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Assessment of left ventricular function by three-dimensional echocardiography.

Accurate determination of LV volume, ejection fraction and segmental wall motion abnormalities is important for clinical decision-making and follow-up assessment. Currently, echocardiography is the most common used method to obtain this information. Three-dimensional echocardiography has shown to be an accurate and reproducible method for LV quantitation, mainly by avoiding the use of geometric assumptions. In this review, we describe various methods to acquire a 3D-dataset for LV volume and wall motion analysis, including their advantages and limitations. We provide an overview of studies comparing LV volume and function measurement by various gated and real-time methods of acquisition compared to magnetic resonance imaging. New technical improvements, such as automated endocardial border detection and contrast enhancement, will make accurate on-line assessment with little operator interaction possible in the near future.

Echocardiography, Three-Dimensional↗

Effects of increased afterload on left ventricular performance and mechanical efficiency are not baroreflex-mediated.

OBJECTIVE: To assess baroreflex intervention during increase in left ventricular afterload, we compared the effects of aortic banding on the intact cardiovascular system and under hexamethonium infusion. METHODS: Six open-chest pigs, instrumented for measurement of aortic pressure and flow, left ventricular pressure and volume, were studied under pentobarbital-sufentanil anesthesia. Vascular arterial properties were estimated with a four-element windkessel model. Left ventricular contractility was assessed by the slope of end-systolic pressure-volume relationship. RESULTS: The effects of aortic banding on mechanical aortic properties were unaffected by autonomic nervous system inhibition. However, increase in peripheral arterial vascular resistance and in heart rate were prevented by hexamethonium. Aortic banding increased left ventricular contractility and stroke work. Left ventricular-arterial coupling remained unchanged, but mechanical efficiency was impaired. These ventricular changes were independent of baroreflex integrity. CONCLUSIONS: Our results demonstrate that an augmentation in afterload has a composite effect on left ventricular function. Left ventricular performance is increased, as demonstrated by increase in contractility and stroke work, but mechanical efficiency is decreased. These changes are observed independently of baroreflex integrity. Such mechanisms of autoregulation, independent of the autonomic nervous system, are of paramount importance in heart transplant patients.

Animals↗

The acute effects of intravenous nisoldipine on left ventricular function 24 to 72 hours after uncomplicated acute myocardial infarction.

The acute effects on left ventricular function of nisoldipine were studied in six patients 56 +/- 12 hours (range 44 to 72 hours) after the onset of uncomplicated acute myocardial infarction. Nisoldipine was administered as a 4.5 micrograms/kg intravenous bolus over 3 minutes followed by an infusion of 0.2 microgram/kg during 60 minutes. Radionuclide angiography and two-dimensional echocardiography were performed before and during infusion with nisoldipine. The left ventricular ejection fraction increased significantly from 38% +/- 10% to 49% +/- 10% (P = 0.028) during nisoldipine infusion. Regional wall motion index was determined both by radionuclide and by two-dimensional echocardiography and showed a significant change during nisoldipine infusion from 1.9 +/- 0.3 to 1.5 +/- 0.3 (p = 0.028, radionuclide angiography) and from 0.7 +/- 0.2 to 0.3 +/- 0.2 (p = 0.043, two dimensional echocardiography). Heart rate increased significantly from 78 +/- 12 min-1 to 92 +/- 13 min-1 (p = 0.028), but mean double product did not change significantly during nisoldipine infusion. It is concluded that nisoldipine significantly improves global and regional left ventricular function in patients shortly after acute myocardial infarction. This beneficial effect may, however, be partially offset by an increase in heart rate. Since mean double product did not change, it is suggested that nisoldipine may improve coronary blood flow in patients with acute myocardial infarction.

Acute Disease↗

Improvement of left ventricular function in chronic alcoholics following abstinence from ethanol.

