Echocardiography during submaximal isometric exercise in children with repaired coarctation of the aorta compared with controls

Objective Patients with repaired coarctation (RCoA) remain at higher risk of cardiac dysfunction, initially often only detected during exercise. In this study, haemodynamics of isometric handgrip (HG) and bicycle ergometry (BE) were compared in patients with RCoA and matched controls (MCs). Methods Case-control study of 19 children with RCoA (mean age 12.9 +/- 2.3 years; mean age of repair 7 months) compared with 20 MC. HG with echocardiography followed by BE was performed in both groups. Results During HG (blood pressure) BP increased from 114 +/- 11/64 +/- 4 mm Hg to 132 +/- 14/79 +/- 7 mm Hg, without significant differences. During HG as well as BE, HR increased less in patients with RCoA. There were no significant differences in (left ventricle) LV dimensions or LV mass. The RCoA group had diastolic dysfunction: both at rest and during HG they had significantly higher transmitral E and A velocities and lower tissue Doppler E' and A' velocities. E/E' was higher, reaching statistical significance during HG (p<0001). Conventional parameters of systolic function (FS and EF) were similar at rest and HG. More sensitive tissue Doppler S' was significantly lower at rest in CoA subjects (5.1 +/- 1.5 cm/s vs 6.5 +/- 1 +/- 1 cm/s; p<0.01), decreasing further during HG by 5% in the CoA group (NS) while unchanged in controls. Conclusions We provide first evidence that HG with echocardiography is feasible, easy and patient-friendly. A decreased systolic (tissue Doppler) and impaired diastolic LV function was measured in the RCoA group, a difference that tended to increase during HG

Different patterns of cerebral and muscular tissue oxygenation 10 years after coarctation repair

The purpose of this study was to assess whether the lower exercise tolerance in children after coarctation repair is associated with alterations in peripheral tissue oxygenation during exercise. A total of 16 children after coarctation repair and 20 healthy control subjects performed an incremental ramp exercise test to exhaustion. Cerebral and locomotor muscle oxygenation were measured by means of near infrared spectroscopy. The responses of cerebral and muscle tissue oxygenation index (cTOI, mTOI), oxygenated (O(2)Hb), and deoxygenated hemoglobin (HHb) as a function of work rate were compared. Correlations between residual continuous wave Doppler gradients at rest, arm-leg blood pressure difference and local oxygenation responses were evaluated. Age, length, and weight was similar in both groups. Patients with aortic coarctation had lower peak power output (Ppeak) (72.3 +/- 20.2% vs. 106 +/- 18.7%, P < 0.001), VO(2)peak/kg (37.3 +/- 9.1 vs. 44.2 +/- 7.6 ml/kg, P = 0.019) and %VO(2)peak/kg (85.7 +/- 21.9% vs. 112.1 +/- 15.5%, P < 0.001). Cerebral O(2)Hb and HHb had a lower increase in patients vs. controls during exercise, with significant differences from 60 to 90% Ppeak (O(2)Hb) and 70% to 100% Ppeak (HHb). Muscle TOI was significantly lower in patients from 10 to 70% Ppeak and muscle HHb was significantly higher in patients vs. controls from 20 to 80% Ppeak. Muscle O(2)Hb was not different between both groups. There was a significant correlation between residual resting blood pressure gradient and Delta muscle HHb/Delta P at 10-20W and 20-30W (r = 0.40, P = 0.039 and r = 0.43, P = 0.034). Children after coarctation repair have different oxygenation responses at muscular and cerebral level. This reflects a different balance between O-2 supply to O-2 demand which might contribute to the reduced exercise tolerance in this patient population

Analysis of the recovery phase after maximal exercise in children with repaired tetralogy of Fallot and the relationship with ventricular function

Background Few studies demonstrate delayed recovery after exercise in children and adults with heart disease. We assess the recovery patterns of gas exchange parameters and heart rate (HR) in children with repaired Tetralogy of Fallot (rToF) compared to healthy peers and investigate the correlation with ventricular function and QRS duration. Methods 45 children after rToF and 45 controls performed a maximal incremental cardiopulmonary exercise test. In the subsequent recovery period, patterns of VO2, VCO2 and HR were analysed. Half-life time (T-1/2) of the exponential decay and drop per minute (Rec(min)) were compared between groups. In the rToF group, correlations were examined between the recovery parameters and QRS-duration and ventricular function, described by fractional shortening (FS) and tricuspid annular plane systolic excursion (TAPSE) measured at baseline prior to exercise. Results Recovery of VO2 and VCO2 was delayed in rToF patients, half-life time values were higher compared to controls (T1/2VO2 52.51 11.29 s vs. 44.31 +/- 10.47 s; p = 0.001 and T1/2VCO2 68.28 +/- 13.84 s vs. 59.41 +/- 12.06 s; p = 0.002) and percentage drop from maximal value was slower at each minute of recovery (p<0.05). Correlations were found with FS (T1/2VO2: r = -0.517; p<0.001; Rec(1min)VO(2): r = -0.636, p<0.001; Rec(1min)VCO(2): r = -0.373, p = 0.012) and TAPSE (T1/2VO2: r = -0.505; p<0.001; Rec(1min)VO(2): r = -0.566, p<0.001; T1/2VCO2: r = -0.466; p = 0.001; Rec(1min)VCO(2): r = -0.507, p<0.001), not with QRS-duration. No difference was found in HR recovery between patients and controls. Conclusions Children after rToF show a delayed gas exchange recovery after exercise. This delay correlates to ventricular function, demonstrating its importance in recovery after physical activity

