Coronary flow reserve in patients with diabetes mellitus and prediabetes.

BACKGROUND: Abnormalities of coronary microcirculation have been reported in patients with diabetes mellitus (DM) even in the presence of normal coronary arteries. It is unknown when the microvascular effects on coronary arteries begin to appear in the DM disease course. Coronary flow reserve (CFR), determined by pharmacological stress transthoracic Doppler echocardiography, is a reliable indicator of coronary microvascular function. We sought to determine the coronary microvascular function of prediabetic patients compared to DM patients and normal population. METHODS: Seventy-four subjects with normal coronary arteries were enrolled. DM and prediabetes were diagnosed according to American Diabetes Association criteria. All subjects had Doppler recordings of the left anterior descending artery with adenosine infusion at a rate of 0.014 mg/kg per minute. RESULTS: The demographical characteristics and laboratory findings of the three groups were similar (DM group: n = 25, mean age 62 ± 7 years, 19 females; prediabetic group: n = 25, mean age 64 ± 12 years, 21 females; control group: n = 24, mean age 63 ± 7 years, 15 females) except fasting glucose levels. CFR values of the three groups were significantly different (DM group: CFR = 1.75 ± 0.50; prediabetic group: CFR = 2.24 ± 0.43; control group: CFR = 2.38 ± 0.32, P < 0.001). CFR values of DM group were lower than those of prediabetic and control groups (DM vs. prediabetic: P < 0.001, DM vs. control: P < 0.001). However, CFR levels of prediabetic group were not different from those of the control group (P = 0.481). DM was an independent factor predictive of CFR < 2 (OR, 22.69; 95% CI, 6.47-79.51; P < 0.001). CONCLUSION: Coronary microvascular function seems to be normal in the prediabetic state, but dysfunction appears after DM becomes overt.

[Cardiac pacemakers designed for magnetic resonance environment]. / Manyetik rezonans ortami için gelistirilmis kalp pilleri.

Electromagnetic fields associated with magnetic resonance imaging (MRI) can cause serious functional disturbances in patients with cardiac pacemakers. Thus, an implanted pacemaker is generally considered a contraindication for an MRI scan. Studies have shown that MRI indication may emerge in about 17% of patients within one year of pacemaker implantation, and up to 75% of these patients may require MRI during the lifetime of their device. Introduction of pacemaker systems designed specifically for the MRI environment is an important development, providing pacemaker patients with access to this important diagnostic modality. In this article, the current status of MR conditional pacemakers is discussed, together with clinical applications.