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Biomedical subjects

R P Dabizzi

Publications and source records attributed to R P Dabizzi.

At least 19 recordsLinked to original sources
PubMed1991

[Changes in the wall motion of left ventricle in dipyridamole-induced ischemic cardiopathy studied by nuclear magnetic resonance. A comparison with myocardial scintigraphy with 99mTc MIBI].

To investigate whether magnetic resonance imaging (NMR) can detect alterations in LV contractility during myocardial ischemia, ten patients aged 32-72 with coronary artery disease underwent ECG gated NMR performed at 0.5 Tesla after intravenous infusion of high dose dipyridamole (DP) (0.7 mg/Kg) over 5 minutes. LV contraction in planes similar to echo short axis projection was imaged under condition, 3' and 15-20' after infusion of DP by fast multiphasic imaging (FMI), multiple angulated cine-NMR sequence with a temporal resolution of 50 m/sec. Entity and size of perfusion defects after DP were determined by Tc 99m MIBI myocardial scintigraphy. In all patients changes in LV contractility appeared at NMR in the same site of perfusion impairments revealed with MIBI. In 8 patients the alterations lasted even more than 20' after the first NMR scan. NMR provides the opportunity of performing long-lasting assessment of ventricular wall contractility and enables to exactly localize the site and extension of kinetic changes as well as their time of onset and time duration.

Contrast Media↗
PubMed1990

Defective coronary prostaglandin modulation in anginal patients.

In order to investigate whether coronary vasodilating prostaglandins (PGI2 and PGE2) have a role in the pathophysiology of myocardial ischemia, 26 patients with angina pectoris and 23 control subjects (nonischemic patients) were studied by assessing coronary hemodynamics and prostaglandin formation in relation to sympathetic stimulation. Following a cold pressor test (CPT), coronary prostaglandin output markedly increased (p less than 0.001) and coronary vascular resistance (CVR) decreased (p less than 0.001) in all control subjects. In contrast, in anginal patients prostaglandins in the coronary sinus were undetectable and after CPT prostaglandin output did not increase, whereas CVR paradoxically increased (p less than 0.001). In control subjects the inhibition of coronary prostaglandin formation (by ketoprofen [1 mg/kg intravenously] or by aspirin [15 mg/kg intravenously]) caused a paradoxical increase of CVR following CPT (p less than 0.001). In anginal patients the inhibition of prostaglandins further exaggerated the increase of CVR after CPT (p less than 0.001). These results indicate that coronary vasodilating prostaglandin PGI2 and PGE2 play a role in modulating coronary vascular response to sympathetic stimulation induced by CPT. Their defective production in anginal patients may be responsible for the paradoxical increase in CVR following sympathetic stimulation.

Adult↗
PubMed1990

Associated coronary and cardiac anomalies in the tetralogy of Fallot. An angiographic study.

Numerous studies have pointed out the frequent association of tetralogy of Fallot (TF) with other cardiovascular defects and coronary tree anomalies. We found cardiac defects in 181 (68%) out of 265 patients with TF investigated by catheterization and selective coronary angiography. These anomalies were isolated in 88 cases (49%) and associated with others in 93 patients. In the case of an isolated anomaly associated with TF, the coronary tree was involved in 37.5% and the cardiovascular system in the remaining 62.5%; in the case of two anomalies, the coronary system was involved in 66% of the patients and the cardiovascular apparatus in 34%; in the case of three or more anomalies, the coronary arteries were involved in 71% and the cardiovascular system in 29%. Anomalies in the course and/or distribution of coronary arteries were present in 96 patients (36%): 10 had a single coronary ostium, 13 a left anterior descending artery arising from the right coronary artery, one a circumflex artery arising from the right coronary artery. Small fistulas between coronary arteries and the pulmonary artery were found in 20 cases; anastomoses between coronary and bronchial arteries or right atrium in 42. In 39 patients we observed a large conus artery or large anterior ventricular branches crossing the right ventricle. A right aortic arch was found in 56 patients (21%), a stenosis of the trunk and/or the peripheral pulmonary artery in 35 (13%) and pulmonary artery atresia in five. Four patients showed a complete atrioventricular canal, three an atrial septal defect (primum type) with cleft of the mitral valve, 61 (23%) an atrial septal defect (ostium secundum). Eleven patients had anomalies of the systemic venous return, 26 (10%) a patent ductus arteriosus. Four patients had valvular abnormalities. In our series, a large proportion of cardiac defects associated with TF consists of anomalies of coronary arteries. Our data confirm the usefulness of performing preoperatively routine coronary angiography in patients with complex congenital heart disease.

