title: Impact of daily life myocardial ischemia in patients with chronic reversible and irreversible myocardial dysfunction.
abstract: Repetitive myocardial ischemia during daily life has been suggested as the underlying mechanism of reversible myocardial dysfunction, which may progress into a hibernating state. Thirty-seven patients with ischemic cardiomyopathy (ejection fraction 35 +/- 7%) underwent positron emission tomography (N-13 ammonia and 18-F-fluoro-2-deoxy-glucose [FDG]) and exercise testing before coronary artery bypass grafting (CABG) and 48- hour ambulatory electrocardiographic monitoring to detect ischemia before CABG and 6 months postoperatively. Reversibility of regional myocardial dysfunction was detected by echocardiographic follow-up at 5 days, 2 months, and 6 months after the operation. Preoperatively, ischemic episodes during daily activities were more common (2 [25th to 75th percentiles 0 to 4] vs 0 episodes, p <0.01) and duration of ischemia longer (9 [25th to 75th percentiles 0 to 37] vs 0 [25th to 75th percentiles 0 to 1] minutes, p <0.02) in patients with reversible dysfunction (n = 15) than in patients with irreversible dysfunction (n = 22). The number of ischemic episodes per patient correlated with the numbers of reversibly dysfunctional segments (p = 0.003), viable segments as seen by positron emission tomography (p <0.05), and flow-metabolic mismatch segments (p <0.05). CABG eliminated ambulatory ischemic episodes in patients with reversible dysfunction (0 episodes, p <0.05 vs before CABG). Preoperatively, all patients with reversible dysfunction had a positive exercise test (14 of 15 patients), whereas daily life ischemia was present in 60% of patients. Reversibly dysfunctional segments in patients with ambulatory ischemia had faster recovery of function (15 of 28 patients vs 2 of 12 patients recovered at 5 days, p <0.05), higher FDG uptake (0.86 +/- 0.19% vs 0.71 +/- 0.24%, p <0.05) than in patients without ambulatory ischemia, whereas perfusion was similar (0.63 +/- 0.20 and 0.62 +/- 0.19 ml/g/min). Thus, exercise-induced myocardial ischemia is associated with reversibility of myocardial dysfunction, but not all patients with reversible ischemic cardiomyopathy have ischemic attacks during daily life.
authors.affiliation: Department of Cardiology, Skejby Hospital, Aarhus University Hospitals, Aarhus, Denmark. henrikwiggers@dadlnet.dk
authors.forename: Henrik
authors.initials: H
authors.lastname: Wiggers
authors.forename: Morten
authors.initials: M
authors.lastname: Bøttcher
authors.forename: Henrik
authors.initials: H
authors.lastname: Egeblad
authors.forename: Henning
authors.initials: H
authors.lastname: Mølgaard
authors.forename: Torsten Toftegaard
authors.initials: TT
authors.lastname: Nielsen
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
mesh_terms: D000203:Activities of Daily Living; D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D014055:Tomography, Emission-Computed; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery