Author Archives: Paul Older

(Obstructive sleep apnoea) Definition of OSA by Dr Older

Mouraux S; Department of Medicine, University of Lausanne
Lechartier B; Imler T; von Garnier C; Heinzer R; Vollenweider
P; Preisig M; Solelhac G; Touilloux B

Chest. 169(4):1091-1100, 2026 Apr.

BACKGROUND: Dyspnea increases mortality and remains unexplained in 15% of
patients. Although OSA is linked to reduced exercise capacity during
cardiopulmonary exercise testing, the association between dyspnea and OSA
remains uncertain.

RESEARCH QUESTION: Is there an association between exertional dyspnea and
OSA in the general population? What are the polysomnographic OSA-related
measures associated with exertional dyspnea?

STUDY DESIGN AND METHODS: We used data from a prospective cohort study of
the general population conducted in an urban area. Participants underwent
polysomnography and completed a respiratory questionnaire. Logistic
regression models were used to determine the association between
self-reported dyspnea (modified Medical Research Council Dyspnea scale >=
1) and OSA categories or apnea-hypopnea index (AHI) cutoffs. We performed
an adjusted model for sex, BMI, age, FEV1, psychiatric disorders, cardiac
and respiratory disorders, and smoking history.

RESULTS: We included 1,200 participants (mean age, 62.1 years; 54%
female), of whom 515 (42.9%) reported exertional dyspnea. The adjusted
model revealed a positive association between exertional dyspnea and AHI
>= 15 events/h (OR, 1.57; 95% CI, 1.13-2.19), AHI >= 30 events/h (OR,
1.72; 95% CI, 1.06-2.78), moderate OSA (OR, 1.60; 95% CI, 1.04-2.46), and
severe OSA (OR, 2.25; 95% CI, 1.28-3.96). Moreover, in the adjusted model,
dyspnea was associated with AHI, respiratory disturbance index,
respiratory pulse wave amplitude drop index, sleep apnea-specific
pulse-rate response, respiratory arousal index, and oxygen desaturation
index 3%.

INTERPRETATION: Our results suggest that exertional dyspnea is associated
with moderate and severe OSA, potentially due to heightened autonomic and
cortical responses to increased respiratory efforts. Further research is
needed to assess the effectiveness of OSA treatment on dyspnea in patients
with OSA.

A Whole-Body Exercise Test to Assess Cardiorespiratory Fitness across the Stroke Recovery Continuum.

Moncion K; School of Physical & Occupational Therapy, McGill University, Quebec, CANADA
Rodrigues L; DE Las Heras B; Wiley E; Sikorska K; Cristini J;
Allison EY; Eng JJ; Tang A; Roig M

Medicine & Science in Sports & Exercise. 58(5):1073-1084, 2026 May 01.

BACKGROUND: Accurate assessment of cardiorespiratory fitness is a critical
component of cardiopulmonary exercise testing (CPET) and prescription for
people with stroke. However, post-stroke disability and neuromuscular
impairments are common and may disproportionately affect females
throughout the continuum of recovery. There is a need to evaluate
alternative whole-body CPET protocols and to characterize the sex-specific
CPET responses throughout the continuum of stroke recovery.

PURPOSE: To characterize the sex-specific CPET responses on a whole-body
recumbent stepper CPET using American College of Sports Medicine (ACSM)
criteria in people with subacute (7-90 d) and chronic (>=6-60 months)
stroke.

METHODS: Participants underwent a whole-body recumbent stepper
symptom-limited CPET. Each CPET was assessed for ventilatory threshold
(VT), peak oxygen uptake ( ) and ACSM maximal oxygen uptake criteria,
including respiratory exchange ratio >=1.10; plateau, heart rate (HR)
within 10 beats of HRmax, and ratings of perceived exertion (RPE) >=17/20
or >=7/10. Sex differences by stroke chronicity were evaluated via t
tests, rank-sum tests, chi 2 , or Fisher exact tests.

