Search

The Widely scalable Mobile Underwater Sonar Technology (WiMUST) project is an H2020 Research and Innovation Action funded by the European Commission. The project aims at developing a system of cooperative autonomous underwater vehicles (AUVs) for geotechnical surveying and geophysical exploration. The paper describes the main objectives of the project, gives an overview of the methodologies adopted to achieve them, and summarizes the work done in the first year of R&D work. [ABSTRACT FROM AUTHOR]

The presence and the characteristics of left ventricular diastolic dysfunction in mild to moderate systemic hypertension were evaluated in 13 normotensive subjects (Group I), in 12 hypertensive subjects without (Group II) and 28 with (Group III) LV hypertrophy who underwent two-dimensional Doppler echocardiographic study. Among Group III patients, a subset (n = 12) with a dilated left ventricle was identified. Diastolic filling parameters were impaired in Group III patients while, in Group II, they were intermediate between Groups I and III. In all Group III patients normalized peak filling rate (nPFR) correlated directly with mean velocity of circumferential fibre shortening (mVCF) (r=0·55; P<0·001) and inversely with left ventricular mass index (LVM) (r=−0·60; P<0·001), left ventricular end-diastolic diameter (LVIDd) (r= −0·63; P<0·001), LV peak systolic stress (LVWST) (r=− 0·64; P < 0·01). A separate analysis showed that these correlations were also present in patients without left ventricular dilation; in the subset with left ventricular dilation nPFR correlated only with LVWST (r= −0·73;P<0·01), but not with LVM, m VCF, L VIDd. Thus, left ventricular hypertrophy is one of the major determinants of diastolic dysfunction in hypertensives; other factors influence nPFR values in hypertensive patients when the left ventricle dilates. [ABSTRACT FROM PUBLISHER]

Besides its effects on water balance, arginine vasopressin (AVP) increases peripheral vascular resistance and decreases cardiac output, mainly by decreasing heart rate. The current study was designed to evaluate cardiac performance in patients with central diabetes insipidus (CDI), focusing on the acute effects of desmopressin replacement withdrawal and its subsequent reinstatement in patients with CDI. Twelve patients with CDI and 12 sex- and age-matched healthy subjects entered the study. All patients were receiving treatment with intranasal desmopressin at standard doses. All patients and controls were assessed for water balance, by measuring plasma osmolality and total body water, anterior pituitary function, heart rate, systolic and diastolic blood pressure. Left ventricular (LV), end-diastolic and end-systolic diameters (LVEDD, LVESD) and volumes (LVEDV, LVESD), end-diastolic and end-systolic interventricular septum thickness (EDIVST, ESIVST) and posterior wall thickness (LVEDPWT, LVESPWT), and mass (LVM) were measured by echocardiography. Moreover, LV systolic function was assessed by measuring the ejection fraction (EF), the fractional shortening (FS), the Suga index, the stroke volume and the cardiac output, while LV diastolic function was assessed by measuring early (M1) and late (M2) maximal transmitral blood flow velocities, the ratio between M1 and M2, the mitral deceleration time (MDT) and the isovolumetric relaxation time. All parameters were assessed in the patient group 24 h after discontinuing treatment with nasal desmopressin (baseline study) and 1 week after re-starting replacement treatment, while in the control group before (baseline study) and after 1-week of a nasally administered placebo. At baseline, compared to controls, patients with CDI had increased plasma osmolality (P < 0.01), plasma ACTH (P < 0.01), serum (P < 0.01) and urinary cortisol (P < 0.01) levels, and heart rate (P < 0.05), and decreased total body water (P < 0.05). Systolic and diastolic blood pressure and the other anterior pituitary hormones were similar in patients and controls. At echo-cardiography, EDIVST (P < 0.05), ESIVST (P < 0.01), LVEDPWT (P < 0.05) and LVESPWT (P < 0.01), EF (P < 0.01), Suga index (P < 0.05), FS (P < 0.05), M2 (P < 0.01) and IRT (P < 0.05) were significantly higher while LVESD (P < 0.01), LVESV (P < 0.01), LVEDD (P < 0.05), LVEDV (P < 0.05), M1 (P < 0.05), and M1/M2 (P < 0.01) were significantly lower in patients than in controls. LVM, stroke volume and cardiac output, were similar in patients and controls. In the patient group, after 1 week of replacement treatment with desmopressin, all echocardiographic parameters were normalized, except IVT, LVPWT and the diastolic parameters that were still abnormal compared to controls. No difference was found in any of the parameters in the control group one week after placebo administration. Patients with central diabetes insipidus have increased heart rate and left ventricular contractility, and impaired diastolic function. The altered heart rate and left ventricular contractility, reversible after desmopressin replacement, is likely to be due to stimulation of sympathetic nervous activity, induced by the hypovolemia associated with arginine vasopressin deficiency. Conversely, the impairment of diastolic function, persistent after desmopressin replacement, probably relates to a stable impairment of the left ventricular compliance.

