Effects of Amrinone and Dobutamine on Regional Myocardial Function and Oxygen Balance in Normal and Stunned Myocardium in Dogs / 대한구급학회지

BACKGROUND: We examined the effects of amrinone and dobutamine on regional mechanical function, coronary blood flow (CBF), and myocardial oxygen consumption (MVO2) in normal and stunned myocardium in an open-chest canine model. METHODS: Dogs were instrumented to measure aortic and left ventricular pressures, pulmonary and left anterior descending (LAD) coronary blood flows, and subendocardial segment length in the region supplied by LAD. Incremental doses of either amrinone (2~10microgram/ml of LAD flow, n=13) or dobutamine (0.05~0.375microgram/ml of LAD flow, n=14) were directly infused into a coronary artery before (normal) and after a 15 min of LAD occlusion and subsequent 30 min-reperfusion (stunned). Percent segment shortening (%SS) and percent post-systolic shortening (%PSS) were evaluated. Myocardial extraction of oxygen (EO2) and lactate (Elac) was calculated. RESULTS: Amrinone or dobutamine in the normal myocardium caused dose-dependent increases in %SS that were comparable (range, 20~40%) but had no effect on %PSS. MVO2 increased in parallel with %SS for both amrinone and dobutamine. With amrinone, CBF increased more than MVO2, resulting in a modest decrease in EO2, whereas with dobutamine, CBF increased in proportion to MVO2, resulting in no change in EO2. After the ischemia and reperfusion, %SS and Elac were reduced, but similar %SS and CBF responses to both agents were observed, except that both agents caused progressive reductions of %PSS. CONCLUSIONS: These results indicate that both amrinone and dobutamine exert positive inotropic effects in normal and stunned canine myocardium. It is also indicated that amrinone causes direct coronary vasodilation, which is not affected by ischemia and reperfusion, while dobutamine has no direct effect on coronary vascular tone in either normal or stunned myocardium.

Effects of Inotropic Drugs on Mechanical Function and Oxygen Balance in Postischemic Canine Myocardium: Comparison of Dobutamine, Epinephrine, Amrinone, and Calcium Chloride

Brief ischemic episodes that induce myocardial and coronary endothelial dysfunction may alter the responses to inotropic drugs. To determine the effects of inotropic drugs in stunned myocardium, the coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and regional mechanical function in response to intracoronary dobutamine, epinephrine, amrinone, and calcium chloride (CaCl2) were measured before (normal) and 30 min after a 15-min-period occlusion of the left anterior descending artery (stunned) in an open-chest canine model. Percent segment shortening (%SS) and post-systolic shortening (%PSS) were determined. Myocardial extraction of oxygen (EO2) and lactate (E(lac)) was calculated. The inotropic drugs increased %SS, CBF, and MVO2 in normal myocardium. Epinephrine and amrinone decreased, while dobutamine and CaCl2 did not affect EO2. The ischemia and reperfusion itself significantly reduced %SS and E(lac), and increased %PSS. In stunned myocardium, the responses to inotropic drugs were not significantly altered, except that they progressively reduced %PSS and epinephrine did not affect EO2. These findings indicate that a brief episode of ischemia does not affect the mechanical and metabolic coronary flow responses to inotropic drugs, although it abolishes direct vasodilator responses to epinephrine.

Effect of Amrinone, a Selective Inhibitor of Phosphodiesterase III, on PMNs-induced Cardiac Dysfunction in Ischemia/reperfusion

Ischemia followed by reperfusion in the presence of polymorphonuclear leukocytes (PMNs) results in a marked cardiac contractile dysfunction. Amrinone, a specific inhibitor of phosphodiesterase 3, has an antioxidant activity against PMNs. Therefore, we hypothesized that amrinone could attenuate PMNs-induced cardiac dysfunction by suppression of reactive oxygen species (ROS) produced fby PMNs. In the present study, we examined the effects of amrinone on isolated ischemic (20 min) and reperfused (45 min) rat hearts perfused with PMNs. Amrinone at 25microM, given to hearts during the first 5 min of reperfusion, significantly improved coronary flow, left ventricular developed pressure (P< 0.001), and the maximal rate of development of left ventricular developed pressure (P< 0.001), compared with ischemic/reperfused hearts perfused with PMNs in the absence of amrinone. In addition, amrinone significantly reduced myeloperoxidase activity by 50.8%, indicating decreased PMNs infiltration (p< 0.001). Superoxide radical and hydrogen peroxide production were also significantly reduced in fMLP- and PMA-stimulated PMNs pretreated with amrinone. Hydroxyl radical was scavenged by amrinone. fMLP-induced elevation of [Ca2+]i was also inhibited by amrinone. These results provide evidence that amrinone can significantly attenuate PMN-induced cardiac contractile dysfunction in the ischemic/ reperfused rat heart via attenuation of PMNs infiltration into the myocardium and suppression of ROS release by PMNs.

