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Amrinone increases ventricular contractility and diastolic compliance in endotoxemia.

Systolic and diastolic dysfunction occur during human septic shock, and sensitivity to beta-adrenergic agents is reduced. We sought to determine whether amrinone, an inotropic agent independent of beta-receptors, increases left-ventricular contractility or diastolic compliance after endotoxin infusion. We measured left-ventricular volume (using a conductance catheter) and pressure (using a Millar catheter) before and after administering amrinone (4.5 mg/kg i.v., then 10 micrograms/kg/min) to six endotoxemic and seven control pigs. The slope of the end-systolic pressure-volume relationship, Ees, was used as the primary measure of contractility. Diastolic stiffness was characterized using stiffness parameters taken from pressure-volume relationships (k) and from pressure-volume strain relationships. Amrinone increased Ees from a median of 10.4 mm Hg/ml (interquartile range, 7.2 to 12.3) to 16.4 (13.7 to 18.6) (p < 0.05) in the endotoxin group (p < 0.05). Amrinone decreased diastolic stiffness (k) in the endotoxin group by 35 +/- 18% (p < 0.05). Amrinone did not significantly change Ees or k in the control group. Mean arterial pressure decreased after endotoxin infusion from 117 +/- 23 mm Hg to 76.5 +/- 14.9 mm Hg (p < 0.05), and decreased further after amrinone to 62.0 +/- 14.8 mm Hg (p < 0.05). We conclude that in this model of sepsis, amrinone may beneficially increase systolic contractility and diastolic compliance, but may dangerously decrease an already low mean arterial pressure.

Amrinone↗

Successful transcatheter closure of a patent ductus arteriosus: using two Gianturco coils in a 41-year-old woman. A case report.

Patent ductus arteriosus (PDA) is a form of congenital heart disease uncommonly diagnosed in adult patients. Transcatheter closure of PDA has been widely used in children. However, the experience is limited in adults especially with use of Gianturco coils. The authors describe a case of successful transcatheter closure of a PDA, incidentally diagnosed in a 41-year-old woman, by successively deploying two coils by a transarterial approach. No residual shunting was seen angiographically after the procedure. A literature review of similar procedures in adult patients is discussed.

Adult↗

The effects of oxytocin on the pulmonary and systemic circulation in pregnant ewes.

The haemodynamic effects of oxytocin on the pulmonary and systemic circulation were studied in six awake, pregnant (greater than 140 days gestation) ewes. Bolus doses of oxytocin 0.2 units/kg and then 0.8 units/kg were administered. A dose of 0.2 units/kg resulted in small but significant increases in mean pulmonary artery pressure (14%, P less than 0.05) and pulmonary vascular resistance (24%, P less than 0.05. A bolus of 0.8 units/kg resulted in a significant increase in mean arterial pressure (20%, P less than 0.05) and systemic vascular resistance (33%, P less than 0.05). Acute pulmonary hypertension was then induced with glass bead microemboli (150-200 microns), with an increase in pulmonary artery pressure of 26 mmHg and pulmonary vascular resistance of 448 dyn. s. cm-5. Boluses of oxytocin 0.2 and 0.8 units/kg were then administered. There were no significant changes, except for a 30% increase in systemic vascular resistance at one minute after oxytocin, 0.8 units/kg (P less than 0.05).

Animals↗

A comparison of the efficacy of dopexamine and dobutamine for increasing oxygen delivery in high-risk surgical patients.

Peri-operative increase of oxygen delivery has been shown to reduce mortality in high-risk surgical patients. This study compares the effectiveness of dopexamine and dobutamine when used to increase cardiac output as part of a regimen to increase oxygen delivery. Sixteen surgical patients were randomly allocated to receive either dopexamine or dobutamine, which was increased to a stable dose defined as either oxygen delivery index > 600 ml/min/m2, or tachycardia > 20% above baseline, other dysrhythmias or angina. At this "stable" dose there were significant increases in cardiac index (2.4 +/- 0.2 vs 3.7 +/- 0.3 l/min/m2) and oxygen delivery (380 +/- 73 vs 579 +/- 40 ml/min/m2) in the dopexamine group (P < 0.05); but not the dobutamine group. Five out of eight patients receiving dopexamine and three out of eight receiving dobutamine reached target oxygen delivery. Three dobutamine patients, but no dopexamine patients, had angina or dysrhythmias. In preoperative high-risk surgical patients, dopexamine can allow greater increases in oxygen delivery than dobutamine, due to cardiac effects that limit the dobutamine infusion rate.

