Systolic and Diastolic Myocardial Response to Exercise in a Healthy Pediatric Cohort

A new protocol for a single-stage combined cardiopulmonary and echocardiography exercise test: a pilot study

Aims

The value of cardiopulmonary exercise testing (CPET) and exercise stress echocardiography (ESE) in managing cardiac disease is well known, but no standard CPET-ESE protocol is currently recommended. This pilot study aims to compare feasibility and cardiac function responses between a new high-intensity single-stage combined test (CPET-hiESE) and a standard maximal ESE (smESE).

Methods and results

After screening and maximal CPET, all volunteers (n = 21) underwent three ESE modalities: (i) based on the gas exchange threshold (hiESE-GET, 40% of peak-GET, 6 min), (ii) based on heart rate (HR) (hiESE-HR, 80% of peak HR, 6 min), and (iii) smESE (85% of predicted peak HR for age, 3 min). Speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI) were measured at each step. There was superior image quality and data completeness for the right ventricle strain for both hiESE modalities compared with smESE (71.4 and 76.2 vs. 42.9%, P = 0.07). Left ventricular STE data completeness was similar for all three conditions. Despite systematically higher HR, work rate and levels of exertion in the smESE compared with hiESE, STE and TDI parameters were not systematically different. Concordance correlation coefficients ranged from 0.56 to 0.88, lowest for strain rate parameters and mean difference from -0.34 to 1.53, highest for TDI measurements.

Conclusion

The novel CPET-hiESE protocol allowed for better data completeness, at lower levels of exertion compared with smESE, without systematically different cardiac reserve measurements in healthy participants. This single-stage protocol can be individualized to clinical populations, which would provide practical advantages to standard testing.

Ventricular myocardial response to exercise in patients with Fontan circulation

BACKGROUND

Exercise stress echocardiography has been used to assess myocardial reserve in various heart diseases. This study examined the ventricular myocardial response to exercise in Fontan patients using exercise stress echocardiography.

METHODS

Twenty-five Fontan patients and 19 control subjects underwent semi-supine bicycle exercise stress echocardiography in this prospective, single-center, cross-sectional study. Pulsed-wave Doppler tissue imaging peak systolic (s') and diastolic (e') velocities, longitudinal strain and systolic strain rate, and early diastolic strain rate data at rest and at peak exercise were obtained for the systemic ventricle. The myocardial reserve of functional parameters was calculated as the difference between peak exercise and rest.

RESULTS

Inter- and intra-observer reliability were both high for exercise stress echocardiography measurements. Compared with controls, Fontan patients had significantly lower s', e', longitudinal systolic strain and strain rate, and early diastolic longitudinal strain rate at rest and at peak exercise as well as reduced myocardial reserve.

CONCLUSIONS

Fontan patients have markedly reduced myocardial reserve during exercise. The use of exercise stress echocardiography assessment may improve the clinical management of Fontan patients.

Echocardiography for the Assessment of Pulmonary Hypertension and Congenital Heart Disease in the Young

While invasive assessment of hemodynamics and testing of acute vasoreactivity in the catheterization laboratory is the gold standard for diagnosing pulmonary hypertension (PH) and pulmonary vascular disease (PVD) in children, transthoracic echocardiography (TTE) serves as the initial diagnostic tool. International guidelines suggest several key echocardiographic variables and indices for the screening studies when PH is suspected. However, due to the complex anatomy and special physiological considerations, these may not apply to patients with congenital heart disease (CHD). Misinterpretation of TTE variables can lead to delayed diagnosis and therapy, with fatal consequences, or–on the other hand-unnecessary invasive diagnostic procedures that have relevant risks, especially in the pediatric age group. We herein provide an overview of the echocardiographic workup of children and adolescents with PH with a special focus on children with CHD, such as ventricular/atrial septal defects, tetralogy of Fallot or univentricular physiology. In addition, we address the use of echocardiography as a tool to assess eligibility for exercise and sports, a major determinant of quality of life and outcome in patients with PH associated with CHD.