A Ratio of Arterial Oxygen Tension to Inspired Oxygen Fraction (PaO2/FiO2 ratio) after Cardiopulmonary Bypass in Coronary Artery Bypass Graft Surgery: Amrinone-Dopamine versus Isosorbide Dinitrate-Dopamine / 대한마취과학회지

BACKGROUND: Cardiopulmonary bypass (CPB) may produce lung injury with decreased PaO2/FiO2 ratio in patients undergoing CABG surgery. We examined PaO2/FiO2 ratio and incidence of PaO2/FiO2 < 300 or 150 to determine the differences in oxygenation with the use of amrinone-dopamine (DP) or isosorbide dinitrate (IDN)-DP in patients undergoing CABG. METHODS: Twenty patients undergoing elective CABG were divided into two groups according to drug used on separation from CPB: IDN-DP (Group 1, n = 10) or amrinone-DP (Group 2, n = 10). Anesthesia was induced and maintained with propofol, fentanyl and vecuronium. IDN infusion (1.0microgram/kg/min) was started preoperatively in both groups. Mild hypothermic CPB was applied with a roller pump and nonpulsatile flow maintained a mean arterial pressure of 60-80 mmHg. In Group 2, amrinone was administered (0.75 mg/kg + 10microgram/kg/min) instead of IDN at the time of CPB separation. DP infusion (3microgram/kg/min) was started at a rectal temperature more than 35.5oC and adjusted to maintain acceptable hemodynamics. IDN-DP or amrinone-DP infusion, monitoring and sedation with propofol were continued in the intensive care unit (ICU). PaO2/FiO2 ratio under controlled ventilation with air/O2 mixture (FiO2 0.6) was checked immediately before CPB (pre-CPB), 30 mins (post-CPB30), 60 mins after CPB (post-CPB60) and 30 mins after admission to ICU (ICU30). RESULTS: There was no significant difference between the groups in the terms of the duration of arotic cross clamp, PaO2/FiO2 at pre-CPB, PaO2/FiO2 at post-CPB60, PaO2/FiO2 at ICU30 or in the incidence of PaO2/FiO2 < 150, PaO2/FiO2 < 300 at ICU30. But there was a significant difference in PaO2/FiO2 post CPB30 (263.3 +/- 105.5 in Group 1 vs. 381.7 +/- 69.5 in Group 2, P<0.05). CONCLUSIONS: Amrinone-DP provides more favorable oxygenation immediately after CPB in CABG surgery than IDN-DP.

Effects of Amrinone on Regional Myocardial Function and Oxygen Balance in Stunned Myocardium in Dogs / 대한마취과학회지

BACKGROUND: Brief myocardial ischaemia has been demonstrated to result in mechanical and coronary endothelial dysfunction. We examined whether the mechanical and vascular responses to amrinone are altered in the postischaemic, reperfused myocardium. The effects of amrinone were compared with those of dobutamine. METHODS: In an open-chest canine model, coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and regional mechanical function in response to either amrinone (2, 5, 7.5, and 10 ng/mL of CBF) or dobutamine (0.05, 0.125, 0.25, 0.375, and 10ng/mL of CBF) directly infused into the left anterior descending (LAD) artery were determined before (normal) and 30 min after 15-min- period of LAD occlusion (stunned). Percent segment shortening (%SS), peak segment lengthening rate (dL/dt(max)), and percent post-systolic shortening (%PSS) in the LAD territory was determined using ultrasonic crystals and CBF using Doppler transducer. Myocardial extractions of oxygen (EO2) and lactate (Elac) were calculated. RESULTS: Both amrinone and dobutamine in the normal myocardium caused a dose-dependent increase in mechanical functions (%SS and dL/dt(max)) and MVO2 that were comparable (range, 20 40%), but they had no effects on %PSS. Amrinone caused an increase of CBF in excess of MVO2, resulting in a modest decrease in EO2, whereas dobutamine increased CBF in proportion to MVO2, resulting in no changes in EO2. The ischemia and reperfusion insult reduced %SS, dL/dt(max), and Elac, while it did not affect mechanical (%SS and dL/dt(max)) and CBF responses to either agent, except for progressive reductions of %PSS. CONCLUSIONS: These results indicate that amrinone, similar to dobutamine, exert positive inotropic and lusitropic effects in normal and stunned canine myocardium. It is also indicated that amrinone causes direct coronary vasodilation, which is not affected by an ischemia and reperfusion insult.

