Masataka Kato

Renal, hormonal, and hemodynamic effects of low-dose infusion of atrial natriuretic factor in acute myocardial infarction☆

The effects of low-dose infusion of atrial natriuretic factor (ANF; 3 pmol/kg/min; i.e., 10 ng/kg/min) were investigated in a single-blind, random-order, placebo-controlled study of 12 patients with uncomplicated acute myocardial infarction (MI). Compared with the placebo, ANF induced an increase in urine volume (p less than 0.05), sodium excretion (p less than 0.05), and chloride excretion (p less than 0.05). Urinary potassium and creatinine clearance were unchanged. The maximal response of urinary sodium excretion rate after ANF infusion was positively correlated with the basal sodium excretion rate (r = 0.579; p less than 0.05) and inversely correlated with basal plasma renin activity (r = -0.623; p less than 0.05). Furthermore, the plasma aldosterone concentration (PAC) after infusion of ANF was significantly decreased compared with the basal level. The maximal change in PAC was closely correlated with the basal PAC (r = -0.857; p less than 0.01). However, no significant effect on hemodynamic variables was detected with infusion of ANF. Although additional studies are needed to assess the clinical efficacy of ANF infusion in acute MI, our observations suggest that low-dose infusion of the peptide is potentially valuable, as either sole or adjunctive therapy, for the management of water-sodium retention in acute MI.

EFFECTS OF LOW DOSE INFUSION OF ATRIAL NATRIURETIC FACTOR ON ACUTE INHIBITION OF ANGIOTENSIN CONVERTING ENZYME IN NORMAL MAN

1. We have studied the effects of low dose infusions of atrial natriuretic factor (human ANF (99–126), 1.95 pmol/min per kg) on angiotensin converting enzyme (ACE) inhibitor‐induced haemodynamic and hormonal changes in healthy subjects.

Changes in hemodynamics due to the contrast medium during left ventriculography.

Seventeen patients with heart diseases examined by left ventricular angiography were divided into two groups consisting of those with a clinical history of heart failure (CHF+) and those without (CHF-). Changes in hemodynamics, circulating blood volume, and plasma volume due to injection of the contrast medium were studied, and the following results were obtained. Both the CHF - and CHF + groups showed an increase in heart rate after injection of the contrast medium, but a statistically significant difference (p < 0.05) was noted only at one and two minutes after angiography in both groups. Left ventricular systolic pressure decreased after injection of the contrast medium in both groups, but the CHF+ group required a longer time for recovery. In the CHF - group, the left ventricular end-diastolic pressure increased slightly after injection of the contrast medium, but in the CHF+ group it increased markedly with a statistically significant difference (p < 0.01). Stroke volume, measured by a noninvasive, continuous cardiac output monitor according to the impedance method, increased upon injection of the contrast medium in the CHF— group. However, in the CHF+ group it decreased, although no statistically significant difference was noted in either group. Cardiac index increased markedly upon injection of the contrast medium in the CHF— group with a statistically significant difference (p < 0.01), but hardly any change was observed in the CHF+ group. Circulating blood volume increased in both groups ten minutes after injection of the contrast medium, but whereas the CHF - group showed no statistically significant increase and had a gradual reduction to the original state an hour afterward, a statistically significant increase over original values in the CHF+ group was observed at ten minutes and one hour after injection. The mean value of the CHF+ group was statistically significantly higher than that of the CHF- group at one hour after injection. Circulating plasma volume showed statistically significant mean increases over original values in both groups at ten minutes and at one hour after injection of the contrast medium. The mean value of the CHF+ group was statistically significantly higher than that of the CHF- group at one hour after injection. In conclusion, patients with heart failure, in comparison with those without, showed different changes in hemodynamics, circulating blood, and plasma volumes caused by the contrast medium, and thus it was necessary to be cautious when the contrast medium was injected into patients with a history of heart failure.

Clinical studies on peripheral hemodynamics in arterial hypertension.

Digital blood pressure and flow were measured in both normal subjects and patients with essential hypertension by means of the apparatus which have been recently devised, and peripheral vascular resistance was calculated according to Poiseuilles law in order to compare them. 1. Digital blood pressure is higher, the digital blood flow is less and the peripheral vascular resistance is stronger in patients with essential hypertension than in normotensives. 2. Hypertensive patients with ischemic heart disease, calcification of the aortic arch, left ventricular hypertrophy and heart size greater than 53% of the cardio-thoracic ratio were higher in the digital pressure, less in the digital flow, and stronger in the peripheral vascular resistance than those without these findings of the heart and the aortic arch. 3. The curve of relationship obtained from many cases of both normotensives and hypertensives between the digital blood flow and the peripheral vascular resistance forms a hyperbola. 4. Peripheral vascular resistance in both normotensives and hypertensives increased gradually with age up to 50-60 years, and decreased slightly thereafter. The resistance was stronger in patients with essential hypertension than in normotensives through all ages.

Venous Pressure and Compliance of the Peripheral Capacitance Vessels

Compliances of the peripheral capacitance vessels decreased gradually in accordance with the increase in pressure of the brachial vein. The relationship between them formed a number of hyperbolic-like curves, the same results as those found in many cases of both normal subjects and patients with congestive heart failure. The decrease of compliance of the peripheral capacitance vessels was not the result of an organic change, but of a functional change of the vessels caused by distention.

Compliance of the Peripheral Capacitance Vessels in Patients With Congestive Heart Failure

A method for measuring compliance of the peripheral capacitance vessels is reported, and the values of compliance in patients with congestive heart failure are compared with those in normal subjects. Peripheral venous compliance and right brachial venous pressure in both patients with congestive heart failure and in normal subjects, when plotted graphically, showed a relationship described by many hyperbolic curves. The mean value of compliance of the peripheral capacitance vessels in patients with congestive heart failure was only half that in normal subjects. This difference was statistically significant (P less than 0.001). After the congestion in the patients with congestive heart failure disappeared following treatment with digitalis and other drugs, the values of compliance became nearly the same as in normal subjects. It seems that the increase of compliance of the peripheral capacitance vessels is not due to an organic change but to a functional change of the vessels caused by distention.

Detection of the Spatial Distribution of Late Potentials by Body Surface Mapping Using Forty-Five Unipolar, Leads

For evaluating the spatial location of late potentials (LPs), the authors designed a new system for the body surface mapping of signal-averaged, filtered ECGs using forty-five thoracic unipolar leads (5 x 9 array). The signals from patients with old myocardial infarction (MI,N = 7) and arrhythmogenic right ventricular dysplasia (ARVD, N = 1) were amplified and passed through a bandpass (100-300 Hz) filter. The departure maps, LP isopotential maps, and LP30 area maps were generated and superimposed. The LP30 duration was determined as the section between the filtered QRS endpoints and points thirty milliseconds (ms) before. Isopotential maps of the LPs showed distinct positive and negative regions. In 7 cases with MI, the extreme was related to the zones indicated by the departure maps, and the LP30 area maps also corresponded to the departure areas. In 1 case of ARVD, endocardial fragmented activity directly recorded at the right ventricle closely corresponded with the region on the LP30 area map. In conclusion, body surface LP isopotential maps and LP30 area maps may provide useful information concerning the spatial distribution of endocardial fragmentation.