Influence of experimental diabetes on the mechanical responses of canine coronary arteries: role of endothelium.

The influence of experimental diabetes on the endothelium mediated relaxation and contractile responses of canine isolated coronary arteries was studied in arteries removed from alloxan treated diabetic (280 mmol.kg-1) and control mongrel dogs. Strips with and without endothelium were suspended in Krebs bicarbonate solution for isometric recording. Relaxation responses to acetylcholine (1.8 X 10(-8) to 9.4 X 10(-6) mol.litre-1, A23187 (10(-8) to 1.28 X 10(-6) mol.litre-1), and sodium nitroprusside (10(-9) to 10(-7) mol.litre-1) as well as contractile responses to prostaglandin F2 alpha, (1.7 X 10(-7) to 5.6 X 10(-4) mol.litre-1) were determined. In all intact strips acetylcholine, and A23187 induced similar concentration dependent reduction of the prostaglandin F2 alpha (2 X 10(-6) mol.litre-1) evoked tone. No significant difference was observed between sodium nitroprusside evoked relaxations of normal and diabetic arteries. Cyclooxygenase blockade reduced the maximal relaxations induced by acetylcholine and A23187 in diabetic vessels, whereas it did not change the endothelium dependent relaxation of normal arteries. Diabetes increased significantly the sensitivity to acetylcholine (EC50 4.1(0.4) X 10(-7) mol.litre-1 in control and 6(0.7) X 10(-8) mol.litre-1 in diabetic arteries; p less than 0.01, n = 7) and to A23187 (EC50: 7(1) X 10(-8) mol.litre-1 in control and 3.8(0.3) X 10(-8) mol.litre-1 in diabetic vessels; p less than 0.01, n = 7); in contrast, prostaglandin F2 alpha remained an equiactive constrictor in normal and diabetic vessels with intact endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased vasoconstrictor response to noradrenaline in femoral vascular bed of diabetic dogs. Is thromboxane A2 involved?

STUDY OBJECTIVE: The aim was to determine the role of cyclo-oxygenase products in the vasoconstrictor response of femoral arterial bed to noradrenaline and to analyse the role of vascular adrenoceptors in the synthesis of cyclo-oxygenase products. DESIGN: The influence of intra-arterially injected cyclo-oxygenase inhibitors indomethacin and acetylsalicylic acid on alterations in conductance of femoral arterial bed induced by noradrenaline was compared in metabolically healthy and alloxan diabetic dogs. PGI2 and TXA2 synthesising ability of isolated femoral arterial rings was measured with and without inhibition of alpha adrenoceptors by phentolamine. SUBJECTS: 18 metabolically healthy and 18 alloxan (560 mumol.kg-1) diabetic dogs of either sex, weight 16-28 kg, were studied. MEASUREMENTS AND MAIN RESULTS: Noradrenaline produced greater (p less than 0.01) pressor effects in the femoral arterial bed of alloxan diabetic dogs than in the hind limb of control animals. Blockade of cyclo-oxygenase either by indomethacin 10 mumol.kg-1 or by acetylsalicylic acid 140 mumol.kg-1 markedly reduced the response to noradrenaline in alloxan treated animals, but not in controls, thereby eliminating the different responsiveness of the two groups. Femoral arterial rings from diabetic animals synthesised similar amounts of PGI2 as control rings but formed more TXA2 (p less than 0.05). Phentolamine pretreatment (5 mumol.litre-1) markedly reduced the production of TXA2, but not of PGI2, in diabetic vessels. CONCLUSIONS: The results show an increased release of TXA2 by isolated diabetic femoral arteries. It is therefore suggested that an alpha adrenoceptor mediated increase in TXA2 biosynthesis may play a part in the vascular hyperreactivity of the diabetic femoral arterial bed.

Characteristics of coronary endothelial dysfunction in experimental diabetes.