Impaired left ventricular global longitudinal strain is associated with elevated left ventricular filling pressure after myocardial infarction

Left ventricular (LV) global longitudinal strain (GLS) has emerged as a significant prognostic marker in patients after myocardial infarction (MI). Although elevated LV filling pressure after MI might alter GLS, direct evidence for this is lacking. This study aimed to clarify the association between GLS and LV filling pressure in a large animal MI model. A total of 104 Yorkshire pigs underwent both echocardiographic and hemodynamic assessments 1-4 wk after induction of large anterior MI. GLS was measured in the apical four-chamber view using a semiautomated speckle-tracking software. LV pressure-volume relationship was invasively measured using a high-fidelity pressure-volume catheter. GLS >-14% was considered impaired. Compared with pigs with LV ejection fraction (LVEF) >40% and preserved GLS (n = 29), those with LVEF >40% and impaired GLS (n = 37) and those with LVEF ≤40% (n = 38) had significantly higher LV end-diastolic pressure (15.5 ± 5.5 vs. 19.7 ± 5.8 and 19.6 ± 6.6 mmHg; P = 0.008 and P = 0.026, respectively) and higher LV mean diastolic pressure (7.1 ± 2.9 vs. 10.4 ± 4.5 and 11.1 ± 5.4 mmHg; P = 0.013 and P = 0.002, respectively). GLS was modestly correlated with τ (r = 0.21, P = 0.039) and slope of LV end-diastolic pressure-volume relationship (r = 0.43, P < 0.001). Impaired GLS was associated with higher LV end-diastolic and mean-diastolic pressures after adjusting for LVEF and baseline characteristics (P = 0.026 and P = 0.001, respectively). Impaired GLS assessed by speckle-tracking echocardiography was associated with elevated LV filling pressure after MI. GLS has an incremental diagnostic value for detecting elevated LV filling pressure and may be particularly useful for evaluating post-MI patients with preserved LVEF.NEW & NOTEWORTHY Strain analysis was performed in 104 pigs after MI, and its relationship to invasive hemodynamic measurements was studied. Impaired longitudinal strain was associated with high ventricular filling pressure independent of LVEF in post-MI setting. Global longitudinal strain is a potential prognostic marker after MI.

Characterisation of LV myocardial exercise function by 2-D strain deformation imaging in elite adolescent footballers

Purpose

Few data exist on the descriptions of LV myocardial mechanics and reserve during dynamic exercise of adolescent athletes. The aim of this study was to describe the LV myocardial and cardiopulmonary changes during exercise using 2-D strain deformation imaging.

Methods

Elite adolescent male football players (n = 42) completed simultaneous cardiopulmonary exercise testing (CPET) and exercise echocardiography measurement of LV myocardial deformation by 2-D strain imaging. LV longitudinal and circumferential 2-D strain and strain rates were analyzed at each stage during incremental exercise to a work rate of 150 W. Additionally, exercise LV myocardial deformation and its relation to metabolic exercise parameters were evaluated at each exercise stage and in recovery using repeated measures ANOVA, linear regression and paired t tests.

Results

LV peak systolic baseline 2-D strain (longitudinal: − 15.4 ± 2.5%, circumferential: − 22.5 ± 3.1%) increased with each exercise stage, but longitudinal strain plateaued at 50 W (mean strain reserve − 7.8 ± 3.0) and did not significantly increase compared to subsequent exercise stages (P > 0.05), whilst circumferential strain (mean strain reserve − 11.6 ± 3.3) significantly increased (P < 0.05) throughout exercise up to 150 W as the dominant mechanism of exercise LV contractility increase. Regression analyses showed LV myocardial strain increased linearly relative to HR, VO₂ and O₂ pulse (P < 0.05) for circumferential deformation, but showed attenuation for longitudinal deformation.

Conclusion

This study describes LV myocardial deformation dynamics by 2-D strain and provides reference values for LV myocardial strain and strain rate during exercise in adolescent footballers. It found important differences between LV longitudinal and circumferential myocardial mechanics during exercise and introduces a methodology that can be used to quantify LV function and cardiac reserve during exercise in adolescent athletes.

Fragmented QRS as an early predictor of left ventricular systolic dysfunction in healthy individuals: a nested case-control study in the era of speckle tracking echocardiography

BACKGROUND

Several studies addressed the association between fragmented QRS (fQRS) on 12-lead EKG and left ventricular (LV) dysfunction in patients with a variety of cardiovascular disorders. We tested such association in healthy individuals.

