Flipping the classroom to teach Millennial residents medical leadership: a proof of concept.

INTRODUCTION: The ongoing changes in health care delivery have resulted in the reform of educational content and methods of training in postgraduate medical leadership education. Health care law and medical errors are domains in medical leadership where medical residents desire training. However, the potential value of the flipped classroom as a pedagogical tool for leadership training within postgraduate medical education has not been fully explored. Therefore, we designed a learning module for this purpose and made use of the flipped classroom model to deliver the training. EVIDENCE: The flipped classroom model reverses the order of learning: basic concepts are learned individually outside of class so that more time is spent applying knowledge to discussions and practical scenarios during class. Advantages include high levels of interaction, optimal utilization of student and expert time and direct application to the practice setting. Disadvantages include the need for high levels of self-motivation and time constraints within the clinical setting. DISCUSSION: Educational needs and expectations vary within various generations and call for novel teaching modalities. Hence, the choice of instructional methods should be driven not only by their intrinsic values but also by their alignment with the learners' preference. The flipped classroom model is an educational modality that resonates with Millennial students. It helps them to progress quickly beyond the mere understanding of theory to higher order cognitive skills such as evaluation and application of knowledge in practice. Hence, the successful application of this model would allow the translation of highly theoretical topics to the practice setting within postgraduate medical education.

Ventricular response to dobutamine stress relates to the change in peak oxygen uptake during the 5-year follow-up in young patients with repaired tetralogy of Fallot.

AIMS: To evaluate the additional value of dobutamine stress testing in patients with repaired tetralogy of Fallot (TOF) by relating stress imaging parameters at baseline to relevant parameters of clinical condition and right ventricular (RV) size during a serial follow-up. METHODS AND RESULTS: We prospectively included 27 patients (14 ± 4 years at baseline), who were studied twice with a 5-year interval. Patients underwent cardiovascular magnetic resonance imaging to assess RV systolic and diastolic function at rest and during dobutamine stress. Normal response to dobutamine was defined as a decrease in RV end-systolic volume, and a increase in RV ejection fraction (EF) during stress. Exercise testing and electrocardiography were performed to determine peak oxygen uptake (peak VO2), QRS duration, and QT interval corrected for heart rate (QTc) interval. RV volumes, QRS duration, and QTc interval increased significantly from baseline to follow-up; peak VO2 tended to decrease (95 ± 20-89 ± 14%, P = 0.086). Response to dobutamine was normal in 26 of 27 patients and remained stable during the follow-up [relative increase in RVEF during stress: +25 ± 9% (baseline) vs. +27 ± 10% (follow-up)]. A smaller relative increase in RVEF during stress at baseline related to a larger relative decrease in peak VO2 during the follow-up (r = 0.59, P = 0.004). No significant associations were found with the relative increase in QRS duration, QTc interval, or RV end-diastolic volume during a 5-year follow-up. CONCLUSION: In a young TOF population, response to dobutamine stress was normal and remained stable during the 5-year follow-up. A smaller increase in RVEF during stress at baseline was predictive for a larger decrease in peak VO2 during the 5-year follow-up.

Exercise capacity and ventricular function in patients treated for isolated pulmonary valve stenosis or tetralogy of Fallot.

BACKGROUND: We hypothesized 1) that long-term ventricular outcome and exercise capacity would be better in patients with isolated pulmonary valve stenosis (PS) treated with balloon pulmonary valvuloplasty (BPV) than in patients operated for tetralogy of Fallot (TOF), and 2) that ventricular outcome and exercise capacity would not be different in PS patients and healthy controls. METHODS: We included 21 PS patients after BPV (16.2 ± 5.2 years) and 21 patients operated for TOF (16.6 ± 5.6 years), matching them for gender, age at treatment, and age at study. Patients underwent cardiovascular magnetic resonance (CMR) imaging, exercise testing, 12-lead ECG and 24-hour Holter monitoring for assessment of right ventricular (RV) size and function, pulmonary regurgitation (PR), exercise capacity and electrocardiographic status. Healthy controls for CMR imaging and exercise testing were matched for gender and age at study. RESULTS: RV volumes and PR percentage were significantly larger in TOF patients than in PS patients; biventricular ejection fraction (EF) was not different. PR was mild in most PS patients. RV end-systolic volume was significantly larger in PS patients than in healthy controls; RVEF was significantly lower. Both patient groups had similar exercise test results. Peak workload and VO(2) max. were significantly lower in PS patients than in healthy controls. CONCLUSIONS: Longstanding mild PR in PS patients can lead to an enlarged RV, reduced RV function and reduced exercise capacity. Despite more PR and larger RV volumes in TOF patients, exercise capacity and biventricular function are similar in both patient groups.