An integrated view on the oxygenation responses to incremental exercise at the brain, the locomotor and respiratory muscles

In the past two decades oxygenation responses to incremental ramp exercise, measured non-invasively by means of near-infrared spectroscopy at different locations in the body, have advanced the insights on the underpinning mechanisms of the whole-body pulmonary oxygen uptake () response. In healthy subjects the complex oxygenation responses at the level of locomotor and respiratory muscles, and brain were simplified and quantified by the detection of breakpoints as a deviation in the ongoing response pattern as work rate increases. These breakpoints were located in a narrow intensity range between 75 and 90 % of the maximal and were closely related to traditionally determined thresholds in pulmonary gas exchange (respiratory compensation point), blood lactate measurements (maximal lactate steady state), and critical power. Therefore, it has been assumed that these breakpoints in the oxygenation patterns at different sites in the body might be equivalent and could, therefore, be used interchangeably. In the present review the typical oxygenation responses (at locomotor and respiratory muscle level, and cerebral level) are described and a possible framework is provided showing the physiological events that might link the breakpoints at different body sites with the thresholds determined from pulmonary gas exchange and blood lactate measurements. However, despite a possible physiological association, several arguments prevent the current practical application of these breakpoints measured at a single site as markers of exercise intensity making it highly questionable whether measurements of the oxygenation response at one single site can be used as a reflection of whole-body responses to different exercise intensities

Characterizing cerebral and locomotor muscle oxygenation to incremental ramp exercise in healthy children : relationship with pulmonary gas exchange

AIMS: To characterize the oxygenation responses at cerebral and locomotor muscle level to incremental exercise in children and to assess the interrelationship with the pulmonary gas exchange responses. METHODS: Eighteen children (9 boys, 9 girls) (mean age 10.9 ± 1.0 years) performed incremental cycle ramp exercise to exhaustion. The concentration of cerebral and muscle oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin (by means of near-infrared spectroscopy) and pulmonary gas exchange was recorded. Cerebral and muscle O2Hb and HHb values were expressed as functions of oxygen uptake (VO2) and breakpoints were detected by means of double linear model analysis. The respiratory compensation point (RCP) was determined. The breakpoints in cerebral and muscle O2Hb and HHb were compared and correlated to RCP. RESULTS: The subjects reached peak power output of 105 ± 18 W and VO2peak of 43.5 ± 7.0 ml min-1 kg-1. Cerebral O2Hb increased to an intensity of 89.4 ± 5.5 %VO2peak, where a breakpoint occurred at which cerebral O2Hb started to decrease. Cerebral HHb increased slightly to 88.1 ± 4.8 %VO2peak, at which the increase was accelerated. Muscle HHb increased to 90.5 ± 4.8 %VO2peak where a leveling-off occurred. RCP occurred at 89.3 ± 4.3 %VO2peak. The breakpoints and RCP did not differ significantly (P = 0.13) and were strongly correlated (r > 0.70, P 0.05). CONCLUSIONS: It was shown that cerebral and muscle oxygenation responses undergo significant changes as work rate increases and show breakpoints in the ongoing response at high intensity (85-95 %VO2peak). These breakpoints are strongly interrelated and associated with changes in pulmonary gas exchange

Intersubject EEG Coherence in Healthy Dyads during Individual and Joint Mindful Breathing Exercise: An EEG-Based Experimental Hyperscanning Study

Intersubject electroencephalogram (EEG) coherence of 11 couples was measured during an individual and joint practice of a guided mindful breathing exercise. Additionally, the relationship of personality dimensions of agreeableness and extraversion with intersubject coherence was examined. There were four male-male pairs, five female-female pairs, and two male-female pairs. The age of the participants ranged between 18 and 28 (M = 22.3, SD = 2.9). During the counterbalanced joint and individual conditions, the same mindfulness listening tape (3 min) was played, while during the individual task, a screen was placed between the two participants. Results showed an increase in intersubject coherence during joint practice compared to individual practice in frontal (F8) and temporal (T5 and T6) electrodes in the alpha band. With respect to personality characteristics, higher agreeableness of a dyad was associated with an increase in intersubject coherence in in temporal (T6) theta band. The increase in intersubject coherence in the theta band in high agreeableness subjects during joint practice might be associated with theory of mind activation. This study provides new insights concerning brain coherence in healthy people during joint mindful breathing, including the association with personality characteristics