Preclinical abnormalities of left ventricular function are frequently found in chronic alcoholics. In 12 chronic alcoholics without cardiomyopathy and in 12 healthy controls, systolic time intervals and echocardiograms were investigated before and after 12 months of abstinence from alcohol. In chronic alcoholics, an increase was found in the PEP/LVET ratio (0.31 +/- 0.06; in controls 0.24 +/- 0.05; t = 3.11; p less than 0.005), the diastolic interventricular septal thickness (6.0 +/- 2.0 mm/m2; in controls 4.1 +/- 1.0; t = 2.95; p less than 0.01), the left ventricular wall thickness (6.3 +/- 1.0 mm/m2; in controls 4.9 +/- 1.0; t = 3.43; p less than 0.005) and the left ventricular diastolic dimension (29 +/- 4 mm/m2; in controls 26 +/- 3; t = 2.08; p less than 0.05). The left ventricular mass (135 +/- 33 g/m2; in controls 113 +/- 40; t = 1.47) did not differ from the controls. After 12 months of abstinence a significant decrease was found in the PEP/LVET ratio (0.26 +/- 0.05, i.e. -16%; t = 3.59; p less than 0.005), the diastolic interventricular septal thickness (4.7 +/- 0.9 mm/m2, i.e. -22%; t = 2.73; p less than 0.02), the left ventricular posterior wall thickness (5.6 +/- 1.0 mm/m2, i.e. -11%; t = 4.08; p less than 0.001) and the left ventricular mass (109 +/- 24 g/m2, i.e. -21%; t = 6.53; p less than 0.001). The left ventricular diastolic dimension (27 +/- 2 mm/m2, i.e. -7%; t = 1.3) did not change. In conclusion, in chronic alcoholics, the abstinence from alcohol can be followed by an improvement of left ventricular function.

Adult↗

Effects of the Na+ antagonist cibenzoline on left ventricular function of postischemic hearts.

The negative inotropic effect of antiarrhythmic drugs is a major drawback in antiarrhythmic drug therapy, especially in patients with reduced contractile function of the left ventricle. The circulatory and myocardial effects of the new class I antiarrhythmic drug (a Na+ antagonist), cibenzoline (2 mg/kg i.v.), were investigated in 47 open-chest rats with normal and postischemic myocardium (3 x 4 minutes of global ischemia). Hemodynamic measurements in the intact circulation and isovolumic registrations (peak isovolumic left ventricular systolic pressure and peak isovolumic dP/dtmax) were compared to saline controls. In rats with postischemic myocardium, cibenzoline caused a significant (p < 0.001) decrease in the cardiac output for 38%, in the dP/dtmax for 30%, and in the peak isovolumic dP/dtmax for 19% at the end of infusion (compared to the control). The heart rate was reduced by 22% (p < 0.001), the mean aortic pressure by 22% (p < 0.001), and the calculated systemic resistance by 20% (p < 0.001). In contrast to the results with postischemic myocardium, no important changes in the hemodynamics were detectable after an identical dose in normal animals without left ventricular dysfunction. The results indicate that standard doses of the Na+ antagonist cibenzoline may induce significant cardiodeperessant effects on postischemic left ventricles with reduced function.

Animals↗

Comparative evaluation of left ventricular function in sick sinus syndrome on different long-term pacing modes.

Single-chamber ventricular pacing has been implicated in the development or progression of congestive heart failure in patients with sick sinus syndrome (SSS). To define the exact role of pacing modality in causation of congestive heart failure, quantitative two-dimensional echocardiographic examination was performed in 51 consecutive patients with SSS who received an initial pacemaker from January 1979 to September 1989 and were free of any structural heart disease at the time of implant. Atrial or dual chamber pacemakers were implanted in 21 patients (Group I) and ventricular pacemakers in 30 (Group II). The two groups were matched for age, gender, paced rate, blood pressure and duration of pacing. After a mean follow-up of 64 +/- 34 months, congestive heart failure developed in one patient in group I and 3 in Group II. Patients in group II, had larger left atrium (41 +/- 5 vs 37 +/- 6 mm, p < 0.05) and left ventricular end-diastolic volume (64 +/- 18 vs 54 +/- 12 ml/m2, p < 0.01) but similar left ventricular end-systolic volume (27 +/- 12 vs 24 +/- 9 ml/m2, p = NS), ejection fraction (59 +/- 10 vs 57 +/- 8%, p = NS), left ventricular mass (84.8 +/- 31 vs 85.6 +/- 29.2 gm/m2, p = NS), meridian end-systolic wall stress (48.3 +/- 22.1 vs 49.8 +/- 25 Kdynes/cm2, p = NS) and wall stress/end-systolic volume ratio (1.27 +/- 0.94 vs 1.42 +/- 0.59, p = NS). Pacing mode does not appear to influence left ventricular systolic function in patients with SSS.