OBJECTIVE: To study the influence of diabetes on the endothelium-dependent vasodilation in the coronary arterial bed. METHODS: The effects of acetylcholine (ACh 2-36 pmol.kg-1; 18 nmol.1(-1)-9.8 mumol.1(-1); 0.1-10 mumol.1(-1), L-arginine (1 mmol.1(-1) and sodium nitroprusside (1 nmol.1(-1)-100 mumol.1(-1)) were measured on coronary conductivity, vascular tone and cGMP release (RIA) in healthy and diabetic dogs. RESULTS: ACh-mediated (in cumulative intra-arterial infusion) increase in coronary conductivity was reduced (P < 0.01) in the diabetic dogs in vivo, whereas no increase in cGMP release was observed in isolated diabetic coronaries (P < 0.05) which could not be enhanced by L-arginine (P < 0.05). Inhibition of cyclo-oxygenase after 20 min further impaired (P < 0.01) responsiveness to ACh in vivo and diminished the ACh response in isolated coronary strips of the diabetic dogs, but not in those of the controls. Relaxation in response to sodium nitroprusside was not altered by diabetes. CONCLUSIONS: Diminished vasodilation in diabetes is due to a defect in endothelial nitric oxide production and action. Vasodilating prostanoids do not sufficiently compensate this defect.

Electrophysiological effects of hypoglycaemic sulphonylureas on rabbit heart.

The hypoglycaemic sulphonylurea drugs glibenclamide and carbutamide were compared as to their influence on the electrical activity of isolated rabbit heart preparations. Carbutamide (10(-5)-10(-3) M) was found to depress slightly the nomotopic and junctional automaticity, while in Purkinje fibres it enhanced automaticity and conduction velocity. On the other hand, glibenclamide (10(-6)-10(-3) M) had no significant influence on the nomotopic and junctional automaticity, and markedly depressed automaticity and conduction velocity in the Purkinje fibres. The atrial conduction system was not much influenced by the sulphonylureas tested. Carbutamide depressed the electrical threshold in Purkinje fibres. It follows that the hypoglycaemic sulphonylurea compounds carbutamide and glibenclamide differ considerably with respect to their influences on cardiac electrical activity.

What kind of cardiovascular alterations could be influenced positively by oral antidiabetic agents?

Since the first publication of the University Group Diabetes Programme in 1970 the possible deleterious cardiovascular effects of certain hypoglycaemic sulphonylurea products has been well known. In contrast, international knowledge of the advantageous cardiovascular effects of certain sulphonylurea compounds became available recently. Glibenclamide decreases the incidence of fatal myocardial infarction and the development of ventricular fibrillation in patients suffering from acute myocardial infarction. It also lowers the incidence of ventricular ectopic beats in digitalized patients compared with patients treated with other investigated sulphonylurea compounds. The survival of patients treated with glibenclamide, insulin or diet alone is longer after the first attack of angina pectoris or after first acute myocardial infarction compared with those on other investigated sulphonylurea therapy. Glibenclamide decreases arrhythmogenesis during acute myocardial infarction in rats and strophanthin cardiotoxicity in rabbits. Arterial blood pressure and myocardial contractile force are not influenced by glibenclamide whereas these parameters are increased by other investigated sulphonylurea compounds. Consequently, deleterious cardiovascular effects of certain hypoglycaemic sulphonylurea drugs may contribute to the high cardiovascular mortality rate in diabetes mellitus, partly due to the effect on membrane channels and partly due to independent cardiac and extracardiac actions. Finally, recent observations suggest that glimepiride has a more advantageous cardiovascular effect than glibenclamide.

Potassium channels in the cardiovascular system.

In vitro and in vivo studies suggest that opening of ATP-sensitive potassium channels following ischaemia enhances recovery of myocardial contraction, dilates blood vessels and has an antiarrhythmic effect. Different sulphonylurea compounds that block the ATP-sensitive potassium channels exert different effects on cardiac functions. Glibenclamide decrease, arrhythmogenesis during acute myocardial infarction in rats and reduces strophanthin cardiotoxicity in rabbits. Other sulphonylurea compounds, but not glibenclamide, increase arterial blood pressure and myocardial contractility. These effects may be partly secondary to blockade of ATP-sensitive potassium channels and partly due to independent cardiac and extracardiac actions. Glimepiride may have a more advantageous cardiovascular effect than glibenclamide. The studies suggest the hypothesis that deleterious cardiovascular effects of some hypoglycaemic sulphonylurea drugs may contribute to the high cardiovascular mortality rate in diabetes mellitus. An observational study suggested glibenclamide decreased the incidence of fatal myocardial infarction and development of ventricular fibrillation in patients suffering from acute myocardial infarction. Glibenclamide may also decrease the incidence of ventricular ectopic beats in digitalized patients compared with other sulphonylurea compounds. The studies suggested the survival of subjects treated with glibenclamide, insulin, or diet alone after the first attack of angina pectoris or after first acute myocardial infarction may be longer compared with those on other sulphonylurea therapies. Further large scale prospective, randomised studies are needed to determine whether the reported effects can be verified and are sufficiently large to affect clinical prescribing.