Comparison of Amrinone and Dopamine-Nitroglycerin on Hemodynamic Parameters in Dogs with Postinfarct Heart Failure / 대한마취과학회지

BACKGROUND: Left ventricular failure (LVF) after an acute myocardial infarction occurs during the perioperative period, and since this condition can lead to severe complications, intensive care is required for the patient. LVF is characterized hemodynamically by a raised left heart filling pressure and volume and global depression of the hearts pumping performance. Several effective drugs for patients with heart failure are catecholamines such as dopamine and dobutamine, vasodilators such as nitroglycerin and nitroprusside, and noncatecholamine inotropes such as amrinone, which are either infused alone or in combination. However, as of now, there has been no study as to clarifying either the exact dosage, drug combination, or how they affect the heart. METHODS: By inducing a state of experimental acute left ventricular failure in 20 dogs through ligation of the left anterior descending coronary artery, this study compared the hemodynamic parameters of two treatment groups-one group using amrinone alone (bolus 1 mg/kg, continuous infusion 15micro gram/kg/min), and another group using a combination of dopamine (10micro gram/kg/min) and nitroglycerin (2micro gram/kg/min). RESULTS: Cardiac output of dogs with postinfarct heart failure increased in both treatment groups. But, there was a significant decrease in systemic vascular resistance, pulmonary vascular resistance and left ventricular end diastolic pressure in the group treated with amrinone than dopamine-nitroglycerin. Amrinone also revealed a favorable effect on oxygen utility. CONCLUSIONS: These results showed that amrinone might be more effective than the combination of dopamine and nitroglycerin for acute left ventricular failure in terms of myocardial function, hemodynamic stability and oxygen utility.

Comparison of Amrinone and Dopamine-Nitroglycerin on Hemodynamic Parameters in Dogs with Postinfarct Heart Failure / 대한마취과학회지

BACKGROUND: Left ventricular failure (LVF) after an acute myocardial infarction occurs during the perioperative period, and since this condition can lead to severe complications, intensive care is required for the patient. LVF is characterized hemodynamically by a raised left heart filling pressure and volume and global depression of the hearts pumping performance. Several effective drugs for patients with heart failure are catecholamines such as dopamine and dobutamine, vasodilators such as nitroglycerin and nitroprusside, and noncatecholamine inotropes such as amrinone, which are either infused alone or in combination. However, as of now, there has been no study as to clarifying either the exact dosage, drug combination, or how they affect the heart. METHODS: By inducing a state of experimental acute left ventricular failure in 20 dogs through ligation of the left anterior descending coronary artery, this study compared the hemodynamic parameters of two treatment groups-one group using amrinone alone (bolus 1 mg/kg, continuous infusion 15micro gram/kg/min), and another group using a combination of dopamine (10micro gram/kg/min) and nitroglycerin (2micro gram/kg/min). RESULTS: Cardiac output of dogs with postinfarct heart failure increased in both treatment groups. But, there was a significant decrease in systemic vascular resistance, pulmonary vascular resistance and left ventricular end diastolic pressure in the group treated with amrinone than dopamine-nitroglycerin. Amrinone also revealed a favorable effect on oxygen utility. CONCLUSIONS: These results showed that amrinone might be more effective than the combination of dopamine and nitroglycerin for acute left ventricular failure in terms of myocardial function, hemodynamic stability and oxygen utility.