Cardiac Pacing, Artificial↗

Long-term effect of mexiletine on left ventricular function and relation to suppression of ventricular arrhythmia.

The effects of oral mexiletine on left ventricular (LV) ejection fraction (EF) and ventricular arrhythmias--and a possible relation between these effects--were evaluated during 3 months of therapy in 29 patients with chronic ventricular premature complexes (VPCs) and a moderately reduced to normal LVEF by 24-hour Holter monitoring and by radionuclide ventriculography at rest and during maximum tolerable exercise testing. After an average titration period of 13 days, a mean daily mexiletine dose of 739 mg was maintained throughout the treatment. At the end of titration and after 3 months of treatment, patients with a baseline LVEF less than or equal to 40% (group 2) responded with a median reduction of the hourly VPC rate by 90 and 81%, respectively, compared with 79 and 72% in those with a baseline LVEF greater than 40% (group 1). Couplets and runs of ventricular tachycardia were almost completely suppressed in nearly all patients. A single patient had a proarrhythmic increase in VPCs during treatment. Compared with baseline, there were no significant changes in resting or exercise LVEF after 1 or 3 months of treatment in either of the 2 groups of patients. No correlation was found between treatment-induced changes in arrhythmia frequency and in resting EF. No symptoms of congestive heart failure developed. The study confirms that long-term use of mexiletine is efficacious and relatively free of cardiac depressant effects even in patients with diminished LV function.

Aged↗

Color-coded tissue Doppler assessment of the effects of acute ischemia on regional left ventricular function: comparison with sonomicrometry.

Echocardiographic assessment of regional left ventricular (LV) function usually consists of subjective visual inspection of endocardial movement and wall thickening. Color-coded tissue Doppler (TD) is a potential means to quantify regional LV function more objectively. Accordingly, in this study, color-coded TD was used to assess the regional effects of acute ischemia in an open-chest canine model of coronary occlusion, with implanted sonomicrometry length crystals as a standard of reference. Eight dogs were studied during baseline conditions and during left anterior descending coronary artery occlusion. Midventricular short-axis images were used to guide the color TD M-mode cursor through circumflex (septal) and left anterior descending (anterolateral) perfusion zones. Off-line conversion of endocardial time-velocity maps was performed. Peak systolic endocardial velocity by TD decreased from 4.4 +/- 1.4 cm/s to 1.8 +/- 1.5 cm/s with coronary occlusion (P < .05 versus baseline). Similar significant decreases in calculated systolic velocity by sonomicrometry occurred with ischemia from 11.1 +/- 3.8 mm/s to 8.2 +/- 1.2 mm/s (P < .05 versus baseline). Peak systolic velocity by TD was inversely correlated with end-systolic length by sonomicrometry as a measure of regional function (r = -0.77, P < .001). Time to peak systolic velocity increased with ischemia from 154 +/- 60 ms to 286 +/- 67 ms by TD and 200 +/- 60 ms to 320 +/- 30 ms by sonomicrometry (P < .05 versus baseline). The delay in time to peak systolic velocity by TD and sonomicrometry were correlated (r = 0.75, P < .001). In conclusion, color-coded TD echocardiography has the potential to quantify regional LV function during coronary ischemia.

Animals↗

Specific tissue Doppler predictors of preserved systolic and diastolic left ventricular function after an acute anterior myocardial infarction.