RESULTS: In total, 145 participants underwent a symptom-limited CPET. In
subacute stroke ( n = 69), no sex differences were found for VT or ( P >
0.05), but females were more likely to achieve a plateau ( P = 0.002). In
chronic stroke ( n = 76), no sex differences were observed for VT or
criteria ( P > 0.05), but females had lower ( P = 0.002). Irrespective of
sex, achieving the RPE ( n = 41 subacute [61%], n = 38 chronic [54%]) or
respiratory exchange ratio criteria ( n = 28 subacute [41%], n = 39 [51%])
was the most commonly met ACSM criteria.

CONCLUSIONS: This whole-body CPET protocol is appropriate for eliciting
peak and maximal efforts in people post-strok

Cardiopulmonary exercise testing before lung resection surgery: still indicated? Evaluating predictive utility using machine learning.

Filakovszky A; Department of Anesthesiology and Critical Care Linz, Austria.
Brat K; Tschoellitsch T; Bartos S; Mazur A; Meier J; Olson L;
Cundrle I

Thorax. 81(5):474-482, 2026 Apr 16.

RATIONALE: Despite significant advances in patient care and outcomes,
criteria for cardiopulmonary exercise testing (CPET) in risk
stratification guidelines for lung resection have not been updated in over
a decade. We hypothesised that CPET no longer holds additional predictive
value for postoperative complications.

METHODS: In this secondary analysis, we included lung resection
candidates from two prospective, multicentre studies eligible for CPET and
assessed with preoperative pulmonary function tests (PFTs) and arterial
blood gas analysis. Postoperative pulmonary (PPCs) and cardiovascular
complications (PCCs) were documented during hospitalisation. We trained
five types of machine learning models applying nested cross-validation to
predict complications and compared predictive performance based on four
metrics, including area under the receiver operating characteristic curve
(AUC-ROC).

RESULTS: A total of 497 patients were included. PPCs developed in 71
(14%) patients. Adding CPET parameters to PFTs and baseline clinical data
did not improve the ability of models to predict PPCs in unselected
patients (AUC-ROC=0.72-0.78; p=0.47), nor in those meeting American
College of Chest Physicians (ACCPs) (n=236; AUC-ROC=0.64-0.78; p=0.70) or
European Respiratory Society/European Society of Thoracic Surgery
(ERS/ESTS) criteria (n=168; AUC-ROC=0.59-0.76; p=0.92). PCCs developed in
90 (18%) patients. CPET parameters likewise did not improve model
performance for the prediction of PCCs in unselected patients
(AUC-ROC=0.65-0.73; p=0.96), nor in the ACCP (AUC-ROC=0.61-0.73; p=0.82)
or ERS/ESTS subgroups (AUC-ROC=0.62-0.69; p=0.87).

CONCLUSIONS: In contemporary surgical practice, CPET did not improve the
predictive performance of machine learning models for PPCs or PCCs in
patients with an indication based on established guidelines or in those
without. The role of CPET in preoperative risk stratification for lung
resection should be re-evaluated.

Omega-6/omega-3 oxylipin imbalance and altered 15-LOX and sEH pathways in Fontan physiology.

Caligiuri SPB; Department of Health Sciences, Virginia USA
Ravandi A; Aukema HM; Shah AH

American Journal of Physiology – Heart & Circulatory Physiology.
330(5):H1466-H1478, 2026 May 01.

