Biomedical subjects

G Barletta

Publications and source records attributed to G Barletta.

At least 37 records · Page 2Linked to original sources

PubMed1999

Simultaneous dobutamine stress echocardiography and 99mTc-tetrofosmin three-head single-photon emission computed tomography in patients with suspected coronary artery disease.

OBJECTIVES AND BACKGROUND: Dobutamine stress echocardiography and 99mTc-tetrofosmin single-photon emission computed tomography (T-SPECT) were performed simultaneously in subjects in whom coronary artery disease (CAD) had been proven or excluded at coronary angiography, in order to establish their accuracy and agreement in the diagnosis of CAD, and in localisation and evaluation of the extension of ischaemia. No simultaneous comparison of the two techniques has been performed previously. METHODS: Seventy patients (50 men, mean age 63 +/- 10 years, 21 with previous myocardial infarction) underwent simultaneous dobutamine stress echocardiography and T-SPECT. The response to stress was blindly and independently analysed, adopting a 16-region segmentation and referring to the three major coronary arteries. RESULTS: Sixty-two patients (agreement 89%, kappa = 0.776) and 91% of left ventricular regions (kappa = 0.665) were classified concordantly, independently of the presence or absence of previous myocardial infarction (90%, kappa = 0.740 versus 91%, kappa = 0.589, respectively). At coronary angiography, 47 patients had CAD (disease prevalence 67%). The sensitivity and specificity of stress echocardiography for the diagnosis of anterior descending, circumflex and right coronary artery disease were 62, 78 and 73%, and 79, 79 and 83%, respectively. The corresponding values for T-SPECT were 70, 75 and 78%, and 94, 79 and 90%, respectively. CONCLUSIONS: These data indicate a high concordance between wall motion abnormalities observed using stress echocardiography and perfusion defects observed using T-SPECT; their sensitivity in identifying critical stenoses was similar. Inadequate stressor amounts, and less frequently hyperdynamic regional response may reduce the accuracy of stress echocardiography, while dobutamine effects on coronary flow may prevent T-SPECT from showing subtle flow maldistributions in the presence of worsened wall motion.

Adult↗

PubMed1999

Effects of reconstructive surgery for left ventricular anterior aneurysm on ventriculoarterial coupling.

OBJECTIVE: To investigate left ventricular elastance (Emax) and effective arterial elastance (Ea) in postinfarction left ventricular aneurysm and evaluate their role in left ventricular function improvement after endoventricular circular patch plasty (EVCPP). Ventriculoarterial coupling has never been studied in these patients. PATIENTS: 22 consecutive patients (49 to 73 years) with left ventricular anterior aneurysm. METHODS: Haemodynamic studies were done before and two weeks after EVCPP. Ventriculography was performed during atrial pacing (100 beats/min). Pressure/volume loops were analysed and derived parameters measured. Emax was estimated by applying the "single beat" method. Ea was calculated as end systolic pressure/stroke volume. RESULTS: Left ventricular volumes and Ea decreased after surgery: end diastolic volume index from mean (SD) 155 (53) to 106 (29); end systolic volume index from 112 (51) to 62 (30) ml/m2 (both p < 0.0001); Ea from 1.65 (0.70) to 1.39 (0.41) mm Hg/ml (p = 0.04). Ejection fraction and Emax increased, without significant changes in stroke volume and work. The decrease in Ea was directly correlated with its preoperative value. The time interval between left ventricular pressure upstroke and peak systolic pressure decreased, from 237 (39) to 191 (41) ms (p < 0.0001), paralleling morphological changes in pressure tracings. CONCLUSIONS: After EVCPP, ventriculoarterial coupling improves because of the fall in Ea caused by end systolic pressure reduction. The improvement is related to aortic pressure waveform changes and improved relaxation.

Aged↗

PubMed1999

In vivo evidence that endogenous dopamine modulates sympathetic activity in man.

Dopamine receptors type 2 (D2)-like receptor blockers cause an increase in the norepinephrine response to intense physical exercise. However, during intense physical exercise, D2-like antagonists also cause an increase in the epinephrine response, which itself might cause an increase in plasma norepinephrine through the activation of beta2 presynaptic receptors. Therefore, we evaluated the effect of domperidone, a D2-like antagonist, on the norepinephrine response to physical exercise in 6 Addison patients (3 were adrenalectomized and 3 had adrenal tuberculosis). In these patients, the norepinephrine increase observed during exercise was significantly higher after the administration of domperidone than a placebo (F=4,328; P<0.001). Because peripheral plasma norepinephrine does not reflect the sympathetic tone to the heart accurately, we evaluated the effect of domperidone administration (20 mg orally) on the sympathovagal balance, which was measured by the ratio between the high- and low-frequency components of heart rate variability, in 9 normal volunteers in the supine and sitting positions. When compared with placebo, domperidone caused a significant increase in the low/high frequency ratio (P<0.05) in the sitting position without modifying basal and stimulated norepinephrine plasma levels or blood pressure. These data support a role for endogenous dopamine in modulating norepinephrine release by human sympathetic nerves in vivo.

Adrenal Gland Diseases↗

PubMed1998

Effects of clonidine on power spectral analysis of heart rate variability in mild essential hypertension.

Patients with essential hypertension often show alterations of the autonomic nervous system. We evaluated the sympathetic and parasympathetic drive to the heart in 12 mildly hypertensive patients and 9 healthy subjects by power spectral analysis of heart rate variability. All subjects underwent measurements of RR interval, low (LF) and high frequency (HF) components of heart rate variability, LF/HF ratio and blood pressure in the resting and sitting positions, both before and after oral clonidine (300 microg), a central sympatholytic agent. In the supine position before clonidine, hypertensive patients had higher blood pressure and lower HF values than healthy subjects. Clonidine induced increases in RR interval and HF in both groups, while LF and LF/HF ratio decreased in healthy subjects, but not in hypertensive patients. On assuming the sitting position, both groups showed reductions in RR and HF and increments in LF and LF/HF. In healthy subjects, the response to the postural challenge was unaffected by clonidine. In contrast, hypertensive patients showed no changes in LF and LF/HF ratio, and a significantly lower decrease in HF. These differences were probably due to the existence of two subsets of patients, one exhibiting similar responses to clonidine as healthy subjects, and the other showing no appreciable response to the drug. These results suggest that hypertensive patients have an altered sympatho-vagal balance to the heart, which can be unmasked by clonidine. This phenomenon should be taken into account to achieve a better control of the overall cardiovascular risk of hypertensive patients.

Administration, Oral↗

PubMed1998

Post-ejection thickening as a marker of viable myocardium. An echocardiographic study in patients with chronic coronary artery disease.

The study aim was to assess whether post-ejection thickening (PT) is an useful marker of viable myocardium in patients with chronic coronary artery disease. Twenty-three patients with critical coronary stenoses were submitted to dobutamine and dipyridamole stress-echocardiographies and dipyridamole-early-redistribution 201Tl SPECT within 15 days from coronary arteriography. They were selected for the presence of PT in segments that could be optimally studied by M-mode echocardiography and were hypo-akinetic in basal conditions. PT (occurring between end-ejection and mitral valve opening) was found in 58% of dysfunctional, critically perfused regions. Ninety-eight percent of the regions with PT and 6% of those without PT improved during low-dose dobutamine stress-echocardiography. Segments with PT had, respectively, higher and lower SPECT early-redistribution thallium activity than dysfunctional segments without PT and normokinetic regions. Therefore, regions with PT were viable and had a moderate decrease in coronary perfusion. Akinetic segments without PT did not show any inotropic reserve. After revascularization almost all the segments with PT improved. In conclusion, PT is a pattern of myocardial contraction easily detected by M-mode echocardiography in the clinical setting. If the results of this study are further confirmed, PT may become a sign for the recognition of myocardial viability.

