Predictors of major in-hospital ischemic complications and length of hospital stay after coronary stenting

Although recent data show that coronary stenting reduces procedural complications and late restenosis, major concern has been expressed about the greater hospital cost associated with the use of this device as compared to conventional coronary angioplasty. Since length of hospital stay after surgical procedures is a major determinant of resource use, the identification of variables associated with an excessively long hospital stay after intracoronary stent placement may have important practical consequences. The purpose of this study was to assess factors responsible for the occurrence of in-hospital complications and prolonged hospital stay after coronary stenting in 939 consecutive patients enrolled in the Registro Impianto Stent Endocoronarico (RISE Study Group). Consecutive patients undergoing coronary stent implantation at 16 medical centers in Italy were prospectively enrolled in the Registry. Clinical data, qualitative and quantitative angiographic findings were obtained from data collected in case report forms at each investigator site. Major ischemic complications were considered death, Q-wave myocardial infarction, emergency bypass surgery and emergency repeat angioplasty. The study group consisted of 939 patients (781 men, 158 women with a mean age of 59 years) in whom 1392 stents were implanted in 1006 lesions and expanded at a maximal inflation pressure of 14.7 +/- 3 atmospheres. The great majority of patients (92%) received only antiplatelet drugs after coronary stenting. During hospitalization, there were 45 major ischemic complications in 39 patients (4.2%): 13 events were related to acute or subacute thrombosis (1.4%). On multivariate logistic regression analysis, the following factors were predictive of in-hospital complications: increasing age (OR 2.19, 95% CI 1.18-4.07), unplanned stenting (OR 3.46, 95% CI 1.65-7.23) and maximal inflation pressure (OR 0.83, 95% CI 0.75-0.93). Mean hospital stay after stent implantation was 4.1 +/- 4.4 days and was related, by multivariate regression analysis, to female sex (p = 0.0001), prior bypass surgery (p = 0.03), non-elective stenting (p = 0.0001), use of anticoagulation (p = 0.0001) and development of major ischemic complications (p = 0.0001). This Registry shows that in an unselected population of patients undergoing coronary stenting, major ischemic complications occur at a relatively low rate (4.2%) and thrombotic events can be kept at 1.4%, despite the omission of anticoagulation in the great majority of patients. Length of hospital stay was affected by the occurrence of major ischemic complications, unplanned stenting, use of anticoagulation, female sex and prior bypass surgery. Accumulating experience, further reduction in complications and complete omission of anticoagulation may decrease length of hospital stay, thus reducing the use of resources after coronary stenting.

[Emergency coronary surgery after failed angioplasty: 11 years of experience (1987-1997)]

METHODS

From January 1987 to December 1997, thirty patients underwent emergent or urgent coronary artery bypass grafting after failed elective percutaneous transluminal coronary angioplasty. Dissection/occlusion of the target artery was the commonest complication, but we also had two cases of stent dislocation and one case of coronary artery wall perforation. Two-thirds of the patients experienced extreme preoperatory hemodynamic instability (i.e., cardiac arrest or cardiogenic shock) and half had to be intubated in the Catheterization Laboratory. An average of 1.73 grafts/patient was performed. Complete coronary revascularization was achieved in 93% of the cases; the internal mammary artery could be employed in one-third only.

RESULTS

In-hospital mortality was 10%, and perioperatory myocardial infarction or persistent ischemia could be detected in half of the patients. The need for aortic counterpulsation, and the use of inotropic and antiarrhythmic drugs were higher than average in this group of patients; while intensive care unit and hospital stay were longer. Patients with deteriorated preoperative hemodynamics fared significantly worse. Late results were encouraging: seventy-five per cent of all patients (and 84% of hospital survivors) were still alive an average of 52 months after surgery. Two-thirds of all patients (and 72% of hospital survivors) were alive and angina-free.

CONCLUSIONS

Even in the current era, revascularization surgery after failed coronary angioplasty still carries an increased risk for postoperative complications and death, especially for patients with deteriorated preoperative hemodynamic conditions. On the other hand, postoperative middle- and long-term results are encouraging, as hospital survivors were similar to elective bypass patients regarding survival and freedom from return of angina.

[Clocking diagnostic and therapeutic procedures in coronary care unit patients: analysis of clinical performance times]

BACKGROUND

An optimal use and exploitation of professional personnel is of paramount importance for health management organizations, as human resources are both their greatest asset and heaviest financial burden. To better understand the amount of medic and paramedic work and time required for the typical diagnostic and therapeutic procedures in a coronary-care unit setting, we measured their average times and analyzed their inherent co-factors.

