Abnormalities of the cardiovascular response to cold pressor test in type 1 diabetes. Correlation with blood glucose control.

Left-ventricular (LV) function in type 1 diabetics without clinical heart disease was compared with that found in matched normal subjects. Although diabetics had a normal LV ejection fraction (66% +/- 6%), they showed a trend toward smaller left ventricles. Their cardiovascular response to a cold pressor test was abnormal and cardiac function after the cold pressor test correlated with hemoglobin A1c levels: Average hemoglobin A1c was inversely related to ejection fraction and early filling volume and directly related to the ratio of pre-ejection period to ejection time (PEP/LVET) after a cold pressor test. Hemoglobin A1c at the time of study correlated more closely with PEP/LVET after cold pressor test than did the six-month average hemoglobin A1c level, suggesting that cardiac function fluctuates with recent changes in blood glucose control. Thus, even when diabetics have a normal LV ejection fraction, an abnormal cardiovascular response to stress may still be present, and such abnormalities correlate with blood glucose control.

Oral contraceptives abolish luteal phase exacerbation of hyperglycemia in type I diabetes.

PIP: For some time it has been recognized that postovulatory exacerbation of hyperglycemia contributes to the instability of diabetes in many women of reproductive age. It has been suggested that increasing plasma levels of progesterone and estrogen may induce insulin resistance and consequently lead to increased hyperglycemia during the luteal phase of the menstrual cycle. Due to the fact that menstrual cycles in a given woman may vary in length and that it takes patients several days on intermediate or long-acting insulin to achieve a steady state with regard to any dosage adjustment, it is difficult to design an insulin regimen that maintains euglycemia throughout the menstrual cycle in these labile patients. Recognition of this problem led to trying a nonsequential low estrogen contraceptive as adjunctive therapy in a 20-year old woman with insulin dependent diabetes mellitus. The patient consistently suffered an exacerbation of hyperglycemia after ovulation in each cycle, lasting until the onset of menses. On 1 occasion the patient developed frank diabetic ketoacidosis. For the first 2 cycles on Lo Ovral, the hyperglycemia was postponed from the 1st postovulatory day until day 18-19 of the cycle. It was reasoned that the serum estrogen and/or progestin level might be building cumulatively, and the oral contraceptives (OCs) were subsequently withdrawn at day 19 of the cycle rather than day 21. A maximum blood glucose level of 400 mg/dl was attained at day 19 and was treated with additional regular insulin. Levels in excess of 240 mg/dl did not recur during that cycle. The following cycle OC therapy was interrupted at day 18; no blood glucose level in excess of 240 mg/dl occurred that month. Hemoglobin A1c fell from a pre-OC treatment value of 12.4% to the current A1c of 9.7%. A modest increase in blood pressure has occurred, but this is easily managed with a 2 g sodium diet and 25 mg of hydrochlorothiazide daily. On the basis of this experience, a controlled trial is warranted of low dose estrogen nonsequential OCs in lean, nonsmoking, 18-30 year old women with insulin dependent diabetes mellitus with postovulatory hyperglycemia.^ieng

Impact of peer review in reduction of permanent pacemaker implantations.

Because of a sharp increase in the number of permanent pacemakers inserted at The Brooklyn Hospital between 1972 and 1976, a peer-review committee was established to monitor subsequent pacemaker implantation. Total initial implants declined from 48 to 22 per year in the two years that followed. The number of implantations for sinoatrial bradycardias declined from 50 to 27 and the number of implantations for intraventricular conduction defects declined from 32 to five in the two years after peer review, compared with the two years before. There was no change in the number of pacemakers implanted for complete or advanced heart block. Almost 10% of patients who received a pacemaker between 1972 and 1976 had other conditions that might have accounted for the events that precipitated the decision to implant a pacemaker. The symptoms for which the pacemaker was implanted persisted in 19% of patients, despite a normally functioning pacemaker system. Patients receiving a permanent pacemaker before peer review had a 17% one-year and a 43% three-year mortality. When a more critical patient selection process was instituted, a smaller percentage remained symptomatic (9% vs 19%) and three-year survival rate was improved (86% vs 57%). From 1977 through 1978, when permanent pacemaker implantations declined, the number of hospital, medical service, and coronary care unit admissions increased. It is concluded that peer review can have substantial impact on permanent pacemaker implantations.

Effect of blood glucose control on retinal vascular permeability in insulin-dependent diabetes mellitus.

Thirteen patients were instructed in a technique of self-management of insulin-dependent diabetes mellitus, using multiple home-monitored blood glucose determinations and multiple injections of regular insulin in conjunction with once-daily Ultra Lente insulin. Hemoglobin A1c and quantitative fluorescein fluorophotometry were used to assess blood glucose control and retinal permeability, respectively. In those patients achieving normal blood glucose control, retinal vascular leakage was statistically identical to that of a nondiabetic control population. In those patients less well controlled, retinal permeability did not differ statistically from values observed in a population of insulin-dependent diabetic patients under "standard" control. It is concluded that with "tight" control of blood sugar and normalized A1c hemoglobin, retinal permeability similarly is normalized.

Administration of aspartame in non-insulin-dependent diabetics.

A study was designed to determine the effect of the consumption of the nutritive sweetener aspartame on non-insulin-dependent diabetics. Forty-three adult diabetics between the ages of 21 and 70 completed a 90-day study; all were diabetics whose conditions were managed by diet and/or hypoglycemic agents. Participants in the blind study were instructed to continue their usual diet and to take two capsules of an assigned preparation three times daily with meals, either the aspartame or the placebo. The 1.8 g of aspartame administered is approximately three times the expected daily consumption of aspartame if used as a sweetener to replace sugar. Throughout the study subjects were examined for (1) symptoms of intolerance, (2) fasting plasma phenylalanine levels exceeding 4 mg/100 ml, and (3) deterioration of diabetic control. At the conclusion of the study subjects exhibited no symptoms that could be traced to the administration of aspartame or the placebo, and diabetic control was unaffected by the chronic administration of these substances. Aspartame seems to be well tolerated by non-insulin-dependent diabetics.