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Biomedical subjects

J Vojacek

Publications and source records attributed to J Vojacek.

6 recordsLinked to original sources

Nebivolol in the treatment of cardiac failure: a double-blind controlled clinical trial.

BACKGROUND: Nebivolol is a highly cardioselective long-acting beta-blocker with vasodilating properties, which acts in part via the endothelial L-arginine/nitric oxide pathway. As an antihypertensive drug it is effective in once-daily dosage. Nebivolol has previously been shown to improve left ventricular function in patients with cardiac impairment. METHODS AND RESULTS: This paper reports a double-blind randomized trial comparing, in patients with heart failure, once-daily nebivolol 2.5 or 5.0 mg (initiated in all at 2.5 mg) with placebo on a constant background of digitalis plus diuretic. There was with nebivolol no overall deterioration of cardiac function or cardiac symptoms, and especially not of exercise capacity, in comparison with placebo. One patient on nebivolol 2.5 mg developed hypotension and pulmonary edema, and one patient on nebivolol 5 mg, bradycardia. All the remaining patients continued with unchanged diuretic and digitalis dosage. Nebivolol was accompanied by a trend toward clinical and functional improvement; rather better results were obtained with 2.5 than 5.0 mg. CONCLUSIONS: In view of increasing interest in beta-blockade in heart failure, nebivolol merits further study in this context. The capacity of nebivolol to enhance endothelial nitric oxide production appears potentially attractive.

Adrenergic beta-Antagonists↗

An index of valvular regurgitation from a radionuclide bolus.

Mitral and aortic regurgitation was assessed from analysis of activity-time curves from right and left ventricles following the intravenous bolus injection of 99Tcm-labelled human serum albumin. The differences in the initial arrival times and the mean transit times for the ventricles were combined to provide an index of regurgitation. The mean index for 18 patients with good ventricular function and no regurgitation was -0.07 +/- 0.55 (SD) seconds. This was not significantly different from the mean value of 0.39 +/- 1.22 s obtained for 9 patients with left ventricular failure but no regurgitation. The indices for 16 patients with mitral or aortic regurgitation agreed well with the severity as assessed by contrast angiography. The mean indices for the mild, moderate and severe regurgitation groups were 2.62 +/- 1.13 s, 5.30 +/- 3.05 s and 10.15 +/- 3.62 s respectively.

Aortic Valve Insufficiency↗

Radionuclide determined pulmonary blood volume in ischaemic heart disease.

Most measurements of pulmonary blood volume have been based on the Stewart-Hamilton dye dilution principle and have required direct catheterisation of the cardiac chambers. Alternatively a precordial counter may be used to detect the composite right and left heart curves after an intravenous injection of radionuclide. We investigated the use of a gamma camera/computer system to determine the radionuclide dilution curves from individual cardiac chambers. Pulmonary transit time and pulmonary blood volume were measured in nine normal subjects, eight patients with angina pectoris but without heart failure, and 13 patients with ischaemic heart disease and left ventricular failure. Patients with heart failure had significantly greater (p less than 0.001) pulmonary blood volumes and pulmonary transit times than normal subjects or patients without heart failure. Reproducibility measurements of pulmonary blood volume, determined in 12 subjects, gave a coefficient of variation of 2.6%. The effect of posture on pulmonary blood volume was determined in six subjects lying supine and tilted at a 45 degree angle. A reduction in pulmonary blood volume in the tilted position was observed in each subject (p less than 0.005). This simple non-invasive measurement should allow more detailed assessment of physiological or pharmacological changes of the pulmonary vascular bed.

Blood Volume↗

Noninvasive Doppler ultrasound evaluation of aortocoronary bypass.

Using ultrasound method, aortocoronary bypass patency was determined by means of bidirectional Doppler's flowmeter. In 8 (3%) of 302 subjects without aortocoronary bypass was recorded diastolic signal which might distort the results of postoperative evaluation of graft patency. Two-hundred and ninety-seven patients with 330 aortocoronary bypasses were studied at the mean time of 8 months after operation. The graft patency was 84.5%. Comparison of 89 ultrasound findings with angiographic results established considerable specificity (90%) and sufficient sensitivity (77%). Reproducibility of this method was also good. The method is inexpensive and not time consuming. The advantages are also its safety and convenience for the patient. In the present level of development it can be used mainly as screening test at long-term follow-up of aortocoronary graft patency.

Angiography↗