METHODS

Out of 500 healthy participants without -overt cardiovascular disease from the Shiraz Heart Study cohort, we identified 20 subjects with fQRS (cases) and 20 peers without fQRS (controls). Global LV longitudinal strain (GLS) was measured by speckle tracking echocardiography in the two groups. Comparison was made between case and control groups by using chi-square or independent sample t-test or ANOVA.

RESULTS

Age, gender, ejection fraction, LV volume and dimensions did not differ between the case and the control groups. Overall, 14 subjects out of 40 had reduced GLS (≤20%) and 10 of them (25%) had fQRS. GLS was significantly lower in the group with fQRS than in the control group (19.9 ± 1.8 vs 21.4 ± 1.6; p = 0.009).

CONCLUSIONS

Healthy subjects with fQRS present regional LV systolic dysfunction, assessed by GLS, in the presence of a normal ejection fraction. These data suggest that fQRS may be a promising tool to identify apparently healthy subjects with regional LV systolic dysfunction.

The adolescent athlete's heart; A miniature adult or grown-up child?

The systematic development of early age talent in sports academies has led to the professionalization of pediatric sport and the sports physician need to be aware of pediatric cardiological problems. Research into the medical cardiac care and assessment of the pediatric athlete are accumulating, but specific pediatric international guidelines are not available yet and reference data for ECG and echocardiography are incomplete, in particular for the age group <12 years of age. This article is an introduction to the physiological and diagnostics specifics of the pediatric athlete. The focus lies in the differences in presentation and diagnosis between pediatric and adult athletes for the most common pathologies. Reference data for electrical and structural adaptations to intensive exercise are sparse particularly in athletes aged below 12 years old. Training related changes include decrease of resting heart rate, increase of cardiac output, ventricular cavity size, and wall thickness. Cardiac hypertrophy is less pronounced in pediatric athletes, as HR mediated cardiac output increase to endurance exercise is the dominant mechanism in peripubertal children. As in adults, the most pronounced cardiovascular adaptations appear in classical endurance sports like rowing, triathlon, and swimming, but the specifics of pediatric ECG and echocardiographic changes need to be considered.

The Assessment of the Paediatric Athlete

The success of systematic early age talent development has led to the professionalisation of youth sports academies used by clubs and governing bodies alike, and sports physicians are nowadays commonly confronted with paediatric cardiological problems. Medical cardiac care of the paediatric athlete is however in its infancy, and the international guidelines that are present for adult athletes, are not yet available. Similarly, reference data for ECG and echocardiography are incomplete. The aim of this article is to provide and introduction to the cardiac care of the paediatric athlete to facilitate healthy and above all, safe talent development, but also provide guidance on how to distinguish adaptive, beneficial cardiovascular remodelling from underlying pathology of congenital or inherited cardiovascular disease. Differences in presentation, diagnosis and treatment between childhood and adult athletes are highlighted and can educate the reader in the emerging field of paediatric sports cardiology.

Left Ventricular Strain and Strain Rate during Submaximal Semisupine Bicycle Exercise Stress Echocardiography in Healthy Adolescents and Young Adults: Systematic Protocol and Reference Values

OBJECTIVE

Combining stress echocardiography with strain analysis is a promising approach for early detection of subclinical cardiac dysfunction not apparent at rest. Data on normal myocardial strain and strain rate (SR) response to exercise in adolescents and young adults are contradictory and limited. The aim of this study was to propose a standardized protocol for semisupine bicycle stress echocardiography and to provide corresponding reference values of left ventricular (LV) two-dimensional speckle-tracking echocardiography (2D STE) strain and SR in adolescents and young adults.

METHODS

Fifty healthy adolescents and young adults (mean age, 17.8 ± 3.2 years, 44% female) were prospectively assessed. Images were acquired at rest, low stress, submaximal stress, and during recovery. Optimal image quality for offline strain analysis was pursued, and image quality was rated. Global longitudinal strain and SR from apical four-/two-/three-chamber views and short-axis circumferential strain and SR were analyzed using vendor-independent software. Interobserver variability was assessed.