METHODS

This study was conducted on 206 consecutive coronary-care unit patients. These patients were divided into subgroups according to their admission diagnosis: acute myocardial infarction, unstable angina, acute cardiac failure, pulmonary embolism or other pathologies. Each subgroup was then subdivided even further according to the severity of their clinical status. Diagnostic and therapeutic procedures ("macroactivities") have been identified and each one was subdivided into sub-procedures ("microactivities"). All microactivities were carefully clocked in every patient in order to calculate the average execution time for every macroactivity.

RESULTS

Our data show that myocardial infarction patients and, in general, a more severe clinical status required a longer stay in the coronary-care unit. Again, longer overall clinical performance times were necessary in myocardial infarction patients as compared to the unstable angina subgroup. There were no statistically significant differences among other subgroups. More severely ill patients required longer clinical performance times because of both a longer coronary-care unit stay and longer clinical performance time per day. More than half of the total clinical performance time for each patient was spent during the first two days. Paramedics supplied more than 80% of the total performance time.

CONCLUSIONS

The authors undertook a study of typical coronary-care unit clinical activities by clocking the performance times of the usual diagnostic and therapeutic procedures. The data thus obtained come from direct measurements and describe the clinical performance of both medics and paramedics in a real-life setting. This could thus be used as a yardstick to verify current workload standards. It is hoped that a deeper understanding of these activities will optimize the full exploitation of available human resources.

Detection of moderate and severe coronary artery stenosis with technetium-99m tetrofosmin myocardial single-photon emission tomography

The aim of this study was to determine the diagnostic accuracy of technetium-99m tetrofosmin myocardial imaging for the localization of coronary artery stenoses of different degrees of severity. Stress-rest single-photon emission tomography (SPET) was performed on separate days in 80 patients (64 males, 16 females; mean age 61 years; 43 patients with previous myocardial infarction; 18 patients with pharmacological stress), within 6 months of coronary angiography. Scintigraphic images were blindly and independently evaluated by three observers. Coronary stenosis was defined as a >50% narrowing in luminal diameter; severe stenosis was defined as a proximal stenosis of >75% or a peripheral stenosis of >90%. Coronary angiography revealed normal coronary arteries or insignificant coronary stenosis in 13 patients and significant coronary stenoses in 67 patients. The sensitivity and specificity of 99mTc-tetrofosmin SPET in respect of severely stenosed vessels were, respectively, 80% and 65% for the left anterior descending artery (LAD), 100% and 46% for the right coronary artery (RCA) and 58 and 78% for the left circumflex artery (LCx) territories. Considering all the significantly stenosed vessels, a significant decrease in sensitivity was observed for LAD territories (to 59%, P=0.05), and a nonsignificant decrease for RCA (88%) and LCx (47%) territories while specificity values remained essentially unchanged. No significant changes in sensitivity or specificity were observed when regions with previous myocardial infarction were excluded. In conclusion, the sensitivity of 99mTc-tetrofosmin SPET for the localization of individual stenosed vessels is only moderate when all significant stenoses are considered, but the ability of this technique to predict the location of severe coronary artery stenoses seems satisfactory, with the exception of the low specificity in respect of RCA territories.

Left main coronary artery atresia: literature review and therapeutical considerations

OBJECTIVE

Left main coronary artery atresia is a rare coronary anomaly in which there is no left coronary ostium, the proximal left main trunk ends blindly, blood flows from the right coronary artery to the left via small collateral arteries and retrogradely in at least one of the left-sided arteries. Since published case reports are few and rather scattered, no comprehensive information about this uncommon anomaly is available.

METHODS

A through search for published cases of left main coronary atresia was performed in the major medical journals by electronic (MEDLINE and INTERNET) and hand-scanning.

RESULTS

The authors found 28 cases of left main atresia (including two from their own experience), 15 of which were pediatric; five of these cases had associated cardiac anomalies. While pediatric patients were usually overtly symptomatic early in their life (syncope, dyspnea, sudden death, failure to thrive, infarction, ventricular tachycardia), adult patients began showing symptoms (angina, dyspnea, sudden death) only at an advanced age; associated coronary atherosclerosis seemed to be uncommon, though (2/13 adult patients, 15%). We know of only one asymptomatic patient, a 76-year old lady who had died of unrelated causes; in her case left main atresia was an unforeseen autopsy finding. Four untreated patients had died suddenly; most of the others were highly symptomatic and required surgical therapy, usually as direct coronary artery revascularization via one or more saphenous vein or mammary artery grafts to the left-sided arteries; all revascularized patients were reported to be alive and well; in one pediatric case the left main coronary artery was reconstructed using an aortic wall baffle, with a good result. In contrast, the outcome of patients who did not receive revascularization has been poor.

