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Biomedical subjects

G Barletta

Publications and source records attributed to G Barletta.

At least 55 records · Page 3Linked to original sources

Impaired cardiovascular autonomic response to passive tilting in cirrhosis with ascites.

The autonomic regulation of cardiovascular function was evaluated in 15 cirrhotic patients with ascites and in 13 healthy subjects by the autoregressive power spectral analysis (PSA) of the intervals between adjacent R waves of the electrocardiogram (RR) interval and arterial pressure variability. Total power, low frequency (LF; index of the sympathetic activity of the heart and circulation), and high frequency (HF; index of vagal tone to the heart) components of the RR interval, systolic, and diastolic arterial pressure were evaluated in the supine position and during passive tilting, together with plasma norepinephrine levels. In the supine position, no significant differences in the PSA data were observed between the control subjects and cirrhotic patients, who had higher plasma norepinephrine levels. In healthy subjects, tilting was associated with an increase in the LF of the RR interval and arterial pressure and a decrease in the HF of the RR interval. In contrast, patients with cirrhosis showed a decrease of both LF and HF. Consequently, the LF/HF ratio significantly increased in healthy subjects, whereas it was unchanged in cirrhotic patients. The LF component of the diastolic pressure also decreased during tilting in cirrhotic patients. Plasma norepinephrine increased after tilting in both groups. These results indicate that the autonomic response to passive tilting is impaired in cirrhotic patients with ascites at both the cardiac and vascular levels, as a result of an altered sympatho-vagal balance, with reduced sympathetic predominance. These alterations occurred despite an appropriate response to the tilting of plasma norepinephrine, pointing to a receptorial or postreceptorial site of the autonomic impairment.

Adult↗

Left-ventricular diastolic dysfunction during pneumonectomy--a transesophageal echocardiographic study.

Left-ventricular dysfunction, with acute increase in capillary pulmonary pressure, can unexpectedly develop in patients submitted to pneumonectomy. In order to study the morphofunctional modifications induced by pneumonectomy on the left cardiac chambers, we performed intraoperative transesophageal echocardiography (TEE) in 8 patients (7 males, mean age 66 years) undergoing pneumonectomy for lung cancer. No patient had any cardiac involvement before surgery. The opening of the pericardium was associated with a slight paradoxical movement of the basal interventricular septum. After ligature of the pulmonary artery, the interventricular septum changed its geometry, losing the normal curvature and becoming rectilinear. These changes were related to an increase in right-ventricular (RV) dimensions. In all patients the pulmonary vein flow-profile (pulsed Doppler) showed an increased turbulence, associated with a reduced amplitude (5 patients) or an inversion (3 patients) of the second systolic component and with the development of mild mitral regurgitation (color Doppler). These changes disappeared at the end of intervention, before chest closure. No alteration in left-ventricular systolic function was found. These results suggest that the altered geometry of the interventricular septum, mainly due to acute RV overload, induces a transient left-ventricular diastolic dysfunction, associated with mild mitral regurgitation.

Aged↗

Quality of life in patients with intermittent claudication: relationship with laboratory exercise performance.

In patients with peripheral arterial disease, limitation of exercise capacity will reduce the level of everyday physical activity and affect the quality of life. This study was designed (1) to examine the health-related quality of life of patients with intermittent claudication, and (2) to verify whether treadmill performance is related to the patient's perceived ability to function in the community. In 251 patients with intermittent claudication and 89 matched normal subjects, quality of life was assessed by a general health index questionnaire, the McMaster Health Index Questionnaire (MHIQ), which covers three dimensions of life (physical, social and emotional function). The maximal walking capacity of intermittent claudication patients was measured by the treadmill test. When controls were compared to intermittent claudication patients using the MHIQ, it was found that intermittent claudication patients showed a significant (p < 0.01) impairment of 'general health' and lower scores for physical (0.90 +/- 0.17 vs 0.65 +/- 0.17; p < 0.01), social (0.71 +/- 0.11 vs 0.63 +/- 0.12; p < 0.01) and emotional (0.75 +/- 0.17 vs 0.65 +/- 0.15; p < 0.01) function. Age, gender and work status had a significant impact upon health scores in several areas. Treadmill performance did not correlate with social or emotional function, whereas there was a small but significant relationship between maximal walking capacity and physical function scores (r = 0.197; p < 0.01). This study suggests that impairment in quality of life experience by patients with intermittent claudication poorly correlates with the reduced exercised capacity assessed by the treadmill test. Therefore, the evaluation of medical and surgical treatment of intermittent claudication should include the administration of a questionnaire for quality of life assessment.

Aged↗

Regional myocardial performance of non-ischaemic zones remote from anterior wall left ventricular aneurysm. Effects of aneurysmectomy.

The aim of this work was to investigate the effects of resecting a post-infarction left ventricular anterior aneurysm on the kinetics of the non-ischaemic inferior wall, remote from the healed lesion. Thirteen patients, with an anterior post-infarction aneurysm and a normal right coronary artery who underwent aneurysmectomy with endoventricular circular patch plasty reconstruction, had a complete haemodynamic study before and shortly after surgery. The shape of the left ventricle was quantitatively analysed by calculating the regional curvature at 90 points of the angiographic outlines (30 degrees right anterior oblique projection). Segmental wall motion was studied by means of the centreline method and by constructing pressure-length loops from the endocardial movement of 18 chords intersecting the left ventricular inferior contour and by simultaneously tracing the high-fidelity left ventricular pressure. Analysis of pressure-length regional loops showed a complex pattern of abnormal contraction and relaxation in the non-ischaemic inferior regions at baseline; after surgery such abnormalities decreased significantly and tended to revert to normal in many cases. Left ventricular shape in the inferior region was abnormal in 10/13 patients in that there was negative curvature at the interface between the aneurysm and the inferior wall that was corrected to positive after surgery. Regional inferior wall motion and global ejection fraction significantly improved after surgery in these 10 patients. The three patients whose global ejection fraction did not improve showed no inferior negative curvature pre-operatively, nor did they show an increase in inferior wall motion. The results indicate that regional function and shape in inferior, non-ischaemic regions, remote from an anterior aneurysm, are abnormal but potentially correctible if the abnormal mechanical burden imposed on the wall is relieved.

Aged↗

Cardiovascular effects of brain natriuretic peptide in essential hypertension.

We evaluated the cardiovascular effects of pathophysiological plasma levels of brain natriuretic peptide in seven patients with mild to moderate essential hypertension by performing equilibrium radionuclide angiocardiography at baseline and during brain natriuretic peptide infusion at increasing doses (4, 8, 10, and 12 pmol/kg per minute for 20 minutes each). Brain natriuretic peptide induced a progressive reduction of left ventricular end-diastolic volume (from 107.5 +/- 10.3 to 89.0 +/- 11.0 mL at the end of all infusion periods) and end-systolic volume, whereas stroke volume did not show any significant change (from 64.9 +/- 5.9 to 62.7 +/- 7.8 mL). Cardiac output, arterial pressure, and peripheral vascular resistance did not change significantly. The lack of effects on systemic hemodynamics was probably due to compensatory activation of the sympathetic nervous system, as indicated by the significant increase in plasma norepinephrine levels (from 1.75 +/- 0.18 to 2.19 +/- 0.21 nmol/L), heart rate (from 68 +/- 6 to 81 +/- 6 beats per minute), peak ejection rate, and peak filling rate. These results indicate that brain natriuretic peptide, at the pathophysiological plasma concentrations reached in this study, influences cardiovascular homeostasis mainly by reducing cardiac preload.

Aged↗

Acute effects of physiological increments of brain natriuretic peptide in humans.

To investigate the effects of physiological increases in plasma brain natriuretic peptide concentration in humans, we studied six healthy volunteers who received incremental infusions (0.25 pmol/kg per minute in the first hour and 0.50 pmol/kg per minute in the second) of synthetic human brain natriuretic peptide-32 in a placebo-controlled, crossover study. Peptide plasma levels were 1.69 +/- 0.39 pmol/L at baseline and rose 1.5- and 3-fold with the lower and higher doses, respectively. These values were within the normal range and also comparable to those reported in patients with mild essential hypertension. The urinary excretion rate of cGMP also increased during brain natriuretic peptide infusion, indicating stimulation of natriuretic peptide receptors. Peptide administration induced a significant 1.7-fold increase in urinary sodium excretion without affecting renal plasma flow (para-aminohippurate clearance), glomerular filtration rate (creatinine clearance), and urine flow rate. Fractional proximal sodium reabsorption (lithium clearance method) was unchanged, and fractional distal sodium reabsorption significantly decreased. Brain natriuretic peptide caused no changes in arterial pressure, heart rate, hematocrit, and serum proteins, but it exerted an inhibitory effect on the renin-aldosterone axis, as indicated by the significant 50% or more decrease of plasma renin activity and urinary excretion rate of aldosterone. These results suggest that brain natriuretic peptide may be involved in the overall regulation of body fluid and cardiovascular homeostasis in humans, mainly through its natriuretic and endocrine effects.

Adult↗

Increased production of nitric oxide by neutrophils and monocytes from cirrhotic patients with ascites and hyperdynamic circulation.

An increased release of nitric oxide (NO), a powerful vasodilating agent, has been proposed to play a role in the pathogenesis of vasodilation and hyperdynamic circulation associated with advanced cirrhosis. We evaluated NO synthase (NOS) activity in peripheral leukocytes of 12 cirrhotic patients and 9 healthy subjects together with plasma endotoxin levels and systemic hemodynamic (by a noninvasive echocardiographic method). NOS activity was evaluated by (1) measuring the capacity of isolated polymorphonuclear cells (PMNs) and monocytes to convert [3H]arginine to [3H]citrulline; (2) measuring the ability of neutrophils and monocytes to inhibit thrombin-induced platelet aggregation and to increase guanosine 3'-5'-cyclic monophosphate content in coincubated platelets, an expression of NO release from these cells. Both neutrophils and monocytes from cirrhotic patients produced significantly higher amounts of [3H]citrulline than cells obtained from healthy subjects (P < .001 and P < .02 for neutrophils and monocytes, respectively) and were more effective than control cells in inhibiting platelet aggregation (P < .05 and P < .001, respectively for 2 x 10(6) cells) and in increasing guanosine 3'-5'-cyclic monophosphate content in coincubated platelets (P < .05 and P < .001, respectively). The anti-aggregating activity expressed by leukocytes has a pharmacological profile similar to that described for NO, because it increased after addition of superoxide dismutase, a superoxide anion scavenger, and markedly decreased after inhibition of nitric oxide synthesis with NG-monomethyl-L-arginine (L-NMMA) and NG-nitro-L-arginine-methyl ester (L-NAME). Cirrhotic patients had significantly higher plasma endotoxin levels (P < .001) and cardiac index (P < .01) when compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Cardiovascular autonomic dysfunction in normotensive awake subjects with obstructive sleep apnoea syndrome.

Cardiovascular autonomic function in normotensive awake patients with obstructive sleep apnoea syndrome was studied in 21 normotensive (mean age 48 +/- 14 years), drug-free men with obstructive sleep apnoea syndrome. Cardiovascular reflex tests with continuous blood pressure monitoring and biochemical indices were performed the morning after a standard polygraphic sleep recording. A group of 20 age-matched (mean age 49 +/- 19 years) normal subjects was used as controls. The obstructive sleep apnoea syndrome patients showed higher heart rate and noradrenaline plasma levels (p < 0.05) at rest and a higher blood pressure response to head-up tilt (p < 0.01), suggesting sympathetic overactivity. Respiratory arrhythmia, baroreflex sensitivity index and Valsalva ratio were significantly lower in the obstructive sleep apnoea syndrome group (p < 0.01) whereas the decrease in heart rate induced by the cold face test was significantly higher (p < 0.05) showing a blunting of reflexes dependent on baroreceptor or pulmonary afferents with normal or increased cardiac vagal efferent activity. These abnormalities in autonomic regulation may predispose obstructive sleep apnoea syndrome patients to cardiovascular complications like hypertension and cardiac arrhythmias.

Adult↗

Left ventricular shape changes induced by aneurysmectomy with endoventricular circular patch plasty reconstruction.

Aneurysmectomy with left ventricular (LV) patch plasty reconstruction for anterior post-infarction LV aneurysm is usually followed by favourable haemodynamic results. The aim of this work was to describe the changes in LV shape induced by the intervention and to correlate them to the pre-operative data and to the surgical results. Twenty-two patients submitted to aneurysmectomy with this technique underwent a haemodynamic study before and 10-15 days after the intervention. Segmental wall motion was studied by the centreline method. LV shape was analysed by calculating the regional curvature of angiographic outlines (RAO 30 degrees projection). Results showed an improvement in LV pump function in 17 patients, which appeared mainly due to increased systolic shortening of the inferior wall. The intervention-induced modifications of LV geometry were characterized by: (1) marked reduction in end-diastolic volume, (2) shift of the angiographic apex counterclockwise, towards the aortic corner, (3) disappearance of the rim with negative curvature corresponding to the infero-apical border of the aneurysm, where the inferior wall resumed a normal outward convexity. No significant difference was found between the pre-operative haemodynamic data of patients who improved after surgery and those who did not. The presence of a rim of negative curvature at the infero-apical border of the aneurysm was the only pre-operative sign with a predictive value for the surgical outcome.

Aged↗

Alterations in left ventricular shape in patients with angina and single-vessel coronary disease.

BACKGROUND: Left ventricular shape alterations, apparently independent of acute ischaemia or previous myocardial infarction, have been described in patients with stable angina. Our previous observations had been made in a group of patients with multivessel coronary disease; it was therefore not possible to establish a clear-cut anatomical relationship between the location of ischaemia and the changes in left ventricular contour. The aim of this work was to extend the previous observations by analysing left ventricular shape in patients with angina and single-vessel coronary disease, in whom the potentially ischaemic region can be easily localized. METHODS: Fifty-eight patients with stable or unstable angina were retrospectively selected if they had single-vessel disease, normal regional and global function and no previous myocardial infarction: 37 had a critical stenosis (more than 75% diameter reduction) of the left anterior descending artery and 21 had a critical stenosis of the right coronary artery. Patients with left ventricular hypertrophy or any other obvious cause of myocardial dysfunction were excluded. All patients underwent haemodynamic study. Left ventricular global shape was evaluated by calculating eccentricity and circular indices; regional curvature was measured at 90 points along the angiographic contours (right anterior oblique projection) by applying a windowed Fourier analysis. Results were compared with those obtained in 16 normal subjects. RESULTS: Patients had significant diastolic alterations in left ventricular shape, which assumed a more rounded aspect than normal. Regional curvature was significantly altered at several points pertaining to the anterior, apical and inferior segments. The pattern of changes in regional curvature was about the same in the left anterior descending and right coronary artery groups, with the involvement of regions supplied by angiographically normal arteries, although the extent of alteration was greater in patients with stable, chronic angina (more than 6 months) and in patients with stenosis of the left anterior descending artery. CONCLUSIONS: Patients with angina, no previous myocardial infarction and normal systolic function had left ventricular shape abnormalities either in the potentially ischaemic or in the remote zones. The mechanism leading to these changes is still speculative.

Adult↗

Dipyridamole angina: a specific symptom of severe multivessel disease.

BACKGROUND: Several studies have indicated that ischemia induced by dipyridamole is frequently associated with angina or ischemic ST-segment depression and that it occurs mainly in patients with three-vessel disease, those with collateral vessels, or those with both. METHODS: In order to analyze the diagnostic relationships among them, we studied 227 consecutive patients who underwent coronary angiography and dipyridamole-thallium scintigraphy. RESULTS: A perfusion defect was found in 134 patients. Of these, 88 patients (66%) showed no significant ECG modifications or angina; 46 (34%) had a transient ST-segment depression, which was associated with typical angina ('dipyridamole angina') in 12. These 12 patients had three-vessel disease with intercoronary collateral circulation. Among the 134 patients with coronary critical stenoses and a positive thallium-dipyridamole test, collateral vessels were detected in 91 (68%). CONCLUSION: Dipyridamole angina, occurring during a positive dipyridamole-thallium test, is usually a manifestation of severe coronary stenoses with collateral circulation. However, as a diagnostic symptom it is characterized by high specificity but low sensitivity.

Aged↗

Left ventricular remodeling in chronic aortic regurgitation.