The degree of left ventricular (LV) dysfunction determines the outcome of patients suffering an acute anterior myocardial infarction (AAMI). Many recent studies have utilized tissue Doppler echocardiography (TDE) parameters in the assessment of LV function. We sought to investigate whether some variables easily obtained from TDE profiles of mitral annulus corners would predict a relatively preserved LV global function traditionally assessed with ejection fraction (EF) and deceleration time (DT), within the acute phase of AAMI. Included were 50 consecutive patients with a first AAMI. Standard echocardiography and TDE of mitral annulus were performed within 36 hours of admission. Pulsed wave sample volumes were set at the septal, lateral, anterior, and inferior corners of the mitral annulus. Preserved LV function was defined as an EF > 40% together with a DT > or = 140 ms and < 220 ms. An inferior annular systolic velocity of > 7.5 cm/s predicts preserved global left ventricular function with a sensitivity of 81% and specificity of 71%. An anterior mitral annular early diastolic velocity of > 8cm/s had a sensitivity of 69% and specificity of 85%. When these two velocities both exceed the limits above, such a combined index yielded a sensitivity of 69%, specificity of 94%, and an overall diagnostic accuracy of 86% for the estimation of preserved LV global function. The parameters derived from TDE profiles of inferior and anterior mitral annulus comers provide valuable information to predict preserved global left ventricular function during the early period of AAMI.

Adult↗

Poststress measurements of left ventricular function with gated perfusion SPECT: comparison with resting measurements by using a same-day perfusion-function protocol.

PURPOSE: To investigate the relationship between the development of ischemia during stress testing and the changes in left ventricular ejection fraction (LVEF) measurements obtained after stress and at rest with a same-day perfusion-function imaging protocol. MATERIALS AND METHODS: One hundred twenty-six patients underwent a same-day rest-stress (61%) or stress-rest (39%) protocol and gated single photon emission computed tomography (SPECT). Perfusion analysis was performed with a 12-segment model. Defects were scored (0 = no defect, 1 = mild defect, 2 = moderate defect, and 3 = severe defect); differences between the summed stress and resting scores of greater than three indicated substantial ischemia. RESULTS: Resting and poststress LVEFs correlated significantly (r = 0.97, P <.001); however, patients with and patients without ischemia had significant differences in poststress versus resting LVEFs (-4.0 vs 1.0, respectively; P <.01). In patients with ischemia versus patients without ischemia, subgroup analysis stress-rest (-2.5 vs 1.0, P =.047) and rest-stress (-4.0 vs 1.0, P =.006) protocols yielded similar results. CONCLUSION: In patients with clinically important stress-induced perfusion abnormalities, the LVEF after stress was significantly lower than the LVEF at rest with same-day rest-stress and stress-rest imaging protocols. In the clinical setting, poststress LVEFs may be lower than true resting measurements, particularly in patients with moderate to severe stress-induced ischemia.

Adenosine↗

Assessment of left-to-right shunt and left ventricular function in isolated ventricular septal defect. Echocardiographic study.

This echocardiographic study was designed to assess left ventricular function and pulmonary blood flow in ventricular septal defect. Fifty-one patients aged 2 weeks to 21 years were investigated (group 2). Five of 10 operated patients were studied one week after surgical closure of the defect (group 3) and seven 3 to 6 weeks postoperatively (group 4). The control group consisted of 45 normal subjects aged 2 weeks to 21 (group 1). Left atrium/aortic root dimension ratio (LA/Ao) was used to express the pulmonary systemic flow ratio. Left ventricular chamber size was assessed by measurement of left ventricular end-diastolic dimension and volume. The left ventricular mass and the ratio of end-diastolic volume to left ventricular mass were determined to relate the degree of left ventricular hypertrophy to volume overload. Myocardial function was evaluated using ejection phase indices. Ventricular septal thickness, posterior wall thickness, and echocardiographic patterns of septal motion were also studied. The left atrium/aortic root dimension, end-diastolic volume, and left ventricular mass were significantly greater in group 2 patients (P less than 0.05) than in the normal controls. There was a very good correlation between LA/Ao and pulmonary/systemic flow ratio (r = 0.83). Eleven of the group 2 patients showed asymmetric septal hypertrophy (unrelated to shunt size) but left ventricular function as assessed by ejection phase indices appeared unimpaired. Immediately after operation (group 3) there was a deterioration in left ventricular function in 5 patients as shown by reduced ejection fraction, mean velocity of circumferential shortening, and relative changes in minor axis with systole. Septal motion was impaired but returned to normal in 3 to 6 weeks in 7 patients (group 4). Left atrial/aortic root dimension, end-diastolic volume, and left ventricular mass decreased significantly immediately after operation (group 3) but were still raised at 3 to 6 weeks (group 4).

