Przybylski R; Fischer IR; Gauvreau K; Alexander ME; Shafer KM; Colan SD; Miliaresis C; Rhodes J;

Pediatric cardiology [Pediatr Cardiol] 2022 Jan 20.
Date of Electronic Publication: 2022 Jan 20.

Exercise function is well characterized in adults with hypertrophic cardiomyopathy (HCM); however, there is a paucity of data in children and young adults with HCM. Here we sought to characterize exercise function in young people with HCM, understand limitations in exercise function by correlating exercise function parameters with echocardiogram parameters and identify prognostic value of exercise parameters. We performed a retrospective, single-center cohort study characterizing exercise function in patients < 26 years old with HCM undergoing cardiopulmonary exercise testing (CPET). Patients with syndromic HCM or submaximal effort were excluded. We compared exercise function in this cohort to population normal values and measured changes in exercise function over time. We correlated exercise function parameters with echocardiographic parameters and investigated the relationship between exercise test parameters and a clinical composite outcome comprised of significant ventricular arrhythmia, death, or heart transplantation. We identified 229 CPETs performed by 117 patients (mean age at time of first CPET 15.6 ± 3.2 years). Mean %-predicted peak VO2, O2 pulse, and peak heart rate were statistically significantly depressed compared to population normal values and exercise function gradually worsened over time. Abnormal exercise testing correlated closely with echocardiographic indices of diastolic dysfunction. There was a trend toward increased incidence of poor clinical outcome in patients with abnormal exercise function. While adverse clinical outcomes were rare, normal exercise function appears to be a marker of low risk for adverse clinical outcomes in this population.

Brat K; Homolka P; Merta Z; Chobola M; Heroutova M; Bratova M; Mitas L; Chovanec Z; Horvath T; Benej M; Ivicic J; Svoboda M; Sramek V; Olson LJ; Cundrle I Jr;

The Annals of thoracic surgery [Ann Thorac Surg] 2022 Jan 21.
Date of Electronic Publication: 2022 Jan 21.

Background: Cardiopulmonary exercise testing parameters including ventilatory efficiency (V_E /VCO ₂ slope) are used for risk assessment of lung resection candidates. However, many patients are unable or unwilling to undergo exercise. V_E /VCO ₂ slope is closely related to the partial pressure of end-tidal carbon dioxide (P_ET CO ₂ ). We hypothesized P_ET CO ₂ at rest predicts post-operative pulmonary complications.
Methods: Consecutive lung resection candidates were included in this prospective multicenter study. Post-operative respiratory complications were assessed from the first 30 post-operative days or from the hospital stay. Student t-test or Mann-Whitney U test was used for comparison. Multivariate stepwise logistic regression analysis was used to analyze association with the development of post-operative pulmonary complications. The De Long test was used to compare AUCs. Data are summarized as median (IQR).
Results: Three hundred fifty-three subjects were analyzed of which 59 (17%) developed post-operative pulmonary complications. P_ET CO ₂ at rest was significantly lower [27 (24-30) vs. 29 (26-32) mmHg; P<0.01] and V_E /VCO ₂ slope during exercise significantly higher [35 (30-40) vs. 29 (25-33); P<0.01] in patients who developed post-operative pulmonary complications. Both rest P_ET CO ₂ with OR=0.90 (95%CI 0.83; 0.97); P=0.01 and V_E /VCO ₂ slope with OR=1.10 (95%CI 1.05; 1.16); P<0.01 were independently associated with post-operative pulmonary complications by multivariate stepwise logistic regression analysis. There was no significant difference between AUCs of both models (rest P_ET CO ₂ : AUC=0.79 (95%CI 0.74; 0.85); V_E /VCO ₂ slope: AUC=0.81 (95%CI 0.75; 0.86); P=0.48).
Conclusions: P_ET CO ₂ at rest has similar prognostic utility as V_E /VCO ₂ slope suggesting rest P_ET CO ₂ may be used for post-operative pulmonary complications prediction in lung resection candidates.

Singh I; Joseph P; Heerdt PM; Cullinan M; Lutchmansingh DD; Gulati M;
Possick JD; Systrom DM; Waxman AB

