Reproducibility of Cardiac Magnetic Resonance Imaging (CMRI)-Derived Right Ventricular Parameters in Repaired Tetralogy of Fallot (ToF).

BACKGROUND: Quantification of right ventricular (RV) volumes is challenging owing to variable reproducibility and is especially so in congenital heart disease. Cardiac magnetic resonance (CMR) has the ability to more comprehensively survey the entire right ventricle and is currently considered the gold standard. AIMS: We aimed to determine the inter-observer reproducibility of CMR-derived RV volumes generated by two independent and experienced (SCMR Level III) observers in Tetralogy of Fallot (ToF) patients with varying degrees of RV dilatation. METHODS: We performed a retrospective analysis of 120 consecutive patients with repaired ToF who underwent CMR. Two blinded observers calculated RV volumes in each oblique short axis slice independently. Bland-Altman analysis and inter-observer correlation coefficients (ICC) were assessed. RESULTS: The coefficients of variation for RV parameters were: 2.9%, 8% and 3.4% for right ventricular end diastolic volume (RVEDV), right ventricular end systolic volume (RVESV) and right ventricular ejection fraction (RVEF) respectively. For RVEDV the interobserver correlation was 0.992 demonstrating excellent volumetric correlation between observers. The mean difference between the observers for right ventricular end diastolic volume index (RVEDVi) was 2.5ml/m2 (95% limits of agreement -7.3 to 12.2ml/m2). For patients with mild-moderate RV dilatation (RVEDVi <150ml/m2) the mean difference of RVEDVi was 1.8ml/m2 (95% limits of agreement -5.7 to 9.3ml/m2). For patients with severe RV dilatation (RVEDVi≥150ml/m2) the mean difference was -3.4ml/m2 (95% limits of agreement -8.6 to 15.4ml/m2). CONCLUSIONS: In patients with repaired ToF and variable degrees of RV dilatation, CMR assessment of RV volumes and function has high inter-observer reproducibility. This allows for optimal timing of pulmonary valve replacement, based on progression of RV dilatation over time.

Stereoscopic Display Is Superior to Conventional Display for Three-Dimensional Echocardiography of Congenital Heart Anatomy.

BACKGROUND: Three-dimensional echocardiography (3DE) improves visualization of cardiac lesions. Current viewing of 3DE studies on a conventional display diminishes the encoded stereoscopic (stereo) information for depth perception. This study aims to evaluate clinician subjective and objective experience of stereo display compared with nonstereo display of 3DE in congenital heart disease. METHODS: In this prospective study, 22 cardiologists, advanced cardiology trainees, and cardiothoracic surgeons used a commercially available stereo display system with proprietary software to view 10 3DE data sets, alternating between simple and complex lesions. In part A, participants viewed each data set, randomized to 1 minute of stereo display followed by 1 minute of nonstereo display, or vice versa. In part B, participants could freely toggle between stereo and nonstereo display for an additional 90 seconds per data set. Participants answered a series of questions and rated their subjective experience using stereo versus nonstereo display mode on a Likert scale. Objective data on time spent in each display mode during part B and duration of interaction and degree of movement of the 3DE data set in parts A and B were also collected. RESULTS: All clinician groups found stereo display preferable to nonstereo display of 3DE (P < .0001). Viewing complex lesions was rated lower than simple lesions when using nonstereo display (P < .01). Simple and complex lesions were equally well rated when using stereo display (P = .14). When given a choice of display modes in part B, participants spent more time in stereo display (P < .0001) and interacted more with the 3DE data sets in stereo display (P < .0001). CONCLUSIONS: Interactive stereoscopic display of 3DE was preferred over conventional nonstereo display by all clinician groups for viewing both simple and complex lesions. This preference is especially true for viewing complex lesions.

Double drainage of total anomalous pulmonary venous connection: A rare variant of mixed total anomalous pulmonary venous connection.

Total Anomalous Pulmonary Venous Connection (TAPVC) is frequently classified based on the system proposed by Craig, Darling and Rothney. Occasionally variants are reported which do not fit into these classic forms. One such variant is the double drainage of TAPVC where the confluence has connections at two different levels. We report two infants with a double drainage pattern of TAPVC.

Severe right ventricular dilatation after repair of Tetralogy of Fallot is associated with increased left ventricular preload and stroke volume.