RESULTS

Strain and SR increased during progressive exercise stress. Mean LV global longitudinal strain was -20.4% ± 1.3%, SR -1.1 ± 0.15/sec at rest (heart rate, 79.4 ± 12.0 beats/minute), increasing to -22.6% ± 1.6% and -1.5 ± 0.16/sec at low stress level (heart rate, 117.1 ± 8.7 beats/minute) and -23.7% ± 1.1% and -1.9 ± 0.29/sec at submaximal stress level (heart rate, 154.2 ± 7.0 beats/minute), respectively, returning to -20.6% ± 1.4% and -1.2 ± 0.16/sec postexercise (heart rate, 90.1 ± 9.4 beats/minute). Restriction on submaximal stress level ensured adequate image quality for 2D STE strain analysis. Interobserver variability for strain was acceptable even during submaximal stress.

CONCLUSIONS

This study provides a systematic, standardized protocol and corresponding reference data for 2D LV STE-derived strain and SR during semisupine bicycle exercise testing in adolescents and young adults. According to our results, global longitudinal strain and SR appear to be the most comprehensible parameters for cross-sectional studies.

Clinical Applications of Echo Strain Imaging: a Current Appraisal

PURPOSE OF REVIEW

This article reviews recent advances in echocardiographic strain imaging, particularly in its ability to prognosticate in cardiovascular outcomes and impact clinical decision making.

RECENT FINDINGS

Strain has been proposed as a sensitive tool in detecting early ventricular dysfunction. Left ventricular global longitudinal strain (LV-GLS) detects subtle changes in myocardial function, often not quantifiable by ejection fraction alone. Thus, LV-GLS provides the opportunity for early decision-making, and the implementation of more effective treatments, improving outcomes in a variety of diseases such as valvular heart diseases, cardio-oncology, ischemic heart disease, cardiomyopathies, heart transplantation, and pericardial diseases and cardiomyopathies. Strain is a promising tool for the early detection of myocardial dysfunction in patients with preserved left ventricular ejection fraction and can prognosticate long-term outcomes.

Right ventricular function during exercise in children after heart transplantation

Aims

Right ventricular (RV) dysfunction is a common problem after heart transplant (HTx). In this study, we used semi-supine bicycle ergometry (SSBE) stress echocardiography to evaluate RV systolic and diastolic reserve in paediatric HTx recipients.

Methods and results

Thirty-nine pediatric HTx recipients and 23 controls underwent stepwise SSBE stress echocardiography. Colour tissue doppler imaging (TDI) peak systolic (s') and peak diastolic (e') velocities, myocardial acceleration during isovolumic contraction (IVA), and RV free wall longitudinal strain were measured at incremental heart rates (HR). The relationship with increasing HR was evaluated for each parameter by plotting values at each stage of exercise versus HR using linear and non-linear regression models. At rest, HTx recipients had higher HR with lower TDI velocities (s': 5.4 ± 1.7 vs. 10.4 ± 1.8 cm/s, P < 0.001; e': 6.4 ± 2.2 vs.12 ± 2.4 cm/s, P < 0.001) and RV IVA values (IVA: 1.2 ± 0.4 vs. 1.6 ± 0.8 m/s2, P = 0.04), while RV free wall longitudinal strain was similar between groups. At peak exercise, HR was higher in controls and all measurements of RV function were significantly lower in HTx recipients, except for RV free wall longitudinal strain. When assessing the increase in each parameter vs. HR, the slopes were not significantly different between patients and controls except for IVA, which was lower in HTx recipients.

Conclusion

In pediatric HTx recipients RV systolic and diastolic functional response to exercise is preserved with a normal increase in TDI velocities and strain values with increasing HR. The blunted IVA response possibly indicates a mildly decreased RV contractile response but it requires further investigation.

Echocardiographic Assessment of Ventricular Function During Exercise in Adolescent Female Patients With Anorexia Nervosa

BACKGROUND

Patients with anorexia nervosa (AN) have altered physiologic responses to exercise. The aim of this study was to investigate exercise capacity and ventricular function during exercise in adolescent patients with AN.

METHODS

Sixty-six adolescent female patients with AN and 21 adolescent female control subjects who exercised to volitional fatigue on a semisupine ergometer, using an incremental step protocol of 20 W every 3 min, were retrospectively studied. Heart rate, blood pressure, and echocardiographic Doppler indices were measured at rest and during each stage of exercise. Fractional shortening, rate-corrected mean velocity of circumferential fiber shortening, stress at peak systole, cardiac output, and cardiac index were calculated. Minute ventilation, oxygen consumption, carbon dioxide production, and respiratory exchange ratio were measured using open-circuit spirometry.

