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Biomedical subjects

G Grassi

Publications and source records attributed to G Grassi.

At least 217 records · Page 12Linked to original sources
PubMed1981

[Does the number of treated rejection episodes in the first transplantation influence the survival of the patient with kidney re-transplantation?].

The records of 77 patients who received a second kidney transplant at the Surgery Department of Addenbrooke's Hospital, Cambridge, have been re-examined to assess the influence of the number of rejection episodes treated during the first transplant on the survival of the second. 61 of the 77 retransplanted patients lost their first kidney for immunological reasons. 6 did not present any treated episode of rejection, 45 one episode only and in 10 greater than 1 episode was treated during the first transplant. P less than 0.05 from 1 to 5 years as regards survival of the second transplants in patients whose first kidney did not present treated rejection episodes by comparison with those presenting 1 or greater than 1. No significant difference was noted in patient survival in the various groups under examination. On the basis of the results obtained, it is concluded that, in addition to the cause of failure and duration of the first transplant, the number of treated rejection episodes during the first transplant should be considered as a critical parameter for better selection of the most suitable candidates for receiving a second transplant.

Graft Rejection↗
PubMed1981

[Influence of ischemia time on the long-term survival of kidney re-transplants].

The influence of warm and cold ischemia times on the long term survival of subsequent renal allografts has been evaluated. The retrospective study has involved 77 patients who in the year period 1966-1977 were submitted to 86 subsequent renal allografts at the Department of Surgery of the Addenbrooke's Hospital-Cambridge. Although a trend to do better was found in the group of allografts having warm ischemia time greater than 45' and less than 90' and cold ischemia time greater than 200' and less than 400', no statistical difference resulted in the survival curves among the various groups at examination.

Body Temperature↗
PubMed1981

Arrhythmia control by cardiac stimulation.

Cardiac programmed stimulation in the control of tachyarrhythmias offers encouraging prospectives. We describe two devices which utilize radiofrequency as a means of synchronization and stimulation and can be triggered by the patient himself when tachycardia occurs. In addition we introduce a third anti-tachycardia device, completely automatic, which can be used in cardiologic departments. The first device described permits critical stimulation and can be programmed to deliver a single or double synchronized impulse. The second device, which utilizes the same implanted unit and electrode as used for critical stimulation, when activated searches the tachycardia interruption zone by scanning. The third device, based on the same principles, has a rate discriminator that activates the scanning stimulation. We treated 12 patients: 8 suffering from paroxysmal supraventricular tachycardia (4 with Wolff--Parkinson--White syndrome, 2 with intranodal reentry, 2 with brady--tachy syndrome); 2 patients with ventricular recurrent tachycardia; 1 with atrial flutter; and another with iterative junctional tachycardia. The follow-up varied for every patient from 6 yr to 3 mth.

Arrhythmias, Cardiac↗
PubMed1981

[Long-term electrical stimulation of tachycardias: control by ambulatory electrocardiographic monitoring (author's transl)].

The Authors suggest a new method, elaborated by their own, for long-term antiarrhythmic stimulation. They used ambulatory electrocardiography in order to evaluate the results. It consists of a radio frequency device for synchronization and stimulation, and allows the scanning stimulation of all the cycle of tachycardia, with automatic search for the zone of interruption. The stimulatory is carried by the patient, who must set it in motion at the onset of the tachycardia. Preliminary results show the efficacy of the method; Holter monitoring seems to be the best guide to the development of a satisfactory implantable automatic tachycardia-terminating pacemaker.

Ambulatory Care↗
PubMed1980

[Is hypersplenism a contraindication of distal splenorenal shunt?].

The effect of the distal spleno-renal shunt on hypersplenism has been investigated on 19 out of 20 patients undergoing this procedure at the 2nd Department of Surgery Pizzamiglio, Niguarda Hospital of Milan. 6 patients had an hypersplenism of high degree (platelet count less than 50;000/mm3), 11 of moderate degree (platelet count greater than or equal to 50,000 and less than 100,000/mm3) and 2 of low degree (platelet count greater than 100,000 and less than 100,000/mm3). Platelet count significantly improved after the operation (p less than 0.01) and hypersplenism resulted cured or ameliorated in 17 out of 19 patients under study. After briefly discussing the pathogenesis of hypersplenism in patients bearing portal hypertension, the A. conclude that hypersplenism also severe is not "per se" a contraindication to Warren shunt.

Adult↗
PubMed1980

Blood pressure variability in man: its relation to high blood pressure, age and baroreflex sensitivity.

1. Intra-arterial blood pressure and heart rate were recorded for 24 h in ambulant hospitalized patients of variable age who had normal blood pressure or essential hypertension. Mean 24 h values, standard deviations and variation coefficient were obtained as the averages of values separately analysed for 48 consecutive half-hour periods. 2. In older subjects standard deviation and variation coefficient for mean arterial pressure were greater than in younger subjects with similar pressure values, whereas standard deviation and variation coefficient for mean arterial pressure were greater than in younger subjects with similar pressure values, whereas standard deviation aations and variation coefficient were obtained as the averages of values separately analysed for 48 consecurive half-hour periods. 2. In older subjects standard deviation and variation coefficient for mean arterial pressure were greater than in younger subjects with similar pressure values, whereas standard deviation and variation coefficient for heart rate were smaller. 3. In hypertensive subjects standard deviation for mean arterial pressure was greater than in normotensive subjects of similar ages, but this was not the case for variation coefficient, which was slightly smaller in the former than in the latter group. Normotensive and hypertensive subjects showed no difference in standard deviation and variation coefficient for heart rate. 4. In both normotensive and hypertensive subjects standard deviation and even more so variation coefficient were slightly or not related to arterial baroreflex sensitivity as measured by various methods (phenylephrine, neck suction etc.). 5. It is concluded that blood pressure variability increases and heart rate variability decreases with age, but that changes in variability are not so obvious in hypertension. Also, differences in variability among subjects are only marginally explained by differences in baroreflex function.