Direct effect of hypoglycemic sulphonylureas on the cardiovascular system of dogs.

The effects of first generation sulphonylurea compounds carbutamide, gliclazide and tolbutamide as well as second generation compounds glibenclamide and glipizide on the cardiovascular system were investigated in dogs. Six dogs received each compound intravenously at cumulative dose levels of 74, 296, 1184 mumol/kg of carbutamide and tolbutamide, 0.4, 2.0, 10.0 mumol/kg of glibenclamide and glipizide, and 16, 48 and 144 mumol/kg of gliclazide. Mean arterial blood pressure, myocardial contractile force, cardiac output and heart rate were measured. The rate of change of myocardial contractile force development (positive dF/dt), as well as of myocardial relaxation (negative dF/dt) were measured. The first generation sulphonylureas were found, in dogs, to exert a positive inotropic effect in contrast to second generation compounds. The clinical importance of our findings may be in the potential for the malfunction of the cardiovascular system (based on cardiopathy, neuropathy, atherosclerosis, and obesity), developing in diabetes, to be further impaired by the first generation sulphonylureas. Therefore, second generation sulphonylureas should be preferred in the therapy of type 2 diabetics, if satisfactory metabolic control cannot be achieved by dietary management alone and sulphonylurea treatment becomes necessary.

Divergent cardiac effects of the first and second generation hypoglycemic sulfonylurea compounds.

The effects of first and second generation hypoglycemic sulfonylureas on the incidence of ventricular ectopic beats and on the duration of transitional ventricular fibrillation in the ischemic rat heart were investigated. First generation sulfonylurea compounds (tolbutamide, carbutamide and gliclazide) in 105 preparations increased, while second generation sulfonylurea compounds (glibenclamide and glipizide) in 50 preparations decreased in a dose-dependent manner both the number of ventricular ectopic beats and the duration of transitional ventricular fibrillation during the first 30 min after ligation of the left anterior descending coronary artery. Therefore, second generation sulfonylureas should be preferred in the treatment of type 2 diabetics with ischemic heart diseases, if satisfactory metabolic control cannot be achieved by a treatment regimen and diet alone.

Influence of diabetic state and that of different sulfonylureas on the size of myocardial infarction with and without ischemic preconditioning in rabbits.

The sensitivity of the myocardium to ischemia and the level of protection achieved by ischemic preconditioning is shaped by the joint influence of several mechanisms in diabetes mellitus. In vivo studies were made in alloxan diabetic and non-diabetic control rabbits to assess if the effects of preconditioning and sulfonylurea pretreatment with either glibenclamide or glimepiride (0.05-0.2-0.6 micromol kg (-1)) influence the extent of the infarcted area caused by one hour ligature of the left coronary artery. For our study, we defined preconditioning as 2 minutes of ischemia followed by 2 minutes of reperfusion, which was repeated 3 times. The interrelationship of the diabetic pathophysiological state, and sulfonylurea treatment during ischemic preconditioning were studied by comparing the infarcted areas and the rate of infarction to risk areas in left ventricular slices using computer planimetry. In healthy control rabbits preconditioning reduced infarcted area (29.6 +/- 3.0% vs. 48.8 +/- 2.8% p < 0.0005), while in diabetic rabbits this protection did not occur (53.3 +/- 7.3% vs. 56.6 +/- 4.4% NS). Glibenclamide in all of applied doses prevented the protective effect in control animals (infarction/ risk area: HP: 0.47 +/- 0.04 vs. HP Glib-0.05 : 0.69+/-0.06 p< 0.004 vs. HP Glib-0.2 : 0.72+/-0.09 p< 0.002 vs. HP Glib-0.6 : 0.75 +/- 0.04 p< 0.001). In contrast, in diabetic rabbits low dose of glibenclamide contributed to the same development of preconditioning. However the highest dose of glibenclamide (infarction/risk area: DP Glib-0.6 : 0.77 +/- 0.17 vs. DP Glib-0.05 : 0.55 < 0.03 p < 0.047) and the consequences of the diabetic state blocked the salutary effect. Glimepiride had no considerable influence on the protective effect, either in control nor in diabetic animals. Glibenclamide and glimepiride, presumably due to their different sulfonylurea receptor affinity in the heart, resulted in different influence on preconditioning in healthy control animals. Glibenclamide treatment seemed to be more harmful when less K (+)ATP channels were activated. The accomplishment of myocardial preconditioning in diabetes mellitus is claimed to be determined by the interaction of both metabolically influenced K (+)ATP channel activity and the dose of sulfonylurea.