Anesthetic Management of Ovarian Bleeding with Eisenmenger's Syndrome: A case report / 대한마취과학회지

Eisenmenger's syndrome is defined as a high pulmonary vascular resistance associated with pulmonary hypertension or high pulmonary pressure close to systemic values with a reverse or bidirectional shunt at aortopulmonary, interventricular or interatrial levels. We report the case of a 42-year-old woman with an emergency operation for ovarian bleeding with Eisenmenger's syndrome secondary to large VSD. She had abdominal pain and vaginal spotting which developed one month earlier. In a preoperative abdominal ultrasonography, there was a fluid collection on the Cul-de-sac. There was no significant cardiorespiratory symptom except peripheral cyanosis. Anesthesia was performed with fentanyl, midazolam and vecuronium in standard monitorings including pulmonary artery pressure monitoring. Bolus and continuous infusions of amrinone were given to decrease right to left shunt. After the administration of amrinone, PaO2, PaO2/FiO2, P(A-a)O2 and P(a/A)O2 were improved and pulmonary arterial pressure was preferentially decreased compared with systemic arterial pressure. There was no significant problem throughout the operation, a right ovarian wedge resection. She was transferred to the intensive care unit in an intubated state postoperatively and discharged one week later without any complications.

Effects of Clonidine on the Requirements of Dopamine Used as a Concomitant Drug of Amrinone in Coronary Artery Bypass Surgery (CABG) / 대한마취과학회지

BACKGROUND: Clonidine premedication has many beneficial effects in patients undergoing CABG surgery. Amrinone, having the ability to increase cardiac performance without increasing myocardial O2 consumption, is a valuable drug in postoperative management after cardiopulmonary bypass (CPB). The use of amrinone with a catecholamine is also important clinically because the cathecholamines support perfusion pressure and the combined use exerts synergistic or additive effects. We performed this study to examine whether clonidine premedication could change the amount of dopamine used concomitantly with amrinone for management after CPB. METHODS: Nineteen patients for elective CABG were allocated to two groups according to their premedication; a placebo (Group 1, n = 13) or clonidine 4 microgram/kg p.o. (Group 2, n = 6). All patients arrived in the operating room with infusion of isosorbide dinitrate (ID). Anesthesia was performed with standard techniques. Before initiation of CPB, significant lowering of BP or HR was treated with phenylephrine or atropine respectively. Amrinone was given bolus (0.75 mg/kg) and infusion (10 microgram/ kg/min) was begun instead of ID at the release of aortic cross-clamp. Dopamine infusion (3 microgram/kg/min) was started at 35degree C (rectal) and its rate was adjusted for maintaining acceptable hemodynamics. We compared the amount of infused dopamine within 90 mins after CPB between the two groups. We also compared systolic BP, HR and CVP before induction, 10 mins after induction and 60 mins after CPB. RESULTS: Systolic BP and HR before induction and HR 10 mins after induction were significantly lower in Group 2 (P < 0.05), but they were all within normal range. The proportion of patients who needed phenylephrine or atropine before CPB was not significantly different in the two groups. The amount of infused dopamine was significantly larger in Group 2 (P < 0.05). Hemodynamics were acceptable after CPB although HR 60 min after CPB was significantly lower within the normal range in Group 2 (P < 0.05). Weaning time from CPB was not significantly different in the two groups. No significant adverse effect was observed throughout this study. CONCLUSIONS: Clonidine, used as premedication, increases the need of catecholamine which is concomitantly administered with amrinone for weaning from CPB. But this method provides clinically effective result without jeopardizing hemodynamics in CABG.

Effects of Amrinone on Systemic and Pulmonary Arterial Pressure in Infants with Intracardiac Left to Right Shunt / 대한마취과학회지