Safety and observer variability of cardiac magnetic resonance imaging combined with low-dose dobutamine stress-testing in patients with complex congenital heart disease.

BACKGROUND: In patients with complex congenital heart disease (CHD) abnormal ventricular stress responses have been reported with dobutamine stress cardiovascular magnetic resonance (DCMR). These abnormal stress responses are potential indicators of long-term outcome. However, safety and reproducibility of this technique has not been reported in a larger study. The aim of this study was to report our experiences regarding safety and intra-observer and inter-observer variability of low-dose DCMR in complex CHD. METHODS: In 91 patients, 110 low-dose DCMR studies were performed with acquisition of a short axis set at rest, and during dobutamine administration (7.5 µg/kg/min maximum). We assessed biventricular end-diastolic volumes, end-systolic volumes, stroke volumes, ejection fraction and ventricular mass. Intra- and inter-observer variability for all variables was assessed by calculating the coefficient of variation (%), i.e. the standard deviation of the difference divided by the mean of 2 measurements multiplied by 100%. RESULTS: In 3 patients minor side effects occurred (vertigo, headache, and bigeminy). Ten patients experienced an increase in heart rate of >150% from baseline, although well tolerated. For all variables, intra-observer variability was <10% at rest and during stress. At rest, inter-observer variability was 10.5% maximal. With stress-testing, only the variability of biventricular end-systolic volumes (ESV) exceeded 10%. CONCLUSIONS: In patients with complex CHD low-dose DCMR is feasible, and safe. Intra-observer variability is low for rest and stress measurements. Inter-observer variability of biventricular ESV is high with stress-testing. Whether this limits the potential usefulness of DCMR for risk assessment during follow-up has to be assessed.

Stress imaging in congenital cardiac disease.

In patients with coronary arterial disease, stress imaging is able to demonstrate abnormalities in the motion of the ventricular walls, and abnormalities in coronary arterial perfusion not apparent at rest. It can also provide information on prognostic factors. In patients with congenitally malformed hearts, stress imaging is used to determine contractile reserve, abnormalities of mural motion, and global systolic function, but also to assess diastolic and vascular function. In most of these patients, stress is usually induced using pharmacological agents, mainly dobutamine given in varying doses. The clinical usefulness of abnormal responses to the stress induced in such patients has to be addressed in follow-up studies. The abnormal stress might serve as surrogate endpoints, predicting primary endpoints at an early stage, which are useful for stratification of risk in this population of growing patients. We review here the stress imaging studies performed to date in patients with congenitally malformed hearts, with a special emphasis on echocardiography and cardiac magnetic resonance imaging.

Assessment of biventricular functional reserve and NT-proBNP levels in patients with RV volume overload after repair of tetralogy of Fallot at young age.

PURPOSE: To assess biventricular functional reserve (FR), NT-proBNP levels and exercise performance, in relation to right ventricular volume in patients with pulmonary regurgitation (PR) after repair of tetralogy of Fallot (TOF) at young age. METHODS: In 53 TOF patients (maximum age at repair 2.0 years, interval since repair 15 (5) years) without residual lesions except PR, biventricular FR (derived from magnetic resonance imaging with dobutamine stress), NT-proBNP levels, maximal workload, and peak oxygen uptake were assessed. RESULTS: Mean right ventricular end-diastolic volume was 140(38) ml/m(2). Median pulmonary regurgitant fraction was 37% (range 0-57%). Biventricular systolic stress response was normal: mean (SD) ESV decreased (DeltaRVESV -17(8) ml/m(2), DeltaLVESV -11(5)), SV increased (DeltaRVSV +12(9) ml/m(2), DeltaLVSV +9(6)), FR was positive in all (RV-FR +11(5)%, LV-FR +13(6)). No serious adverse effects to dobutamine were encountered. NT-proBNP was increased in 2 patients. Median level was 10 pmol/L (range 2-42). NT-proBNP correlated with PR-percentage but not with right ventricular size. High-risk levels of NT-proBNP indicated a smaller RV-FR and a smaller decrease of biventricular ESV. Mean (SEM) VO2(max) was 96(3)%, mean Workload(max) 89(2)% of predicted. CONCLUSION: At mid to long term follow-up overall NT-proBNP levels are normal and biventricular functional reserve and exercise tolerance are well preserved in TOF repaired at young age, irrespective of RV volume. This questions the validity of isolated PR or RV volume criteria for pulmonary valve replacement in this group. Low-dose dobutamine stress testing is well tolerated and may be a useful additional tool for clinical decision making.

Cardiac status after childhood growth hormone treatment of Turner syndrome.