Adult↗

PubMed1998

Effects of exercise on natriuretic peptides and cardiac function in man.

We evaluated cardiac function and the plasma levels of atrial (ANP) and brain (BNP) natriuretic peptides during bicycle (B) and hand-grip (HG) exercises in eight healthy males. Each test was preceded by a control protocol in resting conditions. Left ventricular (LV) function (echocardiography) was evaluated during both exercises. Atrial function was assessed only during HG. Plasma ANP significantly increased during B (+236%) and HG (+77%), while there was a significant trend towards higher plasma BNP levels during B (+41%) and HG (+30%) than during the corresponding control tests. Plasma ANP correlated with heart rate in both tests, with left atrial volume, pulmonary vein flow systolic fraction and mitral flow E/A ratio in HG; BNP in both test correlated with LV dimensions and function. These data suggest that during exercise the cardiac release of ANP and BNP is differently regulated and related to changes in left atrial and LV function, respectively.

Adult↗

PubMed1998

Cardiac autonomic modulation and incidence of late potentials in essential hypertension: role of age, sex, ventricular mass and remodeling.

The influence of age, sex, left ventricular hypertrophy (LVH) and geometry on the autonomic activity to the heart was investigated in 96 hypertensive out-patients (53 men, mean age 53 +/- 9 years) and 39 healthy subjects (19 men, mean age 43 +/- 1 years). Using 24-h Holter recordings, time [the standard deviation of all RR intervals (SDNN) and the square root of the mean of the squared differences between adjacent normal RR intervals (RMSSD)] and power spectral analysis of RR intervals [Fast Fourier algorithm, low/high frequency (LF/HF) ratio] were calculated over 24 h, daytime (D) and nighttime (N) periods in all subjects. Signal averaged electrocardiogram was recorded in 50 patients to detect late potentials. Stepwise multiple linear regression analysis showed that the 24-h LF/HF ratio was influenced by age and sex, D-LF/HF by age and N-LF/HF by sex, a higher LF/HF ratio being found in younger patients and in men. These data suggest a more prominent sympathetic modulation of cardiac activity in these groups. No differences in RR period variations were observed between patients with or without LVH. Late potentials were observed in 10 patients, and did not correlate with any of the measured parameters.

Action Potentials↗

PubMed1998

Regional and temporal nonuniformity of shape and wall movement in the normal left ventricle.

Asymmetry of left ventricular (LV) shape and asynchrony of regional LV movement have been described in the normal human heart, but never correlated to each other. In 16 normal subjects, right anterior oblique ventriculography was used to obtain volumes, regional wall motion (centerline method) and curvature (windowed Fourier series approximation of contours) over the entire cardiac cycle. The apex had the greatest curvature, while the posterior wall had a negative end-diastolic curvature that decreased further at early-systole and became positive at end-systole. The anterior region had the greatest and the anteroapical region the least fractional shortening. Asynchrony was evident as a delayed contraction of the infero- and anteroapical regions, and as a greater rate of late-systolic shortening of the anterior wall than that of the apex. Shape changes and shortening were dyssynchronous in the apical regions where the greatest changes occurred at early diastole. Temporal and regional nonuniformity of shape and movement exists in normal subjects. Dyssynchrony between shape and regional contraction of the apical regions deserves further studies.

Adult↗

PubMed1998

Low-dose C-type natriuretic peptide does not affect cardiac and renal function in humans.