CONCLUSION

In light of the favorable results obtained by surgical therapy, the authors endorse prompt coronary artery revascularization for all patients with left main coronary artery atresia.

[Short and intermediate term clinical outcome in patients with cardiogenic shock treated with aortic counterpulsation]

BACKGROUND

Despite improvements in coronary care, cardiogenic shock (CS) remains the leading cause of death in patients with dramatic cardiac diseases of which acute myocardial infarction (AMI) is the most frequent event. Conventional therapy for CS with coronary care unit (CCU) monitoring and vasopressor agents to support blood pressure has historically been associated with an 80% to 90% mortality rate in large series. Intra-aortic balloon pump (IABP) therapy for shock results in initial favourable clinical and haemodynamic responses, but ultimately, in most patients, death is merely delayed and hospital mortality still exceeds 80%. In several recent non-randomised series, coronary revascularisation performed early in the course of CS with the use of coronary artery by-pass grafting (CABG) or coronary angioplasty (PTCA) resulted in an apparent reduction in the hospital mortality rate to less than 50% in selected patients with shock.

OBJECTIVES

This study reviews our experience of cardiogenic shock treatment at a time when standard care included aggressive use of the intra-aortic balloon pump counterpulsation, cardiac catheterisation, coronary angioplasty and/or coronary artery by-pass grafting, ventricular septal defect and mitral incompetence repair.

METHODS

We retrospectively analysed 20 patients (13 M and 7 F, with an average age of 62 years and a half) affected by cardiogenic shock consecutively admitted to our CCU between October 1, 1992 and April 1, 1995. Fifteen patients (pts) were hospitalised for AMI, shock and pump failure (2 of them with pulmonary oedema), all with admittance delay less than 24 hours. Five patients were hospitalised for AMI with shock and mechanical defects, of which 3 pts with AMI and ventricular septal rupture and 2 pts with AMI and mitral regurgitation. All patients underwent IABP, coronary angiography (CA) and then were treated with PTCA, CABG and cardiac surgery or medical treatment.

RESULTS

On the whole, 7 pts died (35%): 4 of shock, 1 of haemorrhagic complications, 1 of septic shock in the CCU, and 1 of heart failure after CABG in cardiosurgery. One more patient died of heart failure two months after discharge (late mortality 5%). Out of the 15 patients hospitalised with AMI, shock and pump failure, 13 patients with AMI and CS less than 24 hrs were treated as follows: 1 patient was successfully submitted to emergency CABG and 12 patients to PTCA of the infarct related artery (IRA). Eight patients enjoyed a good outcome, but 1 patient died of haemorrhagic complications and 4 with a persistently occluded IRA also died (3 in the CCU and 1 after CABG). Of the 2 remaining pts with AMI, shock and pulmonary oedema, 1 patient underwent CABG with success and 1 patient with the 3-vessel disease was submitted to PTCA with reperfusion of the IRA, but he died from reocclusion three days later. Out of the 5 patients with AMI, shock and mechanical defects, 3 patients with AMI and septal ventricular rupture underwent cardiac surgery and CABG with early and late success. One of the 2 patients with AMI, shock and mitral regurgitation underwent cardiac surgery with valve repair and CABG and had a good outcome, the other died from septic complications in the CCU.

CONCLUSIONS

IABP is an useful device for stabilising patients in cardiogenic shock and safely performing angiography as well as PTCA, CABG or surgical correction of all mechanical complications with a more stable haemodynamic balance. Therefore, IABP is an useful tool to improve successful coronary revascularisation after direct PTCA or direct CABG. These data also suggest that the combination of successful coronary revascularisation and intra-aortic balloon pumping can improve survival in pts with cardiogenic shock complicating AMI with early pump failure.