BACKGROUND: Amrinone is a nonglycosidic noncatecholamine with both vasodilator and positive inotropic effects that has not been evaluated widely in pediatric patients with intracardiac left to right shunts. The present study was performed to evaluate the hemodynamic effects of amrinone in infants and children with intracardiac left to right shunts. METHODS: Twenty patients (aged 2 months to 24 months) who underwent open heart surgery to correct one or more intracardiac left to right shunts were evaluated. Before cardiopulmonary bypass, a 22 gauge angiocatheter was placed at the main pulmonary artery by surgeons to measure pulmonary arterial pressure. Patients with a mean pulmonary arterial pressure or = 25 mmHg were assigned to Group B (n = 10). Mean systemic arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP) and heart rate (HR) were measured before loading of amrinone (3 mg/kg), 5 minutes, and 15 minutes after continuous infusion of amrinone (10 microgram/kg). The mean pulmonary arterial pressure to mean systemic arterial pressure ratio (MPAP/MAP) and rates of changes of mean arterial pressure (delta MAP) and mean pulmonary arterial pressure (delta MPAP) were calculated. RESULTS: Amrinone reduced MAP, MPAP, CVP and increased HR. MPAP/MAP increased in Group A but decreased in Group B (P < 0.05). In Group A, delta MAP was significantly greater than that of Group B (P < 0.005). In Group B, delta MPAP was significantly greater than that of Group A (P < 0.005). CONCLUSION: In infants with intracardiac left to right shunts, amrinone reduces MAP, MPAP, CVP and increases HR. Amrinone appears to have a potent vasodilating effect on the pulmonary artery in infants with pulmonary hypertension. However, more hemodynamic measurements such as cardiac output, vascular resistance and doppler echocardiographic study are necessary to evaluate the hemodynamic effects of amrinone precisely.

Hemodynamic Responses and Changes in Oxygen Extraction When Using Amrinone, Dobutamine and Isoproterenol in Cardiac Tamponade-Induced Dogs / 대한마취과학회지

BACKGROUND: Cardiac tamponade is most commonly treated by needle aspiration or surgical drainage. During this process, it may be necessary to temporarily improve cardiac output and to maintain peripheral perfusion by using vasoactive drugs and volume expanders. The purpose of this study is to examine the hemodynamic effect along with oxygen availability on cardiac tamponade induced dogs caused by the use of dobutamine, isoproterenol and amrinone following pentastarch infusion. METHODS: Twenty-four dogs were divided into four groups including a control group (group I), which received only pentastarch 10 ml/kg after artifical tamponade was induced. Following the administration of pentastarch, group II (n = 6) received dobutamine by dripping 10 microgram/kg/min, and then by 20 microgram/ kg/min, group III (n = 6) received isoproterenal (0.5 microgram/kg/min, 1.0 microgram/kg/min) and group IV (n = 6) received amrinone (50 microgram/kg/min, 100 microgram/kg/min). The hemodynamic parameters were measured in seven intervals: baseline, thoracotomy, tamponade, tamponade plus pentastarch, pentastarch plus dripping (1st dose), pentastarch plus drug (2nd injection = two times the 1st dose), and pericardiostomy. Arterial and mixed venous blood gas analyses were carried out in three intervals: after thoracotomy, tamponade, pentastarch plus drug (infusion). Subsequently, oxygen extraction ratios were calculated from the oxygen delivery and oxygen consumption. RESULTS: The heart rate increased significantly during the infusion of isoproterenol (P = 0.032) 1.0 microgram/kg/min in group III and also during the dobutamine infusion when the pericardiostomy (P = 0.028) was performed in group II. Compared to the control group, cardiac output increased significantly in group II from the infusion of the 1st dose and also in group III with the 2nd dose infusion but there were no significant changes in group IV. Although the average intrapericardial pressure was 0.93 mmHg in each group and was increased to 8.23 mmHg during the induced tamponade, no significant changes occurred in the groups with drug infusion. The oxygen extraction ratio fell significantly in the groupII, III and IV during the drug infusion. CONCLUSIONS: As results of this study, it was concluded that the most effective hemodynamic improvements during the induced cardiac tamponade occured in group II with pentastarch-dobutamine while the least effective combination occurred in group IV with pentastarch-amrinone.

Attenuating Effect of cAMP on Hypoxic Pulmonary Vasoconstriction in the Isolated Perfused Rat Lungs / 대한마취과학회지

