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.
Amrinone* ; Animals ; Bradycardia ; Coronary Vessels ; Depression ; Heart Rate ; Heart* ; Isoflurane ; Milrinone* ; Myocardium* ; Oxygen ; Rats* ; Rats, Sprague-Dawley ; Ventricular Pressure

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.
Amrinone* ; Animals ; Arteries ; Dobutamine ; Dogs* ; Ischemia ; Lactic Acid ; Myocardial Stunning* ; Myocardium ; Oxygen Consumption ; Oxygen* ; Reperfusion ; Reperfusion Injury ; Transducers ; Ultrasonics ; Vasodilation

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.
Amrinone* ; Anesthesia ; Blood Pressure ; Cardiac Output ; Fentanyl ; Heart Rate ; Hemodynamics* ; Humans ; Hypertension ; Hypertension, Pulmonary* ; Isoflurane ; Prospective Studies ; Sternotomy ; Vascular Resistance

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.
Amrinone* ; Anesthesia ; Blood Pressure ; Cardiac Output ; Fentanyl ; Heart Rate ; Hemodynamics* ; Humans ; Hypertension ; Hypertension, Pulmonary* ; Isoflurane ; Prospective Studies ; Sternotomy ; Vascular Resistance

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.
Adenosine ; Adenylyl Cyclases ; Amrinone ; Animals ; Anoxia ; Humans ; Lung* ; Male ; Meclofenamic Acid ; Pulmonary Artery ; Rats* ; Relaxation ; Vasoconstriction* ; Vasodilation

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.
Amrinone* ; Animals ; Blood Gas Analysis ; Cardiac Output ; Cardiac Tamponade ; Dobutamine* ; Dogs* ; Drainage ; Heart Rate ; Hemodynamics* ; Hydroxyethyl Starch Derivatives ; Isoproterenol* ; Needles ; Oxygen Consumption ; Oxygen* ; Perfusion ; Pericardial Window Techniques ; Thoracotomy

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.
Amrinone* ; Anesthesia ; Atropine ; Cardiopulmonary Bypass ; Clonidine* ; Coronary Artery Bypass* ; Coronary Vessels* ; Dopamine* ; Hemodynamics ; Humans ; Isosorbide Dinitrate ; Operating Rooms ; Perfusion ; Phenylephrine ; Premedication ; Reference Values ; Weaning

Verapamil overdose results in cardiac arrhythmia including the complete A-V block, and hypotension due to decreased peripheral resistance and decreased myocardial contractility. However, sustained-release verapamil overdose frequently has atypical presentations, such as delayed and prolonged course of toxic signs and symptoms. Although several cases of sustained-release verapamil overdose have been reported worldwidely, the specific treatment modalities and prognostic indicators for verapamil overdose have not been well-defined. Recently, we experienced a case of sustained-release verapamil overdose in 30-year-old female. 10 hours after verapamil ingestion she presented in severe bradycardia and hypotensive shock state. Initial EKG showed the complete AV block and her systolic blood pressure was below 60 mmHg. Temporary cardiac pacemaker was performed and she was treated with activated charcoal, glucagon, amrinone, and several sympathomimetics, and 48 hours after admission, she was fully recovered.
Adult ; Amrinone ; Arrhythmias, Cardiac ; Atrioventricular Block ; Blood Pressure ; Bradycardia ; Charcoal ; Eating ; Electrocardiography ; Female ; Glucagon ; Humans ; Hypotension ; Shock ; Sympathomimetics ; Vascular Resistance ; Verapamil*

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 < 25 mmHg were assigned to Group A (n = 10) and > 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.
Amrinone* ; Arterial Pressure* ; Cardiac Output ; Cardiopulmonary Bypass ; Central Venous Pressure ; Child ; Echocardiography ; Heart Rate ; Hemodynamics ; Humans ; Hypertension, Pulmonary ; Infant* ; Pulmonary Artery ; Thoracic Surgery ; Vascular Resistance

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.
Amrinone ; Anesthesia ; Arterial Pressure ; Cardiopulmonary Bypass* ; Coronary Artery Bypass* ; Coronary Vessels* ; Fentanyl ; Hemodynamics ; Humans ; Incidence ; Intensive Care Units ; Isosorbide Dinitrate ; Isosorbide* ; Lung Injury ; Oxygen* ; Propofol ; Vecuronium Bromide ; Ventilation