Adrenergic beta-Agonists↗

Effect of low-molecular-weight heparin on recombinant tissue plasminogen activator-induced thrombolysis in canine pulmonary embolism.

We employed a canine model of pulmonary embolism induced by radioactive blood clots to determine if low-molecular-weight heparin augments recombinant tissue plasminogen activator (rtPA)-induced thrombolysis. Following embolization, dogs were randomized: group 1 dogs received heparin; group 2 dogs received low-molecular-weight heparin; group 3 dogs received 1.5 mg/kg of rtPA over 45 minutes; group 4 dogs received rtPA 3 mg/kg over 45 minutes; and group 5 dogs received 1.5 mg/kg of rtPA plus low-molecular-weight heparin. Over three hours, little thrombolysis occurred in groups 1 and 2. In contrast, significant thrombolysis occurred in groups 3 to 5, 46 percent, 49 percent, and 46 percent, respectively (all p less than 0.01 compared with groups 1 and 2). We conclude that there is an upper limit to the dose-thrombolytic rate relationship with rtPA, and that low-molecular-weight heparin does not augment rtPA-induced thrombolysis.

Animals↗

Jugular wave recognition breakthrough: X' descent vs the X descent and trough.

Irrational nomenclature and concentrating on ascents and peaks of waves have made recognition of jugular waves an occult art. By agreeing to call atrial relaxation X: and the systolic fall in atrial pressure due to the descent of the base X', we can begin to teach the easy recognition of jugular contours. Next, it is necessary to realize that the artifacts seen on electronically derived jugular pulse tracings are not to be expected when observing the neck pulsations with the naked eye. Finally, it can be shown that the easiest way to recognize jugular waves is by timing only descents as being either systolic or diastolic according to their relation to either the patient's radial pulse or heart sounds. It is almost unknown that only a single systolic descent due to the descent of the base is usual in the normal adult jugular.

Atrial Function, Right↗

Intravenous esmolol is well tolerated in elderly patients with heart failure in the early phase of non-ST elevation myocardial infarction.

AIM: To investigate the haemodynamic response to and clinical safety and tolerability of intravenous esmolol (Brevibloc), Baxter Healthcare Corporation, Deerfield, Illinois, USA) in elderly and younger patients with acute non-ST elevation myocardial infarction (NSTEMI) and heart failure. PATIENTS AND METHODS: We studied 24 consecutive patients, 12 of them elderly (> or =75 years old) and 12 younger (32-74 years old), with NSTEMI and symptoms of heart failure on presentation. After stabilisation of the patient's condition with standard therapy, intravenous esmolol was administered. An infusion rate of 0.05 mg/kg/min for 30 minutes was instituted and, if no adverse effects developed, this was increased to 0.20 mg/kg/min. All haemodynamic parameters were measured before and at the end of each administration using a Swan-Ganz catheter. RESULTS: Only one patient in the elderly subgroup did not tolerate the augmented infusion rate (because of severe bradycardia) and so had to return to the initial lower infusion rate. The cardiac index (mean +/- SD) was 2.4 +/- 0.9 L/min/m(2) at baseline and decreased to 1.9 +/- 0.4 L/min/m(2) (p < 0.05 vs baseline) at the end of the administration of the second dose of esmolol in the elderly patients and 2.6 +/- 0.5 L/min/m(2) and 2.2 +/- 0.5 L/min/m(2) (p < 0.05 vs baseline), respectively, in the younger patients. Mean pulmonary wedge pressure was 17 +/- 6mm Hg at baseline and increased to 19 +/- 4mm Hg (p < 0.05 vs baseline) at the end of the second dose of esmolol in the elderly patients and 16 +/- 10mm Hg and 18 +/- 10mm Hg (p < 0.05 vs baseline), respectively, in the younger patients. The response of both age groups to esmolol was the same for all of the parameters examined. CONCLUSION: Intravenous esmolol was safe and well tolerated in the early phase of NSTEMI in patients presenting with symptoms of heart failure and ongoing ischaemia, regardless of their age.

Adrenergic beta-Antagonists↗

Anorexia nervosa with left atrial failure.

A 14-year-old girl with anorexia nervosa was admitted to our hospital because of severe weight loss. She was 152 cm in height and weighed 27 kg. An echocardiogram demonstrated normal left ventricular contraction and a small left ventricular end-diastolic dimension. Pulsed Doppler transmitral flow demonstrated normal early filling velocities but a complete absence of late diastolic flow after the apparent electrocardiographic P wave, consistent with atrial electromechanical dissociation, so called atrial failure. Six months after admission, her body weight increased to 42 kg. Pulsed Doppler showed a normal transmitral flow pattern in both early and late diastole. We do speculate that atrial failure was related to malnutrition due to anorexia nervosa. Atrial failure can be one of the clinical features of patients with anorexia nervosa.