The Fontan procedure enhances systemic oxygenation and survival in
patients with complex congenital heart defects not amenable to
biventricular repair. Despite these improvements, individuals with Fontan
circulation often develop progressive multisystem dysfunction, the
biochemical underpinnings of which remain poorly understood. Oxylipins are
bioactive lipid mediators implicated in cardiovascular disease and
represent targetable pathways that may contribute to the pathophysiology
of the Fontan state. The study aims to quantify plasma oxylipins in
individuals with Fontan circulation, compared with matched controls, and
assess correlations with hemodynamic function and exercise capacity. A
total of 20 adult patients with Fontan circulation and 20 matched controls
underwent assessment of body composition, frailty, cardiopulmonary
exercise testing, and noninvasive hemodynamic evaluation. Absolute plasma
oxylipin concentrations were measured using triple quadrupole HPLC-MS/MS.
Compared with controls, Fontan participants exhibited significantly
increased (34%) total plasma oxylipin concentrations, with a 42% elevation
in omega-6 fatty acid-derived oxylipins. Among these, metabolites
generated via the 15-lipoxygenase (15-LOX) pathway were elevated by 52%.
In addition, product-to-substrate ratios reflecting putative soluble
epoxide hydrolase (sEH) activity for omega-6 fatty acids were nearly
threefold higher in the Fontan group. Several oxylipins derived from
omega-3 and omega-6 fatty acids, including those generated by 15-LOX and
sEH pathways, demonstrated significant correlations with key clinical
parameters, including resting and exercise hemodynamics, ventilatory
efficiency, and peak oxygen consumption (Vo2). Individuals with Fontan
circulation exhibit marked alterations in circulating oxylipins,
particularly those involving omega-6 fatty acid metabolism via 15-LOX and
sEH. These findings offer mechanistic insights and identify potentially
modifiable targets. NEW & NOTEWORTHY Fontan patients exhibit a distinct
oxylipin signature characterized by markedly elevated total and
omega-6-derived oxylipins, including increased 15-LOX activity and higher
sEH product-to-substrate ratios, alongside reduced omega-3 species such as
20-hydroxydocosahexanoic acid (20-HDoHE) and
17,18-dihydroxyeicosatetraenoic acid (DiHETE). Elevated omega-6 oxylipins
correlated with poorer exercise capacity, greater frailty, and impaired
hemodynamics, whereas omega-3 oxylipins showed the opposite trend. These
findings identify oxylipin dysregulation as a central metabolic hallmark
and potential therapeutic target in Fontan circulation.

Heart Rate Estimation Using the Galaxy Watch During Maximal Cardiopulmonary Exercise Testing: Cross-Sectional Validation Study.

Inoue A; Sidia Institute of Science and Technology, Brazil
Soares JPF; Antunes-Santos F; Ferreira A; Goncalves A; Alcantara JA; Dos Santos MR

JMIR Cardio. 10:e81917, 2026 Apr 16.

Background: Photoplethysmography-based smartwatches are increasingly used
for continuous heart rate (HR) monitoring. Their accuracy has been
demonstrated at rest or during low-intensity activity, but data are scarce
for maximal-intensity exercise, when motion artifacts and rapid
hemodynamic changes can degrade the photoplethysmography signal.
Validating these devices under such demanding conditions is essential
before they are applied to clinical exercise testing, athletic training,
or remote health monitoring.

Objective: This study aimed to evaluate the validity of the Samsung
Galaxy Watch6 (GW6) in estimating HR throughout a graded, maximal ramp
cardiopulmonary exercise test performed on a treadmill. A secondary aim
was to explore whether measurement error varies across 5 predefined
intensity zones (50%-60%, 60%-70%, 70%-80%, 80%-90%, and 90%-100% of the
maximum HR determined individually for each participant).

Methods: Overall, 55 healthy adults (30 men, 25 women; mean age 30.3, SD
8.2 years) completed a symptom-limited incremental treadmill protocol to
volitional exhaustion. Simultaneous HR recordings were obtained from the
GW6 (left arm) and a Polar H10 chest strap monitor, which served as the
reference standards. For each intensity zone, the following agreement
indices were computed: intraclass correlation coefficient (ICC), median
absolute error, median absolute percentage error, and root mean squared
error. Bland-Altman analysis was performed to quantify the mean bias and
95% limits of agreement between the GW6 and the Polar H10. Statistical
significance was set at P<.05.

