Ariyaratnam JP; Royal Adelaide Hospital, Adelaide, Australia
Elliott AD; Mishima RS; Kadhim K; Emami M; Fitzgerald JL;
Middeldorp M; Sanders P

JACC. Clinical Electrophysiology. 10(7 Pt 2):1608-1619, 2024 Jul.

BACKGROUND: Reduced cardiorespiratory fitness (CRF) is an independent risk
factor for the progression of atrial fibrillation (AF). We hypothesized
that reduced CRF is associated with structural, functional, and electrical
remodeling of the left atrium.
OBJECTIVES: This study sought to correlate objectively assessed CRF with
functional and electrical left atrial (LA) parameters using invasive and
noninvasive assessments.
METHODS: Consecutive patients with symptomatic AF undergoing catheter
ablation were recruited. CRF was objectively quantified pre-ablation by
using cardiopulmonary exercise testing. Using peak oxygen consumption,
participants were classified as preserved CRF (>20 mL/kg/min) or reduced
CRF (<20 mL/kg/min). LA stiffness was assessed invasively with hemodynamic
monitoring and imaging during high-volume LA saline infusion. LA stiffness
was calculated as DELTALA diameter/DELTALA pressure over the course of the
infusion. LA function was assessed with echocardiographic measures of LA
emptying fraction and LA strain. Electrical remodeling was assessed by
using high-density electroanatomical maps for LA voltage and conduction.
RESULTS: In total, 100 participants were recruited; 43 had reduced CRF
and 57 had preserved CRF. Patients with reduced CRF displayed elevated LA
stiffness (P = 0.004), reduced LA emptying fraction (P = 0.006), and
reduced LA reservoir strain (P < 0.001). Reduced CRF was also associated
with reduced LA voltage (P = 0.039) with greater heterogeneity (P = 0.027)
and conduction slowing (P = 0.04) with greater conduction heterogeneity (P
= 0.02). On multivariable analysis, peak oxygen consumption was
independently associated with LA stiffness (P = 0.003) and LA conduction
velocities (P = 0.04)
CONCLUSIONS: Reduced CRF in patients with AF is independently associated
with worse LA disease involving functional and electrical changes.
Improving CRF may be a target for restoring LA function in AF.

Correction to “Cardiopulmonary exercise testing and the 2022 definition of pulmonary hypertension”.

Erratum for: Pulm Circ. 2024 Jun 17;14(2):e12398. doi: 10.1002/pul2.12398. (PMID: 38887743)

Veneman T; Amsterdam UMC location University of Amsterdam, Rehabilitation Medicine, Meibergdreef 9, Amsterdam, The Netherlands
Koopman FS; Oorschot S;de Koning JJ; Bongers BC; Nollet F; Voorn EL;

Archives of physical medicine and rehabilitation [Arch Phys Med Rehabil] 2024 Jul 19.
Date of Electronic Publication: 2024 Jul 19.

Objectives: To determine the content validity of cardiopulmonary exercise testing (CPET) for assessing peak oxygen uptake (VO _2peak ) in neuromuscular diseases (NMD).
Design: Baseline assessment of a randomized controlled trial.
Setting: Academic hospital.
Participants: Eighty-six adults (age: 58.0 ± 13.9 years) with Charcot-Marie-Tooth disease (n=35), post-polio syndrome (n=26), or other NMD (n=25).
Intervention: Not applicable.
Main Outcome Measures: Workload, gas exchange variables, heart rate, and ratings of perceived exertion were measured during CPET on a cycle ergometer, supervised by an experienced trained assessor. Muscle strength of the knee extensors was assessed isometrically with a fixed dynamometer. Criteria for confirming maximal cardiorespiratory effort during CPET were established during 3 consensus meetings with an expert group. The percentage of participants meeting these criteria was assessed to quantify content validity.
Results: The following criteria were established for maximal cardiorespiratory effort; a plateau in oxygen uptake (VO _2plateau ) as primary criterion, or 2 out of 3 secondary criteria; 1) peak respiratory exchange ratio (RER _peak ) ≥1.10, 2), peak heart rate (HR _peak ) ≥85% of predicted maximal heart rate, and 3) peak rating of perceived exertion (RPE _peak ) ≥17 on the 6-20 Borg scale. These criteria were attained by 71 participants (83%). VO _2plateau , RER _peak ≥1.10, HR _peak ≥85%, and RPE _peak ≥17 were attained by respectively 31%, 73%, 69%, and 72% of the participants. Peak workload, VO _2peak , and knee extension muscle strength were significantly higher, and body mass index was lower (all p<0.05), in participants with maximal cardiorespiratory effort compared to other participants.
Conclusions: Most people with NMD achieved maximal cardiorespiratory effort during CPET. Therewith, this study provides high quality evidence of sufficient content validity of VO _2peak as a maximal aerobic capacity measure. Content validity may be lower in more severely affected people with lower physical fitness.