Adolescent↗

Sick sinus syndrome with and without atrial fibrillation: atrial refractoriness and conduction characteristics.

BACKGROUND: Clinical electrophysiology has focused the attention on the electrophysiological properties of the atrial muscle in patients with atrial fibrillation: shortened and inhomogeneous refractoriness and local and regional conduction slowing, as well as prolonged intra- and interatrial conduction disturbances, are well described as electrophysiological parameters associated with the genesis of atrial fibrillation. Patients with sick sinus syndrome are variously included in these studies, but electrophysiological characteristics of patients with sick sinus syndrome alone appear less investigated, even if atrial fibrillation is part of its natural history. The aim of the present study was to define the electrophysiological characteristics of sick sinus syndrome patients with or without paroxysmal atrial fibrillation, compared to subjects without atrial fibrillation and sick sinus syndrome. METHODS: We reviewed the electrophysiological data of 39 patients with sick sinus syndrome (mean age 70 +/- 8 years), who underwent an electrophysiological study in sinus rhythm for the evaluation of the atrial substrate. In 12 patients an associated history of paroxysmal atrial fibrillation was documented. Twenty-seven patients were included in the study with a diagnosis of sinus node dysfunction alone. We also considered as control group 25 subjects (mean age 63 +/- 14 years), referred to our electrophysiological laboratory for unexplained syncope or atrioventricular disturbances. Following pharmacological wash-out and at a drive cycle of 600 ms, effective and functional refractory periods, S1-A1 and S2-A2 latency, A1 and A2 width, and the latent vulnerability index (effective refractory period/A2), were measured. In addition, the P-wave duration during spontaneous sinus rhythm on the surface ECG in D II/V1 leads was measured. RESULTS: Between sick sinus syndrome patients with or without atrial fibrillation, no significant statistical differences in electrophysiological parameters were found. When compared to the control group, sick sinus syndrome patients did not show any differences in effective refractory period (239 +/- 34 vs 250 +/- 29 ms), functional refractory period (276 +/- 28 vs 280 +/- 32 ms), S1-A1 (38 +/- 16 vs 33 +/- 11 ms), and S2-A2 latency (68 +/- 25 vs 63 +/- 25 ms). In contrast, we observed remarkable differences in terms of atriogram duration A1 (60 +/- 20 vs 39 +/- 13 ms, p < 0.001), A2 (95 +/- 34 vs 57 +/- 18 ms, p < 0.001), and effective refractory period/A2 (2.8 +/- 1.2 vs 4.8 +/- 1.7 cm, p < 0.001). Also the duration of the P wave was longer (103 +/- 17 vs 94 +/- 45 ms, p < 0.05). CONCLUSIONS: In sick sinus syndrome patients with or without atrial fibrillation, electrophysiological characteristics appear homogeneous. When compared to the control group, refractoriness was quite similar. In contrast, the most important abnormalities appear based on conduction slowing disturbances, responsible for a low latent vulnerability index. This could explain, at least in part, the tendency of sick sinus syndrome to develop atrial fibrillation as a part of its natural history. At present, the influence of an altered electrophysiological substrate on pharmacological or pacing therapy in patients with sick sinus syndrome is not yet known.

Aged↗

[Non-invasive evaluation of the hemodynamic profile in patients with heart failure: estimation of left atrial pressure].

The management of patients with heart failure requires an accurate and non-invasive estimation of left ventricular filling pressures. This is essential in order to optimize unloading treatment, interpret equivocal symptoms, assess disease severity (and prognosis), and follow up the hemodynamic effect of long-term treatments. Since Doppler technique was implemented, several non-invasive methods to estimate left ventricular filling pressures were developed. Among these, a method based on the calculation of the left ventricular-atrial pressure gradient and its subtraction from systolic arterial blood pressure can be used in patients with significant mitral regurgitation and well-defined continuous wave Doppler signal of the regurgitant flow. Mitral and pulmonary venous flow velocities, as assessed by pulsed Doppler, are closely related to left atrial pressures, and several derived indices can be used to qualitatively estimate left ventricular filling pressures in patients with heart failure due to left ventricular systolic dysfunction who are in sinus rhythm. Furthermore, the combination of these indices in multivariable equations can improve this relationship and allows for a quantitative estimation of filling pressures, even in patients with significant mitral regurgitation and atrial fibrillation. There are, however, several groups of patients with heart failure in whom pulsed Doppler of mitral and pulmonary venous flow provides limited hemodynamic information. These include those with a) sinus tachycardia and/or prolonged P-R interval; b) normal left ventricular systolic function (and "pure" diastolic heart failure); c) primarily abnormal left atrial dysfunction (such as patients who had undergone heart transplantation), and d) technically inadequate Doppler recordings of pulmonary venous flow. To assess left ventricular filling pressures in these patients, two new methods which combine pulsed Doppler mitral flow indices with load-independent indices of left ventricular relaxation (either early diastolic velocity of mitral annulus, as assessed by tissue Doppler, or propagation velocity of mitral inflow, as assessed by color M-mode) can be used.