Elderly patients with acute myocardial infarction (AMI) have a higher subsequent mortality than younger ones, yet the reasons for this adverse prognosis are poorly understood. We compared the clinical course and the prognosis of 163 patients aged 40 to 69 years with 112 patients older than 70 years. During hospitalization period 15.9% of younger and 37.5% of older patients died; at 1 year follow-up the cardiac mortality rate was 8.7% in younger and 12.9% in older patients. In elderly patients a greater prevalence of female gender, diabetes mellitus, anterior myocardial infarction, atrial fibrillation and a greater incidence of heart failure and shock were observed. Multivariate stepwise analysis identified shock and heart rate greater than or equal to 90 bpm at the time of admission as the most important prognostic variables for in-hospital mortality in both groups; heart failure (Killip class II and III) was significant in younger patients, while non Q wave myocardial infarction correlated with a better prognosis in elderly. In elderly patients who survived AMI, predischarge Holter monitoring showed higher frequency and complexity of ventricular arrhythmias, and radionuclide angiography lower left ventricular ejection fraction (E.F.) values. In these patients no difference was found in E.F. values despite myocardial infarction sites. At 1 year follow-up E.F. less than 40% and ventricular arrhythmias (3-4 Moss grading system) were significantly related to prognosis in younger patients, while E.F. less than 40% and clinical signs of heart failure in elderly. Therefore, low E.F. and heart failure account for a worse prognosis in elderly patients, while ventricular arrhythmias in younger ones. The results of this study support aggressive management even in elderly patients following AMI to preserve left ventricular function. In elderly patients a large use of antiarrhythmic drugs is not recommended because of low prognostic value of ventricular arrhythmias.

The incidence and prognostic significance of silent myocardial ischemia were assessed in 175 patients who survived a first acute myocardial infarction (AMI). This was done by means of a 24-hour continuous ECG monitoring which was performed before discharge. Twenty-six out of 175 patients (14.8%) showed one episode or more of S-T segment depression; 19 of these reported no pain at all while the other 7 reported both painful and painless episodes. A total of 65 ischemic episodes were registered; of these 53 (81.5%) were painless and 12 (18.5%) were painful. No difference in the duration of ischemic episodes or in heart rate at the onset of S-T segment depression was detected for painless or painful episodes. The S-T segment depression episodes showed a peak in the morning but were higher in the afternoon and this circadian pattern was statistically significant both with regard to duration (p less than 0.05) and to the number of episodes (p less than 0.05). Cardiac death occurred in 5 of the 26 patients (19.2%) with S-T segment depression during continuous ECG monitoring, and in 5 of the 149 (3.4%) without S-T segment depression (p less than 0.01). In patients with ischemia duration greater than 60 min/24 hours, the mortality rate was higher (p less than 0.05). No cardiac events (unstable angina, non-fatal re-infarction, balloon angioplasty and/or coronary by-pass) occurred in 117 out of 149 patients (78.5%) without ST-segment depression, while these events were observed in 13 out of the 26 patients (50%) with ischemic episodes during Holter monitoring (p less than 0.01). Sensitivity and specificity of S-T segment depression was respectively 29.3 and 89.5% for cardiac death and cardiac events considered together.(ABSTRACT TRUNCATED AT 250 WORDS)