RESULTS

Patients with AN had significantly lower body mass index (16.7 vs 19.7 kg/m², P < .001), total work (1,126 vs 1,914 J/kg, P < .001), and test duration (13.8 vs 20.8 min, P < .001) compared with control subjects. Peak minute ventilation, oxygen consumption, and carbon dioxide production were significantly decreased in patients with AN. Heart rate, systolic blood pressure, cardiac index, fractional shortening, and rate-corrected mean velocity of circumferential fiber shortening demonstrated similar patterns of increase with progressive exercise between groups but were decreased at peak exercise in patients with AN. Body mass index percentile, age, peak oxygen consumption, and peak cardiac output were independently associated with exercise duration.

CONCLUSIONS

Adolescent patients with AN have reduced exercise capacity and peak cardiovascular indices compared with control subjects but normal patterns of cardiovascular response during progressive exercise. Systolic ventricular function is maintained during exercise in adolescents with AN.

Right Ventricular Contractile Reserve Is Impaired in Children and Adolescents With Repaired Tetralogy of Fallot: An Exercise Strain Imaging Study

BACKGROUND

Pulmonary insufficiency (PI) and right ventricular (RV) dysfunction are long-term complications in patients with repaired tetralogy of Fallot (rTOF). The aim of this study was to investigate RV contractile reserve and changes in PI that occur during exercise in patients with rTOF and the associations of these changes with exercise performance using stress echocardiography.

METHODS

Subjects with rTOF (n = 32) and healthy control subjects (n = 10) were prospectively enrolled and underwent rest and peak exercise echocardiography during standard cardiopulmonary exercise test protocol on a cycle ergometer or treadmill. RV contractile reserve was defined as the change in RV global longitudinal strain from rest to peak exercise. PI was assessed with the diastolic-to-systolic time-velocity integral ratio and diastolic/systolic velocity ratio from pulmonary artery Doppler interrogation. Exercise measures included heart rate reserve, percentage predicted maximum oxygen consumption, percentage predicted maximum work, and oxygen pulse.

RESULTS

RV contractile reserve was impaired in patients with rTOF compared with control subjects, with a significant drop in the absolute value of RV global longitudinal strain from 17% (range, 8%-27%) at rest to 13% (range, 5%-28%) at peak exercise. Similarly, PI decreased at peak exercise, with decreases in diastolic-to-systolic time-velocity integral and diastolic/systolic velocity ratios. Reduction in PI was directly associated with percentage predicted maximum oxygen consumption, percentage predicted maximum work, and greater oxygen pulse. Heart rate reserve was directly associated with percentage predicted maximum oxygen consumption and percentage predicted maximum work. RV contractile reserve was not associated with any exercise parameters.

CONCLUSIONS

Patients with rTOF have an abnormal myocardial response to exercise with impaired RV contractile reserve compared with control subjects. Heart rate reserve and reduction in PI at peak exercise are associated with better exercise performance and appear to be significant contributors to exercise performance in rTOF. Measures to improve chronotropic health in rTOF should be explored.

Left ventricular diastolic function is enhanced after peak exercise in endurance-trained adolescents as well as in their non-trained controls

The aims of the study were to explore the temporal change of cardiac function after peak exercise in adolescents, and to investigate how these functional changes relate to maximal oxygen uptake (VO2max ). The cohort consisted of 27 endurance-trained adolescents aged 13-19 years, and 27 controls individually matched by age and gender. Standard echocardiography and colour tissue Doppler were performed at rest, and immediately after as well as 15 min after a maximal cardio pulmonary exercise test (CPET) on a treadmill. The changes in systolic and diastolic parameters after exercise compared to baseline were similar in both groups. The septal E/e'-ratio increased immediately after exercise in both the active and the control groups (from 9·2 to 11·0; P<0·001, and from 8·7 to 10·2; P = 0·008, respectively). In a comparison between the two groups after CPET, the septal E/e'-ratio was higher in the active group both immediately after exercise and 15 min later compared to the control group (P = 0·007 and P = 0·006, respectively). We demonstrated a positive correlation between VO2max and cardiac function including LVEF and E/e' immediately after CPET, but the strongest correlation was found between VO2max and LVEDV (r = 0·67, P<0·001) as well as septal E/e' (r = 0·34, P = 0·013). Enhanced diastolic function was found in both groups, but this was more pronounced in active adolescents. The cardiac functional response to exercise, in terms of LVEF and E/e', correlates with the increase in VO2 uptake. These findings in trained as well as un-trained teenagers have practical implications when assessing cardiac function.