Adolescent↗

[Radionuclide study of left ventricular function and regional myocardial perfusion in patients with a DDD pacemaker].

In order to determine the influence of right ventricular artificial pacing on left ventricular function, particularly on diastolic specificity and regional myocardial perfusion, 99mTc multigated blood pool study and 201Tl myocardial SPECT at rest were performed on 12 patients with a DDD pacemaker implanted due to atrio-ventricular block at various degrees and on 7 normal adults without pacemaker as controls. Studies were performed on the pacing group during both ventricular pacing (VP) and atrio-ventricular sequential pacing (AVSP) at a rate of 80 beats/min. Although global left ventricular ejection fraction (LVEF) showed no significant differences between the control group (63.7 +/- 9.1%) and the pacing group, or between during AVSP (57.8 +/- 9.6%) and during VP (55.8 +/- 10.0%), global early diastolic peak filling rate (EDPFR) in the pacing group were significantly lower during AVSP (0.90 +/- 0.52 counts/second/end-diastolic counts) than during VP (1.55 +/- 0.52) (p less than 0.01), which were both found to be lower than those seen in control group (2.37 +/- 0.48 (p less than 0.01). Functional images disclosed regional prolongation of left ventricular ejection time (ET) in septal and apical areas of the left ventricle adjacent to the pacing site in 7 of the 12 patients (58.3%) during AVSP and in 3 of them (25%) during VP, and also revealed regional decrease in EDPFR in the similar areas in all of the patients during both modes, being more remarkable during AVSP than during VP. On 201Tl myocardial SPECT at rest, regional perfusion impairment was observed in septum, apex and the infero-posterior wall on the septal side adjacent to the pacing site in 8 of 10 patients (80%) during AVSP and in 6 of 9 patients (66.7%) during VP. These results suggest that a change in electrical conduction by right ventricular pacing may disturb regional myocardial relaxation, probably resulting in a regional impairment of myocardial perfusion.

Adult↗

Left ventricular function of survivors of a first complicated acute myocardial infarction. A prehospital discharge cross-sectional echocardiographic study.

To assess the left ventricular function of patients who suffer from post-infarction angina and left ventricular failure in the coronary care unit, 79 consecutive survivors (mean age 48 years) of a first acute myocardial infarction were prospectively studied and followed-up for a mean 18- (10-34) month period. Forty-seven had an uncomplicated infarction, 17 suffered from post-infarction angina and 15 had left ventricular failure. The left ventricular function of these patients prior to discharge from hospital was assessed by cross-sectional echocardiography and radionuclide angiography. Analysis of left ventricular wall motion was performed in all patients using a 11-segment model of the left ventricular. The ejection fraction was determined by echocardiography in 47 patients and by radionuclide angiography in 50. The mean echocardiographic wall motion score of post-infarction angina patients (4.8 +/- 0.8) (+/- SEM) was lower than that of patients with left ventricular failure (9.5 +/- 0.5) (P less than 0.001), but was not different from patients suffering uncomplicated infarctions (4.6 +/- 0.3). The mean echocardiographic ejection fraction was also similar in post-infarction angina (45.3 +/- 4.0; n = 16) and patients with uncomplicated infarction (51.9 +/- 2.7; n = 17), but was lowest in the group of patients with left ventricular failure (35.1 +/- 3.3; n = 14). Similarly, the radionuclide ejection fraction of patients with post-infarction angina (41.4 +/- 3.4; n = 17) and patients with uncomplicated infarction (45.6 +/- 2.7; n = 19) did not differ, but was lower in patients with left ventricular failure (25.9 +/- 2.8; n = 14). The echocardiographic ejection fraction correlated with that obtained by radionuclide angiography in all 46 patients (r = 0.71, P less than 0.001). The wall motion score correlated with the radionuclide ejection fraction in all 50 patients (r = -0.73, P less than 0.001) and with the echocardiographic ejection fraction in 47 patients (r = -0.55, P less than 0.001). During follow-up, 3 (18%) patients suffering post-infarction angina and 2 (13%) with left ventricular failure died. New infarction was seen in 2 (12%) and 1 (7%) patients in these groups, respectively. We conclude that the left ventricular function of patients who suffer from post-infarction angina in the coronary care unit is good, but is impaired in those with even transient left ventricular failure. Echocardiographic assessment of cardiac function prior to hospital discharge was highly successful and may be performed in all such patients.