Metabolic energy metabolism in diabetes: therapeutic implications.

Diabetic alterations of myocardial metabolism result mainly from malfunctions of acetyl-coenzyme A carboxylase, carnitine-palmitoyl-transferase-I and pyruvate-dehydrogenase inducing an overshoot of fatty acid oxidation that inhibits glucose oxidation. Gene expression of pyruvate-dehydrogenase and glucose transporters and depression of the third step of the mitochondrial respiratory chain also contribute to the diabetic alterations of myocardial metabolism. Ischaemic cardiovascular alterations are common and treatment is rarely successful in cases of diabetes since fatty acid oxidation is the costliest metabolic pathway for oxygen. Thus, in diabetes, aerobic glycolysis gradually shifts to anaerobic glycolysis under ischaemia, with accumulation of lactate and acid metabolites that in turn induce myocardial deterioration, Animal experiments have demonstrated that elective depression of activity of carnitine-palmitoyl-transferase-I enzyme-activity promotes glucose oxidation and early rapid recovery of myocardial contractility, especially under diabetic conditions. To reduce diabetic alterations of myocardial metabolism, anti-diabetic treatment must be switched to insulin during the acute ischaemic and post-ischaemic period of coronary diseases. Trimetazidine optimizes energy metabolism by selectively inhibiting action of the 3-ketoacyl-coenzyme A thiolase enzyme involved in beta-oxidation and inhibiting the overshoot of fatty oxidation. Trimetazidine, as the first 3-ketoacyl-coenzyme A thiolase inhibitor, therefore provides permanent myocardial cytoprotection in stable angina pectoris. However, in our experience, this beneficial anti-anginal effect is only observed in well-controlled situations.

Direct cardiac effects of an ionic and a non-ionic contrast medium in dogs.

Direct cardiac effects of ionic diatrizoate (Uromiro) and non-ionic iopamidol (Iopamiro) were investigated in "in situ" heart-lung preparation of 19 vagotomized dogs. Diatrizoate was found to induce considerably greater alteration in plasma osmolality and subsequent dehydration of the myocardium compared with iopamidol. Myocardial dehydration resulted in a decrease of left ventricular compliance and in that of cardiac performance. Diatrizoate was shown to influence the myocardium not only by its hyperosmolarity but also by a direct action. Heart rate was reduced by both contrast media.

Cardiac autonomic neuropathy and QT interval length. A follow-up study in diabetic patients.

For evaluating the clinical significance of QT interval prolongation in diabetics with cardiac autonomic neuropathy (CAN), 53 diabetic patients were followed-up for 5 years or to death and the results of cardiovascular function tests as well as the values of QT intervals were repeatedly determined. At baseline investigation, the QTc intervals were significantly longer in diabetics with definitive (456 +/- 5 ms, mean +/- SEM, n = 17) than those with early (435 +/- 5 ms, n = 13, p less than 0.01) and without (413 +/- 4 ms, n = 23, p less than 0.001) signs of CAN or in controls (414 +/- 5 ms, n = 15, p less than 0.001). Thirteen patients died during the follow-up period (1 without, 2 with early and 10 with definitive signs of CAN) but QTc intervals did not differ significantly between patients with cardiac (456 +/- 9 ms, n = 8) and non-cardiac (459 +/- 15 ms, n = 5) causes of death. At reinvestigation of 40 patients, the severity of CAN worsened in 22 patients, remained unchanged in 15 patients and improved in 3 patients. Accordingly, the mean values of autonomic function tests decreased (beat-to-beat variation from 15 +/- 2 to 9 +/- 1 beats/min, p less than 0.01; 30:15 ratio from 1.19 +/- 0.03 to 1.09 +/- 0.02, p less than 0.01) while QTc interval increased (from 424 +/- 3 to 431 +/- 4 ms, p less than 0.01). It was concluded that CAN carries a poor prognosis in diabetic patients. Nevertheless, QTc interval prolongation could be evaluated as rather an additional sign of CAN than the only explanation for mechanism in the pathogenesis of sudden cardiac death in diabetic patients.

