10.3, respectively. Of those with ECHO available (111), 14 (13%) were abnormal, and 12 of 14 required cardiology follow-up. Of those with PFT available (90), the results were abnormal in 15 (17%), including 9 (11%) obstructive, 4 (5%) restrictive, and 2 (2%) mixed. The presence of symptoms did not predict abnormal ECHO or PFT, but each standard deviation increase in the CI was associated with abnormal PFT and ECHO by a factor of 2.2 and 2.0 respectively. HI severity was only associated with ECHO. CONCLUSION: The rates of abnormal ECHO and PFT testing in PE patients are low, and do not correlate with symptoms. Routine ECHO is still recommended to detect anomalies requiring follow-up. Elevated CI severity may be used to guide selective PFT testing. LEVELS OF EVIDENCE: Retrospective Study, Level III.

Incremental Detection of Severe Congenital Heart Disease by Fetal Echocardiography Following a Normal Second Trimester Ultrasound Scan in Québec, Canada.

BACKGROUND: The benefit of fetal echocardiograms (FE) to detect severe congenital heart diseases (SCHD) in the setting of a normal second-trimester ultrasound is unclear. We aimed to assess whether the increase in SCHD detection rates when FE are performed for risk factors in the setting of a normal ultrasound was clinically significant to justify the resources needed. METHODS: This is a multicenter, population-based, retrospective cohort study, including all singleton pregnancies and offspring in Quebec (Canada) between 2007 and 2015. Administrative health care data were linked with FE clinical data to gather information on prenatal diagnosis of CHD, indications for FE, outcomes of pregnancy and offspring, postnatal diagnosis of CHD, cardiac interventions, and causes of death. The difference between the sensitivity to detect SCHD with and without FE for risk factors was calculated using generalized estimating equations with a noninferiority margin of 5 percentage points. RESULTS: A total of 688 247 singleton pregnancies were included, of which 30 263 had at least one FE. There were 1564 SCHD, including 1071 that were detected prenatally (68.5%). There were 12 210 FE performed for risk factors in the setting of a normal second-trimester ultrasound, which led to the detection of 49 additional cases of SCHD over 8 years. FE referrals for risk factors increased sensitivity by 3.1 percentage points (95% CI, 2.3-4.0; P<0.0001 for noninferiority). CONCLUSIONS: In the setting of a normal second-trimester ultrasound, adding a FE for risk factors offered low incremental value to the detection rate of SCHD in singleton pregnancies. The current ratio of clinical gains versus the FE resources needed to screen for SCHD in singleton pregnancies with isolated risk factors does not seem favorable. Further studies should evaluate whether these resources could be better allocated to increase SCHD sensitivity at the ultrasound level, and to help decrease heterogeneity between regions, institutions and operators.

Alternative to Body Surface Area as a Solution to Correct Systematic Bias in Pediatric Echocardiography z Scores.

BACKGROUND: Z scores are the method of choice to report dimensions in pediatric echocardiography. Z scores based on body surface area (BSA) have been shown to cause systematic biases in overweight and obese children. Using aortic valve (AoV) diameters as a paradigm, the aims of this study were to assess the magnitude of z score underestimation in children with increased body mass index z score (BMI-z) and to determine if a predicting model with height and weight as independent predictors would minimise this bias. METHODS: In this multicentre, retrospective, cross-sectional study, 15,006 normal echocardiograms in healthy children 1-18 years old were analyzed. Residual associations with body size were assessed for previously published z score. BSA-based and alternate prediction models based on height and weight were developed and validated in separate training and validation samples. RESULTS: Existing BSA-based z scores incompletely adjusted for weight, BSA, and BMI-z and led to an underestimation of > 0.8 z score units in subjects with higher BMI-z compared with lean subjects. BSA-based models led to overestimation of predicted AoV diameters with increasing weight or BMI-z. Models using height and weight as independent predictors improved adjustment with body size, including in children with higher BMI-z. CONCLUSIONS: BSA-based models result in underestimation of z scores in patients with high BMI-z. Prediction models using height and weight as independent predictors minimise residual associations with body size and generate well fitted predicted values that could apply to all children, including those with low or high BMI-z.

In Vitro Feasibility and Accuracy of Three-Dimensional Echocardiography for Ventricular Volume Assessment in Very Small Hearts.

To evaluate the in vitro accuracy of three-dimensional echocardiography (3-DE) for estimation of ventricular volume in very small hearts, left ventricular (LV) volume was determined by 3-DE in the excised hearts of 10 guinea pigs and 10 rabbits, and right ventricular (RV) volume was determined in 20 rabbits. The effect of edge enhancement, Sigma filter, and slice distance (1 mm versus 0.5 mm) was assessed in each heart. True volumes were obtained from ventricular casts. Mean cast volume was 1.38 +/- 0.83 mL for LVs and 1.63 +/- 1.01 mL for RVs. Correlations between 3-DE and true volumes were r > 0.99 (P < 0.0001) for both ventricles. Accuracy was not affected by ventricular type, slice distance, or Sigma filter. Mean percent difference from true volume was significantly less (P = 0.03) with edge enhancement. Ventricular volume can be assessed reliably by 3-DE in very small hearts. The edge enhancement feature improved the accuracy of the measurements.

Rationale and design of the Canadian Outcomes Registry Late After Tetralogy of Fallot Repair: the CORRELATE study.

BACKGROUND: Chronic hemodynamically relevant pulmonary regurgitation (PR) resulting in important right ventricular dilation and ventricular dysfunction is commonly seen after tetralogy of Fallot (TOF) repair. Late adverse clinical outcomes, including exercise intolerance, arrhythmias, heart failure and/or death accelerate in the third decade of life and are cause for considerable concern. Timing of pulmonary valve replacement (PVR) to address chronic PR is controversial, particularly in asymptomatic individuals, and effect of PVR on clinical measures has not been determined. METHODS: Canadian Outcomes Registry Late After Tetralogy of Fallot Repair (CORRELATE) is a prospective, multicentre, Canada-wide cohort study. Candidates will be included if they are ≥ 12 years of age, have had surgically repaired TOF resulting in moderate or severe PR, and are able to undergo cardiovascular magnetic resonance imaging. Enrollment of > 1000 individuals from 15 participating centres (Toronto, Montreal, Quebec City, Sherbrooke, Halifax, Calgary, Edmonton, and Vancouver) is anticipated. Clinical data, health-related quality of life metrics, and adverse outcomes will be entered into a web-based database. A central core lab will analyze all cardiovascular magnetic resonance studies (PR severity, right ventricular volumes, and ventricular function). Major adverse outcomes (sustained ventricular tachycardia and cardiovascular cause of death) will be centrally adjudicated. RESULTS: To the best of our knowledge, CORRELATE will be the first prospective pan-Canadian cohort study of congenital heart disease in children and adults. CONCLUSIONS: CORRELATE will uniquely link clinical, imaging, and functional data in those with repaired TOF and important PR, thereby enabling critical evaluation of clinically relevant outcomes in those managed conservatively compared with those referred for PVR.