Myocardial oxidative metabolic supply-demand relationships in patients with nonischemic dilated cardiomyopathy.
BACKGROUND
Nonischemic dilated cardiomyopathy (NIDCM) is associated with left ventricular remodeling, hypertrophy, and mitochondrial metabolic abnormalities in vitro. We evaluated the hypothesis that energy supply, as judged by the rate of myocardial oxidative metabolism, is inadequate to meet oxygen demand in patients with NIDCM compared with normal subjects.


RESULTS
We used positron emission tomography to determine the myocardial carbon 11 acetate decay rate (kmono) as an index of energy supply, and we compared kmono with the rate-pressure product (RPP) as an index of metabolic demand in 7 patients with NIDCM and 7 normal subjects. The mean kmono value (SEM) was 0.060 +/- 0.006 min(-1) in NIDCM patients versus 0.054 +/- 0.002 in normal subjects (P = not significant). The RPP was 9949 +/- 931 beats/min.mm Hg in NIDCM patients and 6521 +/- 476 in normal subjects (P = .007). The relationship of kmono to this index of demand (kmono/RPP) was 6.2 x 10(-6) in NIDCM patients but was 8.5 x 10(-6) in normal subjects (P = .003). Thus RPP, as an index of myocardial oxygen demand, was poorly matched by the rate of oxidative metabolism in those patients with NIDCM. The kmono was closely related to RPP in normal subjects (r = 0.83, P = .02) but not in NIDCM patients. Furthermore, there was no significant relationship between kmono and wall stress as another index of oxygen demand.


CONCLUSIONS
These results are consistent with a mitochondrial metabolic abnormality in heart failure. This metabolic mismatch detected by positron emission tomography may contribute to the pathophysiology of congestive heart failure and left ventricular remodeling.
Kronenberg
Marvin W
MW
Division of Cardiology, Wayne State University School of Medicine, Detroit, Mich, USA. marvin.w.kronenberg@vanderbilt.edu
Cohen
Gerald I
GI
Leonen
Marlo F
MF
Mladsi
Thomas A
TA
Di Carli
Marcelo F
MF
D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*; D006352:Heart Ventricles / Q000378:metabolism*; D006801:Humans; D008657:Metabolic Clearance Rate; D008659:Metabolic Diseases / Q000000981:diagnostic imaging / Q000378:metabolism*; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011877:Radionuclide Imaging; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000378:metabolism*; D020257:Ventricular Remodeling
D010100:Oxygen