Braga F; Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Milani M; Department of Cardiology, Heart Centre Hasselt, Jessa Hospital, Hasselt, Belgium.
Espinosa G; Goulart Prata Oliveira Milani J; Hansen D; Cipriano G Junior; Myers J;  Mourilhe-Rocha R;

European journal of preventive cardiology [Eur J Prev Cardiol] 2024 Jul 04.
Date of Electronic Publication: 2024 Jul 04.

No abstract available

Chavez-Guevara IA; Faculty of Sports Campus Ensenada, Autonomous University of Baja California, Mexico.;
Helge JW; Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Amaro-Gahete FJ; Department of Physiology, Faculty of Medicine, University of Granada,  Spain.

The Journal of physiology [J Physiol] 2024 Jul 07.
Date of Electronic Publication: 2024 Jul 07.

No abstract available

Kasiak P; Medical University of Warsaw, Warsaw, Poland.
Kowalski T; Rębiś K; Klusiewicz A; Sadowska D; Wilk A; Wiecha S;Barylski M; Poliwczak AR; Wierzbiński P; Mamcarz A; Śliż D;

BMC sports science, medicine & rehabilitation [BMC Sports Sci Med Rehabil] 2024 Jul 10; Vol. 16 (1), pp. 151.
Date of Electronic Publication: 2024 Jul 10.

Background: Endurance athletes (EA) are an emerging population of focus for cardiovascular health. The oxygen uptake efficiency plateau (OUEP) is the levelling-off period of ratio between oxygen uptake (VO ₂ ) and ventilation (VE). In the cohort of EA, we externally validated prediction models for OUEP and derived with internal validation a new equation.
Methods: 140 EA underwent a medical assessment and maximal cycling cardiopulmonary exercise test. Participants were 55% male (N = 77, age = 21.4 ± 4.8 years, BMI = 22.6 ± 1.7 kg·m ^- 2 , peak VO ₂  = 4.40 ± 0.64 L·min ^- 1 ) and 45% female (N = 63, age = 23.4 ± 4.3 years, BMI = 22.1 ± 1.6 kg·m ^- 2 , peak VO ₂  = 3.21 ± 0.48 L·min ^- 1 ). OUEP was defined as the highest 90-second continuous value of the ratio between VO ₂ and VE. We used the multivariable stepwise linear regression to develop a new prediction equation for OUEP.
Results: OUEP was 44.2 ± 4.2 mL·L ^- 1 and 41.0 ± 4.8 mL·L ^- 1 for males and females, respectively. In external validation, OUEP was comparable to directly measured and did not differ significantly. The prediction error for males was - 0.42 mL·L ^- 1 (0.94%, p = 0.39), and for females was + 0.33 mL·L ^- 1 (0.81%, p = 0.59). The developed new prediction equation was: 61.37-0.12·height (in cm) + 5.08 (for males). The developed model outperformed the previous. However, the equation explained up to 12.9% of the variance (R = 0.377, R ²  = 0.129, RMSE = 4.39 mL·L ^- 1 ).
Conclusion: OUEP is a stable and transferable cardiorespiratory index. OUEP is minimally affected by fitness level and demographic factors. The predicted OUEP provided promising but limited accuracy among EA. The derived new model is tailored for EA. OUEP could be used to stratify the cardiorespiratory response to exercise and guide training.

Smarz K; Jaxa-Chamiec T; Zaborska B; Tysarowski M; Budaj A;

Original Publication: San Francisco, CA : Public Library of Science
[This corrects the article DOI: 10.1371/journal.pone.0255682.].

Baidats Y; Public Health and Sport Sciences, Medical School, University of Exeter, Exeter, UNITED KINGDOM. & Israel
Kadosh S; Jones AM; Wilkerson D; Velner A;Reuveny R;Segel MJ;

Medicine and science in sports and exercise [Med Sci Sports Exerc] 2024 Jul 11.
Date of Electronic Publication: 2024 Jul 11.