Left ventricular (LV) shape in chronic volume overload due to aortic regurgitation is commonly described as rounder than in normal subjects. This statement derives from observations of qualitative nature or based on the measure of eccentricity index. We analyzed LV shape and function in 16 normal subjects (N) and in 24 patients with chronic pure aortic regurgitation (AR), without coronary artery disease or associated mitral regurgitation. LV cavity geometry was quantitatively evaluated from end-diastolic and end-systolic outlines obtained in 30 degrees RAO angiographic projection, by calculating: 1. the eccentricity and circularity indexes, 2. the regional curvature at 90 equidistant points using a windowed Fourier series approximation of contours, in which the number of harmonics and filter-window were locally chosen in order to minimize the reconstruction errors and to maximize the smoothness of the curve, 3. by measuring the length of the anterior and posterior hemi-perimeter of LV outlines and 4. by performing a Fourier analysis of LV contours. Neither eccentricity nor circularity indexes were adequate to differentiate shape abnormalities, whereas Fourier geometric analysis indicated abnormalities of shape in AR. Regional curvature showed that diastolic outline of AR had a greater curvature of the anterobasal, anterolateral and inferoapical regions and a lower curvature of the anteroapical one. Systolic outline showed a greater curvature of the inferoapical region and a lower curvature of the anteroapical one.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Effects of positive inotropic stimulation (post-extrasystolic potentiation) on non-uniformity of left ventricular contraction in patients with coronary artery disease.

In patients with chronic coronary artery disease, post-extrasystolic potentiation (PESP) slightly worsens relaxation, increasing the constant tau of ventricular pressure decay. However, it does not negatively influence left ventricular (LV) diastolic filling. To our knowledge, no data are available on the effects of PESP on segmental relaxation in chronic coronary artery disease. The effects of PESP on the LV pressure-volume (P/V) relationship and on segmental pressure-length loops (P/L) were studied in eight patients with coronary artery disease submitted to LV angiography. P/V loops were constructed by means of frame-to-frame analysis of ventriculograms and simultaneous high-fidelity LV pressure tracings; P/L loops were calculated by the endocardial movement of 45 chords intersecting the LV outline (centreline method). PESP was produced by programmed stimulation during ventriculography. P/V and P/L loops were studied in basal conditions and after PESP.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Early hemodynamic results of left ventricular reconstructive surgery for anterior wall left ventricular aneurysm.

To assess the efficacy of left ventricular (LV) reconstruction after aneurysmectomy, 35 consecutive patients with anterior LV aneurysm were studied before and after surgery. Surgical technique was performed by applying a circular patch after aneurysmectomy to maintain a "more physiological" LV cavity. Myocardial revascularization was performed in all but 1 patient concurrently. Global perioperative mortality was 4.8%. LV filling pressure and volumes and regional wall motion were assessed before and after surgery. The major indication for surgery was angina; 8 patients were in New York Heart Association class III/IV. The results showed a significant decrease in end-diastolic volume index (from 120 +/- 55 ml/m2 to 76 +/- 22 ml/m2, p less than 0.001), end-systolic volume index (from 74 +/- 44 ml/m2 to 40 +/- 18 ml/m2, p less than 0.001) and end-diastolic pressure (from 17 +/- 7 mm Hg to 13 +/- 5 mm Hg, p less than 0.05). Ejection fraction significantly increased (from 39 +/- 13% to 49 +/- 15%, p less than 0.001). LV wall motion significantly improved in all but the anterobasal region; the extent of LV asynergy significantly decreased after surgery. Six of the 35 patients had a deterioration of postintervention ejection fraction (from 44 +/- 14% to 34 +/- 9%). They had no reduction in LV volumes and no improvement in wall kinetics. It is concluded that LV reconstruction after aneurysmectomy induces significant early improvement of global and regional LV function in most patients; postoperative functional improvement is mainly related to the increase in inferior LV wall motion.

Female↗

Synergistic action of postextrasystolic potentiation and diperdipine on left ventricular wall motion abnormalities in coronary heart disease.

