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Biomedical subjects

C Contini

Publications and source records attributed to C Contini.

At least 55 records · Page 3Linked to original sources
PubMed1990

Atrial natriuretic peptide during different pacing modes in a comparison with hemodynamic changes.

The study investigates the response of atrial natriuretic peptide (ANP) to different cardiac pacing modes in comparison with hemodynamic changes. Ten patients underwent Swan-Ganz catheterization during pacemaker implant. Atrioventricular and ventricular pacing were performed consecutively at three pacing rate levels (80, 100, and 110 ppm). Blood samples were taken from the pulmonary artery for ANP determination, both basally and at the end of each pacing period. Concomitantly, mean pulmonary capillary wedge pressure (PCWP) and mean pulmonary artery pressure (PAP) were measured. Cardiac output (CO) was determined by thermodilution both basally and during the 110 ppm steps. During atrioventricular pacing, whereas no significant changes were observed for ANP, PCWP and PAP, CO increased significantly (P less than 0.0005). At the beginning of ventricular pacing hemodynamic parameters and ANP levels were comparable with those of baseline conditions. During subsequent ventricular pacing PCWP and ANP increased significantly at the 110 ppm rate step (P less than 0.05). PAP did not change significantly, whereas CO decreased in all cases (P less than 0.01). A positive correlation was observed between ANP and PCWP during ventricular (P less than 0.001), but not atrioventricular pacing. The results, while confirming the hemodynamic advantages of atrioventricular pacing, point to a major stimulation of ANP secretion during ventricular pacing. This fact, together with the observed drop in CO and the correlation between ANP and PCWP, suggest that the increase of ANP in ventricular pacing may be the expression of a compensatory mechanism to the hemodynamic disadvantages of atrioventricular asynchrony.

Aged↗
PubMed1990

Evaluation of rate-responsive pacemakers by transesophageal Holter monitoring of spontaneous atrial rate.

One of the most important problems in rate responsive (RR) pacing is the clinical experimental evaluation of the reliability of various sensors. In particular, it is difficult to test their sensitivity and specificity during daily activity of the patients. Atrial rate, when present and normal, is the most physiological marker of metabolic requirements, but sometimes it is impossible to analyze the P wave in ventricular paced rhythm during routinely performed tests (e.g., ergometric test and 24-hour Holter monitoring). During various physical activities, we monitored atrial electrograms on an esophageal lead on the first channel of a standard Holter tape recorder; on the second channel a surface ECG lead was recorded. We selected 10 patients with high grade heart block and normal sinus node function paced in RR-VVI mode. RR pacing was obtained using various sensors (body activity, blood temperature, spike-T interval, minute ventilation). The good quality of recording allowed an easy evaluation of atrial and ventricular rates. In four cases an appropriate increase in heart rate was documented; sensitivity threshold and/or rate response slope were reprogrammed when indicated. The pacing rate of one patient did not parallel the atrial rate during walking only. In three cases, we observed a delay in the ventricular rate increase, with ventricular rate decreasing at peak exercise despite further atrial rate increase. In the last two patients, we observed inappropriate pacing response; pacing rate increased later and to a lower level than the atrial one. This new method is applied easily and appears reliable to evaluate the response of RR pacemakers to individual metabolic needs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Ultrafiltration: a rational treatment for heart failure.

Patients with late-stage congestive heart failure with significant fluid overload respond well to ultrafiltration. The response is relatively long-standing and includes enhanced responsiveness to diuretics. Ultrafiltration is simple and highly cost effective. Furthermore, it possesses many advantages over massive or drastic pharmacological therapy. In the following paper, we report our own experience and review the world literature.

Blood Volume↗
PubMed1989

[Blood antigens and specific anti-core and anti-envelope antibodies as markers of the course of HIV infection].

The antigenemia and the patterns of antibodies to core protein (p24) and envelope glycoproteins (gp41, gp120) have been investigated in 81 patients with Human Immunodeficiency Virus (HIV) infection followed prospectively for 24 months. HIV antigen was detectable in 23 (28.4%) patients at entry to the study (13/13 with AIDS and 10/23 with ARC) and in 33 (40.7%) at the end (25/28 with AIDS, 5/12 with ARC e 3/14 with LAS). Anti-p24 were positive in 51 (63.0%) patients at the entry (26/30 symptomless, 13/15 with LAS e 12/23 with ARC) and in 41 (50.6%) at the end of the study (23/27 symptomless, 9/14 with LAS, 7/12 with ARC e 2/28 with AIDS). All patients were positive for anti-gp41 and showed no significant changes in the antibody titers during the two years of follow-up; by contrast, anti-gp120 was undetectable in most patients (26/28) with AIDS. Clinical progression in a high proportion of patients was associated with the appearance of HIV antigen, with the decline of anti-p24 titers and with no antibody reactivity to gp120 glycoprotein.

AIDS-Related Complex↗
PubMed1988

Long-term efficacy of oral encainide in frequent and repetitive ventricular arrhythmias.

The short- and long-term efficacy of oral encainide was studied in 14 patients with chronic high-frequency ventricular arrhythmias and in 14 patients with chronic frequent episodes of non-sustained ventricular tachycardia (NSVT). Encainide efficacy was assessed during a dose-titration period and in a 36-month follow-up also studying the drug effects on routine haematologic data and left ventricular function (LVF). During dose-titration, encainide caused a 78.3% decrease in the average hourly frequency of isolated PVC and a 96.1% reduction in NSVT episodes in the two groups of patients. On follow-up (11 patients in each group) the mean percentage reductions were 95.1% in isolated PVC and 99.7% in NSVT episodes. Encainide did not impair LVF as showed by the comparison of echocardiographic fractional shortening before and after 12 months of treatment. Minor adverse effects of encainide were dose-related visual disturbances in two patients. A major adverse effect was the appearance of sustained VT in one NYHA class IV patient. Oral encainide effectively reduces the frequency of PVC and NSVT, it does not impair left ventricular function and it is associated with infrequent minor side effects. Uncommon, but severe, side effects may appear in patients with marked impairment of left ventricular function.

