الفهرس 
Normal Physiology of the HeartOnly 14 pages are availabe for public view
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Abstract
The aim of the present study 15 to evaluate biochemically and clinically
the relatively new inotropic drug, amrinone (lnocor), in comparison with a preceding
commonly used inotropic drug, dobutamine hydrochloride (Dobutrcx). when both arc used
in different situations of cardiovascular failure and/or insmbility.
The total number of patients submitted for this study are 70 patients divided
into 3 groups according to the clinical type of cardiovascular instability present.
Group 1: Post open heart surgical patients
20 Patients were submined for this study. they had all undergone single or
double valve replacement and in a state of haemodynamic instability commonly met
with after such open heart surgeries. Amrinone was given for I 0 patients while
dobutaminc hydrochloride was given for the other 10 patients. The biochemical and
clinical studies were carried on, synchronized together at the same time on 12
patients from this group (6 patients from each drug group).
Administration of amrinone or dobutamine hydrochloride was started about 6 hours after
the operation after taking constant basal haemodynamic
Summary l\ Concluswn :: 4
parameters. The dosages used for both drugs were equal 4--f1-IO 11gfkg/min. But in case
of amrinone an intravenous holus of 0.75 mg./kg was J.d.ministcred before starting the
Erst infusion dose.
The haemodynamic parameters that were recorded arc: arterial blood pressures
(systolic. diastolic and mean), heart rate, CV.P. and urine output. The readings
were taken at t1xcd intervals for both drugs which were 20, 40 and 60 minutes and
then after 6 hours.
Biochemical et·aluation for these patients was done by taking blood samples (and
separation of the sera) and the levels of the cardiac enzymes and/or isoenzymes
were estimated. Regarding this study, the cardiac enzymes that were estimated are
creatin phosphokinase-ME isoenzyme (CPK-MB), alpha
hydroxybuterate dehydrogenase isoenzyme (a-HBDH) and serum glutamic
oxalacetic transaminase (SGOD.
The samples were taken 6 hours after the end of the operation before starting
administration of either inotropic drugs. Then other blood samples were taken again 6
hours after starting the drugs, i.e. at the end of the clinical srudy, and the
same cardiac enzymes were again measured.
1be dinicaJ. results regarding this group showed that:
Amrinone produced insigni11cant decrease in systolic and mean pressures with all the
doses given. However, after 6 hours infusion with dose of
Summary: & Cunclusmn
\0 f.ig/kg/min the systolic and mean blood pressures showed minimal increases.
hut these increases were also insignificanl.
The diastolic pressures showed insigniticant changes throughout the study
pcnod.
Heart rate showed insigniticant increase throughout the infusion time and with all
dosages except a significant increase at a Jose of 10 ).lg/k.g/min after one hour
infusion. But with proper volume correction it returns to be insignificant after
6 hours infusion (advantage). C.V.P. showed marked and progressive decrease with increasing
the dosage with time, with very high significant values.
Urine output showed marked increase (117.4%) after the first hour. The increase was
also marked after fi hours infusion with (65.1%).
Dobutcmune hydrochloride. on the other hand. showed insignificant increase in
systolic ami mean pressures with the small dose (4 ).lg/kg/min), but the increase in
systolic and mean pressures started to be highly significant with dose of 6 g!kg/min
and very highly significant with l 0 g/kg/ITUn.
The diastolic pressure remained almost unchanged with insignificant increase at all
da;agcs given.
The heart rate (as in case of amrinone) also insignillcantly increased \’lith the doses
of 4 and 6 ).lg/kg/min. But \’lith increasing the dose to 1 0 ,LJ.g/kg/min, it started
to show very highly significant increase (disadvantage).
Summary & Conclusion 25h
C.V.P. also showed marked decrease which is more with increasing the dose (but to a
lesser extent than in the case of amrimme).
The urine output showed also marked increase of 69.1% after one hour infusion.
After 6 hours of continuous infusion of dobutamine, we noticed a decrease in
the haemodynamic effects than those shown after one hour. The blood pressures
(systolic and mean) became less increased, the decrease in C. V.P. became less.
Also the increase in the amount of urine t1ow became much less (almost halved) than
that after the frrst hour.
These decreases in the haemodynamic effects with time, denote development of an element of
tachyphylaxis towards dobutamine.
Group II: Post acute myocardial infarction patients in a state of cardiogenic shock
20 Patients were submitted for this study, all with acute pump failure due to
acute myocardial infarction (cardiogenic shock) (Patients with severe systolic
hypotension <RO mm!hg. were excluded).
10 patients received amrinone while the other 10 patients received dohutamine
hydrochloride. The tluid balance was maintained throughout the study period with IV
fluids, taking into consideration the C.V.P.