Adult↗

[Relationship between redox state of whole arterial blood glutathione and left ventricular function after acute myocardial infarction].

OBJECTIVES: To investigate the role of oxidative stress in left ventricular function after acute myocardial infarction. METHODS: We studied 41 patients with acute myocardial infarction (30 men and 11 women, mean age 61.7 +/- 11.6 years) with Thrombolysis in Myocardial Infarction grade 3 recanalization of occluded coronary arteries within 12 hr after onset. Cardiac catheterization was performed at the time of admission and before discharge. Three markers for oxidative stress were measured: plasma lipid hydroperoxide, plasma creatol and whole arterial blood glutathione at the time of admission. RESULTS: Mean time from onset to recanalization was 5.2 +/- 0.6 hr. The patients were divided into two groups according to the changes in left ventricular wall motion (LVWM); patients who showed improvement in LVWM and those without improvement. There were no significant differences in age, sex, coronary risk factors, severity of coronary artery disease, time from onset to recanalization or ejection fraction between two groups. Maximum creatine kinase and C-reactive protein levels in patients without LVWM improvement were significantly higher than in patients with improvement. Plasma levels of lipid hydroperoxide and creatol did not differ significantly between two groups. On the other hand, reduced glutathione/oxidized glutathione ratio in arterial blood in patients without LVWM improvement was significantly lower than in patients with LVWM improvement (69.8 +/- 3.4 vs 85.5 +/- 2.9, p < 0.05). CONCLUSIONS: Our results suggest that whole arterial blood glutathione is more oxidized in acute myocardial infarction patients without LVWM improvement than in patients with improvement. Redox state of arterial blood can be a predicting factor for left ventricular function after acute myocardial infarction.

Aged↗

[Intracoronary stent implantation and left ventricular function in primary PTCA in acute myocardial infarct].

In acute myocardial infarction intracoronary stenting is superior to PTCA regarding interventional success and occurrence of cardiac events. It is, however, uncertain whether myocardial function also improves with stenting. We, therefore, assessed angiographic parameters of myocardial function in patients with acute myocardial infarction who were treated with primary PTCA and received additional stenting in case of an unsatisfactory angiographic result (provisional stenting). Nineteen patients with acute myocardial infarction, in whom a "stent-like" angiographic result was achieved by PTCA alone, were compared with an equal number of patients receiving provisional stenting. The groups were exactly matched with respect to severity of coronary heart disease, segment of coronary occlusion, Killip class, and TIMI flow after intervention. We only included patients without inhospital cardiac events, in whom repeat angiography after ten days revealed a patent target vessel. There were no differences between both groups regarding age, gender, enzymatic infarction size, duration of ischemia (< or = 12 h), and cardiac risk factors. Myocardial function was assessed by ventriculography and was analyzed quantitatively by the center-line method. The group treated by intracoronary stenting showed a significantly improved ejection fraction (60.3 +/- 2.1% vs. 52.6 +/- 2.9%). All parameters of regional wall motion also indicated significantly less functional disturbance in the stented group compared to PTCA alone (circumferential extend of hypokinesia: 7.4 +/- 2.4% vs. 16.1 +/- 3.4% chords, maximum hypokinesia in the central infarct region: -0.98 +/- 0.20 vs. -1.52 +/- 0.15 SD, severity of regional hypokinesia: 7.3 +/- 2.6 vs. 21.9 +/- 5.4 area). In summary, these results in patients undergoing primary PTCA in acute myocardial infarction indicate that intracoronary stenting is superior to PTCA alone with respect to myocardial recovery, even if an angiographically "stent-like" result can be achieved. Probably, stenting results in a more efficient reperfusion.