In experimental animals, C-type natriuretic peptide (CNP) has vasodilating, hypotensive, and natriuretic activities. The role of circulating CNP in the overall regulation of cardiac and renal function in humans is less defined, in both health and disease. We measured cardiac volumes, diastolic and systolic functions, systemic (Doppler echocardiography) and renal hemodynamics, intrarenal sodium handling (lithium clearance method), plasma and urinary cGMP, plasma renin concentration, and plasma aldosterone level in six healthy volunteers (mean age, 33+/-3 years) receiving CNP (2 and 4 pmol/kg per minute for 1 hour each) in a single-blind, placebo-controlled, random-order, crossover study. During CNP infusion, plasma CNP increased from 1.17+/-0.23 to 41.52+/-4.61 pmol/L (ie, 4- to 10-fold higher levels than those observed in disease states) without affecting plasma and urinary cGMP, cardiac volumes, dynamics of left and right heart filling, cardiac output, arterial pressure, renal hemodynamics, intrarenal sodium handling, sodium excretion, or plasma levels of renin and aldosterone. The finding that increments in plasma CNP within the pathophysiological range have no effects on systemic hemodynamics, renal function, or the renin-angiotensin system do not support the hypothesis that CNP may act as a circulating hormone in humans.

Adult↗

PubMed1997

Effect of propionyl-L-carnitine on quality of life in intermittent claudication.

A double-blind, dose titration study was designed to assess the efficacy of propionyl-L-carnitine in intermittent claudication. The effect on walking capacity was described in a previous article. This study reports on the effect on quality of life, assessed by the McMaster Health Index Questionnaire (MHIQ). After 24 weeks of treatment, the global MHIQ score did not show any difference from baseline in patients randomized to placebo (n = 102). Conversely, it increased from 0.59 +/- 0.12 to 0.64 +/- 0.12 in those taking propionyl-L-carnitine (n = 85). Analysis of variance showed a significant difference between treatments (p = 0.018). Stepwise multiple regression analysis identified baseline maximal walking capacity (cutoff point 250 m) as a predictor of treatment outcome. In patients walking < 250 m, propionyl-L-carnitine significantly improved physical function (p = 0.027), emotional function (p = 0.002), and global MHIQ score (p = 0.002) compared with placebo. Also, for maximal walking capacity, group difference significantly favored propionyl-L-carnitine (p = 0.009). In patients with baseline maximal walking capacity > or = 250 m, propionyl-L-carnitine did not affect the MHIQ scores, nor improve walking performance. These data indicate that propionyl-L-carnitine exerts beneficial effects on quality of life and walking performance in patients with more severely limited walking capacity.

Aged↗

PubMed1997

T-wave alterations at the onset of wall motion abnormalities during dobutamine echocardiographic stress test.

At the onset of wall motion alterations during dobutamine echocardiographic stress testing, a steeper increase in the overall T-wave amplitude in the precordial leads was observed in 17 patients with baseline normal wall motion, electrocardiogram, and critical coronary stenoses compared with 11 control subjects. Eleven patients with increasing T-wave amplitude had localized apical dyssynergy, whereas 6 patients with downward displacement of the ST segment had widespread wall motion alterations also located at the basal and midsegments.

Aged↗

PubMed1997

Altered cardiovascular responsiveness to active tilting in nonalcoholic cirrhosis.

BACKGROUND & AIMS: The hyperdynamic circulation of cirrhosis has been related either to plasma volume expansion (increased preload) or peripheral arterial vasodilation (reduced afterload). The aim of this study was to evaluate cardiovascular function in patients with nonalcoholic cirrhosis by echocardiography. METHODS: Nineteen patients with abnormal sodium handling (11 sodium excretors and 8 sodium retainers) and 15 healthy volunteers underwent echocardiographic evaluation of left ventricular end-diastolic volume index (LVEDVI) and left ventricular end-systolic volume index (LVESVI), left ventricular ejection fraction (LVEF), cardiac index (CI), mean arterial pressure, and systemic vascular resistance (SVR) during supine resting and after 5 minutes of standing. RESULTS: Supine patients had increased LVEF and CI and reduced LVESVI and SVR. LVEDVI was increased only in sodium excretors. Standing induced a decrease in LVEDVI in all subjects. Healthy volunteers maintained cardiovascular homeostasis by increasing LVEF and heart rate, whereas cirrhotic patients experienced a decrease in SVI and CI despite marked increments in heart rate, plasma renin activity, and plasma norepinephrine level. CONCLUSIONS: In patients with cirrhosis, the increased LVEF and reduced LVESVI while in a supine position point at reduced afterload as an important determinant of the hyperdynamic circulation. Evidence of an increased preload secondary to increased blood volume, indicated by a high LVEDVI and increased plasma atrial natriuretic peptide levels, was found only in sodium excretors. The altered response to active tilt in cirrhotic patients suggests an impaired myocardial contractility.