Dynamic Myocardial Response to Exercise in Childhood Cancer Survivors Treated with Anthracyclines

BACKGROUND

Anthracycline cardiotoxicity can cause significant long-term morbidity in childhood cancer survivors (CCS), but many CCS do not manifest clinical symptoms until adulthood. The aims of this study were to characterize the dynamic myocardial response to exercise of CCS at long-term follow-up by combining semisupine bicycle exercise stress echocardiography with myocardial imaging techniques and to establish whether semisupine bicycle exercise stress echocardiography could identify CCS with abnormal exercise response.

METHODS

This was a single-center prospective cross-sectional study. One hundred CCS and 51 control subjects underwent semisupine bicycle exercise stress echocardiography. Color Doppler tissue imaging peak systolic (s') and diastolic (e') velocities, myocardial acceleration during isovolumic contraction, and longitudinal strain were measured at rest and at incremental heart rates in the left ventricular (LV) lateral wall, basal septum, and right ventricle. The relationship with increasing heart rate was evaluated for each parameter by plotting the values against heart rate at each stage of exercise. Kernel density estimate was used to establish the normality of the individual CCS exercise responses.

RESULTS

At rest, no significant differences were found for LV lateral wall, right ventricular (RV), and basal septal systolic and diastolic velocities between CCS and control subjects. Only septal e' was lower in CCS. LV longitudinal strain was similar between groups, while RV longitudinal strain was lower in CCS. At peak exercise, LV lateral wall, RV, and septal s' were not different between groups, while e' were significantly lower in CCS. LV lateral wall and septal isovolumic acceleration were also reduced in CCS. LV longitudinal strain was different between groups, while RV longitudinal strain was similar. The dynamic response of Doppler tissue imaging velocities, isovolumic acceleration, and strain was similar between CCS and control subjects. Kernel density estimate analysis confirmed that most CCS responses were within the normal range.

CONCLUSIONS

At 10-year follow-up, anthracycline-treated CCS with normal baseline ejection fractions have LV and RV systolic and diastolic myocardial exercise response comparable with that of control subjects. Minor differences were observed between CCS and control subjects at rest and at peak exercise, but the dynamic response is within the normal range.

A Doppler Echocardiographic Study of the Myocardial Inotropic Response to Peak Semisupine Exercise in Healthy Children: Development of a Simplified Index of Myocardial Reserve

BACKGROUND

Stress echocardiography has been advocated for the detection of abnormal myocardial function and unmasking diminished myocardial reserve in pediatric patients. The aim of this study was to create a simplified index of myocardial reserve, derived from the myocardial inotropic response to peak semisupine exercise in healthy children, and illustrate its applicability in a sample of pediatric oncology patients.

METHODS

In this prospective analysis, children (7-18 years of age) with normal cardiac structure and function performed semisupine stress echocardiography to volitional fatigue. The quotient of wall stress at peak systole and heart rate-corrected velocity of circumferential fiber shortening were calculated at baseline and at peak exercise, the difference of which was termed the index of myocardial reserve (IMR). The IMR was also calculated in a retrospective sample of pediatric oncology patients with normal resting left ventricular function who had received anthracycline treatment and had performed the same exercise protocol to illustrate utility.

RESULTS

Fifty healthy subjects (mean age, 13.2 ± 2.6 years) and 33 oncology patients (mean age, 12.7 ± 4.0 years) were assessed. In the healthy children at peak exercise, heart rate-corrected velocity of circumferential fiber shortening significantly increased (from 1.17 ± 0.17 to 1.58 ± 0.24 circ · sec^-1, P < .001), while the quotient of wall stress at peak systole significantly decreased (from 75.3 ± 17.1 to 55.3 ± 13.8 g · cm^-2, P < .001), shifting the plot of the relationship between the two parameters upward and to the left. The mean IMR was -30.8 ± 17.8, and the normal distribution ranged from -4.7 (fifth percentile) to -67.3 (95th percentile). The IMR was abnormal in 10 oncology patients who were treated with anthracyclines.