AIMS: Pulmonary regurgitation (PR) and right ventricular (RV) dilatation are common in repaired tetralogy of Fallot (rTOF). Left ventricular (LV) dysfunction is an important risk factor in rTOF. The effect of PR/RV dilatation on LV performance and RV-LV interactions in rTOF are incompletely understood. We examined LV responses and exercise capacity in rTOF, both before and after pulmonary valve replacement (PVR). METHODS AND RESULTS: Cardiac magnetic resonance imaging scans in 126 rTOF patients (age 17.3 ± 7.6 years) were analysed, comparing subjects with indexed RV end-diastolic volume (RVEDVi) <170 mL/m2 (mild/moderate dilatation, n = 95) and RVEDVi ≥170 mL/m2 (severe dilatation, n = 31). Indexed PR volume (PRVi), RV end-systolic (RVESVi), RV end-diastolic (RVEDVi), RV stroke volume (RVSVi), net pulmonary forward flow (NPFFi), LV end-diastolic (LVEDVi), LV end-systolic (LVESVi), LV stroke volume (LVSVi), RV and LV ejection fraction (EF), and diastolic septal curvature were obtained. Peak aerobic capacity (VO2 max) was measured. In a subset (n = 30), measures were obtained pre-and-post surgical PVR. Compared to those with mild/moderate RV dilatation, patients with severe RV dilation had greater PRVi (38 ± 12 vs. 24 ± 9 mL/m2, P < 0.0001), NPFFi (53 ± 9 vs. 44 ± 11 mL/m2, P < 0.0001), LVEDVi (87 ± 14 vs. 73 ± 13 mL/m2, P < 0.0001), LVESVi (39 ± 12 vs. 30 ± 8 mL/m2, P < 0.0001), and LVSVi (48 ± 7 vs. 43 ± 8 mL/m2, P = 0.002) but lower RV ejection fraction (46 ± 8 vs. 53 ± 7%, P < 0.0001). Septal curvature and VO2 max were similar in both groups. After PVR, there was no change in LVEDVi, LVSVi, septal curvature, or VO2 max. CONCLUSIONS: Chronic PR with severe RV dilatation is associated with increased NPFFi, LVEDVi, and LVSVi. This may potentially explain preserved exercise capacity in rTOF with severe PR and RV dilatation.

Relations between right ventricular morphology and clinical, electrical and genetic parameters in Brugada Syndrome.

BACKGROUND: Increasing evidence suggests the presence of structural changes affecting the right ventricular outflow tract (RVOT) in patients with Brugada Syndrome (BrS). The aim of this study was to characterise the RV morphology in BrS and explore associations between morphologic, clinical, electrical, and genetic parameters using non-invasive multimodality testing. METHODS: Consecutive BrS patients (recruited 2013-2015) underwent clinical assessment, dedicated RV imaging using cardiac magnetic resonance (CMR) imaging (unless contra-indicated), electrical assessment (electrocardiogram, Holter monitoring, signal-averaged ECG[SAECG]) and genotyping. Morphologic data were compared to matched control and unmatched ARVC (arrhythmogenic right ventricular cardiomyopathy) cohorts, and potential associations between morphologic parameters and other variables were explored. RESULTS: BrS patients (n = 42, male 86%, age 46±12 years) exhibited normal global RV volume and function, comparable to control, in contrast to significantly larger, impaired RVs in ARVC cohort (RVESV p = 0.0001; RVEDV p<0.0001, RVEF p = 0.002). Compared with control, BrS patients exhibited larger RVOT volumes (7.4 ± 0.7 vs 5.8 ± 0.7 mL/m2, p<0.0001) and wall motion abnormalities (RWMA) (31% vs 0%, p = 0.005); compared with ARVC cohort, the RVOT volumes were similar (7.4 ± 0.7 vs, 8.1 ± 1.7, p = 0.52) and there were less RWMA (31% vs 76%, p = 0.01). Overall 67% BrS patients had abnormal RVOT morphology. Patients with abnormal RVOT tended to be older (48 ± 12 y vs 41 ± 12y, p = 0.06). Rare genetic variants were only observed in patients with abnormal RVOT morphology (36% vs 0%, p = 0.02). CONCLUSIONS: Patients with BrS frequently exhibit structural abnormalities localised to the RVOT and these changes may be age- and gene-dependent.

