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Biomedical subjects

O Visioli

Publications and source records attributed to O Visioli.

At least 109 records · Page 6Linked to original sources
PubMed1989

[Prognostic significance of clinical, ergometric and coronarographic data in patients soon after myocardial infarction].

The relative prognostic value of the clinical evaluation (Clin), exercise testing (ET), and cardiac catheterization (Cath), was assessed in 167 consecutive patients who underwent these exams within 40 days after an acute myocardial infarction. Each patient was followed at least 24 months; 12 patients died and 59 presented major cardiac events (angina, reinfarction and death). All the parameters were analyzed by univariate and discriminant and Cox regression analysis. For purposes of analysis, the predictive power of 3 sets of variables was analyzed separately: Clin, Clin + ET, Clin + ET + Cath. In the prediction of major cardiac events, only previous myocardial infarction was selected among the Clin parameters by multivariate analysis while ST segment depression, maximal systolic blood pressure, exercise duration and, though less significantly, coronary artery disease extension were selected among the ET and Cath var. The percentage of patients correctly classified was very low using only the Clin variables (60%) and significantly improved when ET and, to a lesser degree, Cath were added (77% and 80%, respectively). Multivariate discriminant analysis selected, as significant predictors of cardiac death, digitalis therapy, appearance of bundle branch block, previous myocardial infarction and anterior location of the myocardial infarction among the Clin variables, while exercise duration and LV ejection fraction were selected among the ET and Cath variables, respectively. The predictive power of the Clin variables alone was only slightly improved by the use of ET and Cath as the percentage of patients correctly classified was 76%, 81% and 84% using only the Clin, the Clin + ET and the combination of the Clin + ET + Cath var, respectively. In conclusion, the variables associated with a depressed LV function are the best predictors of future death and cardiac events; coronary angiography can only slightly improve the specificity of the exercise testing in the prediction of major cardiac events.

Angiography↗
PubMed1988

Lack of tolerance development during chronic ibopamine administration to patients with congestive heart failure.

Beta-adrenergic agonists can progressively lose their efficacy during chronic therapy in patients with heart failure. Ibopamine is a new dopamine derivative, active on dopaminergic and beta-adrenergic receptors, whose hemodynamic activity has been acutely demonstrated. To assess whether any attenuation of its efficacy occurs, the variations of the cardiac output induced during chronic therapy were monitored by impedance cardiography in 15 patients with dilated cardiomyopathy who showed a significant increase of the cardiac output (20.7 +/- 10.0%) after acute ibopamine administration. The efficacy of ibopamine was also assessed after 6 and 12 months of therapy by echocardiography, exercise testing, and 24-hour dynamic electrocardiogram (EKG) monitoring. The cardiac output response to ibopamine did not show any significant attenuation (range 15% to 19%) in the evaluations at 1, 2, 3, 4, 8, and 12 months of therapy. No significant change, was noted, after 6 and 12 months, in the exercise capacity (505 vs. 602 and 604 seconds) and the fractional shortening (16.2 vs. 18.3 and 18.5) without any change of the diastolic diameter. Ventricular arrhythmias were significantly reduced after 6, but not 12, months of therapy. No significant change in the New York Association (NYHA) functional class was noted at 6 and 12 months of therapy (2.4 +/- 5 vs. 2.3 +/- 7 and 2.4 +/-0.6, respectively). Our results show that ibopamine can maintain its hemodynamic activity even during chronic therapy.

Adult↗
PubMed1988

A randomized double-blind crossover study of nicardipine and nifedipine in patients with angina pectoris and concomitant essential hypertension.

The two dihydropyridine calcium antagonists, nicardipine and nifedipine, were compared in 12 patients with both stable angina pectoris and systemic hypertension using a double-blind, crossover protocol. After a 2-week placebo run-in period, each patient was randomized to either nicardipine or nifedipine; each drug was titrated up to either blood pressure normalization, appearance of adverse effects, or maximal dosage (40 mg, three times a day with nicardipine and 30 mg, three times a day with nifedipine) and then administered for 4 weeks. Maximal symptom-limited exercise tests were performed at the end of the placebo run-in and each treatment period, 3 and 8 hours after drug administration. Nicardipine and nifedipine were used at the mean doses of 100 +/- 20 mg/day and 57 +/- 20 mg/day, respectively. Both drugs reduced, significantly and similarly, standing and supine blood pressure, frequency of anginal episodes, and nitroglycerin consumption. At 3 hours after drug administration, exercise duration and time to 1-mm ST depression increased significantly from 402 +/- 84 and 306 +/- 108 seconds, respectively, with placebo; to 533 +/- 135 and 442 +/- 138 seconds during nicardipine; and to 518 +/- 118 and 437 +/- 133 seconds during nifedipine, with a concomitant reduction of peak ST depression. Both submaximal and maximal exercise diastolic blood pressure were significantly reduced by the two calcium antagonists whereas systolic blood pressure was decreased only at submaximal but not at maximal exercise; the heart rate was not significantly modified by the two drugs at any exercise stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Metabolic changes during post-ischaemic reperfusion.

