Biomedical subjects

A Saadjian

Publications and source records attributed to A Saadjian.

At least 55 records · Page 3Linked to original sources

PubMed1977

[Use of sodium nitroprusside in cardiology].

Sodium nitroprusside (SNP) is rarely used in cardiology. It is reserved traditionally for severe episodes of arterial hypertension. Certain states of refractory heart failure represent new indications for use, which implies a double haemodynamic monitoring system: continuous control of systemic blood pressure by intra-arterial catheterization; control of pulmonary pressure and repeated measurements of cardiac output. Prolonged treatment requires continuous biological monitoring of toxicity and careful control of kidney function. As a moderator of blood pressure, SNP is remarkably effective. The hypotensive effect is immediate, readily reversible and generally tachyphylaxis is not observed. The effect of SNP on cardiac work is one of double load reduction: mainly a reduction in afterload or pressure and systemic resistance and a reduction in preload or pressure of ventricular filling. In this respect, SNP can be used effectively for severe cases of heart failure intractable to traditional cardio-stimulatory and diuretic treatments and stemming from diverse causes: acute stage of myocardial infarction, ventricular dilatation, mitral papillary syndrome, heart failure, either subacute or chronic, of various causes. As a rule, the immediate results are positive. Taking the patient off the drug can be difficult and may cause a return to the previous haemodynamic situation.

Adult↗

PubMed1977

[Hemodynamic profile of acute myocardial infarction as a function of electrocardiographic localization].

The haemodynamic profiles of 147 cases of myocardial infarction investigated within 30 hours of the clinical onset were studies in relation to the topography of the necrosis on the ECG: there were 36 inferior (I), 29 postero-inferior (PI), 22 antero-septal (AS), 38 antero-lateral (AL), 15 deep septal (DS), and 7 strictly posterior or lateral (PL). Simultaneous recordings of the diastolic pulmonary arterial pressures and the left ventricular diastolic pressures (pre-and post-a) have shown different degrees of correlation with the topographical site. The correlation found in AS, AL and I necrosis are clearer with respect to the pre-a. The PI necroses show no correlation. Graphs of left ventricular function as well as an analysis of the various other parameters show that the DS, the AL, and to a lesser extent the PI are associated with the grossest depression of left ventricular function. A study of the amplitude of the "a" wave also shows that the effect of infacts of the free wall of the left ventricule on the compliance is greater. A study of right ventricular function as well as the correlations between the pulmonary and right atrial pressures confirms the presence of right ventricular disfunction in DS and PI necroses. Impaired left ventricular function, impaired right ventricular function, and disorders of compliance seem to be the determining factors in changing the haemodynamics in the various ECG sites of infarction.

Acute Disease↗

PubMed1976

Cardiac output measurement by thermodilution: methodologic problems.

In clinical practice, thermodilution technique for cardiac output measurement is generally applied to the right heart (injection of a saline cold bolus in the right atrium, temperature measurement downstream in the pulmonary artery). This technique is well adapted to repetitive measurements using a single catheter. However, its validity is dependent on several methodologic requirements: quantitation of the indicator, control of the catheter's dead-space effect, conservation and mixing of the cold bolus, accurate measurement of small thermal gradients. Calculations from the thermal dilution curve must be adapted to possible baseline shifts. All these different methodologic aspects are studied. Several solutions (heat exchanger, automatic injection, calculation method) are proposed. Comparison between an automatic thermodilution device and dye dilution has been performed successfully.

Cardiac Catheterization↗

PubMed1976

[Approach to the prognosis of myocardial infarct from the initial hemodynamic examination].

Hemodynamic investigations (right and left heart catheterization, cardiac output measurement) were performed in 132 patients with acute myocardial infarction. Retrospective study of the first 100 patients allowed determination of prognostic indices. A new statistical method is proposed which was used prospectively in the 32 following patients and resulted in an error of prediction of about 3 per cent. The establishment of prognosis from hemodynamic data is a necessary condition prior to new therapeutic approaches of cardiac failure in acute myocardial infarction.

Adult↗

PubMed1975

Mechanical aspect of the heart sound emission.

The present paper deals with a physical study of the relation between the phonocardiogram and left ventricular pressure (LVP) fluctuations. Fourier analysis comparison of the two signals-simultaneously recorded either on pathologic human hearts or during experiments on dogs-does not point out an obvious relation between the phonocardiogram and a linear combination of the first pressure derivatives.-A mechanical model of the heart enabling the description of the sound emission mechanism provides a qualitative relation between the phonocardiogram and LVP fluctuations: the acceleration of the thoracic area is equal to the product of LVP by a time function depending on the mechanical properties of the muscle. - A theoretical thoracic acceleration obtained by transformation of the experimental LVP is compared with the experimental phonocardiogram through linear filtering analysis. The theoretical signal is in good agreement with the experimental one.

Fourier Analysis↗

PubMed1975