CONTEXT: In Turner syndrome (TS), GH treatment is well established. Data on cardiac status after discontinuation of treatment are scarce. This study aimed to assess biventricular size and function in TS at least 6 months after discontinuation of GH treatment. METHODS: TS patients and healthy women prospectively underwent cardiac magnetic resonance imaging. Ventricular two-dimensional tomographic cine data were acquired to obtain biventricular volume, mass, and ejection fraction. Atrioventricular valve flow measurements were performed using a two-dimensional flow-sensitized sequence. Flow velocity curves were calculated and indices of biventricular diastolic filling were derived. RESULTS: Thirty-one patients [mean (sd) age 20 (2) yr, body surface area 1.75 (0.15) m(2), 5 (2) yr after GH discontinuation] and 23 normal control women [age 21 (2) yr, body surface area 1.80 (0.13) m(2)] were included. Compared with controls, patients had smaller mean end-diastolic volumes [right ventricle (RV), 84 (11) ml/m(2) vs. 79 (10), P = 0.02; left ventricle (LV), 81 (10) vs. 72 (9), P < 0.001], end-systolic volumes [RV 38 (7) ml/m(2) vs. 36 (6), P = 0.04; LV 34 (5) vs. 29 (4), P < 0.001], and stroke volumes [RV 46 (6) ml/m(2) vs. 43 (6), P = 0.03; LV, 47 (7) vs. 44 (4), P = 0.02]. Patients had a higher mean heart rate [79 (13) beats/min vs. 71 (10), P < 0.05]. Biventricular ejection fraction, mass, cardiac output, and diastolic filling pattern were comparable. CONCLUSION: After discontinuation of GH treatment TS patients showed no myocardial hypertrophy and well-preserved biventricular function. Ventricular volumes were smaller in Turner patients, compared with controls, whereas mean heart rate was higher. These last observations may be part of the natural development in TS and not linked to GH treatment, which at this point we consider safe.

Changes during exercise of ECG intervals related to increased risk for ventricular arrhythmia in repaired tetralogy of Fallot and their relationship to right ventricular size and function.

PURPOSE: Our study aimed to assess pro-arrhythmogenic electrocardiographic changes during maximal physical exercise in patients operated for Tetralogy of Fallot (TOF). METHODS: TOF patients prospectively underwent: 1) bicycle ergometry, 2) cardiac MRI, and 3) 24-hour Holter. ECG data was analyzed at rest, at 60% of peak exercise and at peak exercise. R-R duration, QRS-, QT- and JT-duration and dispersions were assessed. Changes of ECG parameters during exercise were calculated and correlated to RV volume, RVEF, RV wall-mass, PR-percentage and VO(2max). Exercise ECG data from healthy controls were used as reference. RESULTS: Thirty-one patients (mean age at repair (SD) 0.8 (0.5) years, age at study 16 (5) years) and 25 controls (age 12 (2) years) were included. With exercise mean QTc and JTc dispersions increased in patients (p<0.001), but not in controls. At peak exercise JTc dispersion was larger in patients (p<0.01). QTc did not change with exercise in patients (p=0.14) and decreased in controls (p<0.05). At all levels of exercise mean QTc, QRS and QRS dispersion were larger in patients (all p<0.001). Significant associations were found for; 1) a larger increase of JTc dispersion with a higher PR-percentage, a larger RV volume, a larger RV wall-mass, 2) a larger QTc increase with a larger RV volume and worse RVEF. CONCLUSION: During physical exercise inhomogeneity of repolarisation, known to predispose for re-entry ventricular arrhythmia, increases in repaired TOF. Larger inhomogeneity is found with more severe PR.

Diastolic function in repaired tetralogy of Fallot at rest and during stress: assessment with MR imaging.

PURPOSE: To prospectively assess, with magnetic resonance (MR) imaging, right ventricular (RV) diastolic function after repair of tetralogy of Fallot (TOF) at rest and during pharmacologic stress and to study relationship between main pulmonary artery end-diastolic forward flow (EDFF) (indicative of restrictive RV physiology) and clinical status. MATERIALS AND METHODS: Institutional medical ethics committee approval and patient or parent informed consent were obtained. Patients with TOF corrected through the transatrial-transpulmonary approach underwent MR imaging at rest and during dobutamine stress and maximal exercise testing. Two-dimensional (2D) cine volumetric data were acquired. Flow measurements were performed with a standard 2D flow-sensitized sequence. MR imaging flow curves for tricuspid and pulmonary valves were combined into RV time-volume change curves, from which indexes of RV filling were derived. Patient results were compared with published data in control subjects. Student t tests, Mann-Whitney U tests, analysis of covariance, and paired and one-sample t tests were used. RESULTS: Thirty-six patients (mean age at repair, 0.9 year +/- 0.5 [standard deviation]; median age at study inclusion, 17 years [range, 7-23 years]; 26 male and 10 female patients) were included. Abnormalities in RV filling included impaired relaxation (prolonged deceleration time, P = .002; smaller early filling fraction, P = .02) in the entire group compared with published data in healthy control subjects and signs of restriction to RV filling (smaller atrial filling fraction and higher early filling/atrial filling peak ratio, P < .05 for both) in patients with EDFF (n = 24) compared with patients without EDFF (n = 12). Stress response was abnormal in patients with EDFF, who developed impaired RV relaxation not appreciated at rest. Patients with EDFF had more severe pulmonary regurgitation (P < .05) and poorer exercise performance (P < .001). CONCLUSION: In patients with TOF corrected with currently widely accepted surgical strategies, pulmonary artery EDFF relates to worse clinical state at mid- to long-term follow-up. Dobutamine stress imaging may unmask abnormalities in RV diastolic filling not appreciated with rest imaging alone.