Results: Agreement between the GW6 and Polar H10 varied across exercise
intensities. ICC indicated moderate to good agreement at low to moderate
intensities (ICC=0.71 at 50%-60%; ICC=0.89 at 60%-70%; ICC=0.54 at
70%-80%; and ICC=0.64 at 80%-90% HRmax), and at 90%-100% of HRmax the
agreement was good-to-excellent (ICC=0.90). Absolute error metrics showed
stable or reduced errors with increasing intensity, with median absolute
error consistently around 1-3 bpm and median absolute percentage error
declining from 2.90% at 50%-60% HRmax to 0.60%-0.75% at >=70% HRmax. Root
mean squared error ranged from 4.62 to 4.88 bpm across intensity zones.
Bland-Altman analysis showed that the GW6 consistently underestimated HR
compared with the Polar H10, with an overall mean bias of -2.67 bpm and
wide limits of agreement (-16.90 to 11.57 bpm). This negative bias was
present across all HR zones. The agreement was adequate for group-level
comparisons but displayed substantial individual variability.

Conclusions: The GW6 provides a good degree of validity for HR monitoring
during a maximal treadmill cardiopulmonary exercise test in healthy young
adults. Although measurement error increases modestly at near-maximal
workloads, absolute errors remain well within clinically acceptable
thresholds. These findings support the potential use of GW6 as a
convenient, noninvasive alternative for HR tracking in laboratory-based
exercise testing.

Physiological assessment of endoscopic mitral valve repair using cardiopulmonary exercise testing.

Ozeki T; Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
Ito T; Hosoba S; Shintani A; Orii M; Tokoro M; Shimizu S; Sawaki
S; Usui A; Mutsuga M

General Thoracic & Cardiovascular Surgery. 74(4):369-375, 2026 Apr.

OBJECTIVES: Few physiological assessments are available for patients who
undergo mitral valve repair for severe mitral regurgitation (symptomatic
or asymptomatic). The aim of the study was to evaluate change in exercise
tolerance as a means of physiological assessment following mitral valve
repair.

METHODS: We studied 41 consecutive patients who received elective
isolated mitral valve repair for severe mitral regurgitation in a
minimally invasive manner via a completely endoscopic platform and who
underwent cardiopulmonary exercise testing in our institution between
February 2018 and August 2019. There were 21 asymptomatic (group A) and 20
symptomatic (group S) patients. Physiological assessment was performed by
cycle ergometer cardiopulmonary exercise testing pre-operatively and at
approximately 6 months post-operatively.

RESULTS: Mean age was 59 +/- 11.6 years and 24 patients were male
(58.5%). Overall, there was no significant change in peak oxygen
consumption or anaerobic threshold after surgical repair. There were no
intergroup differences in terms of peak oxygen consumption, anaerobic
threshold, ventilation/carbon dioxide production, or gas exchange ratio.
There were no intergroup differences in any transthoracic
echocardiographic variable except for post-operative left atrial dimension
(group A: 35.2 +/- 5.9 vs. group S: 39.8 +/- 6.2, p = 0.01).

CONCLUSIONS: There was no statistically discernible change in functional
capacity at 6-12 months after endoscopic mitral valve repair. The
physiological assessment found no improvements in cardiopulmonary exercise
testing values post-operatively despite improvement of the symptoms.

Reference standards and diagnosis-specific trends in cardiorespiratory fitness in paediatric patients with repaired CHD.

Griffith, Garett J; Mayo Clinic, Rochester, MN, USA.
Wang, Alan; Ward, Kendra.

Cardiology in the Young. 36(2):244-251, 2026 Feb.

BACKGROUND: Exercise capacity (VO2peak) predicts mortality in adult
patients with CHD. There is a lack of paediatric exercise capacity data
based on specific CHD lesions, limiting the ability to contextualise
interpretation based on expected performance during testing. The primary
aim of this study was to establish VO2peak percentiles for paediatric
patients with repaired CHD undergoing treadmill-based cardiopulmonary
exercise testing (CPET).