We attempted to identify the nature and time-course of metabolic changes occurring during ischaemia followed by reperfusion either in coronary artery disease patients undergoing intracoronary thrombolysis or in isolated and perfused rabbit hearts. Arterial and coronary sinus differences for oxygen, lactate, glucose, free fatty acid and creatine kinase were measured in patients undergoing successful intracoronary thrombolysis of left anterior descending occlusion. Early reperfusion (after 160 mins of ischaemia) restored aerobic metabolism and myocardial contractility. In contrast, reperfusion after more prolonged ischaemia (335 mins) did not restore mitochondrial function or contractile activity of the myocytes. Results obtained using isolated and perfused rabbit hearts also confirm that the likelihood of recovery during reperfusion depends on the rapidity of recanalization. Furthermore the data reported indicate that on reperfusion after prolonged ischaemia (90 mins) cell damage occurs, leading to a breakdown of the permeability barrier to ions and to larger molecules such as creatine phosphokinase. As a consequence, reperfusion produces a large increase of intracellular calcium, whilst the intracellular magnesium content is severely reduced. Under these conditions, with the observed loss of magnesium from the cell, mitochondrial calcium transport is highly stimulated and the equilibrium between ATP synthesis and calcium influx is shifted towards calcium influx. This sequence of events leads to mitochondrial calcium overload with subsequent damage of mitochondrial structure and loss of the ability to synthesize ATP. Reperfusion of the isolated rabbit hearts with solutions containing high magnesium and low calcium for 10 mins reduced mitochondrial calcium overload. This, in turn, resulted in maintenance of ATP synthesis and, on return to normal perfusate, in partial recovery of developed pressure and myocardial ATP content. These findings may be of importance in the restoration of blood flow to ischaemic heart muscle during thrombolysis.

Adenosine Triphosphate↗
PubMed1988

Importance of early recanalization of the occluded coronary artery in acute myocardial infarction for preservation of left ventricular function.

Ninety-two patients with acute myocardial infarction, treated with intracoronary thrombolysis within 3 h from the onset of ischemic symptoms, were studied with coronary arteriography and left ventriculography. These examinations were repeated after 2 to 4 weeks to assess the importance of duration of ischemia on recovery of regional and global left ventricular pump function. Patency was achieved acutely and maintained at control angiography in 73 patients (87%), who were subdivided into three groups according to duration of ischemia before reperfusion: group 1 (29 patients): revascularized within 3 h; group 2 (22 patients): revascularized between 3 and 4 h; group 3 (22 patients): revascularized after 4 h. Patency was acutely achieved, but not maintained at control angiography in 11 patients (group 4), while thrombolysis was unsuccessful in eight patients (group 5). In group 1 there was a significant reduction in the number of hypokinetic segments (P less than 0.001) and a significant increase in mean percentual area change of hypokinetic segments (P less than 0.001) and in global ejection fraction (P less than 0.001). A still significant, but less evident improvement in these parameters was also seen in group 2 (P less than 0.05, P less than 0.01, P less than 0.01 respectively). Insignificant changes, with only occasional improvements were observed on group 3, while a tendency toward deterioration was found in group 4. A clear and significant (P less than 0.001) worsening of local and global ventricular function was detected in group 5. Our results indicate a significant inverse relationship between duration of ischemia and left ventricular functional improvement. Particularly, the first 3 to 4 h after onset of ischemic symptoms are critical for preservation of left ventricular function (group 1 and 2). Reperfusion after 4 h (group 3) is only rarely associated with improvement of ventricular motion. The importance of very early pharmacological thrombolysis and of maintenance of coronary patency is stressed.

Aged↗
PubMed1988

Protective effect of a prostacyclin-mimetic on the ischaemic-reperfused rabbit myocardium.

