title: Dobutamine-induced mechanical alternans is a marker of poor prognosis in idiopathic dilated cardiomyopathy.
abstract: 1. To date, few prognostic indicators for ambulatory patients with idiopathic dilated cardiomyopathy (IDCM) have been identified. The purpose of the present study was to investigate the relationship between the occurrence of dobutamine-induced mechanical alternans (MA) and prognosis in ambulatory patients with IDCM. 2. Left ventricular pressure was measured during right atrial pacing and after intravenous infusion of dobutamine at incremental doses in 90 ambulatory patients with IDCM in sinus rhythm. Endomyocardial biopsy specimens were also obtained for quantitative analysis of gene expression. The patients were followed up for a mean of 2.5 years. 3. Patients were classified into three groups: (i) 60 patients who exhibited neither pacing- nor dobutamine-induced MA (Group N); (ii) 20 patients who manifested only pacing-induced MA (Group P); and (iii) 10 patients who developed both pacing- and dobutamine-induced MA (Group D). The sarcoplasmic/endoplasmic reticulum calcium ATPase 2a:phospholamban mRNA ratio was significantly higher in Group D patients than in patients in Groups N or P. Multivariate analysis revealed that dobutamine-induced MA (odds ratio 4.05; 95% confidence interval 1.35-12.2) was a significant independent predictor of cardiac events. Cardiac event-free survival in Group D was significantly lower than in Groups N or P, as determined by Kaplan-Meier analysis (P=0.002). 4. The occurrence of dobutamine-induced MA is a potentially useful clinical predictor of poor prognosis in ambulatory patients with IDCM in sinus rhythm.
authors.affiliation: Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan. hirasiki@med.nagoya-u.ac.jp
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hirashiki
authors.forename: Hideo
authors.initials: H
authors.lastname: Izawa
authors.forename: Xian Wu
authors.initials: XW
authors.lastname: Cheng
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Unno
authors.forename: Satoru
authors.initials: S
authors.lastname: Ohshima
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Murohara
mesh_terms: D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization / Q000187:drug effects / Q000379:methods; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000503:physiopathology*; D004280:Dobutamine / Q000494:pharmacology; D025401:Echocardiography, Stress / Q000187:drug effects / Q000379:methods*; D005080:Exercise Test / Q000187:drug effects / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000502:physiology; D055815:Young Adult
chemical_list: D004280:Dobutamine