Randomized comparison of rescue angioplasty with conservative management of patients with early failure of thrombolysis for acute anterior myocardial infarction

BACKGROUND

When used in the setting of acute myocardial infarction, intravenous thrombolytic agents fail to achieve early infarct artery patency in 15% to 50% of patients. We tested the hypothesis that immediate balloon angioplasty applied to patients with failed early reperfusion would improve left ventricular function and clinical outcome at 30 days compared with conservative management alone.

METHODS AND RESULTS

One hundred fifty-one patients with first anterior wall infarction treated with any accepted intravenous thrombolytic regimen and angiographically demonstrated to have an occluded infarct vessel within 8 hours of chest pain onset were randomized to aspirin, heparin, and coronary vasodilators (conservative therapy) or to this therapy and balloon angioplasty supplemented by further thrombolytic therapy as needed. Left ventricular function was assessed using multiple-gated equilibrium radionuclide technique to determine ejection fraction, and adverse clinical outcome was assessed evaluating death, ventricular tachycardia, and class III or IV heart failure at 30 days. Seventy-three patients were randomized to conservative therapy and 78 to angioplasty. The two groups were well balanced for patient age (59 +/- 11 years), sex (82% were male), and time to randomization (4.5 +/- 1.9 hours). Angioplasty was technically successful in 72 of 78 randomized patients (92%). Two patients randomized to conservative therapy crossed over to angioplasty within 72 hours. Resting 30-day ejection fraction was 40 +/- 11% in the angioplasty group and 39 +/- 12% in the conservative group (P = .49), but ejection fraction with exercise was 43 +/- 15% and 38 +/- 13% for the angioplasty and conservatively treated groups, respectively (P = .04). Adverse clinical outcomes included death in 5% and 10% (P = .18), severe heart failure in 1% and 7% (P = .11), and either death or severe heart failure in 6% and 17% (P = .05) of the angioplasty and conservatively managed groups, respectively.

CONCLUSIONS

When applied to patients with first anterior infarction, rescue angioplasty appears to be useful in the prevention of death or severe heart failure, with improvement in exercise, but not resting, ejection fraction. This strategy deserves further study and highlights the potential advantage of early mechanical restoration of infarct vessel patency when thrombolytic therapy has failed.

[The recurrence of pulmonary embolism during heparin therapy after thrombolysis in the acute phase: a clinical case report]

We report a case of a 61-year-old woman admitted to our Coronary Care Unit for pulmonary embolism following cholecystectomy. After thrombolytic therapy, and during treatment with heparin (administered as a continuous intravenous infusion in the standard dose), the patient had a recurrence of pulmonary embolism and a subsequent implant of a Gianturco-Rohem vena cava filter. The patient presented an initial reduction in the number of platelets from 477 x 10(3)/microliters to 360 x 10(3)/microliters that was ascribed to a heparin side effect or to a blocking of the platelets in a massive pulmonary thrombosis. A predischarge platelet count, however, showed an elevated number of thrombocytes (944 x 10(3)/microliters) and hyperfibrinogenemia (fibrinogen = 750 mg/dl). Essential thrombocythemia was demonstrated and treated with interferon alpha-2b-recombinant 3,000,000 U.I. on alternate days with a reduction in platelets to 450 x 10(3)/microliters. This case demonstrates the necessity of exploring, during pulmonary embolism, all possible causes of hypercoagulability in the course of thrombolytic therapy.

Iopamidol in cardioangiography: a retrospective, multicentre study. Part II. Paediatric patients

To evaluate the complication rate in paediatric cardioangiography with the nonionic contrast medium iopamidol data on 8,166 procedures were retrospectively collected in 12 centres. The overall complication rate was 3.78% (309/8,166). 3.44% were related to the procedure, and 0.34% to the contrast medium. The mortality rate varied with age. It was higher in patients less than 2 months (0.38%) than in patients greater than 2 months-2 years (0.06%) and in patients older than 2 years (0.03%). The total complication rate was higher than the one observed in a similar retrospective analysis performed in adult patients (1.89%). This difference is probably due to higher risk conditions of the younger patients. However the contrast medium related complication rate (0.34% vs 0.4%) and the mortality rate (0.11% vs 0.1%) were comparable, confirming the good tolerability of iopamidol in cardiac catheterisation also in paediatric patients.