The effects on left ventricular function of postextrasystolic potentiation and the dihydropyridinic calcium antagonist diperdipine, alone or in combination, were studied in 14 patients with coronary heart disease by means of two consecutive left ventricular angiographies. To ensure the reproducibility of coupling intervals of the extrasystolic and postextrasystolic beats, the heart was paced during both angiographies. Results showed that postextrasystolic potentiation and diperdipine improved left ventricular ejection fraction to the same degree, but the mechanisms of such an improvement were different and consisted, respectively, of a positive inotropic effect associated with an increase in preload and a slight increase in preload coupled with a marked decrease in afterload. Diperdipine did not abolish the inotropic component of postextrasystolic potentiation, and a combination of the two interventions had additive effects on the improvements in left ventricular ejection fraction and regional wall motion analyzed by the centerline method. Ventricular segments that were normokinetic or hypokinetic during the control basal cycle responded equally to postextrasystolic potentiation and to diperdipine, whereas the former intervention alone had no significant effect on akinetic segments. Diperdipine restored the responsiveness of akinetic segments to postextrasystolic potentiation, a finding that, although it remains to be confirmed by independent techniques, may be interpreted as a possible consequence of improved calcium metabolism or coronary flow in ischemic but still viable myocardium. However, it is concluded that the calcium antagonist revealed a contractile reserve in most of the severely asynergic areas, which would have otherwise been judged to be irreversibly damaged on the basis of the unresponsiveness to postextrasystolic potentiation alone.

Calcium Channel Blockers↗

[Analysis of regional kinetics of the left ventricle by integration of morphologic data].

Regional left ventricular (LV) curvature analysis is a useful tool to assess the pathomorphological changes in LV shape which occur in different heart diseases. As LV shape changes follow regular trajectories, we used the curvature extrema and the normalized curvature variations as the features for identifying the movement of the borders during the cardiac cycle (curvature-motion method: CM). The regional curvature was calculated using a windowed Fourier series approximation of contours, in which the number of harmonics and filter-window were locally chosen in order to minimize the reconstruction errors and to maximize the smoothness of the curve. Analysis programs were tested on a series of ventricle-shaped contours, software generated. Left ventricular diastolic and systolic outlines obtained from RAO 30 degrees LV angiography in 24 patients with aortic insufficiency and in 16 subjects without heart disease were analyzed. Left ventricular curvature and regional wall motion were calculated in each subject. In respect to normal subjects, LV shape in aortic regurgitation definitely appears asymmetric because of the elongation of the anterior hemiperimeter and the prevailing expansion of the apical and anterolateral regions. These alterations in cavity geometry correlate to the decrease in pump function. According to these results wall motion analysis using the CM showed a greater extension of LV asynergy, while usual methods as the centerline or the radial one indicate a greater damage of the apical regions. Thus, the CM method seems to be a promising tool for wall motion analysis.

Angiocardiography↗

Abnormalities of left ventricular shape in patients with stable angina.

In this study, left ventricular shape was evaluated quantitatively by calculating the power spectrum and the regional curvatures of angiographic outlines as seen in the right oblique anterior projection. Two groups of patients were studied: 16 normal subjects and 16 patients with stable angina who were selected because of normal left ventricular function (normal left ventricular volumes, pressures, ejection fraction and no regional wall motion abnormality at subjective analysis of ventriculograms). The two groups did not differ in terms of mean age of the patients. Regional curvatures were calculated using the Frenet-Serret formula starting from the mitral corner (point 1) and extending to the aortic corner (point 90). The power spectrum was calculated by means of Fourier analysis. The ventricular shape during diastole of the patients with angina differed significantly from that of the normal group in that there was a greater posterobasal curvature; a lower curvature of the inferior wall showing an inward convexity; a greater parietal curvature of the inferoapical region and a minor curvature of the anterobasal region. The power spectrum differed significantly from that of the normal subjects. The 1st and 2nd harmonics were reduced and the 3rd, 4th, 5th and 6th ones increased. The end-systolic contour of the group of patients with stable angina showed a higher amplitude of the 3rd and 5th harmonics and a lower amplitude of the 1st, 2nd, 9th, 10th and 11th harmonics with respect to the group of normal patients. Regional curvatures showed significant differences between the two groups in the antero-basal region. These modifications of left ventricular shape in patients with stable angina did not appear to be related to age and/or heart rate; to abnormalities in hemodynamics and wall motion; or to acute ischemia. Abnormalities of shape in patients with stable angina, therefore, may indicate a remodeling of the left ventricle due to the structural effects (myocardial and/or interstitial) of chronic ischemia.

Adult↗