2024
The metabolic and physiologic impairments underlying long COVID associated exercise intolerance
Leitner B, Joseph P, Quast A, Ramirez M, Heerdt P, Villalobos J, Singh I. The metabolic and physiologic impairments underlying long COVID associated exercise intolerance. Pulmonary Circulation 2024, 14: e70009. PMID: 39544193, PMCID: PMC11560803, DOI: 10.1002/pul2.70009.Peer-Reviewed Original ResearchPeak VO<sub>2</sub>Long COVID patientsCOVID patientsReduced peak VOSeverity of SARS-CoV-2 infectionSystemic oxygen extractionSARS-CoV-2 infectionLong COVIDArterial blood samplesQuantitative metabolomicsPeak VOVenous lactateCardiac outputImpaired mitochondrial ATP productionMild infectionExercise capacityPatientsMitochondrial ATP productionExercise intoleranceArteriovenous gradientBlood samplesOxygen extractionDependent mannerMetabolomicsPhysiological impairment
2023
Differential cardiopulmonary haemodynamic phenotypes in PASC-related exercise intolerance
Kahn P, Joseph P, Heerdt P, Singh I. Differential cardiopulmonary haemodynamic phenotypes in PASC-related exercise intolerance. ERJ Open Research 2023, 10: 00714-2023. PMID: 38348243, PMCID: PMC10860209, DOI: 10.1183/23120541.00714-2023.Peer-Reviewed Original ResearchInvasive cardiopulmonary exercise testingRight heart catheterizationPASC patientsExertional intoleranceCardiac outputPulmonary artery wedge pressurePeak VO 2Supranormal cardiac outputPeak exercise capacityCardiopulmonary exercise testingMaximal voluntary ventilationPost-acute sequelaeBody mass indexSystemic oxygen extractionMild acute illnessSARS-CoV-2Exercise hemodynamicsHFpEF patientsHFpEF phenotypeHeart catheterizationWedge pressureAcute illnessExercise capacityExercise testingHemodynamic abnormalities
2020
Systemic vascular distensibility relates to exercise capacity in connective tissue disease
Singh I, Oliveira RKF, Naeije R, Oldham WM, Faria-Urbina M, Waxman AB, Systrom DM. Systemic vascular distensibility relates to exercise capacity in connective tissue disease. Rheumatology 2020, 60: 1429-1434. PMID: 33001175, DOI: 10.1093/rheumatology/keaa510.Peer-Reviewed Original ResearchConceptsCTD patientsSystemic oxygen extractionExercise capacityVascular distensibilityCardiopulmonary diseaseOxygen extractionDecreased exercise capacityStroke volume augmentationReduced exercise capacityCommon clinical manifestationsRadial arterial catheterConnective tissue diseaseAerobic exercise capacityPulmonary vascular distensibilityCardio-pulmonary diseasePressure-flow plotsPulmonary hypertensionCardiopulmonary exerciseHeart failureArterial catheterExercise intoleranceTissue diseaseClinical manifestationsNormal controlsPatients
2019
Dynamic right ventricular–pulmonary arterial uncoupling during maximum incremental exercise in exercise pulmonary hypertension and pulmonary arterial hypertension
Singh I, Rahaghi F, Naeije R, Oliveira R, Vanderpool RR, Waxman A, Systrom D. Dynamic right ventricular–pulmonary arterial uncoupling during maximum incremental exercise in exercise pulmonary hypertension and pulmonary arterial hypertension. Pulmonary Circulation 2019, 9: 1-10. PMID: 31218910, PMCID: PMC6643191, DOI: 10.1177/2045894019862435.Peer-Reviewed Original ResearchPulmonary arterial hypertensionExercise pulmonary hypertensionRV-PA couplingMaximum incremental exerciseRV-PA uncouplingPulmonary hypertensionExercise pHRV contractilityArterial hypertensionExercise capacityIncremental exerciseInvasive cardiopulmonary exercise testingReduced peak oxygen consumptionPressure-volume loop analysisPulmonary arterial elastanceCardiopulmonary exercise testingRight ventricular functionPeak oxygen consumptionAge-matched controlsEnd-systolic elastanceContractile reserveExercise testingRV functionSuch patientsVentricular functionPulmonary Vascular Distensibility and Early Pulmonary Vascular Remodeling in Pulmonary Hypertension
Singh I, Oliveira RKF, Naeije R, Rahaghi FN, Oldham WM, Systrom DM, Waxman AB. Pulmonary Vascular Distensibility and Early Pulmonary Vascular Remodeling in Pulmonary Hypertension. CHEST Journal 2019, 156: 724-732. PMID: 31121149, DOI: 10.1016/j.chest.2019.04.111.Peer-Reviewed Original ResearchConceptsPulmonary arterial hypertensionAerobic exercise capacityExercise pulmonary hypertensionPulmonary hypertensionPulmonary vascular distensibilityExercise capacityUnexplained dyspneaControl subjectsVascular distensibilitySex-matched normal control subjectsInvasive pulmonary hemodynamicsRV pressure curveRV-PA couplingRV-PA uncouplingPulmonary vascular remodelingExercise stress testingEes/EaPeak oxygen consumptionNormal control subjectsPressure-flow plotsArterial hypertensionPulmonary hemodynamicsEjection fractionHeart failureRight ventricular