Iopamidol in cardioangiography: a retrospective, multicenter study. Part I. Adult patients

To evaluate the occurrence of complications during diagnostic or interventional catheterization a retrospective analysis of catheterization procedures in 12 Italian laboratories using the nonionic contrast medium (CM) iopamidol (370 mgI/ml) was performed. Data obtained on 26,219 patients greater than or equal to 14 years are presented. The overall complication rate was 1.89% (485/26,219). The overall mortality rate was 0.1% (27/26,219). Procedure related complications were 389 (1.48%) and CM related complications were 106 (0.4%). No death was attributed to CM. Ventricular fibrillation (VF) rate was 0.11% comparable to the low rate observed with nonionic CM in other studies and less than the rate observed in surveys concerning the use of ionic CM. Fifty-seven thrombotic events were recorded (0.22%), a rate comparable with other surveys with ionic and nonionic CM. The total complication rate (6.1%), the rates of coronary occlusion (1.34%), myocardial infarction (0.37%) and urgent coronary artery by-pass grafting (0.5%) in 1,348 coronary angioplasties were lower than those recorded in previous surveys. These data confirm a good tolerability and no increased risk of VF and thrombotic events with iopamidol in cardiac catheterization.

Effects of urokinase and heparin on minimal cross-sectional area of the culprit narrowing in unstable angina pectoris

The immediate and delayed effects of urokinase and heparin on minimal cross-sectional area of a patent ischemia-producing coronary artery were prospectively investigated in 43 patients with unstable angina. After baseline angiography, patients were randomized to 3 different treatment groups: group I--urokinase (1,000,000 U intravenous bolus dose), followed by heparin infusion 3 hours later; group II--heparin (10,000 U intravenous bolus, followed by continuous infusion); and group III--conventional therapy only (intravenous nitroglycerin, beta blockers and calcium antagonists). Angiography was repeated at 1 hour and at 8 days of treatment and minimal cross-sectional area was determined in the 35 patients who completed the study. In group I, minimal cross-sectional area increased from 0.84 +/- 0.48 mm2 at baseline to 0.94 +/- 0.49 mm2 at 1 hour (p less than 0.05), and to 1.00 +/- 0.51 mm2 at 8 days (p less than 0.01 vs baseline). In group II, a significant increase in minimal cross-sectional area was observed only at the 8-day angiography (0.64 +/- 0.39 mm2 at baseline; 0.67 +/- 0.37 mm2 at 1 hour [p = not significant]; and 0.79 +/- 0.48 mm2 at 8 days [p less than 0.01] vs baseline). In group III, no significant changes in minimal cross-sectional area occurred either at 1 hour or at 8 days. Thus, both urokinase and heparin improved lesion geometry in patients with unstable angina, although a large individual variation was noticed. The effect occurred earlier with urokinase than with heparin.

Angiographic morphology and response to therapy in unstable angina

The coronary anatomy of 69 patients with unstable angina, subgrouped according to response to medical therapy, was investigated. All patients received oral treatment with nitrates, calcium antagonists, and beta-blocking agents. When combined oral treatment was not effective, an intravenous infusion of nitrates (10-100 micrograms/min) was subsequently administered. Coronary arteriography was performed within hours (14 +/- 9 h) from the last episode of chest pain in 28 patients refractory to medical treatment, while in 41 patients who became asymptomatic during medical therapy, angiography was performed after an observation period of several days (8 +/- 6 days). On angiography, the nonresponder group was characterized by a prevalence of eccentric and multiple lesions, and by a 46% incidence of thrombi (p less than 0.001). Recurrent symptoms requiring emergency bypass operation were common in this group. In patients responsive to medical treatment, a high percentage of concentric lesions (37%) and totally occluded (34%) coronary arteries was found (p less than 0.05). No infarcts and low rate of recurrent angina were noted in these patients during hospitalization. In conclusion, the finding of intracoronary thrombotic material and eccentric or multiple lesions can be an accurate markers of the active phase of the disease, while "silent" occlusion of the involved vessel may be accompanied by relief of symptoms during medical therapy.