Adolescent↗
PubMed1987

Immunoblot analysis of Salmonella typhi lipopolysaccharide (LPS) using typhoid sera.

Lipopolysaccharide (LPS) of Salmonella typhi has been analyzed by immunoblotting with pooled sera from typhoid patients. Pooled typhoid sera have recognized all the antigenic determinants of S. typhi LPS, giving a strong reaction with the repeating units on the O-side chains as well as with the core region. Cross-reacting antigens have been observed with the LPS of S. typhimurium and S. enteritidis, while no heterologous reactions were seen with the LPS of E. coli strains.

Cross Reactions↗
PubMed1987

[Ambulatory electrocardiography in the screening of patients with palpitations].

The role of 24 hour Holter monitoring in the screening of patients complaining of palpitations is reviewed. The term "palpitations", although not always unequivocally used, implies the presence of an arrhythmia. The clinical-instrumental correlation of an intermittent symptom is made possible by continuous electrocardiographic monitoring. Answers to be expected from a 24 hour Holter monitoring in order to achieve an early characterization of the arrhythmia are related to: site of origin, incidence, circadian distribution, prognostic stratification, events aggregation, presence of other asymptomatic abnormalities (rhythm, ST-T).

Arrhythmias, Cardiac↗
PubMed1987

[Technical ambulatory ECG innovations in performance evaluation].

Evaluating the performances of the instrumentation for Ambulatory ECG (AECG) analysis is a need largely recognized by both manufacturers and users. The most generally accepted method is the beat-by-beat comparison with annotated data bases, representing the different ECG abnormalities. Available data bases are aimed at arrhythmias detection evaluation, while it is recognized that the AECG ST-T changes detection has a great relevance in the analysis of ischemic heart disease. A concerted action of the European Community on Ambulatory Monitoring has been approved for achieving a comprehensive reference standard for assessing the quality of AECG instrumentation. The European project has been concentrated on the problem of ST-T analysis. An annotated data base is being developed with the contribution of european experts. A pilot study has been performed for establishing the criteria related to the development and annotation; particularly the definition of significant ST-T changes has been established. The data base will include 2-hour double channel AECG records, which contain at least one ST-T episode. Each record is annotated beat by beat according to the established scheme, identifying arrhythmic beats, rhythm changes, ST-T changes and noisy segments. A coordinating center has been established for interacting with the participating groups and for performing the operations related to the generation and management of the data base. For the time being 14 Groups of 8 Countries are participating to the annotation of the data base. A minimum number of 100 records is planned within June 1988.

Algorithms↗
PubMed1987

[Ambulatory ECG in the peroperative period].

The clinical recognition of perioperative myocardial necrosis represents one of the clue factors in the management of cardiac surgical patients (pts). This study was performed to determine whether there is any relationship between reperfusion ventricular fibrillation and/or ST-segment elevation and postoperative enzymatic release. Serum enzyme levels and ECG were monitored during and after cardiac operations in 23 pts (15 for valvular replacement and 8 for aortocoronary bypass graft). After aortic unclamping only 6 pts showed stable rhythm. Of the 17 pts who developed ventricular fibrillation 10 showed ST-segment elevation (83% of the 12 pts with ST-segment elevation). Although no significant difference was observed, pts with ST-segment elevation showed higher average enzyme (CK, CKMB) levels. Pts who had valvular replacement showed significantly higher serum CK and CKMB levels. Of the 4 pts who showed a second enzymatic peak, one died and another one presented complex ventricular arrhythmias. No correlation was observed between electrocardiographic data and post-operative enzymatic release. New theories concerning oxygen free radical generation during and after cardiopulmonary by-pass, with the related therapeutic perspectives, are discussed.

Cardiac Surgical Procedures↗
PubMed1986

Prognostic value of ventricular arrhythmias and transient ST-T changes after myocardial infarction: a two-year follow-up with ambulatory ECG recording.

The aim of this study is to evaluate the frequency and prognostic significance of ventricular arrhythmias (VA) and of ST-T changes found during 24-h ECG recording in patients who survived an acute myocardial infarction. Eighty-nine patients (2 females and 87 males) discharged from hospital after acute myocardial infarction were studied. Mean age was 52.2 years (SD +/- 10) with a range of 26-68. Serial observations were carried out at 1, 2, 3, 6, and 12 months after the acute event. Eight patients died during the first two years of follow-up, of these, 2 deaths were of noncardiac origin: one was due to gastric carcinoma and the other to pulmonary neoplasm. Of the 6 cardiac deaths, 4 were sudden and unexpected and 2 were due to reinfarction. Statistical analysis of the results obtained in the first three months of follow-up has not shown any significant correlation between pathologic patterns and cardiac death. In the second period we found a statistically significant relationship between cardiac death and multiform VPBs (p less than 0.05), CVA (p less than 0.05), and ST-T changes (p less than 0.05). More significant was the correlation between cardiac death and the presence at the same time of ST-T changes and multiform VPBs (p less than 0.01).

Adult↗