CONCLUSIONS

The authors have developed a novel IMR. Relative to the normal distribution of this IMR in healthy subjects, it is possible to identify patients with abnormal myocardial reserve. Thus, this study demonstrates the application of the IMR to aid in clinical decision making in individual patients.

Feasibility of exercise stress echocardiography and myocardial response in patients with repaired congenital heart disease

BACKGROUND

Exercise stress echocardiography (ESE) can unmask ventricular dysfunction in asymptomatic patients with congenital heart disease (CHD), but its acquisition and interpretation is often challenging, and the method has not been validated in CHD. This study aimed to evaluate the feasibility of ESE using Doppler imaging and to assess myocardial response to exercise in patients with biventricular (BiV) and univentricular (UniV) circulation after CHD repair.

METHODS

In this single-center prospective study, we recruited 55 participants (17 females), median age 14 years (8-22 years). Our analysis categorized participants in these three groups: with structurally normal hearts as controls (n=21), with BiV circulation (n=20) and with UniV circulation (n=14). We acquired ESE images of the systemic ventricle including pulsed-wave flow and spectral tissue Doppler imaging (TDI) of lateral free wall before and immediately after standard, symptom-limited exercise tests on an electronically braked cycle ergometer.

RESULTS

During ESE we obtained inflow E-wave and TDI systolic (S') and early diastolic (E') velocities in 93% to 100% of participants at rest and in 90% to 100% of participants post exercise. Feasibility to obtain Doppler imaging parameter was the same across study groups. The myocardial response to exercise was increase in heart rate (HR), S' and inflow E-wave velocity in all participants. Patients with BiV circulation had preserved ventricular function at rest. While patients with UniV circulation had low S', E', and E-wave velocities at rest in comparison to controls and to BiV group (all P<.001), both patients with BiV and UniV circulation showed significant increases in HR, S' velocity and inflow E-wave velocity post exercise, with magnitudes of these increases higher in controls than in the BiV and UniV group. The S' and E' velocities were strongly associated with lower percent predicted peak oxygen consumption VO₂ (r_s=0.614 and r_s=0.64, respectively, both P<.001).

CONCLUSION

ESE with Doppler imaging is a practical noninvasive diagnostic method and sufficiently robust for the assessment of morphologic LV/systemic ventricles under exercise in patients after biventricular and univentricular CHD repair. Although patients with BiV and UniV circulation had both preserved myocardial response to exercise, the magnitude of this response was the lowest in patients with UniV circulation.

Global Deformation Parameters Response to Exercise in Adolescents with Repaired Tetralogy of Fallot

Exercise stress echocardiography is rarely used in the follow-up of children with congenital heart disease following surgical repair. There are no data on global longitudinal strain (GLS) and global circumferential strain (GCS) during exercise in adolescents with repaired tetralogy of Fallot (TOF). The purpose of this prospective study was to investigate GLS and GCS using speckle tracking two-dimensional echocardiography (2D-STE) at rest and during exercise in adolescents with repaired TOF. Twenty patients with repaired TOF and 20 controls were included. The subjects exercised on a semi-supine cycle ergometer using a two-staged 3-min step protocol of 20-40 W at 60-75 rpm. Exercise images with 2D-STE measurements were available for all 40 subjects. In the study group, the GLS values changed significantly between the baseline and third and sixth minute of exercise (-18.10 ± 2.20, -16.23 ± 4.47, -14.22 ± 2.63, respectively, p < 001). GCS did not vary significantly from baseline to end of the exercise testing (-17.49 ± 5.14, -17.15 ± 9.20, -15.66 ± 3.59, respectively, p > 0.05). There was a statistically significant difference between the Stage I longitudinal strain values of the study and control groups (-14.26 ± 9.13 and -20.22 ± 2.88, respectively, p = 0.02) but no significant difference between the Stage II values of these groups (-14.22 ± 2.63 and -15.11 ± 2.45, respectively, p > 0.05). The results revealed significant changes in GLS during exercise in patients with repaired TOF. Data gathered from deformation analysis of 2D-STE during exercise testing can enhance the ability to detect subtle ventricular dysfunction in the follow-up of children with repaired TOF.