Adult↗

PubMed1997

Cerebral autoregulation in patients with cirrhosis and ascites. A transcranial Doppler study.

BACKGROUND/AIMS: Patients with cirrhosis and ascites usually show alterations of systemic hemodynamics and are thus prone to develop arterial hypotension, which might result in cerebral hypoperfusion if cerebral autoregulation is impaired. METHODS: We evaluated cerebral autoregulation in 15 patients with cirrhosis and ascites and 15 healthy subjects by monitoring mean blood flow velocity in the middle cerebral artery and arterial pressure during supine rest and passive tilting. RESULTS: Tilt provoked a drop of arterial pressure in both groups. Control subjects had a prompt recovery of mean flow velocity and a progressive recovery of arterial pressure, so that, after 120 s, both parameters had returned to baseline: at 20 s the recovery of flow velocity was faster (p<0.01) than that of blood pressure. By contrast, patients with cirrhosis had a delayed and incomplete recovery of both parameters (p<0.01 vs healthy subjects). In eight patients, the recovery of mean flow velocity paralleled that of arterial pressure, indicating an impaired cerebral autoregulation. These patients had a worse liver function, a higher cardiac index and lower peripheral resistance. CONCLUSIONS: Cerebral autoregulation is often impaired in patients with cirrhosis and ascites. These patients can develop cerebral hypoperfusion if arterial pressure falls abruptly.

Aged↗

PubMed1997

Parallel increase in carotid, brachial and left ventricular cross-sectional areas in arterial hypertension.

Few data have been published about the relation between the vessels geometry and development of left ventricular (LV) hypertrophy in patients with arterial hypertension. The aim of this study is to describe arterial and LV geometry changes due to mild-to-moderate arterial hypertension in an untreated hypertensive population. In 95 untreated patients with mild-to-moderate hypertension and 23 age- and sex-matched healthy normotensives, we measured the end-diastolic diameter and wall thickness of the left ventricle and the internal diameter and intimal-medial thickness (IMT) of carotid and brachial arteries. From these data, the cross-sectional areas (CSAs) of arterial and myocardial walls were calculated. Hypertensive patients were further subdivided on the basis of the presence of LV hypertrophy defined according to Devereux et al as anatomical LV mass >125 g/m. In hypertensive patients with hypertrophy, carotid and brachial CSAs increased, without significant changes in thickness/diameter ratio (arterial 'enlargement'), while the left ventricle developed 'concentric' hypertrophy. Arterial and LV CSAs showed a significant direct correlation with systolic blood pressure (BP). However, when data were corrected for BP, the correlation between the increase in arterial and LV CSAs became much improved than for the raw data. In conclusion patients with untreated mild-to-moderate hypertension, both carotid and brachial arterial walls showed an enlargement that was proportional to the development of LV hypertrophy. These results suggest that the effects of arterial hypertension on carotid, brachial and LV wall geometry have a common modulation.

Adult↗

PubMed1997

Power spectral analysis of heart rate and diastolic blood pressure variability in migraine with and without aura.

Autonomic function in migraineurs during headache-free periods was studied by means of cardiovascular reflexes and power spectral analysis of heart rate and diastolic blood pressure variability. We examined 56 patients: 37 suffering from migraine without aura and 19 from migraine with aura. Cardiovascular responses to the tilt test and Valsalva manoeuvre showed a normal function of the overall baroreceptor reflex arc. Normal heart rate responses to Valsalva manoeuvre and deep breathing suggested an intact parasympathetic function. Power spectral analysis of both heart rate and diastolic blood pressure variability in basal conditions and during orthostatic test showed similar sympathovagal interactions modulating cardiovascular control in migraine patients and in controls.