Adult↗
PubMed1980

A simple new method for atrial triggered pacemaker. Preliminary clinical trials.

Inadequacy of cardiac output in the ventricular paced complete heart block is generally related to lack of rate adaptation to varying atrial contribution. The status of the art in leads technology had not yet freed the clinicians from the necessity to use a double lead system (atrial and ventricular) in order to maintain the atrial synchronization. Authors present a new simple catheter with double electrode (atrial receptor and ventricular stimulator) which, connecting to a new conceived VAT generator, let to obtain atrial synchronization with a single catheter-electrode implantation. External units were tried in 22 patients who needed temporary treatment. The results appear to be positive in all cases and encourage the Authors to continue with the task undertaken until the system is made implantable.

Clinical Trials as Topic↗
PubMed1980

[Antiarrhythmic pacemaker: a proposal (author's transl)].

We feel more and more the necessity to have an antiarrhythmic device able to interrupt a tachycardia. Unfortunately, at the present time, an implantable antiarrhythmic device isn't available. Personalized devices are used; these, in spite of useful results in single case, present some limitations for the standardization. Through positive preliminary results, we propose an antiarrhythmic device able to allow the automatic research of the interruption zone by tachycardia cycle "scanning". This device, which utilizes the radiofrequency as synchronizing and stimulating mean, permits the long-term treatment of re-entry tachycardia.

Arrhythmias, Cardiac↗
PubMed1980

Review of 119 cases of cervical interbody fusion by Cloward's method.

The long term results (not less than two years) of 119 out of 178 operations for cervical interbody fusion by Cloward's technique, performed at the Istituto Ortopedico Toscano between 1965 and 1978, are presented. The great majority of cases were cervical and root pain due to postero-lateral disc prolapse. In this group of cases the results were classified as excellent in 60 per cent of cases. The results were also rewarding in central disc prolapse with cord compression syndromes. They were less satisfactory in cervical spondylosis and in myelopathy due to spondylosis. In these groups, some arrest of the symptoms was achieved, but no effective regression. One indication for Cloward's operation is post-traumatic instability following trauma, or after biopsy and evacuation of lesions of the vertebral bodies.

Adult↗
PubMed1980

Intracardiac electrogram parameters, electrode surface area and pacer input impedance: their correlations.

Small surface area electrodes are accused of sensing defects which were related to alterations that they induce in the endocardiac electrograms. Since several factors affect the cardiac signal coming from electrode to sensing circuit, i.e. electrode surface area, electrode-tissue interface, pacemaker input impedance and sensing amplifier pass-band, Authors present their studies performed on 252 implanted electrodes of various type. Study was carried out by connecting in parallel to the recorder a variable resistor in order to simulate different pacer input impedances. The results showed a significant reduction in RS amplitude when recorder was paralleled with resistor values lower than 40 K. Slew rates showed a similar behaviours since RS steep tract did not change his duration with load, while total QRS duration is reduced. High speed analysis has shown that the RS segment is not linear in about 40% of cases: the main tract is used for calculations. The most significant attenuations and distortions of endocardial electrogram were observed with smallest electrodes and lowest resistances parallel connected: in these cases the sensing impedance at the electrode-tissue interface appears to be between 3 to 5 K ohms. The results suggest that the most of the alledged sensing faults experienced in the past were probably due to small tip electrodes connected to low input impedance generators or to impending failure situations. The AA. conclude that the main question does not concerne a true electrode inefficiency but a wrongly chosen pacemaker-electrode combination, i.e. small tip electrode connected with old generator models. To avoid the evaluation error, it would be instrumental that the pacemaker manufacturers would specify input characteristics of their generators. So, the implanting clinician becomes able to exactly evaluate the true signal arriving to the sensing circuit by connecting in parallel with the recorder input a resistor whose value approximates the input resistance of the generator to be implanted.

Cardiac Pacing, Artificial↗
PubMed1979

Automatic "scanning" by radiofrequency in the long-term electrical treatment of arrhythmias.

The use of programmed electrical stimulation in the long term treatment of re-entry tachycardia offers encouraging perspectives. Among the others proposed, the "scanning" system seems to be the most effective. However, an implantable stimulator with these features is not yet available and, thus, a temporary external lead is required. These difficulties have been overcome by utilizing radiofrequency to synchronize and stimulate. An implantable device was therefore designed which is triggered by the patient and automatically searches the interruption zone of the tachycardia by exploring the R-R cycle. The external transmitter, which can produce one or two synchronized impulses, is programmed to scan the R-R cycle with progressive steps of 5 or 10 ms; when tachycardia is interrupted, further stimulation is inhibited. The implanted module connected to an endocavitary lead does not have any power supply and, therefore, is very small. The efficacy of this method has been demonstrated in 4 patients with supraventricular tachycardia (3 with WPW syndrome) resistant to conventional pharmacologic therapy.

Chronic Disease↗