BACKGROUND: Pulmonary vessels constrict when they are exposed to hypoxia, unlike other vessels. It is hypothesized that the decreased concentration of cAMP in the hypoxic condition causes this reaction, HPV (hypoxic pulmonary vasoconstriction). When cAMP concentration is increased by either activating adenylate cyclase, using adenosine, or inhibiting the cAMP hydrolysing enzyme, phosphodiesterase type 3, using amrinone, then HPV can be reversed. The aims of this study were to develop HPV in an isolated perfused rat lung preparation, and to investigate the vasodilating effects of adenosine and amrinone on HPV. METHODS: Isolated lungs from male rats (270 330 g) were ventilated with a normoxic gas mixture (21%O2-5%CO2-74%N2) or a hypoxic gas mixture (3%O2-5%CO2-92%N2) alternately, and perfused with calcium-containing perfusate solution. Adenosine (6 x 100-2 microgram, n = 6) and amrinone (5 x 101-3 microgram, n = 6) were mixed to perfusate solution, and the initial hypoxic pressor response { Pin = Pmax (maximum pulmonary artery pressure) - Pin (initial pulmonary artery pressure)} and hypoxic pressor responses after drug administration { Pdrug = Pmax (maximum pulmonary artery pressure) - Pbase (baseline pulmonary artery pressure)} were measured. Meclofenamate was used to block prostaglandin-mediated vasorelaxation. RESULTS: Adenosine did not decrease Pdrug compared to Pin. But amrinone inhibited HPV effectively a with a linear dose-response relationship (r = 0.842, P< 0.05). y = 26.72 x log (x) 35.79y: % relaxation = 100 [ Pdrug/ Pin] 100 , x: amount of drug, microgram, CONCLUSIONS: Amrinone attenuated HPV, and it can be concluded that increased levels of cAMP helpful to relax pulmonary vessels in hypoxic condition.

Effects of Amrinone on the Vascular Tension of the Isolated Rabbit Pulmonary Artery / 대한마취과학회지

BACKGROUND: Amrinone is a noncatecholamine, nonglycoside compound, which is known to possess both cardiac inotropic and vasodilatory actions. This drugs has been increasingly used in clinical practice for the management of low cardiac output syndrome during anesthesia, particularly for patients associated with right heart failure and pulmonary hypertension. The aim of this study was to explore the direct vasoactive effect of amrinone and its action mechanisms in the isolated rabbit pulmonary artery. METHODS: The rabbits' pulmonary arteries were dissected free and cut into rings (3 4 mm) and mounted for isometric tension in a tissue chamber. The effects of amrinone (5 10 6 5 10 4 M) on the vascular tension were assessed in the by KCl (40 mM)- or norepinephrine (NE, 10 6 M)- precontracted pulmonary arterial rings with or without endothelium. Also effects of K channel blockers (tetraethyl ammonium 20 mM, glybenclamide 2.5 10 5 M, 4-aminopyridine (4-AP) 5 10 4 M), protein kinase A & G inhibitor (H8), L-NAME, methylene blue and indomethacin on the amrinone- induced vascular responses were investigated. Also studied was effects of amrinone on the Ca2 influx through voltage operated channel (VOC) and receptor operated channel (ROC) of the vascular cells. RESULTS: Amrinone produced vasorelaxation of KCl- or NE-precontracted pulmonary artery in a dose-dependent fashion. The amrinone-induced vasorelaxation was not affected by the denudation of the endothelium. Pretreatment with L-NAME and methylene blue did not affect the vasodilatory effect of amrinone, suggesting that nitric oxide is not involved. Following pretreatment with indomethacin (a cyclooxygenase inhibitor) or K channel blockers, the amrinone-induced vasorelaxation was not altered. After exposure to Ca2 free solution, amrinone attenuated the KCl- or NE-induced contraction even in the presence of Ca2 , implying that VOC and ROC are blocked by amrinone. On the other hand, protein kinase A blocker (H8) completely abolished the amrinone-induced relaxation in the KCl-precontracted pulmonary artery. CONCLUSIONS: These findings suggest that the amrinone-induced vasorelaxations result from inhibition of VOC and ROC as well as from the activation of protein kinase A in the isolated rabbit pulmonary artery.