Clinical condition at mid-to-late follow-up after transatrial-transpulmonary repair of tetralogy of Fallot.

OBJECTIVES: To assess the clinical condition at mid-to-late follow-up in tetralogy of Fallot corrected by a transatrial-transpulmonary approach at a young age and to identify risk factors associated with right ventricular dilation/dysfunction and with decreased exercise tolerance. METHODS: Patients with tetralogy of Fallot underwent cardiac magnetic resonance imaging, maximal bicycle ergometry, electrocardiography, Holter monitoring, and spirometry. Multivariate linear regression analyses were used to determine independent predictors for selected clinical parameters. RESULTS: Fifty-nine patients (mean +/- SD), age at repair 0.9 +/- 0.5 years, interval since repair 14 +/- 5 years, were included. The median pulmonary regurgitant fraction was 32% (0%-57%). Compared with published data on healthy controls, Fallot patients had significantly larger right ventricular end-diastolic and end-systolic volumes and smaller right ventricular and left ventricular ejection fractions. Maximum oxygen consumption was 97% +/- 17% and maximum workload 89% +/- 13% of predicted. Median QRS duration was 110 ms (82-161 ms). No important ventricular arrhythmias were found. Compared with patients without a transannular patch, patients with a patch had more pulmonary regurgitation, a larger right ventricle, worse right ventricular and left ventricular ejection fractions, but comparable exercise capacity. Multivariate regression analysis identified the following independent determinants for larger right ventricular volumes: longer interval since repair, longer QRS duration, and higher pulmonary regurgitation percentage. The following were independent determinants for smaller right ventricular ejection fraction: abnormal right ventricular outflow tract wall motion, longer interval since repair, and longer QRS duration. For smaller maximum oxygen consumption, the independent determinants were smaller right ventricular ejection fraction and longer QRS duration. CONCLUSIONS: At mid-to-late follow-up, clinical condition in tetralogy of Fallot corrected according to contemporary surgical approaches appears well preserved. However, even these patients show right ventricular dilation and dysfunction associated with impaired functional capacity. Abnormalities relate to right ventricular outflow tract motion abnormalities, longer interval since repair, longer QRS duration, and more severe pulmonary regurgitation.

Aortic distensibility and dimensions and the effects of growth hormone treatment in the turner syndrome.

In Turner's syndrome (TS), an increased risk for cardiovascular malformations exists, including aortic dilation of unknown cause. Abnormal biophysical wall properties may play an important role. Magnetic resonance imaging has been successfully used to assess aortic size and wall distensibility. The aim of this study was to assess aortic biophysical properties and dimensions in TS. Thirty-eight former participants of a growth hormone (GH) dose-response study in TS (mean age 12 +/- 2 years, mean body surface area 1.7 +/- 0.2 m2) and 27 controls (mean age 21 +/- 2 years, mean body surface area 1.8 +/- 0.1 m2) were enrolled. Previously, patients had been assigned to 1 of 3 groups treated with different GH dosages: group A (0.045 mg/kg/day), group B (0.067 mg/kg/day), and group C (0.09 mg/kg/day). All underwent magnetic resonance imaging > or =6 months after GH discontinuation to determine aortic dimensions and distensibility at 4 predefined levels: (1) the ascending aorta, (2) the descending aorta, (3) the level of the diaphragm, and (4) the abdominal aorta. Patients had larger aortic diameters at all but level 4 and tended to have reduced distensibility at level 3. Distensibility in group A was significantly less compared with that in group C at level 4. Compared with controls, patients in group A had larger aortic diameters at all but level 4 and reduced distensibility at level 4. The results for patients in groups B and C were not different from those for controls. In conclusion, patients with TS formerly treated with GH have dilated aortas and signs of impaired wall distensibility. The severity of abnormalities seems related to the GH dose, with a beneficial effect of a larger GH dose on the abnormalities.