Clinical experience with urokinase in intracoronary thrombolysis

A prospective nonrandomized study of the thrombolytic efficacy and dose-response effect of a high-molecular-weight urokinase, administered into the coronary artery, was conducted in 63 patients with acute myocardial infarction. Urokinase was infused (up to 180 min) at rates of 2000, 4000, 6000, and 10,000 IU/min in four consecutive groups of patients within 184 +/- 70 min following onset of chest pain. Of 54 patients with complete occlusion of the infarct-related vessel, 48 (89%) exhibited complete reperfusion. In 9 patients with incomplete occlusion, the degree of coronary stenosis was reduced with concomitant improvement in antegrade flow. The median effective dosage requirement of urokinase to reperfuse 50% of the treated patients was 180,000 IU. A relationship between the four infusion regimens and successful reperfusion was not found. The time to reperfusion, however, ranging from 42 +/- 30 to 60 +/- 41 min, appeared to be dose dependent. The reocclusion rate at follow-up (10-14 days) was 18%. Ejection fraction improved (40 +/- 8 vs. 47 +/- 8%, p = 0.002) in patients with low pretreatment values and in those treated within 2 h of the onset of symptoms. In-hospital mortality was 9%. Hemorrhage requiring transfusion occurred in 8% of the patients. None of the patients had levels of circulating fibrinogen inferior to 100 mg/dl. We conclude that urokinase can induce timely coronary reperfusion in patients with evolving myocardial infarction, at moderate infusion rates, and with concomitant induction of an only mild systemic lytic state.

[The influence of age on left ventricular function in patients with recent myocardial infarct]

To assess the effects of age on the left ventricular function at rest and during exercise in patients with first recent myocardial infarction, a symptom-limited exercise test was performed in 470 patients within 2 months from the acute episode, in supine position during hemodynamic and electrocardiographic monitoring after drug interruption and wash-out period. According to the age, the patients were divided into 3 groups: group 1 (less than or equal to 40 years) 68 patients; group 2 (41-59 years) 319 patients and group 3 (greater than or equal to 60 years) 83 patients. Coronary angiography was performed within 6 months in 159 patients. The possible differences in the hemodynamic pattern of these groups were analyzed with ANOVA and chi 2 test. Pulmonary artery end-diastolic pressure and cardiac output of each patient were compared to the normal values obtained in different age groups. The normal limits adopted are reported. At rest cardiac output and stroke volume were significantly lower and the rate pressure product higher in patients of group 3. Maximal work load was significantly lower (62 +/- 26 watts p less than .05) and pulmonary artery end-diastolic pressure higher (27 +/- 7 mmHg, p less than .05) in group 3 as compared to groups 2 (78 +/- 29 watts, 23 +/- 8 mmHg) and 1 (94 +/- 28 watts, 19 +/- 9 mmHg). However using different normal limits according to age (less than or equal to 20 mmHg in patients less than or equal to 60 years and less than or equal to 25 mmHg in patients greater than 60 years) the number of patients with an abnormal increase of pulmonary artery end-diastolic pressure was similar in all groups: 39.7%, 60.6% and 50.6% (NS) in group 1, 2 and 3 respectively. On the contrary cardiac output was abnormally low during exercise in 16.8% of group 3 vs 5.6% and 5.8% of groups 2 and 1 (p less than .05). The greater hemodynamic impairment of group 3 was independent from the electrocardiographic size of necrosis, from ST-segment depression during exercise and from the number of involved coronary vessels. In conclusion, age seems to play a significant role in determining the hemodynamic pattern in patients with recent myocardial infarction.

Efficacy of intracoronary and intravenous urokinase in acute myocardial infarction

The efficacy of intracoronary and intravenous urokinase was studied in 83 patients with acute evolving myocardial infarction. Urokinase was administered intracoronary in 48 patients with a success rate of 89% obtained after 47 +/- 32 minutes of infusion of a dose of 255.000 +/- 224.000 IU. In-hospital mortality in this group of patients was 10%. Severe arrhythmias were observed in 33% of the patients and the reocclusion rate at the re-study was 16%. Intravenous urokinase was administered as 200.000 IU bolus followed by 1.220.000 IU infusion in 21 patients. Angiography performed in this group of patients 48 hours after therapy showed a patency rate of 66%. A single intravenous bolus of 500.000 IU of urokinase was administered to 14 patients. At angiography all patients but one were found reperfused. The value of intravenous low-dose bolus injection of urokinase in acute myocardial infarction needs hower to be assessed with a properly designed clinical trial.

The effect of physical training on the sympathoadrenal response to exercise

The urinary excretion of catecholamines was measured in six healthy male volunteers at rest and during a fixed amount of work before and after physical training. It was found that, although training resulted in a significantly lower heart rate during exercise, the output of catecholamines was unaltered, indicating that the total activation of the sympathoadrenal system by exercise was similar before and after training. A similar heart rate study before and after training was also made during beta-adrenergic receptor blockade. Under these conditions the heart rate during exercise was not significantly changed by training. It is suggested that physical training reduces the sensitivity of the beta-receptors of the heart.