Abstract 3270: Diabetes Mellitus is Associated With Impairment of Myocardial Relaxation and Accumulation of Collagen in Patients With Dilated Cardiomyopathy
Introduction: Diabetes mellitus (DM) is a potent and prevalent risk factor for heart disease. Patients with DM who develop heart failure also have an increased mortality rate. However, the effect of DM on myocardial relaxation function and fibrosis in ambulatory patients with dilated cardiomyopathy (DCM) has remained unknown.
Hypothesis: We assessed the hypothesis that DM might impair myocardial relaxation and promote myocardial collagen accumulation in patients with DCM.
Methods: A total of 102 consecutive DCM patients with a New York Heart Association functional class of I or II was enrolled in the study. Patients were divided into two groups on the basis of the presence (DCM-DM group, n=30) or absence (DCM-alone group, n=72) of type 2 DM. DM was diagnosed on the basis of standard criteria. Left ventricular (LV) pressure was measured with the use of a pigtail catheter equipped with a micromanometer. The maximal first derivative of LV pressure (LV dP/dtmax) and the pressure half-time (T1/2) were determined as indexes of myocardial contractility and relaxation, respectively. LV endomyocardial biopsy specimens were also obtained and stained with the collagen-specific dye picrosirius red for determination of the collagen volume fraction (CVF). The patients were followed up for a mean of 32 months for determination of the occurrence of cardiac events.
Results: The mean age and LV ejection fraction for all subjects were 52±11 years and 35.1±10.3%, respectively. No patients had coronary artery disease. Age, body mass index, LV ejection fraction, plasma brain natriuretic peptide concentration, and LV dP/dtmax did not differ significantly between the two patient groups. However, T1/2 was significantly longer in the DCM-DM group (44.4±7.9 ms) than in the DCM-alone group (39.7±5.6 ms, P <0.01). In addition, CVF was significantly greater in the DCM-DM group (6.9±1.8%) than in the DCM-alone group (5.2±1.6%, P=0.01). The probability of cardiac event-free survival in the DCM-DM group was significantly lower than that in the DCM-alone group by the log-rank test (P <0.01).
Conclusions: Our findings suggest that impairment of LV relaxation function and increased myocardial fibrosis associated with DM might contribute to the poor prognosis of DCM patients with DM.