Myocardial systolic alterations of insulin-dependent diabetics in rest.

Left ventricular systolic function was tested in 27 insulin-dependent diabetic patients by measuring the systolic time intervals. In diabetics longer pre-ejection period, and higher PEP/LVET quotient were found showing a good correlation with the values of glycosylated haemoglobin. These findings emphasize the importance of metabolic control in the development of cardiac dysfunction.

The role of diabetic vascular alterations in the development of myocardial ischemia.

During the last fifteen years it has become evident that in diabetes there is an increased vasoconstrictor tendency in the arterial bed of different organs. This vasoconstrictor tendency is most expressed in the coronary arteries where sympathetic stimulation exerts vasodilation in the healthy and vasoconstriction in the diabetic arterial bed. Accordingly, myocardial tissue blood flow decreases during hypoxia in the diabetic, whereas it increases in nondiabetic states. Furthermore, 48 hours after ligation of the anterior left descending coronary artery the infarcted myocardial zone was extended below its first major oblique branch in diabetic dogs compared to nondiabetic ones. Since pretreatment with adrenergic antagonists or with cyclooxygenase inhibitors diminished considerably the increased vasoconstrictor tendency in the diabetic state alterations in the endothelium as well as in adrenergic vascular and prostaglandin mechanisms are involved in the pathomechanisms of this phenomenon. Moreover, after mechanical removal of the endothelial layer in coronary arterial strips the maximum force generated by diabetic vessels exceeded the maximum contraction produced by nondiabetic arteries, and the dose-response curve of diabetic arteries to phenylephrine was steeper than in nondiabetic strips. All these phenomena appeared at an early stage when macro- and microscopic alterations could not yet be observed in the vessels. Sodium nitrite or papaverine evoked similar vasodilation in the diabetic and nondiabetic coronary arterial bed.

[Changes in the heart in diabetes]. / Zmeny na srdci pri cukrovce.

The structure of the heart muscle, its metabolism and functional changes which develop in diabetes are the basic concepts elucidated by the author from the aspect of present knowledge. Attention is drawn to possible prevention of their development.

[New concepts in the therapy of diabetic cardiopathies]. / Uj szempontok a diabeteses cardiopathia kezelésében.

Most reasonable cause of diabetic cardiopathy might be the impaired energy fuel supply and metabolism producing inevitably a hypotic condition and needing myocardial cytoprotection. Under diabetic conditions glucose disposal of the heart muscle-decreases, but working myocardial cell remains penetrable for glucose even in the absence of insulin. Therefore, it is worth to stimulate aerobic glycolysis to protect diabetic heart from frequent ischaemic events induced by diabetic late complications, since fatty acids oxidation wastes more oxygen than glycolysis for ATP production. Trimetazidine has an original cytoprotective mode of action reducing oxygen demand without altering heart activity. Consequently, trimetazidine protects structure and functions of the ischemic myocardial cell. On the other hand, glycation and altered turnover of proteins play also an important role in the development of diabetic cardiopathy. Consequently, not only trimetazidine but aminoguanidine could also reduce the development of alterations in diabetic cardiopathy inhibiting the glycation of proteins. Finally, calcium antagonists are also very usefull in myocardial cytoprotection of the diabetic heart, according to the altered cellular calcium regulation and a calcium overload which play the main role in the development of diabetic cardiopathy.

[From type 2 diabetes to metabolic X syndrome]. / A 2-es típusú cukorbetegségtöl a metabolicus X-syndromáig.

