European heart journal
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European heart journal · Dec 1990
Continuous cardiac output monitoring by pulse contour during cardiac surgery.
Most pulse contour methods are unreliable under changing haemodynamic conditions, because no corrections are made for pressure-dependent compliance and reflections of pressure waves. The pulse contour method of Wesseling includes such corrections. Four thermodilution measurements equally spread over the ventilatory cycle were used to calibrate and evaluate this pulse contour method. ⋯ COth, (r = 0.94). The standard deviation for the difference between the methods against the mean of the methods was 10.6%. We concluded that the corrected pulse contour method estimates cardiac output accurately, even when heart rate, blood pressure, and total peripheral resistance change substantially.
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Cardiac output estimation is an important and much needed measurement for assessing patients in heart failure. In hypertension, it is vital for understanding the haemodynamic basis of the disease and the mode of action of drugs. Measurements of blood pressure and cardiac output provide the only means of estimating peripheral resistance. ⋯ Doppler velocimetry is the most promising technique, but it requires complex computer analysis and, as yet, can reliably be used only to measure changes in cardiac output in an individual. The technique has been assessed against the electromagnetic flowmeter in man and gives reasonable accuracy and repeatability. Echocardiography and impedance cardiography are not yet satisfactory for clinical use; neither are the radionuclide methods, apart from the 'first pass' method, but this also needs further verification.
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European heart journal · Nov 1990
Exercise testing for assessment of the significance of ST segment depression observed during episodes of paroxysmal supraventricular tachycardia.
Sixteen patients who had manifested ST segment depression during episodes of paroxysmal supraventricular tachycardia (PSVT) were studied with exercise testing in order to detect coronary artery disease and myocardial ischaemia. No ST segment depression was observed during exercise testing in 15 out of the 16 patients tested. Paroxysms of supraventricular tachycardia associated with ST segment depression occurred during exercise testing in three cases. ⋯ These results suggest that coronary artery disease and myocardial ischaemia are not involved in the genesis of ST segment depression during PSVT. Tachycardia per se may be the cause of ST segment depression by altering the slope of phase 2 of the ventricular action potential. Retrograde atrial activation may also induce ST segment shifts in some of the cases.
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European heart journal · Nov 1990
Comparative StudyDoppler echocardiographic study of the consequences of aging and hypertension on the left ventricle and aorta.
The aims of the study were (1) to describe the consequences of aging and hypertension on left ventricular geometry and physical properties of the aorta, (2) to study interactions between some physical properties of the aorta and left ventricular geometry in normal (NT) and hypertensive patients (HT) using Doppler echocardiography. Forty-five healthy normotensive subjects (age range 21 to 84 years) and 20 untreated sustained hypertensive patients (age range 20 to 70 years) were studied. We measured (1) resting arterial blood pressure with a Dinamap, (2) left ventricular radius (r), thickness (th), mass (LVM), th/r ratio and aortic diameter (AD) by M-mode echocardiography with 2D control, and (3) pulse wave velocity (PWV) in the descending thoracic aorta from aortic velocity tracings recorded by pulsed wave Doppler in the isthmus and near the diaphragm. ⋯ The Doppler echocardiographic method of PWV measurement is feasible, reproducible and gives similar results to other methods, especially the invasive haemodynamic method. Doppler echocardiography is an adequate method to study left ventricular geometry and some physical properties of the aorta. It can be used to assess the consequences of aging and hypertension on both left ventricle (concentric hypertrophy) and aorta (increase of aortic stiffness).
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European heart journal · Feb 1990
Aortic valve area evolution after percutaneous aortic valvuloplasty. A prospective trial using a combined Doppler echocardiographic and haemodynamic method.
The aortic valve area was serially evaluated in 45 patients, mean age 78 years, suffering from severe aortic stenosis who underwent percutaneous aortic valvuloplasty. The aortic valve area was calculated from haemodynamic data prior to and immediately after the procedure using the mean gradient. Serial determinations of the aortic valve area were also obtained 1 day before, 1 day after and 2 months after valvuloplasty from the thermodilution cardiac output and Doppler echocardiography mean left ventricle-to-aorta gradient. ⋯ In conclusion, in this study one third of the patients submitted to percutaneous aortic valvuloplasty had no objective improvement in calculated valve area or early restenosis after 2 months. Functional improvement was observed in one third of the patients. Immediate re-estimation of the aortic valve area from haemodynamic data at the end of the procedure may not reflect the actual effect of valvuloplasty on the aortic orifice.