The Effects of Amrinone and Milrinone on Myocardium in the Isolated Isoflurane-Exposed Rat Heart / 대한마취과학회지

BACKGROUND: The aims of this study were to test if amrinone or milrinone reverses cardiac depression induced by the exposure to isoflurane in the isolated heart and to determine whether amrinone or milrinone dilates the coronary artery directly. METHODS: Using the isolated Sprague-Dawley rat hearts, heart rate, left ventricular pressure, dp/dt (differentiated rate of pressure development), O2 delivery(DO2), myocardial oxygen consumption(MVO2), and percent O2 extraction were measured. After the isolated hearts were exposed to isoflurane at 1.2 vol% during 10 min, amrinone(10, 50, 100 M) or milrinone(1, 5, 10 M) was separately given to six groups. RESULTS: Amrinone and milrinone reversed, not statistically significant, the depression of cardiac contractility induced by isoflurane, while the isoflurane-induced bradycardia substantially returned to normal by amrinone 100 M. And amrinone and milrinone elevated coronary flow, DO2, MVO2, while isoflurane increased in coronary flow and DO2, except MVO2. CONCLUSIONS: These results suggest that amrinone and milrinone did not counteract the isoflurane-induced cardiac depression and indirectly increased in coronary blood flow through the elevation of cardiac work.

Comparison of Hemodynamic Effects between Dobutamine and Amrinone in the Patients with Pulmonary Hypertension / 대한마취과학회지

BACKGROUND: Dobutamine and amrinone, phosphodiesterase-III inhibitor, are known to have both inotropic and vasodilatory properties. We evaluated the effects of both drugs on systemic and pulmonary hemodynamics in patients with pulmonary hypertension (PH). METHODS: With Institutional Review Board approval, 45 patients whose mean pulmonary arterial pressure was greater than 30 mmHg were studied. After sternotomy under the steady state of anesthesia and controlled ventilation (30 mmHg < PaCO2 < 40 mmHg), patients recieved one of following drugs for 30minutes (min); dobutamine 5.0ug/kg/min (Group I), low dose amrinone (loading dose 1.0 mg/kg, followed by infusion 7.5 g/kg/min, Group II) or high dose amrinone (loading dose 2.0 mg/kg, followed by infusion 10 g/kg/min, Group III). Hemodynamic variables were measured at 10 min and 30 min after start of infusion. RESULTS: Dobutamine didn't decrease pulmonary arterial pressure (PAP) and cause no hemodynamic change while low and high dose amrinone reduced PAP and especcially decrease of PAP in low dose amrinone group was statistically significnat. High dose amrinone increased cardiac index (CI) and decreased both systemic vascular resistance index (SVRI) and central venous pressure (CVP) more significantly than control value. CONCLUSIONS: In patients with chronic right ventricular failure associated with PH, amrinone may decrease the PAP and improve cardiac performance more effectively than dobutamin does. Increment of dosage of amrinone may not result in significant reduction of PAP.

Effects of Amrinone on the Systemic and Pulmonary Hemodynamics in Patients with Pulmonary Hypertension / 대한마취과학회지

BACKGROUND: Amrinone is a noncatecholamine, nonglycoside agent with both inotropic and vasodilatory properties and therefore seems suitable for therapy of right ventricular(RV) dysfunction. The effects of amrinone on systemic and pulmonary hemodynamics in patients with secondary pulmonary hypertension were evaluated. METHODS: With IRB(Institutional Review Board) approval, 21 patients with pulmonary hypertension whose mean pulmonary arterial pressure(mPAP) was greater than 30 mmHg consented to participate in this prospective study. After the sternotomy under the steady state of anesthesia with fentanyl and low concentration of isoflurane, hemodynamic variables including heart rate, systemic arterial pressure(SAP), PAP, cardiac output were measured as control values. Patients recieved an initial bolus dose(1.0 mg/kg) of amrinone followed by a continuous infusion(7.5 mcq/kg/min) for 30 minutes. Hemodynamic variables were measured at 10 minutes and 30 minutes after the start of the continuous infusion. RESULTS: Amrinone reduced SAP and PAP and vascular resistance without tarchycardia. There was no significant change of cardiac output. Ratio of mPAP to mean SAP was decreased after the administration of amrinone. CONCLUSIONS: In cases of chronic RV failure with pulmonary hypertension, amrinone is especially useful because it improve cardiac performance without tarchycardia and reduce RV afterload. Indeed in this study, the fact that amrinone decreased SAP and systemic vascular resistance but reduced PAP and pulmonary vascular resistsnce more significantly(p<0.01) was revealed.

