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
2021
Persistent Exertional Intolerance After COVID-19 Insights From Invasive Cardiopulmonary Exercise Testing
Singh I, Joseph P, Heerdt PM, Cullinan M, Lutchmansingh DD, Gulati M, Possick JD, Systrom DM, Waxman AB. Persistent Exertional Intolerance After COVID-19 Insights From Invasive Cardiopulmonary Exercise Testing. CHEST Journal 2021, 161: 54-63. PMID: 34389297, PMCID: PMC8354807, DOI: 10.1016/j.chest.2021.08.010.Peer-Reviewed Original ResearchConceptsInvasive cardiopulmonary exercise testingCardiopulmonary exercise testingCardiopulmonary diseaseExercise testingControl participantsPeak VOExertional limitationCOVID-19Greater ventilatory inefficiencyPeak cardiac indexSex-matched control participantsCohort of patientsSystemic oxygen extractionDead space ventilationOnly mild symptomsExertional intoleranceCardiac indexPulmonary hemodynamicsAcute infectionVentilatory inefficiencyExercise intolerancePathophysiologic mechanismsMild symptomsHyperventilatory responseOxygen extractionSex-Related Differences in Dynamic Right Ventricular-Pulmonary Vascular Coupling in Heart Failure With Preserved Ejection Fraction
Singh I, Oliveira RKF, Heerdt PM, Pari R, Systrom DM, Waxman AB. Sex-Related Differences in Dynamic Right Ventricular-Pulmonary Vascular Coupling in Heart Failure With Preserved Ejection Fraction. CHEST Journal 2021, 159: 2402-2416. PMID: 33388286, DOI: 10.1016/j.chest.2020.12.028.Peer-Reviewed Original ResearchMeSH KeywordsAgedCardiac CatheterizationEchocardiographyExercise ToleranceFemaleFollow-Up StudiesHeart FailureHeart VentriclesHumansIncidenceMalePulmonary ArteryPulmonary Wedge PressureRetrospective StudiesSex DistributionSex FactorsStroke VolumeSystoleUnited StatesVascular ResistanceVentricular Function, RightVentricular PressureConceptsRV-PA couplingRV-PA uncouplingFemale patientsMale patientsPeak VORV contractilityEjection fractionHeart failureRight ventricular-pulmonary vascular couplingRV-pulmonary arterial couplingAge-matched control subjectsInvasive pulmonary hemodynamicsMaximum incremental exercisePulmonary arterial elastanceRV pressure waveformsPeak exercise capacityRight ventricular dysfunctionSingle-beat analysisEnd-systolic elastanceSex-related differencesPA elastanceRV afterloadVentricular dysfunctionAfterload mismatchContractile impairment
2020
Dynamic right ventricular function response to incremental exercise in pulmonary hypertension
Singh I, Oliveira RKF, Heerdt P, Brown MB, Faria‐Urbina M, Waxman AB, Systrom DM. Dynamic right ventricular function response to incremental exercise in pulmonary hypertension. Pulmonary Circulation 2020, 10: 1-8. PMID: 33062259, PMCID: PMC7534091, DOI: 10.1177/2045894020950187.Peer-Reviewed Original ResearchRight ventricle functionRight ventricle stroke work indexStroke work indexPulmonary hypertensionVentricle functionPeak oxygen uptakePeak VOIncremental exerciseArterial elastanceWork indexInvasive cardiopulmonary exercise testingGender-matched normal controlsExercise pulmonary hypertensionMaximum incremental exercisePulmonary arterial elastancePulmonary hypertension groupRight ventricle adaptationVentricular function responseCardiopulmonary exercise testingPulmonary hypertension patientsRight ventricle dysfunctionPulmonary arterial hypertensionOxygen uptakeArterial hypertensionHypertension group