The more and more exact and simple determination of insulin provides an opportunity for exploration of the states of insulin resistance. It turned out hereby that the so-called type 1 diabetes is merely a consequence of insulin deficiency and it occurs mainly in the young. In contrary, the so-called type 2 diabetes is a multifactorial, often hyperinsulinaemic condition of insulin resistance and it occurs mainly in the adults. Furthermore, the epidemiological observations of the last decades elucidated that insulin resistance and compensating hyperinsulinaemia are common not only in type 2 diabetes but in other conditions as in ischaemic vascular diseases, hypertension, obesity, lipid alterations, coagulation disturbances, too. It became evident that the so-called late vascular complications of diabetes mellitus may develop before or without the existance of any disturbances in carbohydrate metabolism. These facts encouraged the recognition of metabolic syndrome-X. According to this hypothesis, insulin resistance and compensatorial hyperinsulinaemia are the causes of atherosclerosis, hypertension, upper body obesity, dyslipidaemia, type 2 diabetes and disturbances of coagulation. Following the last years, it became evident that hyperuricaemia, microalbuminuria and even type A personality are common in this syndrome of insulin resistance.

[Pen-type insulin dispenser for intensive insulin therapy]. / A "pen" inzulinadagoló eszköz alkalmazása az intenzív inzulinkezelésben.

The authors investigate the advantage of the intensified insulin therapy and the use of pen-type devices in the practice of the Diabetic Outpatient Clinic of National Institute of Cardiology. The metabolic control improved markedly during intensified insulin therapy already after a short time as three months without any change in the applied dosage. Furthermore pen-type devices have been recognized to let the patients better accept the daily more than two injections, to improve the life-style, and last but not least to decrease the waste quantity of insulin. Authors want to draw attention to the fact that more than 33% of diabetic patients with intensified insulin therapy have a higher demand for insulin, then it could be injected by the pen devices used at this time and by cartridges available in Hungary at this moment. Therefore, availabilities of both cartridges of 3 ml volume would become necessary without any delay.

[Amidaron-induced dermatopathy resulting from unnecessary Cordarone therapy of ventricular parasystole]. / Kamrai parasystolia felesleges Cordarone-kezelése kapacsán jelentkezö amiodaron-dermatopathia.

The case history of a patient is reported who was treated with a variety of antiarrhythmics over a period of years because of refractory ventricular "bigeminy". As the arrhythmia did not respond to any kind of therapy, amiodarone treatment was started, which the patient received in a maintenance dose of 600-400 mg/day for 4 years. More recently, a bluish-grey hyperpigmentation of the face and other areas of the skin exposed to sunlight developed. A cutaneous biopsy of the hand revealed pigment deposits and lamellated lysosomal inclusions characteristic for amiodarone dermatopathy. The interactive, computer-assisted analysis of the ventricular ectopic activity has clearly demonstrated its innocent, parasystolic nature. The differentiation between ventricular extrasystolic and parasystolic activity is essential, because the latter arrhythmia does not require specific antiarrhythmic pharmacotherapy.

[Correlations between cardiorespiratory reflex impairment and distal neuropathy in diabetics free of clinical symptoms of autonomic neuropathy]. / A kardiorespiratorikus reflexkárosodás és a distalis típusú neuropathia összefüggésének vizsgálata autonom neuropathia klinikai tüneteitöl mentes cukorbetegekben.

Signs of autonomic cardiac neuropathy and its association with distal symmetrical polyneuropathy were investigated in adult diabetic patients free from clinical symptoms of autonomic neuropathy. Cardiorespiratory reflexes were assessed by non-invasive tests (deep-breathing, Valsalva manoeuvre and lying-to-standing) evaluating parasympathetic function of cardiac innervation. Measurement of motor nerve conduction velocity in both peroneal nerves and neurological physical examination were carried out for assessment of distal somatic neuropathy. Among 64 diabetics, definitive signs of cardiac autonomic neuropathy were found in 28 patients (44%), early signs of cardiac autonomic neuropathy were observed in 19 patients (30%) while no alterations were documented in 17 patients (26%). The values of motor nerve conduction velocity in peroneal nerves (41.8 +/- 0.7 m/s) were significantly (p less than 0.01) lower in patients with definitive cardiac autonomic neuropathy (n = 28) than those (45.8 +/- 1.1 m/s) of patients without any signs of cardiac autonomic neuropathy (n = 17). These latter values were, however, significantly (p less than 0.001) lower than those (53.7 +/- 0.7 m/s) of control subjects (n = 50). Abnormal results of non-invasive tests for autonomic neuropathy, i.e. alterations of cardiorespiratory reflexes indicating parasympathetic impairment in cardiac innervation could be often found in diabetics without clinical signs of autonomic neuropathy. These alterations could be frequently observed in diabetics with distal symmetrical neuropathy as well as in diabetic patients with one or more late specific complications.