Effects of Amrinone on the Systemic and Pulmonary Hemodynamics in Patients with Pulmonary Hypertension / 대한마취과학회지

BACKGROUND: Amrinone is a noncatecholamine, nonglycoside agent with both inotropic and vasodilatory properties and therefore seems suitable for therapy of right ventricular(RV) dysfunction. The effects of amrinone on systemic and pulmonary hemodynamics in patients with secondary pulmonary hypertension were evaluated. METHODS: With IRB(Institutional Review Board) approval, 21 patients with pulmonary hypertension whose mean pulmonary arterial pressure(mPAP) was greater than 30 mmHg consented to participate in this prospective study. After the sternotomy under the steady state of anesthesia with fentanyl and low concentration of isoflurane, hemodynamic variables including heart rate, systemic arterial pressure(SAP), PAP, cardiac output were measured as control values. Patients recieved an initial bolus dose(1.0 mg/kg) of amrinone followed by a continuous infusion(7.5 mcq/kg/min) for 30 minutes. Hemodynamic variables were measured at 10 minutes and 30 minutes after the start of the continuous infusion. RESULTS: Amrinone reduced SAP and PAP and vascular resistance without tarchycardia. There was no significant change of cardiac output. Ratio of mPAP to mean SAP was decreased after the administration of amrinone. CONCLUSIONS: In cases of chronic RV failure with pulmonary hypertension, amrinone is especially useful because it improve cardiac performance without tarchycardia and reduce RV afterload. Indeed in this study, the fact that amrinone decreased SAP and systemic vascular resistance but reduced PAP and pulmonary vascular resistsnce more significantly(p<0.01) was revealed.

OBSERVATION OF HEART DIASTOLIC FUNCTION USING PULSED DOPPLER ECHOCARDIOGRAPHY FOR CHRONIC HEART FAILURE AND INTERFERENCE OF TREATMENT USING AMRINONE / 重庆医科大学学报

China-made amrinone (AMR) was orally administered to 10 patients with chro- nic congestive heart failure(CHF) for 72 hours, its mitral valve blood flow spectral shift was observed by pulsed Doppier echocardiograp hy(PDE). We found that peak A decreased, and peak A/peak E ratio decreased significantly. It suggested that AMR could improve left ventricular diastolic function. Early diastolic drag acceleration increased, it is one index of left ventricular diastolic function, its elevation suggested that left ventricular diastolic function had some improvement. These observation suggested that AMR could improve left ventricular diastolic function for hypertensive heart disease, coronary artery disease, congestive cardiom-yopathy with limited left ventricular diastolic function

Effects of load-dose Amrinone on left ventricular function in heart failure patients evaluated by echocardiography / 中国药理学通报

The effects of Amrinone (AMR)on left ventricular function in 30 cases of congestive heart failure patients was assessed by M-mode and pulsed Doppler echocardiography. AMR improves the systolic and diastolic function of left ventricle during and after 10 min (AMR lmg ? kg-1, infusion ). The mean stroke volume increased 20% and 18% ; cardiac output increased 23% , 19% ; cardiac index increased 23% and 23% ; ejection fraction increased 32% , 30%; mVcf increased 50% and 48% ; filling velocity in early diastole increased 30% and 21 %; respectively. There were no significant differently between during and after AMR infusion, but there were signifcantly difference a-mong before, during and after AMR infusion. The heart rate changed slightly without statistic significance. The results suggest that AMR could improve the systolic and diastolic function of left ventricle in congestive heart failure patients.

EFFECTS OF AMRINONE ON CONTRACTION AND ACTION POTEN-TIAL OF ISOLATED PAPILLARY MUSCLES IN GUINEA PIGS / 西安交通大学学报(医学版)

The effects of amrinone on the contraction and action potential of isolated guinca pig papillary muscles were studied with intracellular microelectrodes. When the preparations were exposed to 25 ?mol/L amrinone, their pcak developed tension(DT) was inereased by 65.4%, the maximum rate of force development (dT/dt_(max)) was increased by 50.8% the time to peak developed tension (tPT) was shortened by 15.9%. By raising the concentration of amrinone to 250 ?mol/L, DT and dT/dt_(max) were increased by 98.5% and 91.3%, respectively, and tPT was shortened by 24.7%. Concomitantly, amrinone can prolong the durations of action potential (APD50, APD90)and the effective refractory period (ERP) of the ventricular cells.These results suggest that amrinone (made in China) possesses the obvious positive inotropic effect.