Aged↗

Long term spontaneous evolution of left ventricular function after experimental acute coronary occlusion.

In a canine model of acute occlusion of the left anterior descending artery (LAD), left ventriculography was performed before and immediately after occlusion and also one and three weeks later. Regional left ventricular function was evaluated by the centreline method. Global and regional left ventricular function were significantly depressed immediately after occlusion and showed no significant recovery after one and three weeks, except for a decrease in the paradoxical motion of the LAD territory, which was probably due to stiffening of the infarct area.

Angiocardiography↗

Thrombolytic therapy: then and now.

Although thrombolytic agents were discovered nearly 60 years ago, it is only within the past decade that the clinical use of these agents has revolutionized the treatment of acute myocardial infarction. There are four currently available agents approved for use in treatment of myocardial infarction: streptokinase, urokinase, tissue plasminogen activator, and anistreplase. Although each of these agents works in a unique fashion, the common end point of therapy is the dissolution of a fibrin clot by the conversion of plasminogen to plasmin. A number of clinically measurable end points have been used to determine the effectiveness of these agents in the treatment of acute myocardial infarction, including mortality, reperfusion, patency, left ventricular function, left ventricular volumes, and quantitative creatine kinase isoenzyme analysis. Secondary end points have included bleeding and stroke, as well as recurrent ischemic events. Numerous clinical studies have demonstrated the effectiveness of all of these agents in achieving the desired end points and comparative studies, including several large-scale trials, have failed to differentiate among these agents with regard to efficacy. Newer dosing regimens for currently available thrombolytic agents, as well as new thrombolytic agents, are currently under active investigation and will be the subject of intense research over the next few years. Despite the lack of consensus as to which agent is superior, it is clear that thrombolytic therapy for acute myocardial infarction is the treatment of choice.

Angioplasty, Balloon, Coronary↗

Accelerated recovery after coronary artery bypass surgery in patients with poor left ventricular function: preliminary report.

The success of "fast-track" accelerated recovery pathways in improving patient outcomes after coronary artery bypass graft surgery (CABG) has prompted expanded application. Although initially used only in routine cases, higher-risk cohorts may also benefit from this collection of management techniques. Twenty-seven consecutive patients with ejection fractions (EFs) less than or equal to 30 per cent (group I) undergoing CABG requiring cardiopulmonary bypass were started on our routine care path. The results of this effort were retrospectively compared with 27 concurrent patients with an EF greater than or equal to 50 per cent (group II) undergoing CABG at our institution. Outcome criteria included postoperative extubation (by 6 hours), transfer from intensive care unit (in < or = 24 hours), and hospital discharge on or before postoperative day 5. As anticipated, group I patients deviated from pathway criteria more frequently than did group II. However, despite severely compromised preoperative cardiac function, 52 per cent of group I patients were extubated within the first 6 hours postoperatively, 51 per cent were discharged from the intensive care unit on the 1st postoperative day, and 52 per cent were discharged from the hospital within the first 5 postoperative days. Group II patients' values for these parameters were 96, 96, and 70 per cent, respectively. No adverse effects could be attributed to pathway expectations. The results of this preliminary study suggest that accelerated care pathways may be safely applied to patients with severely low EFs and deserve further study.

Adult↗