Chest. 161(1):54-63, 2022 01.VI 1

BACKGROUND: Some patients with COVID-19 who have recovered from the acute
infection after experiencing only mild symptoms continue to exhibit
persistent exertional limitation that often is unexplained by conventional
investigative studies.
RESEARCH QUESTION: What is the pathophysiologic mechanism of exercise
intolerance that underlies the post-COVID-19 long-haul syndrome in
patients without cardiopulmonary disease?
STUDY DESIGN AND METHODS: This study examined the systemic and pulmonary
hemodynamics, ventilation, and gas exchange in 10 patients who recovered
from COVID-19 and were without cardiopulmonary disease during invasive
cardiopulmonary exercise testing (iCPET) and compared the results with
those from 10 age- and sex-matched control participants. These data then
were used to define potential reasons for exertional limitation in the
cohort of patients who had recovered from COVID-19.
RESULTS: The patients who had recovered from COVID-19 exhibited markedly
reduced peak exercise aerobic capacity (oxygen consumption [VO2]) compared
with control participants (70 +/- 11% predicted vs 131 +/- 45% predicted;
P < .0001). This reduction in peak VO2 was associated with impaired
systemic oxygen extraction (ie, narrow arterial-mixed venous oxygen
content difference to arterial oxygen content ratio) compared with control
participants (0.49 +/- 0.1 vs 0.78 +/- 0.1; P < .0001), despite a
preserved peak cardiac index (7.8 +/- 3.1 L/min vs 8.4+/-2.3 L/min; P >
.05). Additionally, patients who had recovered from COVID-19 demonstrated
greater ventilatory inefficiency (ie, abnormal ventilatory efficiency
[VE/VCO2] slope: 35 +/- 5 vs 27 +/- 5; P = .01) compared with control
participants without an increase in dead space ventilation.
INTERPRETATION: Patients who have recovered from COVID-19 without
cardiopulmonary disease demonstrate a marked reduction in peak VO2 from a
peripheral rather than a central cardiac limit, along with an exaggerated
hyperventilatory response during exercise.

Hayward N; Shaban M; Badger J; Jones I; Wei Y;  Spencer D; Isichei S; Knight M; Otto J; Rayat G; Levett D; Grocott M; Akerman H; White N;

Journal of clinical monitoring and computing [J Clin Monit Comput] 2022 Jan 18.
Date of Electronic Publication: 2022 Jan 18.

Respiratory rate (RR) is a marker of critical illness, but during hospital care, RR is often inaccurately measured. The capaciflector is a novel sensor that is small, inexpensive, and flexible, thus it has the potential to provide a single-use, real-time RR monitoring device. We evaluated the accuracy of continuous RR measurements by capaciflector hardware both at rest and during exercise. Continuous RR measurements were made with capaciflectors at four chest locations. In healthy subjects (n = 20), RR was compared with strain gauge chest belt recordings during timed breathing and two different body positions at rest. In patients undertaking routine cardiopulmonary exercise testing (CPET, n = 50), RR was compared with pneumotachometer recordings. Comparative RR measurement bias and limits of agreement were calculated and presented in Bland-Altman plots. The capaciflector was shown to provide continuous RR measurements with a bias less than 1 breath per minute (BPM) across four chest locations. Accuracy and continuity of monitoring were upheld even during vigorous CPET exercise, often with narrower limits of agreement than those reported for comparable technologies. We provide a unique clinical demonstration of the capaciflector as an accurate breathing monitor, which may have the potential to become a simple and affordable medical device.

Canada JM; Weiss E; Grizzard JD; Trankle CR; Gharai LR; Dana F; Buckley LF; Carbone S; Kadariya D; Ricco A; JH; Evans RK; Garten RS; Van Tassell BW; Hundley WG;Abbate A;

Cardio-oncology (London, England) [Cardiooncology] 2022 Jan 18; Vol. 8 (1), pp. 1.
Date of Electronic Publication: 2022 Jan 18.

Background: Radiation-induced myocardial fibrosis increases heart failure (HF) risk and is associated with a restrictive cardiomyopathy phenotype. The myocardial extracellular volume fraction (ECVF) using contrast-enhanced cardiac magnetic resonance (CMR) quantifies the extent of fibrosis which, in severe cases, results in a noncompliant left ventricle (LV) with an inability to augment exercise stroke volume (SV). The peak exercise oxygen pulse (O ₂ Pulse), a noninvasive surrogate for exercise SV, may provide mechanistic insight into cardiac reserve. The relationship between LV ECVF and O ₂ Pulse following thoracic radiotherapy has not been explored.
Methods: Patients who underwent thoracic radiotherapy for chest malignancies with significant incidental heart dose (≥5 Gray (Gy), ≥10% heart) without a pre-cancer treatment history of HF underwent cardiopulmonary exercise testing to determine O ₂ Pulse, contrast-enhanced CMR, and N-terminal pro-brain natriuretic peptide (NTproBNP) measurement. Multivariable-analyses were performed to identify factors associated with O ₂ Pulse normalized for age/gender/anthropometrics.
Results: Thirty patients (median [IQR] age 63 [57-67] years, 18 [60%] female, 2.0 [0.6-3.8] years post-radiotherapy) were included. The peak VO ₂ was 1376 [1057-1552] mL·min ^- 1 , peak HR = 150 [122-164] bpm, resulting in an O ₂ Pulse of 9.2 [7.5-10.7] mL/beat or 82 (66-96) % of predicted. The ECVF, LV ejection fraction, heart volume receiving ≥10 Gy, and NTproBNP were independently associated with %O ₂ Pulse (P < .001).
Conclusions: In patients with prior radiotherapy heart exposure, %-predicted O ₂ Pulse is inversely associated markers of diffuse fibrosis (ECVF), ventricular wall stress (NTproBNP), radiotherapy heart dose, and positively related to LV function. Increased LV ECVF may reflect a potential etiology of impaired LV SV reserve in patients receiving thoracic radiotherapy for chest malignancies.

