title: Mechanisms of Effort Intolerance in Patients With Rheumatic Mitral Stenosis: Combined Echocardiography and Cardiopulmonary Stress Protocol.
abstract: This study sought to evaluate mechanisms of effort intolerance in patients with rheumatic mitral stenosis (MS).
  
  
  
  Combined stress echocardiography and cardiopulmonary testing allows assessment of cardiac function, hemodynamics, and oxygen extraction (A-Vo2difference).
  
  
  
  Using semirecumbent bicycle exercise, 20 patients with rheumatic MS (valve area 1.36 ± 0.4 cm2) were compared to 20 control subjects at 4 pre-defined activity stages (rest, unloaded, anaerobic threshold, and peak). Various echocardiographic parameters (left ventricular volumes, ejection fraction, stroke volume, mitral valve gradient, mitral valve area, tissue s' and e') and ventilatory parameters (peak oxygen consumption [Vo2] and A-Vo2difference) were measured during 8 to 12 min of graded exercise.
  
  
  
  Comparing patients with MS to control subjects, significant differences (both between groups and for group by time interaction) were seen in multiple parameters (heart rate, stroke volume, end-diastolic volume, ejection fraction, s', e', Vo2, and tidal volume). Exercise responses were all attenuated compared to control subjects. Comparing patients with MS and poor exercise tolerance (<80% of expected) to other subjects with MS, we found attenuated increases in tidal volume (p = 0.0003), heart rate (p = 0.0009), and mitral area (p = 0.04) in the poor exercise tolerance group. These patients also displayed different end-diastolic volume behavior over time (group by time interaction p = 0.05). In multivariable analysis, peak heart rate response (p = 0.01), tidal volume response (p = 0.0001), and peak A-Vo2difference (p = 0.03) were the only independent predictors of exercise capacity in patients with MS; systolic pulmonary pressure, mitral valve gradient, and mitral valve area were not.
  
  
  
  In patients with rheumatic MS, exercise intolerance is predominantly the result of restrictive lung function, chronotropic incompetence, limited stroke volume reserve, and peripheral factors, and not simply impaired valvular function. Combined stress echocardiography and cardiopulmonary testing can be helpful in determining mechanisms of exercise intolerance in patients with MS.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Laufer-Perl
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Yaniv
authors.initials: Y
authors.lastname: Gura
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Jason
authors.initials: J
authors.lastname: Shimiaie
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Jack
authors.initials: J
authors.lastname: Sherez
authors.affiliation: Division of Cardiovascular Diseases, Heart and Vascular Institute USA, Einstein Medical Center, Philadelphia, Pennsylvania.
authors.forename: Gregg S
authors.initials: GS
authors.lastname: Pressman
authors.affiliation: Division of Radiology, Tel Aviv Medical Center, Tel Aviv, Israel.
authors.forename: Galit
authors.initials: G
authors.lastname: Aviram
authors.affiliation: Division of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Simon
authors.initials: S
authors.lastname: Maltais
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ricki
authors.initials: R
authors.lastname: Megidish
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Amir
authors.initials: A
authors.lastname: Halkin
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Meirav
authors.initials: M
authors.lastname: Ingbir
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Simon
authors.initials: S
authors.lastname: Biner
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Gad
authors.initials: G
authors.lastname: Keren
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. Electronic address: topilskyyan@gmail.com.
authors.forename: Yan
authors.initials: Y
authors.lastname: Topilsky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001642:Bicycling; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D018619:Echocardiography, Doppler, Pulsed; D025401:Echocardiography, Stress / Q000379:methods*; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006439:Hemodynamics; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015999:Multivariate Analysis; D015588:Observer Variation; D010101:Oxygen Consumption; D056888:Patient Positioning; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012214:Rheumatic Heart Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013997:Time Factors; D016276:Ventricular Function
keywords: congestive heart failure; echocardiography; exercise testing