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      Cardiopulmonary Exercise Response in Patients with Left Ventricular Dysfunction or Heart Failure: A Noninvasive Study by Gas Exchange and Impedance Cardiography Monitoring

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          Abstract

          We investigated the upright bicycle exercise cardiopulmonary response in 20 patients with left ventricular dysfunction (LVD, secondary to previous myocardial infarction, left ventricular ejection fraction range 18-44%). Ten patients (48 ± 7 years) were asymptomatic (I NYHA class) without drug treatment (LVD group). The others (n = 10) (50 ± 1 years) complained of dyspnea and/or fatigue despite therapy (NYHA II–III). They represented the heart failure (HF) group. Eight sedentary men (40 ± 10 years) served as controls. Controls and patients performed stress testings under drug treatment, when administered. Anaerobic ventilatory threshold (ATge) was considered as an index of submaximal exercise while peak exercise VO<sub>2</sub> (PeakVO<sub>2</sub>) was considered the maximal volitional exercise capacity. The ratio between minute ventilation (VE) to carbon dioxide release (VCO<sub>2</sub>) (VE/VCO<sub>2</sub>) was assessed to evaluate the ventilatory response during exercise. We coupled gas exchange assessment (2001, MGC) with noninvasive monitoring of stroke volume (SV) by impedance cardiography (NCCOM3, BOMED) and total systemic vascular resistances (TSVR; by auscultatory blood pressure measurement). In controls VO<sub>2</sub> increase during exercise was related to higher heart rate (HR) and SV both from resting to ATge and from this point to the peak. TSVR declined during both steps. In patients with HF VO<sub>2</sub> rose from resting to ATge (by faster HR and unchanged SV). VO<sub>2</sub> increased slightly from this point to PeakVO<sub>2</sub>. This result was related to flat HR increase and unchanged SV as well as TSVR. In patients with LVD VO<sub>2</sub> increased similarly to controls from resting to ATge and less above the threshold. In these patients both HR and SV increased during submaximal exercise. From ATge to PeakVO<sub>2</sub> only HR increased. TSVR declined significantly similarly to controls. The VE/VCO<sub>2</sub> ratio was higher at peak exercise in patients with HF compared to controls. Different determinants were demonstrated in patients with left ventricular dysfunction with mild or symptomatic chronic heart failure (CHF). These findings and the increased ventilatory response in patients with CHF can explain different changes of VO<sub>2</sub> in these patients during submaximal and maximal voluntary exercise and contribute to explain exercise-induced exertion in these subjects.

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          Author and article information

          Journal
          CRD
          Cardiology
          10.1159/issn.0008-6312
          Cardiology
          S. Karger AG
          0008-6312
          1421-9751
          1996
          1996
          19 November 2008
          : 87
          : 2
          : 147-152
          Affiliations
          Cardiopulmonary Stress Laboratory, I Clinica Medica, Medical School, University Federico II, Napoli, and IRCCS Sanatrix, Pozzilli, Italy
          Article
          177078 Cardiology 1996;87:147–152
          10.1159/000177078
          8653732
          © 1996 S. Karger AG, Basel

          Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

          Page count
          Pages: 6
          Categories
          Noninvasive and Diagnostic Cardiology

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