To assess whether the administration of the stable prostacyclin-mimetic ZK 36374 (iloprost) protects the myocardium in a dose-dependent manner against ischaemia and reperfusion, isolated rabbit hearts were infused with three different concentrations of iloprost: 2.7, 27 and 270 nM. Diastolic and developed pressures were monitored; coronary effluent was collected and assayed for creatine phosphokinase (CPK) activity and for noradrenaline concentration; mitochondria were harvested and assayed for respiratory activity; ATP production and calcium content and tissue concentration of adenosine triphosphate (ATP) and creatine phosphate (CP) were determined. Treatment with iloprost altered neither developed pressure under normoxic conditions nor the rate and extent of depletion of ATP and CP during ischaemia. The ischaemic-induced deterioration of mitochondrial function, however, was attenuated. On reperfusion, hearts treated with iloprost recovered better than the untreated hearts with respect to left ventricular performance, replenishment of ATP and CP stores and mitochondrial function. The reperfusion-induced mitochondrial calcium overload and release of CPK and of noradrenaline were also significantly reduced. The effect of iloprost was dose-dependent. The lower concentration (2.7 nM) failed to modify ischaemic and reperfusion damage. The best protective effect was found at 27 nM. An increase of the dose to 270 nM did not result in further protection. It is concluded that iloprost infusion provides a dose-dependent protection of the heart against some of the deleterious effects of ischaemia and reperfusion and, in particular, prevents mitochondrial calcium overload and maintains mitochondrial function. Because this protection occurred in the absence of negative inotropic effect during normoxia or of a coronary dilatory effect during ischaemia, it cannot be attributed to an energy sparing effect or to improvement of oxygen delivery. Therefore, alternative mechanisms of action are to be considered.

Adenosine Triphosphate↗
PubMed1988

Newer data on the configuration and variability ranges of body surface maps in a sample of normal subjects.

Quantitative data on the normal variability of body surface maps (BSM) are scarce in the literature. This is one of the reasons why BSM are not yet widely used in clinical practice despite their superior information contents. In this study we determined the average value and variability of a number of parameters derived from BSM in a group of 36 normal adult males, ages 22 to 60. Forty to 60 homogeneous beats were averaged for each subject. This enabled us to extend our study to the low voltage intervals (P,PQ,ST,U) which encompass more than 60% of the entire P-U duration and to contribute new data to controversial issues, such as the presence of two simultaneous maxima during atrial excitation. The following parameters were measured: a) the coordinates of the absolute potential maximum and minimum on the chest surface during the entire cardiac cycle; b) the time course of four voltage-related functions, namely: highest instantaneous potential value on the chest surface, lowest (most negative) potential, highest potential difference, and surface integral of the absolute value of the potential function. In recent studies these parameters were shown to be of considerable value in discriminating normal subjects from different categories of cardiac patients.

Adult↗
PubMed1988

The role of glutathione status in the protection against ischaemic and reperfusion damage: effects of N-acetyl cysteine.

It is known that myocardial ischaemia causes a marked decline of cellular thiol pool and of protein sulphydryl groups content. Reperfusion under these conditions results in oxydative damage which is concomitant with poor recovery of mechanical function. We have evaluated the role of glutathione status in the protection against ischaemic and reperfusion damage by treating the isolated rabbit hearts with N-acetylcysteine (10(-6) M), a sulphydryl group donor. Ischaemic and reperfusion damage was determined in terms of mechanical function, rate of lactate and creatine kinase (CPK) release, mitochondrial function and tissue content of reduced (GSH) and oxidized (GSSG) glutathione and of protein sulphydryl groups (SH). After 60 mins of ischaemia (induced by reducing coronary flow from 24 to 1 ml/min) followed by 30 mins of reperfusion there was an increase of diastolic pressure to 51.6 +/- 3.5 mmHg with only a 22% recovery of systolic pressure, massive CPK release and a deterioration in mitochondrial function. Tissue contents of GSH and of protein SH were severely decreased, while those of GSSG were increased. The GSH/GSSG ratio was reduced from the aerobic value of 50 to 13.4, suggesting that an oxidative stress has occurred. N-acetylcysteine infused for 60 mins before ischaemia determined a 38% increase in tissue content of GSH with no major changes of GSSG or protein SH. The ischaemic-induced decrease of GSH and protein SH was also limited by pretreatment with N-acetylcysteine and there was no accumulation of GSSG after reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1988

Effect of L-carnitine derivatives on heart mitochondrial damage induced by lipid peroxidation.

We have incubated heart mitochondria with ferrous ions as catalyst of lipid peroxidation. Ferrous ions induced an increase of malondialdehyde formation and a reduction of mitochondrial oxygen consuming and calcium transporting capacities. L-Carnitine and Acetyl-L-Carnitine failed to prevent mitochondrial damage. Propionyl-L-Carnitine significantly improved mitochondrial function, but failed to reduce malondialdehyde formation. This protective effect was specific for Propionyl-L-Carnitine as propionic acid and L-Carnitine did not modify mitochondrial damage.

Acetylcarnitine↗
PubMed1988

Effects of changes in intravascular volume on atrial size and plasma levels of immunoreactive atrial natriuretic peptide in uremic man.

