Mechanisms of Effort Intolerance in Patients With Rheumatic Mitral Stenosis: Combined Echocardiography and Cardiopulmonary Stress Protocol.

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-Vo2 difference). 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-Vo2 difference) 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-Vo2 difference (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.

Laufer-Perl M ，Gura Y ，Shimiaie J ，Sherez J ，Pressman GS ，Aviram G ，Maltais S ，Megidish R ，Halkin A ，Ingbir M ，Biner S ，Keren G ，Topilsky Y ... -  《-》

Determinants of Effort Intolerance in Patients With Heart Failure: Combined Echocardiography and Cardiopulmonary Stress Protocol.

The purpose of this study was to assess individual mechanisms of effort intolerance in patients with heart failure with preserved ejection fraction (HFpEF), heart failure with reduced ejection fraction (HFrEF), or normal cardiac function using combined echocardiography and cardiopulmonary stress testing. Combined stress echocardiography and cardiopulmonary tests visualize cardiac chambers in 4 well-defined activity levels (rest, unloaded, anaerobic threshold, and peak), allowing noninvasive assessment of cardiac function, hemodynamics, and arterial venous oxygen content difference (AVo(2)Diff) during all stages. Left ventricular volumes, stroke volume (SV), S', E/e', oxygen consumption (Vo(2)), and AVo(2)Diff were measured in all effort stages using ramp semirecumbent cycle prolonged (≥8 min) exercise in 45 consecutive subjects evaluated for effort intolerance (14 normal cardiac function, 16 HFpEF, and 15 HFrEF patients; age 56.5 ± 16 years; 73% male). In HFpEF and HFrEF, the changes in Vo2 were attenuated (between group p = 0.003; group by time interaction p < 0.0001), as well as peak heart rate (p = 0.0001; p = 0.0001) and SV (p = 0.006; p = 0.0001). End-diastolic volume to E/e' ratio (measure of compliance) was superior in HFrEF and normal patients at baseline but worsened in HFpEF and HFrEF at peak exercise (8.3 ± 4 vs. 11.6 ± 5 vs. 19.1 ± 8; p = 0.004; p = 0.01). Functional mitral regurgitation worsened even during the unloaded stage, mostly in patients with HFrEF, but also in several patients with HFpEF. In multivariable analysis, heart rate response (p = 0.007), and AVo(2)Diff (p < 0.0001) were the most significant independent predictors of effort capacity; SV was not. Combined tests are feasible and allow noninvasive evaluation of effort intolerance. In HFpEF and HFrEF patients, exercise intolerance is predominantly due to chronotropic incompetence and peripheral factors. Combined stress echocardiography and cardiopulmonary tests may have potential for clinical management and selection of patients for trials.

Shimiaie J ，Sherez J ，Aviram G ，Megidish R ，Viskin S ，Halkin A ，Ingbir M ，Nesher N ，Biner S ，Keren G ，Topilsky Y ... -  《-》

Exercise-Stress Echocardiography and Effort Intolerance in Asymptomatic/Minimally Symptomatic Patients With Degenerative Mitral Regurgitation Combined Invasive-Noninvasive Hemodynamic Monitoring.

Utsunomiya H ，Hidaka T ，Susawa H ，Izumi K ，Harada Y ，Kinoshita M ，Itakura K ，Masada K ，Kihara Y ... -  《-》

Mechanisms of Effort Intolerance in Patients With Heart Failure and Borderline Ejection Fraction.

Combining echocardiography and cardiopulmonary stress testing allows noninvasive assessment of hemodynamics, and oxygen extraction (A-VO2 difference). We evaluated mechanisms of effort intolerance in patients with heart failure with borderline (40% to 49%) left ventricular ejection fraction (EF) (HF and Borderline Ejection fraction). We included 89 consecutive patients with HF and Borderline Ejection fraction (n = 25; 63.6 ± 14 years, 64% men), control subjects (n = 22), patients with HF with preserved EF (n = 26; EF ≥50%), and patients with HF with reduced EF (n = 16; <40%). Various echo parameters (left ventricular volumes, EF, stroke volume, mitral regurgitation [MR] volume, e', right ventricle end-diastolic area, and right ventricle end-systolic area), and ventilatory or combined parameters (peak oxygen consumption [VO2] and A-VO2 difference) were measured at 4 predefined activity stages. Effort-induced functional MR was frequent and more prevalent in HF and Borderline Ejection fraction than in all the other types of HF. In multivariable analysis heart rate response (p <0.0001), A-VO2 difference (p = 0.02), stroke volume (p = 0.002), and right ventricle end-systolic area were the only independent predictors of exercise capacity in HF and Borderline Ejection fraction but peak EF was not. In HF and Borderline Ejection fraction exercise intolerance is predominantly due to chronotropic incompetence, peripheral factors, and limited stroke volume reserve, which are related to right ventricle dysfunction and functional MR but not to left ventricular ejection fraction. Combined testing can be helpful in determining mechanisms of exercise intolerance in HF and Borderline Ejection fraction.

Topilsky Y ，Rozenbaum Z ，Khoury S ，Pressman GS ，Gura Y ，Sherez J ，Man A ，Shimiaie J ，Edwards S ，Berookhim J ，Le Tourneau T ，Halkin A ，Biner S ，Keren G ，Aviram G ... -  《-》

Exercise behavior of degenerative mitral stenosis.

Horn B ，Lo KB ，Sengupta SP ，Pressman GS ... -  《-》