NT-pro-BNP levels in patients with acute pulmonary embolism are correlated to right but not left ventricular volume and function

SummaryN-terminal pro-Brain Natriuretic Peptide (NT-pro-BNP) is primarily secreted by left ventricular (LV) stretch and wall tension. Notably, NT-pro-BNP is a prognostic marker in acute pulmonary embolism (PE), which primarily stresses the right ventricle (RV). We sought to evaluate the relative contribution of the RV to NT-pro-BNP levels during PE. A posthoc analysis of an observational prospective outcome study in 113 consecutive patients with computed tomography (CT)-proven PE and 226 patients in whom PE was clinically suspected but ruled out by CT. In all patients RV and LV function was established by assessing ECG-triggered-CT measured ventricular end-diastolic-volumes and ejection fraction (EF). NT-pro-BNP was assessed in all patients. The correlation between RV and LV end-diastolic-volumes and systolic function was evaluated by multiple linear regression corrected for known con-founders. In the PE cohort increased RVEF (β-coefficient (95% confidence interval [CI]) –0.044 (± –0.011); p<0.001) and higher RV enddiastolic-volume (β-coefficient 0.005 (± 0.001); p<0.001) were significantly correlated to NT-pro-BNP, while no correlation was found with LVEF ( β-coefficient 0.005 (± 0.010); p=0.587) and LV end-diastolic-volume (β-coefficient –0.003 (± 0.002); p=0.074). In control patients without PE we found a strong correlation between NT-pro-BNP levels and LVEF ( β-coefficient –0.027 (± –0.006); p<0.001) although not LV enddiastolic-volume (β-coefficient 0.001 (± 0.001); p=0.418). RVEF (β-co-efficient –0.002 (± –0.006); p=0.802) and RV end-diastolic-volume (β-coefficient <0.001 (± 0.001); p=0.730) were not correlated in patients without PE. In PE patients, lower RVEF and higher RV end-diastolic-volume were significantly correlated to NT-pro-BNP levels as compared to control patients without PE. These observations provide patho-physiological ground for the well-known prognostic value of NT-pro-BNP in acute PE.

Nuklearmedizinische Shunt-Bestimmung beim Ductus arteriosus Botalli

ln 9 patients with patent ductus arteriosus, quantification of left-to-right shunt was performed with dye dilution curves after peripheral injection and with radionuclide ventriculography. The study was repeated within 7 days after successful transluminal occlusion of the ductus with an lvalon®-plug. Reproducubility of the method could be studied in one patient in whom reopening of the ductus occurred. Dye dilution curves were analyzed using the method of Carter et al. (2). Radionuclide ventriculography was performed as a combined first-pass and equilibrium study: effective stroke volume was derived from the first pass of the tracer through the heart; during the equilibrium phase left ventricular ejection fraction (EF) and left ventricular enddiastolic volume (EDV) were evaluated. The difference between total left ventricular stroke volume (product of EF and EDV) and effective stroke volume was taken as shunt volume. This volume as a fraction of total left ventricular-stroke volume resulted in percent left-to-right shunt. The sensitivity of the dye technique was 78%; a quantification of the shunt lesion was possible in 55% of all cases (shunt greater than 35%). The sensitivity of the radionuclide technique was 90%. The severity of the lesion could not be determined in one patient with a minimal shunt. After successful occlusion of the ductus, dye dilution curves normalized in all cases. Radionuclide ventriculography showed normalization in all but one patient. This patient with concomitant mitral regurgitation still showed moderate left ventricular volume overload. After occlusion, left ventricular enddiastolic volume significantly decreased (from 224 to 181 ml, p <0.05), effective cardiac output increased (from 6186 to 7476 ml, p <0.01) and ejection fraction remained unchanged (55 vs. 51 %). It is concluded, that combined first-pass and equilibrium radionuclide ventriculography permits reliable determination of left-to-right shunts in patients with patent ductus arteriosus. It provides important additional information concerning the follow-up of EF, EDV and cardiac output. This method is superior to dye dilution techniques

Modulation of Output from an Isolated Gastropod Heart: Effects of Acetylcholine and FMRFamide

In this study, two cardioactive drugs, acetylcholine (ACh) and the tetrapeptide FMRFamide, are perfused through the isolated systemic heart of the gastropod, Busycon canaliculatum. Their effect is examined in terms of the regulation of output, and is then related to the in vivo regulation of stroke volume. ACh decreases cardiac output by reducing both stroke volume and heart rate. End-diastolic volume and cardiac reserve increase with drug concentration. These effects are accompanied by a slowing in the rise time of the electromyogram prepotential and an increase in the duration of the plateau phase. Low concentrations of FMRFamide increase output by accelerating the heart rate. Stroke volume is only affected at higher concentrations (5×10−7 moll−1), and then negatively. Enddiastolic volume is reduced. Between 10−9 and 10−8 moll−1, FMRFamide increases the rise time of the prepotential and the amplitude of the plateau; the duration of the plateau is markedly shortened. At 5×10−7 moll−1 and above, the plateau is extended and the cardiac reserve is reduced to zero. The two drugs have opposite effects on the characteristics of the aortic pressure pulse: ACh reduces the amplitude of the pulse, but increases its duration.

About the Possibilities of Registration of Drug Influence by Means of Radiocardiographic Function Analysis

Changes in cardiac dynamics were analyzed by means of radiocardiographic function analysis under an infusion of epinephrine using the method of RAB. Typical changes in heart rate, stroke volume and blood pressure were observed after the application of epinephrine. Compared to examinations under physical exercise in case of healthy control subjects there was no typical decrease of enddiastolic volume dependent on the heart rate. Ejection time and ejection velocity were placed within the variation compared to values of a control group under physical exercise but there was a steeper increase of the curve under the effect of epinephrine. Under the influence of SolcoserylR no significant change could be observed in this series of tests compared to the basic values. The effect of epinephrine was changed by SolcoserylR in the way of an essentially smaller rise in heart rate and of a definite prolongation in diastolic time. A change in ejection time under the influence of epinephrine after the application of SolcoserylR could not be found. This allows the conclusion, that under the influence of SolcoserylR and after the administration of epinephrine better conditions for the metabolic restitution of heart muscle are given and consequently a direct effect of SolcoserylR on the heart muscle can be assumed.

Estimation of Cardiac Function by Means of Radio-cardiographic Function Analysis

The radiocardiographic function analysis represents a relatively simple procedure for the clinician to collect information concerning the changes of cardiac dynamics.The advantage of this method is to register non-invasively changes in cardiac dynamics at rest and during exercise such as those of enddiastolic volume, stroke volume, endsystolic volume, ejection time and filling time, and to permit the calculation of mean ejection velocity, etc.After insertion of a cardiac catheter, it is possible to record the corresponding pressure pulse in the right ventricle or in the pulmonary vessels simultaneously.