Van Ryckeghem L, Keytsman C, De Brandt J, Verboven K, Verbaanderd E, Marinus N, Franssen WMA, Frederix I, Bakelants E, Petit T, Jogani S, Stroobants S, Dendale P, Bito V, Verwerft J, Hansen D

Eur J Appl Physiol. 2022 Jan 17. doi: 10.1007/s00421-022-04884-9. Online ahead of print.

PURPOSE: Exercise training improves exercise capacity in type 2 diabetes mellitus (T2DM). It remains to be elucidated whether such improvements result from cardiac or peripheral muscular adaptations, and whether these are intensity dependent.
METHODS: 27 patients with T2DM [without known cardiovascular disease (CVD)] were randomized to high-intensity interval training (HIIT, n = 15) or moderate-intensity endurance training (MIT, n = 12) for 24 weeks (3 sessions/week). Exercise echocardiography was applied to investigate cardiac output (CO) and oxygen (O2) extraction during exercise, while exercise capacity [([Formula: see text] (mL/kg/min)] was examined via cardiopulmonary exercise testing at baseline and after 12 and 24 weeks of exercise training, respectively. Changes in glycaemic control (HbA1c and glucose tolerance), lipid profile and body composition were also evaluated.
RESULTS: 19 patients completed 24 weeks of HIIT (n = 10, 66 ± 11 years) or MIT (n = 9, 61 ± 5 years). HIIT and MIT similarly improved glucose tolerance (pTime = 0.001, pInteraction > 0.05), [Formula: see text] (mL/kg/min) (pTime = 0.001, pInteraction > 0.05), and exercise performance (Wpeak) (pTime < 0.001, pInteraction > 0.05). O2 extraction increased to a greater extent after 24 weeks of MIT (56.5%, p1 = 0.009, pTime = 0.001, pInteraction = 0.007). CO and left ventricular longitudinal strain (LS) during exercise remained unchanged (pTime > 0.05). A reduction in HbA1c was correlated with absolute changes in LS after 12 weeks of MIT (r = - 0.792, p = 0.019, LS at rest) or HIIT (r = - 0.782, p = 0.038, LS at peak exercise).
CONCLUSION: In patients with well-controlled T2DM, MIT and HIIT improved exercise capacity, mainly resulting from increments in O2 extraction capacity, rather than changes in cardiac output. In particular, MIT seemed highly effective to generate these peripheral adaptations.

Mazaheri R; Sadeghian M; Nazarieh M; Niederseer D; Schmied C

International Journal of Environmental Research & Public Health
[Electronic Resource]. 18(24), 2021 12 08.

BACKGROUND: Peak oxygen consumption (VO2) measured by cardiopulmonary
exercise testing (CPET) is a significant predictor of mortality and future
transplantation in heart failure patients with severely reduced ejection
fraction (HFrEF). The present study evaluated the differences in peak VO2
and other prognostic variables between treadmill and cycle CPETs in these
patients.
METHODS: In this cross-over study design, thirty males with severe HFrEF
underwent CPET on both a treadmill and a cycle ergometer within 2-5 days
apart, and important CPET parameters between two exercise test modalities
were compared.
RESULTS: Peak VO2 was 23.12% higher on the treadmill than on cycle (20.55
+/- 3.3 vs. 16.69 +/- 3.01, p < 0.001, respectively). Minute ventilation
to carbon dioxide production (VE/VCO2) slope was not different between the
two CPET modes (p = 0.32). There was a strong positive correlation between
the VE/VCO2 slopes during treadmill and cycle testing (r = 0.79; p <
0.001). VE/VCO2 slope was not related to peak respiratory exchange ratio
(RER) in either modality (treadmill, r = 0.13, p = 0.48; cycle, r = 0.25,
p = 0.17). The RER level was significantly higher on the cycle ergometer
(p < 0.001).
CONCLUSION: Peak VO2 is higher on treadmill than on cycle ergometer in
severe HFrEF patients. In addition, VE/VCO2 slope is not a modality
dependent parameter and is not related to the patients’ effort during
CPET.