Atrial Function, Left↗

Non-invasive evaluation of central venous pressure by echocardiography.

INTRODUCTION: Central venous pressure (CVP) is an important hemodynamic parameter, reflecting the patient's volume status. Although some studies of non-invasive evaluation of CVP by echocardiography exist, an exact quantitative method has not been described. OBJECTIVES: Analyzing several echocardiographic variables, the authors present an equation to calculate CVP with good statistical correlation with CVP measured invasively. MATERIAL AND METHODS: The study included 45 patients, 32 undergoing mechanical ventilation, 32 in sinus rhythm and 13 with atrial fibrillation. Patients underwent simultaneous CVP measurement and transthoracic Doppler echocardiography. Statistical analysis was performed using bivariate correlation and analysis of variance. RESULTS: Several echocardiographic parameters measured showed a good correlation with the measured CVP. Standardized coefficients were applied to them and an equation to calculate CVP was obtained (tricuspid E decelaration) x 0.11 + (RU/RA gradient) x 0.16 - (IVC variation). CONCLUSION: This new method seems reliable to evaluate non-invasively a hemodynamic parameter that until now has only been measured approximately by this approach.

Atrial Function, Right↗

Value of haemodynamic studies during pericardiocentesis in a cardiac catheterisation laboratory.

Pericardiocentesis was performed in 20 patients using a 7F diagnostic catheter in a cardiac catheterisation laboratory under fluoroscopic control, with haemodynamic and electrocardiographic monitoring. This technique offers several advantages over the bedside technique which utilises a sharp needle. The technique utilised for percutaneous aspiration is safe and simple and allows complete drainage of fluid. The haemodynamic monitoring before and after drainage aids in detecting cases of effusive constriction.

Adolescent↗

Effects of nimodipine administration during cardiopulmonary resuscitation in pigs.

The haemodynamic effects of nimodipine during cardiopulmonary resuscitation (CPR) were investigated in 25 anaesthetized pigs. After 5 min of ventricular fibrillation (VF) and 5 min of closed-chest CPR, adrenaline (50 micrograms kg-1), either nimodipine (10 micrograms kg-1 as a bolus followed by 1 microgram kg-1 min-1 continuously) or the equivalent volume of placebo (solvent for nimodipine) were administered followed by the first countershock. If this failed to restore spontaneous circulation, adrenaline and countershocks were repeated for a maximum of 30 min. CPR was successful in nine out of 10 nimodipine-treated animals, but only in six out of 15 placebo-treated animals (P less than 0.02). In resuscitated pigs there were no significant differences in the number of countershocks, the number of seconds required for restoration of spontaneous circulation and the total doses of adrenaline required for both nimodipine and placebo pigs. After restoration of spontaneous circulation haemodynamic responses to nimodipine were characterized by decreases in systemic vascular resistance and mean arterial pressure with consequent increases in heart rate and cardiac output, but they were not significantly different from those of the placebo-treated animals. We therefore conclude that high doses of nimodipine are well tolerated during and after CPR; nimodipine administration may even result in higher initial CPR success rates. The underlying mechanisms need further investigation.

Animals↗

[Doppler echocardiographic assessment of left atrial and left ventricular function during right bundle branch block].

Electrocardiographic, echocardiographic and Doppler echocardiographic studies were performed in 44 patients with coronary heart disease and complete right bundle branch block. The patients were found to have an impaired phase pattern of left ventricular systole and diastole as more prolonged length of its isometric relaxation and contraction, lower economic feasibility and efficiency of its contraction, moderate dilation and hypertrophy. Hemodynamic abnormalities in the left heart in these patients are closely correlate with the changes in the phase pattern of right ventricular systole and they turn out to be so greater as the degree of its hypertrophy is. In complete right bundle branch block, left ventricular pump dysfunction leads to decreased cardiac output and cardiac index, increased total peripheral vascular resistance, thus predisposing to impaired greater circulation.

Adult↗