Can kinetics of oxygen uptake at onset of exercise identify contractile reserve in patients with ischemic left ventricular dysfunction?

Massimo Baravelli, Cecilia Fantoni, Andrea Rossi, Paolo Cattaneo, Teresio Forzani, Giansiro Bargiggia, Claudio Anza'

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Prior studies demonstrated that kinetics of oxygen uptake (KVO2) at the onset of exercise is delayed in patients with ischemic left ventricular dysfunction (LVD), since it reflects a slower cardiac output increase. Given the myocardial contractile reserve elicited by endogenous catecholamines during exercise, it may be speculated that patients with a significant amount of myocardial viability (MV) could show a faster KVO2 at the onset of exercise attributable to a faster increase in stroke volume compared to patients without MV. Objectives: To demonstrate a relationship between contractile reserve detected by low-dose dobutamine Echocardiography (LDDE) and KVO2 obtained during cardiopulmonary testing in patients with ischemic LVD. Methods: Forty-one consecutive patients (62.5 ± 10.1 years) with ischemic LVD underwent LDDE and constant work rate exercise with KVO2 determination. The time constant for VO2 (tau) was determined by a curve fitting breath-by-breath data. Ten healthy subjects served as control group (59.5 ± 13.4 years). Results: LDDE identified contractile reserve in 20 (48%) subjects. Patients without MV detected by LDDE showed a significantly longer tau compared to patients with MV and to healthy subjects (p = 0.03 and p = 0.01, respectively). Sensitivity, specificity, positive and negative predictive value of tau in detecting MV were 90%, 95%, 95% and 91%, respectively. Moreover, the percentage reduction of LV wall motion score index detected at LDDE was significantly related to KVO2 (r = 0.71, p <0.01). Conclusions: Our data suggest that KVO2 represents a reasonable initial approach to estimate presence of MV in patients with ischemic LVD.

Original languageEnglish
Pages (from-to)427-429
Number of pages3
JournalInternational Journal of Cardiology
Volume129
Issue number3
DOIs
Publication statusPublished - Oct 13 2008

Keywords

  • Dobutamine echocardiography
  • Ischemic cardiomyopathy
  • Kinetics of oxygen uptake
  • Left ventricular dysfunction
  • Myocardial contractile reserve
  • Myocardial viability

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Medicine(all)

Fingerprint Dive into the research topics of 'Can kinetics of oxygen uptake at onset of exercise identify contractile reserve in patients with ischemic left ventricular dysfunction?'. Together they form a unique fingerprint.

Cite this