Abnormalities, Multiple↗
PubMed1988

[Aneurysms of the left sinus of Valsalva].

The acquired aneurysm of the left aortic sinus is a rare lesion. We observed two cases: the former ruptured in the left ventricle, the latter in the right ventricle. Both cases were identified by echocardiographic examination. The diagnosis was confirmed by the cardiac catheterization and aortography and then at cardiac surgery. In the latter case the diagnosis of rupture was done using Doppler technique. Our experience indicates that, at least in selected cases, the diagnosis of aneurysm of Valsalva sinus and that of rupture are possible by means of two-dimensional and Doppler echocardiography.

Adult↗
PubMed1979

Hemodynamic effects of nitroglycerin.

The authors have studied the hemodynamic effects of sublingually administered nitroglycerin (NG). Obtained data indicate that the response to NG is time-dependent. A first phase, lasting about 2 minutes, is characterized by a reduction of total systemic resistance (TSR) and an increase of cardiac output (CO), without significant variations of left ventricular filling pressure (FP) and blood pressure (BP). A modest increase of heart rate (HR) is observed. The second phase is characterized by a reduced FP and later, after 5 minutes, of BP. Subsequently HR increases to a greater degree, CO decreases and TRS presents a variation toward control values.

Female↗
PubMed1979

[Distribution and anomalies of coronary arteries in tetralogy of Fallot (author's transl)].

Anomalies in the course and distribution of coronary arteries may complicate the surgical correction of tetralogy of Fallot (TF). With the aim of preventing possible serious, and even lethal, cardiac events caused by the injury of aberrant vessels, 119 patients with TF were subjected to selective coronary angiography. Apart from demonstrating anastomoses between the coronary and bronchial arteries in 31 cases, small fistulas between the coronary arteries and pulmonary artery (in 14 cases) and hypoplasia of the entire coronary tree in 1 case, this investigation revealed anomalies in the origin of coronary branches in 11 cases. In some cases the first septal branch was absent and the diagonal branches were poorly developed. An injury to the coronary system, following the closure of the interventricular septal defect, may possibly explain the onset of a "left anterior hemiblock" after total correction of TF. Selective coronary angiography in small children presents no riskes provided it is correctly performed. In our cases no complications arose.

Adolescent↗
PubMed1979

The cardiac electrophysiological effects of nifedipine.

A study was carried out on the electrophysiological effects of a sublingually administered antianginal drug: nifedipine (20 mg). The results show a significant shortening of sinus cycle length from 925 +/- 249 msec to 810 +/- 245 msec, (p less than 0.005) and the disappearance of some interpolation and echo zones. There are no significant effects on the other evaluated parameters of sino-atrial and AV-node function. In one case, during atrial pacing, a second-degree, Wenckebach type, A-V block was present only before nifedipine. The following conclusions were reached: 1. nifedipine has no significant electrophysiological effect on the human heart; 2. the electrophysiological effects observed are probably indirect and related to the vasodilating effect of the drug; 3. the absence of direct cardiac electrophysiological actions may be useful in patients suffering from coronary artery disease and presenting disturbances in the formation and/or conduction of the cardiac impulse.

Adult↗
PubMed1978

[Dynamic geometry of the left ventricle. Relaxation and elasticity indices].

A study was made of 34 patients with valve defects or arterial hypertension and a haemodynamic picture of left ventricle pressure or volume load. Echocardiography and haemodynamic investigated-established the size and mass of the left ventricle and also enabled its indices of contractility, relaxation and distensibility to be determined. The series was divided in accordance with the dynamic geometry of the left ventricle. In concentric hypertrophy, telediastolic rigidity increased in proportion to ventricular thickness and mass. In eccentric forms and ventricular dilatation, diastolic distensibility was reduced in cases with a high filling pressure. The relaxation values bore no relationship to distensibility and telediastolic compliance. The relaxation rate in protodiastole diminishes in proportion to functional depression of the left ventricle.

Cardiac Catheterization↗