Purpose: We studied the effect of O2 supplementation on physiological response to exercise in patients with moderate to severe interstitial lung disease (ILD).
Methods: 13 patients (age 66 ± 10 yrs., 7 males) with ILD (TLC 71 ± 22% predicted, carbon monoxide diffusion capacity (DLCO) 44 ± 16% predicted) and 13 healthy individuals (age 50 ± 17 yrs., 7 males) were tested. ILD patients performed symptom-limited cardiopulmonary exercise tests and constant work-rate tests (CWRTs) at 80% of the work-rate (WR) at the gas exchange threshold (GET). Tests breathing room air (RA, 21% O2) were compared to tests performed breathing 30% O2. Oxygen-uptake (V̇O2) kinetics were calculated from the CWRT results.
Results: In the ILD group, peak WR, peak V̇O2 and V̇O2 at the GET improved significantly when breathing 30% O2 compared to RA (mean ± SD 66 ± 23 vs 75 ± 26 watts, 15 ± 2 vs 17 ± 4 ml/kg/min and 854 ± 232 vs 932 ± 245 ml/min; p = 0.004, p = 0.001 and p = 0.01, respectively). O2 saturation (SPO2%) at peak exercise was higher with 30% O2 (97 ± 4% vs 88 ± 9%, p = 0.002). The time constant (tau) of V̇O2 kinetics was faster in ILD patients while breathing 30% O2 (41 ± 10 sec) compared to RA (52 ± 14 sec, p = 0.003). There was a negative linear relation between tau and SPO2% with RA (r = -0.76, p = 0.006) and while breathing 30% O2 (r = -0.68, p = 0.02).
Conclusions: Using a clinically applicable level of O2 supplementation (30%) improved maximal, aerobic exercise capacity and V̇O2 kinetics in ILD patients, likely due to increased blood O2 content subsequently increasing the O2 delivery to the working muscles.
Competing Interests: Conflict of Interest and Funding Source: This work was supported by the G. Baum Fund of the Israeli Lung Association, Tel-Aviv. The authors have no conflict of interest and no financial disclosure related to this report.

Simovic T; Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, United States.
Matheson C; Cobb K; Heefner A; Thode C; Colon M; Tunon E; Salmons H; Ahmed SI; Carbone S; Garten R; Breland A; Cobb CO; Nana-Sinkam P;
Rodriguez-Miguelez P;

Journal of applied physiology (Bethesda, Md. : 1985) [J Appl Physiol (1985)] 2024 Jul 11.
Date of Electronic Publication: 2024 Jul 11.

Background: Electronic nicotine delivery systems, often referred to as e-cigarettes, are popular tobacco products frequently advertised as safer alternatives to traditional cigarettes despite preliminary data suggesting a potential negative cardiovascular impact. Cardiorespiratory fitness is a critical cardiovascular health marker that is diminished in individuals who consume traditional tobacco products. Whether the use of e-cigarettes impacts cardiorespiratory fitness is currently unknown. Thus, the purpose of this study was to investigate the impact of regular e-cigarette use on cardiorespiratory fitness in young healthy adults.
Methods: Twenty-six users of e-cigarettes (ECU, 13 males, and 13 females; age: 24±3 yr; e-cigarette usage 4±2 yr.) and sixteen demographically matched non-users (NU, 6 males, and 10 females; age: 23±3 yr.) participated in this study. Cardiorespiratory fitness was measured by peak oxygen consumption (VO _2peak ) during a cardiopulmonary exercise test. Measurements of chronotropic response, hemodynamic, oxygen extraction and utilization were also evaluated.
Results: Our results suggest that regular users of e-cigarettes exhibited significantly lower peak oxygen consumption when compared to non-users, even when controlled by fat-free mass and lean body mass. Hemodynamic changes were not different between both groups during exercise, while lower chronotropic responses and skeletal muscle oxygen utilization were observed in users of e-cigarettes.
Conclusions: Results from the present study demonstrate that young, apparently healthy, regular users of e-cigarettes exhibit significantly reduced cardiorespiratory fitness, lower chronotropic response, and impaired skeletal muscle oxygen utilization during exercise. Overall, our findings contribute to the growing body of evidence that supports adverse effects of regular e-cigarette use on cardiovascular health.

Singh I; Division of Pulmonary, Critical Care, and Sleep Medicine,  New Haven, CT, USA inderjit.singh@yale.edu.
Waxman AB;

The European respiratory journal [Eur Respir J] 2024 Jul 11; Vol. 64 (1).
Date of Electronic Publication: 2024 Jul 11 (Print Publication: 2024).

No abstract available