To study the trigger for the release of atrial natriuretic peptide (ANP) in man, we measured the atrial areas (AA) by 2-D echocardiography, the total blood volume (TBV) by 131I-serum albumin and plasma immunoreactive ANP (i-ANP) concentrations by radioimmunoassay, after prior plasma extraction, for 10 dialyzed uremic patients. Measurements were made when the patients were volume-loaded or volume-depleted by isoosmotic ultrafiltration and again 48 h later, when they were again volume-loaded. Analysis of plasma extracts by high-performance gel permeation chromatography revealed that the greatest amount of the i-ANP fraction was a peptide eluting like human synthetic alpha-ANP. Ultrafiltration consistently decreased the TBV, while spontaneous regain of body-fluids caused TBV to rise to pre-ultrafiltration levels. Changes in TBV were closely related in time to changes in both right (RAA) and left (LAA) atrial area and in plasma i-ANP concentrations. Significant direct relationships were found between TBV and RAA, TBV and i-ANP and between both LAA and RAA and i-ANP. Furthermore, the decreases and the increases in TBV, RAA and LAA were closely correlated with changes in i-ANP. Multiple regression analysis, however, revealed that the changes in plasma i-ANP were mainly related to the changes in RAA, with little or no relationship to the changes in TBV or LAA. These findings are evidence for a positive feed-back between the level of intravascular filing volume, extent of atrial distention and amount of i-ANP released into the blood stream.

Adult↗
PubMed1988

[A new reflex cardiovascular syndrome: recurrent vasodepressive syncope caused by lesions or tumors of the parapharyngeal space. Etiopathogenesis, clinical picture, differential diagnosis with carotid sinus syndrome and glossopharyngeal neuralgia-asystole syndrome. Therapy by intracranial resection of the 9th cranial nerve].

An intense vaso-vagal reaction characterizes all the reflex induced cardiovascular syncopes. In these syndromes the vagal cardio-inhibitor effect on heart rate is more evident than the vasodilatation and fall in blood pressure. The vasodepressor mechanism is uncommon even in carotid sinus syndrome. We have studied 6 male patients, age range 56-73 years (mean age: 64) with recurrent vasodepressor syncopes. The following were always present during such episodes: generalized malaise, profound fatigue, pallor, cyanosis, copious sweating, lack of peripheral pulses, severe fall in blood pressure (BP) (systolic BP less than or equal to 50-60 mmHg or unrecordable), mental disorientation and/or syncope. The first diagnosis in our patients was carotid sinus syndrome, but, the clinical picture was quite different from classic carotid sinus syndrome: triggering factors were not present, the vasovagal episodes were longer, the syncopes more frequent and severe, and the VVI pacing uneffective. Further investigations, including computerized axial tomography, showed--in all these patients--a malignant tumour originally localized in or near the parapharyngeal space. We think that the symptoms of our patients can be attributed to parapharyngeal tumour and that the parapharyngeal space lesions are able to cause severe vasovagal attacks and syncope. The pathogenetic mechanism in this syndrome, due to neural irritation of the glossopharyngeal afferent fibres, is similar to the glossopharyngeal neuralgia-asystole syndrome, but it obviously doesn't involve pain-pathways since none of our patients had pain. Therefore, this syndrome differs from glossopharyngeal neuralgia- asystole syndrome in the presence of tumours and in the absence of neuralgia and initiating factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Diagnostic accuracy of rest-exercise first pass ventriculography with a fast single crystal gamma camera in detecting coronary artery disease. Study of a group of male subjects without previous myocardial infarction.

Rest and exercise radionuclide ventriculograms were performed in 61 non infarcted, male, patients who underwent cardiac catheterization for chest pain and in 16 normal control subjects. Studies were performed using the first pass method with a fast single crystal gamma camera, which allowed a count rate of 140 +/- 19 Kcounts/sec to be reached during left ventricular filling; the count integral on left ventricular area was 10.8 +/- 1.6 Kcounts and the maximum count/pixel 155 +/- 16. We analyzed sensitivity, specificity, positive and negative predictive value of global ejection fraction (EF) and of the regional wall motion in identifying ventricular function abnormalities due to obstructive coronary artery disease. The regional wall motion was evaluated with four functional images: regional ejection fraction (REF), amplitude (A) and phase (PH) from Fourier analysis and systolic transit times (TT). Sensitivity was near 90% for EF, REF, A and TT, while PH was less sensitive (80%); all functional images were more specific (nearly 90%) than EF (80%). Both sensitivity and specificity were lower for the exercise EKG (59% and 63%, respectively) in this patient group. Significant differences between single vessel and multiple vessel disease were also observed either for the EF increase/decrease (-1.34 +/- 7.4 and -7.82 +/- 9.96; P less than 0.05) or for the number of segments which developed wall motion abnormalities during exercise (1.22 +/- 0.73 and 2.15 +/- 1.04; P less than 0.02). In conclusion, with our method, a fast single crystal gamma camera is suitable for obtaining optimal first pass radionuclide ventriculograms with a count density sufficient either for global or regional left ventricular function evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