Adult↗

PubMed1997

Cardiovascular and renal effects of low-dose atrial natriuretic peptide in compensated cirrhosis.

OBJECTIVES: Patients with cirrhosis and ascites have high plasma levels of atrial natriuretic peptide (ANP). Pharmacological doses of this hormone usually worsen systemic hemodynamics of cirrhotic patients. We assessed whether ANP influences cardiovascular homeostasis and renal function in patients with compensated cirrhosis at plasma levels comparable to those observed in patients with cirrhosis and ascites. METHODS: Radionuclide angiocardiography was performed in eight compensated cirrhotic patients during placebo (three periods of 15 min each) and ANP infusion (2, 4, and 6 pmol/kg.min for 15 min each), together with appropriate blood and urine sampling, to evaluate left ventricular diastolic, systolic, and stroke volume, heart rate, cardiac output, arterial pressure, peripheral vascular resistance, creatinine clearance, urinary sodium excretion, plasma renin activity, plasma aldosterone, norepinephrine and hematocrit. RESULTS: The infusion increased plasma ANP up to levels (52.03 +/- 2.29 pmol/L) comparable with those observed in 35 patients with ascites (46.42 +/- 1.57 pmol/ L). This increment was associated with significant reductions in left ventricular end diastolic volume, stroke volume, cardiac index (from 3.7 +/- 0.7 to 3.1 +/- 0.5 L/min.m2, p < 0.05) and mean arterial pressure (from 96.7 +/- 6.5 to 88.5 +/- 9.5 mmHg, p < 0.05), while heart rate and hematocrit significantly increased. Peripheral vascular resistance did not change. These hemodynamic effects occurred despite significant increases in plasma renin activity and norepinephrine. ANP also induced increases in creatinine clearance, urinary sodium excretion, and fractional sodium excretion. CONCLUSIONS: Low-dose ANP affected cardiovascular homeostasis and renal sodium handling in compensated cirrhosis, suggesting that this hormone may be involved in the pathophysiology of systemic hemodynamic and renal functional abnormalities of cirrhosis.

Aldosterone↗

PubMed1997

A closed hole.

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Aneurysm, False↗

PubMed1997

Echocardiographic diagnosis of coronary sinus type atrial septal defect. A case report.

BACKGROUND: Coronary sinus type atrial defect is the result of an incomplete formation of the atriovenous fold. This is a rare anomaly that in a very few cases took advantage of echocardiographic diagnosis before surgery. We report on a case of coronary sinus type atrial septal defect diagnosed by means of transthoracic and transesophageal echocardiography. PATIENT: A 65 year old woman who was admitted to hospital for evaluation of dyspnea and pre-syncope. A diagnosis of secundum type atrial septal defect had been achieved few months before. METHOD DESCRIPTION: Color Doppler transthoracic echocardiography demonstrated evidence of left-to-right shunt through the coronary sinus-left atrium common wall, while transesophageal echocardiography showed a defect in the coronary sinus roof in its terminal portion, proximal to the atrial septum. At that level the shunt flow was demonstrated by the presence of a negative contrast after contrast injection. Both transthoracic and transesophageal contrast echocardiographies demonstrated the persistence of a left superior vena cava draining into the enlarged coronary sinus: the existence of a right-to-left shunt at the coronary sinus level suggested by transthoracic echocardiographic examination was not confirmed by transesophageal echocardiography. CONCLUSIONS: This is one of the few reported cases of coronary sinus type atrial defect diagnosed noninvasively and the diagnostic usefulness of both transthoracic and transesophageal echocardiographic approaches is stressed.

Aged↗