Henning Kelbæk

Cardiac performance in patients with asymptomatic alcoholic cirrhosis of the liver

Twenty patients with biopsy-proved alcoholic cirrhosis of the liver and no cardiac symptoms entered a noninvasive investigation program in which cardiac performance was evaluated. One patient was excluded from the study because of a significant ethanol content in the serum at the time of investigation and 4 patients were excluded because of significant electrocardiographic ST-segment changes during exercise testing. Fifteen patients (12 men, 3 women, median age 47 years) who had abstained from alcohol drinking for at least 2 months were studied by exercise testing, echocardiography, measurement of systolic time intervals and left ventricular (LV) radionuclide ejection fraction (EF) at rest and during submaximal exercise. Twelve healthy persons of the same age served as control subjects. Heart rate at rest was significantly elevated in the patient group, median 90 beats/min (range 62 to 128) vs 73 beats/min (range 61 to 89) (p less than 0.02). No significant differences were found in physical work capacity and systolic time intervals, and echocardiographic parameters did not differ with the exception of left atrial dimension (median 36 mm [range 22 to 47] in the patient group and 31 mm [range 17 to 38] in the control subjects, p less than 0.05). No significant difference was found in LVEF at rest. During exercise, however, the median LVEF increased only 6% in the patients versus 14% in the control subjects (p less than 0.05). The results of this study suggest that patients with alcoholic liver cirrhosis, although free of cardiac symptoms, may have a latent or preclinical cardiomyopathy that is manifest during physical stress.

Acute effects of alcohol and food intake on cardiac performance

Alcohol and food intake induce changes in LV performance which can be evaluated by radionuclide cardiographic methods. Alcohol probably exerts its effects by a direct action of ethanol in the blood on the myocardium, while the postprandial hemodynamic changes are related to the effects of food in the intestine. Alcohol intoxication causes a dose-dependent impairment of LV emptying at rest, whereas compensatory mechanisms other than an increased sympathetic nervous activity counterbalance this effect during exercise. In patients with coronary artery disease, alcohol induces only small changes in LV volumes at rest, possibly because of a concomitant vasodilation. Food intake seems to have a considerable influence on central hemodynamics leading to an increase in cardiac output both in healthy subjects and in patients with coronary artery disease. In healthy subjects an increase is recorded in the LVEDV and LVESV after a meal. The autonomic nervous system is probably responsible for most of the hemodynamic changes.

A new 99mTc-red blood cell labeling procedure for cardiac blood pool imaging: clinical results

The first clinical results of a new 99mTc-red blood cell labeling procedure avoiding cell centrifugation are presented. One ml heparinized blood samples were incubated with small amounts of a stannous kit. By titration studies, ideal quantities of sodium hypochlorite for oxidation of extracellular tin and of EDTA as stabilizer of the label were found. The Cl- concentration and pH of the labeled blood were acceptable, and EDTA increased labeling yield and stability determined in vitro by a few percent. The new procedure gave a slightly higher labeling yield than a current technique using centrifugation of cells. Labeling efficiency expressed as cell bound/total activity was 96.6%±1.3% in healthy subjects and 95.5%±2.2% in cardiac patients and remained high for 2 h after reinjection. The biological halflife of labeled cells following the new procedure was 11–12 h rendering it suitable for serial determinations of radionuclide cardiography.

Cardiac function and plasma catecholamines during upright exercise in healthy young subjects

Radionuclide left ventricular ejection fraction, left ventricular volume changes and plasma catecholamines were recorded in six healthy untrained male subjects at rest and during upright exercise at increasing work loads. During mild submaximal exercise mean left ventricular ejection fraction increased 10% because of end-diastolic dilation, while a further 4% increase of left ventricular ejection fraction was recorded at heavy submaximal exercise mainly due to increased end-systolic contraction. Great individual changes were recorded during maximal exercise. Alterations in plasma catecholamines were most pronounced at the high exercise levels indicating that changes in cardiac contractility are not linearly correlated with changes in sympathetic nervous activity. Repeat studies showed only minor variations of mean left ventricular ejection fraction and plasma catecholamines indicating an acceptable reproducibility of the measurements. Variations of both left ventricular ejection fraction and catecholamines were smaller during exercise than at rest.

First passage radionuclide cardiography for determination of cardiac output: evaluation of an improved method

A noninvasive method for determination of cardiac output by aid of first passage radionuclide cardiography is presented. As opposed to most other scintigraphic methods, a forward blood flow is measured, even in patients with valvar incompetence. In addition, the technique allows measurement of cardiac output in the presence of cardiac arrhythmias. No geometrical assumptions, corrections for radiation attenuation, loss of tracer, or empirical correction factors due to extracardiac radioactivity are required. We have evaluated the method in 19 patients with various heart diseases by comparison of the radionuclide cardiac outputs with those derived from the thermodilution technique performed simultaneously. Eight patients had valvar incompetence and 2 had cardiac arrhythmias. The mean radionuclide and thermodilution cardiac output values were 5.03 l/min (SD 1.21) and 5.18 l/min (SD 1.09), respectively. The 95% confidence interval for the bias was -0.40 to 0.10 l/min, and correlation analysis demonstrated an excellent correlation between results obtained with the two methods, r = 0.91 (P less than 0.001). This study shows that the improved gamma camera method represents a valid noninvasive technique for determination of cardiac output.

Reliability of first-pass radionuclide determination of cardiac output in the upright position at rest and during exercise

The reliability of non-invasive determination of cardiac output using first-pass radionuclide cardiography at rest and during exercise in the upright position was evaluated in 20 patients with coronary artery disease. Cardiac output values ranged from 2.97 to 5.99 1/min at rest and from 5.08 to 10.821/min during exercise. Cardiac output results obtained by the radionuclide method were compared with those derived from the thermodilution technique performed simultaneously. The mean difference between the two techniques was 0.02 1/min at rest and −0.341/min during exercise; the limits of agreement (mean±1.96 SD) were −1.29 to 1.33 1/min and −1.97 to 1.29 1/min, respectively, indicating an acceptable level of agreement. A high reproducibility of the radionuclide technique was found, with a mean difference between determinations by two observers of 0.03 1/min at rest and 0.21 1/min during exercise, the corresponding limits of agreement being −0.75 to 0.811/min and −0.79 to 1.21 1/min, respectively. With the aid of a variance component analysis of two determinations by each of four observers, 95% confidence intervals of ±10% at rest and ±12% during exercise were computed for the radionuclide cardiac output measurements. The observer variation was most pronounced for the part of the cardiac output determination related to measurement of left ventricular equilibrium activity during exercise. First-pass radionuclide cardiography is a reliable method for determination of cardiac output in cardiac patients at rest and during exercise in the upright position.