title: Right Ventricular Contractile Reserve and Pulmonary Circulation Uncoupling During Exercise Challenge in Heart Failure: Pathophysiology and Clinical Phenotypes.
abstract: Right ventricular (RV) exercise contractile reserve (RVECR), its phenotypes, and its functional correlates are among the unresolved issues with regard to the role of the right ventricle in heart failure (HF) syndrome, and understanding these issues constitutes the objective of this study.
  
  
  
  Although the role of the right ventricle in HF syndrome might be fundamental, the pathophysiology of the failing right ventricle has not been extensively investigated.
  
  
  
  Ninety-seven patients with HF (mean age 64 years, 70% men, mean left ventricular ejection fraction 33 ± 10%) underwent maximal exercise stress echocardiographic and cardiopulmonary exercise testing. RVECR and RV-to-pulmonary circulation (PC) coupling were assessed using the length-force relationship (tricuspid annular plane systolic excursion [TAPSE] vs. pulmonary artery systolic pressure) and the slope of mean pulmonary artery pressure versus cardiac output. On the basis of TAPSE, patients were categorized into 3 groups: those with TAPSE at rest ≥16 mm (group A, n = 60) and those with TAPSE at rest <16 mm, who were divided according to median TAPSE at peak exercise (15.5 mm) into 2 subgroups (group B, ≥15.5 mm, n = 19; group C, <15.5 mm, n = 18).
  
  
  
  Although they had similar left ventricular ejection fractions and rest RV impairment, compared with patients in group C, those in group B showed some degree of RVECR (upward shift of the length-force relationship), better RV-to-PC coupling (lower mean pulmonary artery pressure vs. cardiac output slope), and greater ventilatory efficiency (lower slope of minute ventilation to carbon dioxide output). Rest mitral regurgitation and net changes in pulmonary artery systolic pressure were the variables retained in the best regression model as correlates of RVECR.
  
  
  
  In patients with HF, RVECR unmasks different phenotypes. Impaired RV function at rest might not invariably lead to unfavorable RVECR and exercise RV-to-PC coupling. Testing these variables appears useful even in more advanced stages of HF to define various clinical conditions and, most likely, to define different levels of risk.
authors.affiliation: Heart Failure Unit, IRCCS Policlinico San Donato, University of Milan, Milan, Italy. Electronic address: marco.guazzi@unimi.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Guazzi
authors.affiliation: Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Villani
authors.affiliation: Heart Failure Unit, IRCCS Policlinico San Donato, University of Milan, Milan, Italy.
authors.forename: Greta
authors.initials: G
authors.lastname: Generati
authors.affiliation: Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy.
authors.forename: Ottavia Eleonora
authors.initials: OE
authors.lastname: Ferraro
authors.affiliation: Heart Failure Unit, IRCCS Policlinico San Donato, University of Milan, Milan, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Pellegrino
authors.affiliation: Heart Failure Unit, IRCCS Policlinico San Donato, University of Milan, Milan, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Alfonzetti
authors.affiliation: Heart Failure Unit, IRCCS Policlinico San Donato, University of Milan, Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Labate
authors.affiliation: Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Gaeta
authors.affiliation: Heart Failure Unit, IRCCS Policlinico San Donato, University of Milan, Milan, Italy.
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Sugimoto
authors.affiliation: Heart Failure Unit, IRCCS Policlinico San Donato, University of Milan, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bandera
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002302:Cardiac Output; D025401:Echocardiography, Stress; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010641:Phenotype; D011651:Pulmonary Artery / Q000503:physiopathology; D013318:Stroke Volume / Q000502:physiology*; D016278:Ventricular Function, Right / Q000502:physiology*
keywords: exercise; heart failure; pulmonary circulation; right ventricular function