METHODS: Retrospective analysis of CPET data from 2004 to 2022. CPETs
were analysed for patients with CHD aged 6-18 years. Patients with
repaired CHD were categorised based on their most haemodynamically
significant CHD lesion. Percentiles and age-based trends were plotted for
each group.

RESULTS: A total of 887 patients were included. CHD patients were divided
into ten diagnostic subgroups. The mean percent expected VO2peak for each
of the subgroups were as follows: Atrial and ventricular septal defect
(94.5 +/- 25.1%), pulmonary valve repair (88.1 +/- 18.4%), aortic valve
repair (92.7 +/- 16.4%), tricuspid and mitral valve repair (81.3 +/-
20.4%), coarctation of the aorta (93.6 +/- 18.8%), transposition of the
great arteries (90.5 +/- 19.4%), double outlet right ventricle and truncus
arteriosus (80.5 +/- 16.2%), tetralogy of Fallot (85.6 +/- 20.9%), left
ventricle dominant Fontan (74.7 +/- 18.3%), and right ventricle dominant
Fontan (75.7 +/- 16.7%).

CONCLUSION: There is a varying degree of reduced exercise capacity in
paediatric patients with repaired CHD. Univentricular hearts and tricuspid
and mitral valve repair have the lowest VO2peak. These CHD-specific
percentiles may help providers risk-stratify and counsel patients with
CHD.

Five-year outcomes in a paediatric and young adult Fontan cohort: the relevance of atrial function and body mass index.

Rato J; Pediatric Cardiology Department, Hospital de Santa Cruz
– Unidade Local de Saude Lisboa
Cordeiro S; Anjos R

Cardiology in the Young. 36(2):332-337, 2026 Feb.

INTRODUCTION: The Fontan procedure enables survival in individuals with
univentricular physiology but is associated with progressive circulatory
failure. Identifying predictors of adverse outcomes is essential to
improve long-term management. This study evaluated five-year outcomes and
baseline predictors of major events in a previously characterised
paediatric and young adult Fontan cohort.

METHODS: This retrospective longitudinal study included 51 patients
(median age 18 years, interquartile range 11) who underwent comprehensive
evaluation between 2018 and 2019, including echocardiography with atrial
strain analysis and cardiopulmonary exercise testing. The composite
outcome comprised death, heart transplantation listing, hospitalisation
for heart failure, or conduit thrombosis. Univariable and multivariable
logistic regression identified predictors of adverse outcomes.

RESULTS: During a five-year follow-up, 7 patients (14%) met the composite
outcome. Those with events had lower body mass index (19.8 kg/m2 [4.1] vs
16.9 [3.6]; p = 0.007), lower atrial conduit strain (10.95% [8.95] vs 2.8
[6.2]; p = 0.011), reduced peak oxygen uptake, and higher VE/VCO2 slope.
In multivariable analysis, lower body mass index (OR 0.49, 95% CI
0.26-0.93; p = 0.028) and reduced atrial conduit strain (OR 0.70, 95% CI
0.51-0.96; p = 0.026) were independently associated with adverse outcome,
with excellent model discrimination (AUC = 0.95).

DISCUSSION: Both nutritional status and atrial functional parameters
demonstrated a strong association with the outcome. Reduced atrial conduit
strain, reflecting diastolic dysfunction, and lower body mass index,
possibly reflecting myopenia or cachexia, identified higher-risk patients
and potential areas for intervention. Routine assessment of atrial
function and nutritional status should be integrated into clinical
surveillance and risk stratification of the Fontan population.

Evaluation of the Efficacy of Transcatheter Aortic Valve Replacement in Asymptomatic Patients With Severe Aortic Stenosis Using Cardiopulmonary Exercise Testing.