Jonathan Wagner, Max Niemeyer, Denis Infanger, Otmar Pfister, Jonathan Myers; Arno Schmidt-Trucksäss and Raphael Knaier

Frontiers in Physiology | www.frontiersin.org
November 2021 | Volume 12 | Article 775601

Objective: The aim of this study was to analyze whether V˙ O2-kinetics during
cardiopulmonary exercise testing (CPET) is a useful marker for the diagnosis of
heart failure (HF) and to determine which V˙ O2-kinetic parameter distinguishes healthy
participants and patients with HF.
Methods: A total of 526 healthy participants and 79 patients with HF between 20 and
90 years of age performed a CPET. The CPET was preceded by a 3-min low-intensity
warm-up and followed by a 3-min recovery bout. V˙ O2-kinetics was calculated from
the rest to exercise transition of the warm-up bout (on-kinetics), from the exercise to
recovery transition following ramp test termination (off-kinetics) and from the initial delay
of V˙ O2 during the warm-up to ramp test transition (ramp-kinetics).
Results: V˙ O2 off-kinetics showed the highest z-score differences between healthy
participants and patients with HF. Furthermore, off-kinetics was strongly associated
with V˙ O2peak. In contrast, ramp-kinetics and on-kinetics showed only minimal z-score
differences between healthy participants and patients with HF. The best on- and
off-kinetic parameters significantly improved a model to predict the disease severity.
However, there was no relevant additional value of V˙ O2-kinetics when V˙ O2peak was
part of the model.
Conclusion: V˙ O2 off-kinetics appears to be superior for distinguishing patients with HF
and healthy participants compared with V˙ O2 on-kinetics and ramp-kinetics. If V˙ O2peak
cannot be determined, V˙ O2 off-kinetics provides an acceptable substitute. However, the
additional value beyond that of V˙ O2peak cannot be provided by V˙ O2-kinetics.

T. Takken;  H. J. Hulzebos;

ObjectiveThe purpose of the present study was to investigate the association between cardiorespiratory fitness (CRF) measured as peak oxygen uptake (VO2peak, expressed in mL/min) and body mass index (BMI) in a large cohort of apparently healthy subjects.
MethodsBMI and VO2peak were measured in a cross-sectional study of 8470 apparently healthy adults. VO2peak (mL/min) was determined by an incremental cycle ergometer test to exhaustion. Linear regression analyses were performed to identify predictors of CRF.
ResultsThere was no difference in CRF between adults with a normal weight (BMI between 18.5–24.9 kg/m2) and those who were overweight (BMI 25.0–29.9 kg/m2). Subjects who were underweight (BMI < 18.5 kg/m2) as well as females who were obese (BMI ≥ 30.0 kg/m2) showed a reduced CRF compared to the normal and overweight groups. Age, height, and gender were significant predictors of CRF (R2 = 0.467, P < 0.0001); BMI did not add significantly to this relationship.
ConclusionOur findings indicate that BMI was not associated with CRF in addition to age, height, and gender. In subjects with a BMI < 18.5 kg/m2, CRF was lower compared to subjects with a BMI between 18.5 and 29.9 kg/m2. In obese subjects, CRF was only lower in females compared to females with a BMI between 18.5 and 29.9 kg/m2. Correcting CRF for BMI may be beneficial for subjects with a low BMI, and females with a BMI ≥ 30.0 kg/m2. The outcome of this study might help to improve the interpretation of exercise testing results in individuals with a low or high BMI.

T. Takken · H. J. Hulzebos

Journal of Science in Sport and Exercise https://doi.org/10.1007/s42978-021-00143-z

ObjectiveThe purpose of the present study was to investigate the association between cardiorespiratory fitness (CRF) measured as peak oxygen uptake (VO2peak, expressed in mL/min) and body mass index (BMI) in a large cohort of apparently healthy subjects.
MethodsBMI and VO2peak were measured in a cross-sectional study of 8470 apparently healthy adults. VO2peak (mL/min) was determined by an incremental cycle ergometer test to exhaustion. Linear regression analyses were performed to identify predictors of CRF.
ResultsThere was no difference in CRF between adults with a normal weight (BMI between 18.5–24.9 kg/m2) and those who were overweight (BMI 25.0–29.9 kg/m2). Subjects who were underweight (BMI < 18.5 kg/m2) as well as females who were obese (BMI ≥ 30.0 kg/m2) showed a reduced CRF compared to the normal and overweight groups. Age, height, and gender were significant predictors of CRF (R2 = 0.467, P < 0.0001); BMI did not add significantly to this relationship.
ConclusionOur findings indicate that BMI was not associated with CRF in addition to age, height, and gender. In subjects with a BMI < 18.5 kg/m2, CRF was lower compared to subjects with a BMI between 18.5 and 29.9 kg/m2. In obese subjects, CRF was only lower in females compared to females with a BMI between 18.5 and 29.9 kg/m2. Correcting CRF for BMI may be beneficial for subjects with a low BMI, and females with a BMI ≥ 30.0 kg/m2. The outcome of this study might help to improve the interpretation of exercise testing results in individuals with a low or high BMI.