The safety and efficacy of a new dihydropyridine calcium antagonist, nisoldipine, were studied in comparison with propranolol, in patients with stable angina. Following 2 weeks of wash-out of the current therapy and 1 week of placebo, 26 patients underwent two cycloergometer tests, before and 2 hours after placebo administration. Subsequently, 10 mg of nisoldipine twice daily or 40 mg of propranolol three times daily were administered over a 4 week period, in a randomized single-blind fashion. Cycloergometer tests were performed after 2 and 4 weeks, before and two hours after drug administration. Two patients, one out of the nisoldipine group and one out of the propranolol, were considered drop outs. Statistical analysis of the results was performed using two-way variance analysis. With both drugs, time to 1 mm exercise induced ST-segment depression (p less than 0.01), time to angina (p less than 0.01), and exercise tolerance (p less than 0.01) improved furthermore, ST-segment and heart rate recovery time decreased (p less than 0.01). Rate-pressure product values at ischemic threshold and at peak exercise remained unchanged with nisoldipine, while significant reductions were observed with propranolol (p less than 0.01). Maximum ST-segment depression was reduced (p less than 0.01) with both drugs and a further improvement was observed two hours after drug administration (p less than 0.05). At submaximum work-load, rate pressure product values and ST-segment depression were improved with both drugs (p less than 0.01); this improvement was more evident two hours after drug administration. No significant side effects were observed with either drug.(ABSTRACT TRUNCATED AT 250 WORDS)

In our study we compared the prognostic significance of clinical variables, laboratory results and different classification models of ventricular ectopic beats recorded by means of a pre-discharge 24 hour ambulatory electrocardiographic monitoring, in 210 survivors of acute myocardial infarction. In addition a full multivariate analysis of the factors affecting survival time was carried out using Cox's proportional hazards (multiple) regression model. Multivariate stepwise discriminant analysis identified hypertension, congestive heart failure assessed by Killip class, and the grading system for ventricular arrhythmias as the most important prognostic variables. When Moss grading system for ventricular arrhythmias was used, the relative risk was a superior as heavy Moss grading system (Moss 2 vs Moss 1 and Moss 3-4 vs Moss 1, relative risk = 1.2 and 3.6 total death, respectively). Furthermore, the hazard ratio of Moss grading system was higher utilizing as comparison patients without ventricular ectopic beats (relative risk = 1.7 for Moss 2 and 5.3 for Moss 3-4) than patients with ventricular ectopic beats less than one/hour (relative risk = 1.2 for Moss 2 and 3.7 for Moss 3-4). Thus, in survivors of acute myocardial infarction, a rational and useful ventricular ectopic beats categorization includes both frequency and the presence or absence of malignant characteristics.

The relationship between 31 variables and survival after acute myocardial infarction was evaluated in 432 patients discharged from our Coronary Care Unit from 1975 to 1984. The patients were followed for 1 to 105 months and either univariate and multivariate analysis were performed. For end-point death the significant variables (p less than 0.05) selected by the univariate analysis were: age, diabetes, smoke, heart rate at recovery, supraventricular arrhythmias, cardiac failure and complex ventricular arrhythmias either during recovery, either after discharge and finally spontaneous angina after hospital discharge. Meanwhile, for the end-point cardiac death age, smoke and supraventricular arrhythmias were not yet significant while arterial pressure at recovery and effort angina after hospital discharge were. Multivariate analysis identified cardiac failure during recovery, diabetes, complex ventricular arrhythmias before and spontaneous angina after discharge as independent variables contributing to total mortality: effort angina was a further significant one relatively to cardiac death. Thus, our study points out the importance of multivariate survival analysis when evaluating the relationship between survival after discharge for the effect of other prognostic factors. Moreover, providing identification of high risk cohorts permits appropriate interventions designed to lessen risk.

We studied left ventricular diastolic function by equilibrium gated radionuclide angiography in patients as follows: 75 with acute myocardial infarction (AMI), 35 with anterior or anteroseptal necrosis (Group A) and 40 with inferior, inferolateral, or posterior necrosis (Group I). The ejection fraction (EF) was lower in Group A than Group I (41.9 +/- 2.5 vs. 57.1 +/- 2.0%, p less than 0.001), as was peak diastolic filling rate normalized to end diastolic volume (PDFR-EDV/sec) (1.9 +/- 0.1 vs. 2.4 +/- 0.1 EDV/sec, p less than 0.05). PDFR normalized to stroke volume was similar in both groups. An excellent linear correlation was found between EF and PDFR-EDV/sec in the total study population. Isovolumic relaxation period (IRP) was beyond our upper normal value of 94 msec in 64% of patients and it was shorter in Group A than I (95.8 +/- 12.7 vs. 147.0 +/- 13.6 msec, p less than 0.05). The presence of shorter IRP in Group A than in I is probably a result of an earlier mitral valve opening as a consequence of higher left atrial pressure.