Anomalous origin of the left brachiocephalic artery in the right aortic arch: Is there a method to the madness?

The anomalous origin of the left brachiocephalic artery in a right sided aortic arch is a rare vascular ring which might lead to esophageal compression. The exact embryological origin of this anomaly is still widely debated. We present an infant who presented with esophageal compression symptoms and review the various hypotheses about the embryological origin of this anomaly.

Inspiratory Muscle Training Is Associated With Improved Inspiratory Muscle Strength, Resting Cardiac Output, and the Ventilatory Efficiency of Exercise in Patients With a Fontan Circulation.

BACKGROUND: Patients with a Fontan circulation have reduced exercise capacity and respiratory muscle strength. Inspiratory muscle training (IMT) improves exercise capacity and quality of life in adults with heart failure. We assessed whether 6 weeks of a home-based program of IMT improves inspiratory muscle strength and the ventilatory efficiency of exercise in adolescent patients with a Fontan circulation. METHODS AND RESULTS: Twenty-three adolescent participants (aged 16±2 years) with a Fontan circulation underwent 6 weeks of IMT for 30 minutes daily. Respiratory muscle strength (maximal inspiratory pressure and expiratory pressure), lung function, and exercise capacity (cardiopulmonary exercise testing) were assessed. Fourteen of 23 participants also underwent exercise cardiac magnetic resonance imaging to examine the effects of IMT on cardiac output and systemic and pulmonary blood flow. Six weeks of IMT improved maximal inspiratory pressure by 36±24 cm H2O (61±46%) with no change in maximal expiratory pressure. Ventilatory efficiency of exercise improved after 6 weeks of IMT (from 34.2±7.8 to 32.2±5.6, P=0.04). In those who underwent exercise cardiac magnetic resonance imaging, IMT increased resting cardiac output (from 4.2±1.2 to 4.5±1.0 L/min, P=0.03) and ejection fraction (from 50.1±4.3 to 52.8±6.1%, P=0.03). CONCLUSIONS: Six weeks of IMT is associated with improved inspiratory muscle strength, ventilatory efficiency of exercise, and resting cardiac output in young Fontan patients. IMT may be a simple beneficial addition to the current management of Fontan patients, potentially reducing exercise intolerance and long-term morbidity and mortality.

Isolated Anomalous Origin of Left Pulmonary Artery From the Descending Aorta: An Embryologic Ambiguity.

Anomalous origin of a branch pulmonary artery from the aorta is a rare malformation, accounting for 0.12% of all congenital heart defects. Anomalous origin of the left pulmonary artery from the aorta (ALPA) constitutes a small proportion of these cases. ALPA has been reported to arise from the ascending aorta with various embryologic postulates. We report a case of isolated ALPA arising from the descending aorta in association with a patent ductus arteriosus, to emphasize its embryologic ambiguity.

Outcome of complex adult congenital heart surgery in the developing world.

BACKGROUND: There is scanty information on the outcome of adult congenital heart disease surgery from the developing world. METHODS: This was a retrospective chart review of the surgical outcome of 153 adults with congenital heart disease over a 5-year period. Surgical atrial septal defect closure was considered "simple" while all other surgeries were considered "complex." RESULTS: There were 102 patients in the "simple" group and 51 in the "complex" group. Only three (2%) patients had prior operations. The "complex" group had longer bypass time and cross clamp time. Intensive care unit stay, ventilation time, and inotrope administration were longer. Major complications were more common and there were two deaths in the "complex" group. Age more than 30 years, cyanosis, and New York Heart Association class more than II were predictors of longer stay in the intensive care unit. Surgical repair of Tetralogy of Fallot in adults tended to have a longer ventilation time and intensive care unit stay with a mortality of 4%. At follow up, all patients were in New York Heart Association class I or II. Improvement of the functional class with negligible adverse events was noted in both groups. CONCLUSIONS: A retrospective evaluation of 153 adults with congenital heart disease who underwent open heart surgery at a single center in India showed strikingly fewer reoperations compared with large European studies. There was a similar prevalence of complex lesions. Surgical mortality was low, and long-term functional outcome was gratifying.