Peak oxygen uptake (VO(2 peak)) in patients with heart failure (HF) is inversely related to muscle sympathetic nerve activity (MSNA) at rest. We hypothesized that the MSNA response to handgrip exercise is augmented in HF patients and is greatest in those with low VO(2 peak). We studied 14 HF patients and 10 age-matched normal subjects during isometric [30% of maximal voluntary contraction (MVC)] and isotonic (10%, 30%, and 50% MVC) handgrip exercise that was followed by 2 min of posthandgrip ischemia (PHGI). MSNA was significantly increased during exercise in HF but not normal subjects. Both MSNA and HF levels remained significantly elevated during PHGI after 30% isometric and 50% isotonic handgrip in HF but not normal subjects. HF patients with lower VO(2 peak) (<56% predicted; n = 8) had significantly higher MSNA during rest and exercise than patients with VO(2 peak) > 56% predicted (n = 6) and normal subjects. The muscle metaboreflex contributes to the greater reflex increase in MSNA during ischemic or intense nonischemic exercise in HF. This occurs at a lower threshold than normal and is a function of VO(2 peak).

Background-In the present study, we sought to determine whether opening a persistently occluded infarct-related artery (IRA) by percutaneous coronary intervention (PCI) in patients beyond the acute phase of myocardial infarction (MI) improves patency and indices of left ventricular (LV) size and function. Methods and Results-Between May 2000 and July 2005, 381 patients with an occluded native IRA 3 to 28 days after MI (median 10 days) were randomized to PCI with stenting (PCI) or optimal medical therapy alone. Repeat coronary and LV angiography was performed 1 year after randomization (nϭ332, 87%). Coprimary end points were IRA patency and change in LV ejection fraction. Secondary end points included change in LV end-systolic and end-diastolic volume indices and wall motion. PCI was successful in 92%. At 1 year, 83% of PCI versus 25% of medical therapy-only patients had a patent IRA (PϽ0.001). LV ejection fraction increased significantly (PϽ0.001) in both groups, with no between-group difference: PCI 4.2Ϯ8.9 (nϭ150) versus medical therapy 3.5Ϯ8.2 (nϭ136; Pϭ0.47). Median change (interquartile range) in LV end-systolic volume index was Ϫ0.5 (Ϫ9.3 to 5.0) versus 1.0 (Ϫ5.7 to 7.3) mL/m 2 (Pϭ0.10), whereas median change (interquartile range) in LV end-diastolic volume index was 3.2 (Ϫ8.2 to 13.3) versus 5.3 (Ϫ4.6 to 23.2) mL/m 2 (Pϭ0.07) in the PCI (nϭ86) and medical therapy-only (nϭ76) groups, respectively. Conclusions-PCI with stenting of a persistently occluded IRA in the subacute phase after MI effectively maintains long-term patency but has no effect on LV ejection fraction. On the basis of these findings and the lack of clinical benefit in the main Occluded Artery Trial, routine PCI is not recommended for stable patients with a persistently occluded IRA after MI. (Circulation. 2006;114:2449-2457.)