Thrombolytic therapy in acute myocardial infarct

Numerous studies have demonstrated a high prevalence of coronary thrombi in the early hours of acute myocardial infarction leading to a complete occlusion of the coronary artery. Thrombolysis and reperfusion in the very early hours can preserve jeopardized myocardium from necrosis. Using intravenous streptokinase early reperfusion can be achieved in 50% of the patients with occluded coronary arteries. Using rt-PA and prourokinase reperfusion rate is 60 to 70%. Both agents have more fibrin-specific activity, therefore the risk of bleedings is reduced. However, thrombolytic treatment with early reperfusion seems to be just the first step. Further procedures (percutaneous transluminal coronary angioplasty = PTCA or early bypass surgery) have to be added to improve not only the short-term but also the long-term prognosis. If the ongoing randomized trials confirm a significant reduction in mortality due to reperfusion and improved ventricular function this "aggressive treatment" of the evolving myocardial infarction will change our strategy from a symptomatical to a more causal therapy.     

Experiences with laser therapy in acute myocardial infarct

Our clinical and instrumental investigations showed that invasive laser therapy has a multiple therapeutic effect. Acting favourably on principal pathogenetic mechanisms of acute myocardial infarction, it decreases the pain syndrome, normalize electrical instability of the heart, limits myocardial ischemic damage area and accelerates scarring process. It leads to a decrease in mortality and in the incidence of severe complications of myocardial infarction such as ventricular fibrillation, cardiogenic shock, cardiac insufficiency. Thus, the new method of treating acute myocardial infarction with He-Ne laser irradiation significantly enhances treatment efficacy, improves the course and prognosis of myocardial infarction.     

Effects of intravenous diltiazem in acute myocardial infarction: hemodynamic evaluation

The acute hemodynamic effects of intravenous Diltiazem were studied in 20 pts. with acute myocardial infarction, admitted to Coronary Care Unit within 24 hours from onset of Symptoms--19 men, 1 woman, aged from 46 to 83 years, 14 with anterior myocardial infarction, 6 with inferior myocardial infarction. All, but one, where at the time of their admission to CCU in first Forrester's hemodynamic subset (CI greater than 2.2 L/min/m2, WP less than 18 mmHg); in the last patient WP was 21 mmHg, CI 2.6 L/min/m2. Hemodynamic measurements were performed before (no drugs with hemodynamic effects were allowed during 4-6 hours before the study protocol) and after the administration of Diltiazem, 0,3 mg/kg i.v. administered in 2 min. (bolus) in 12 patients, Group A. In 8 pts--Group B--the bolus was followed by continuous infusion of Diltiazem at the rate of 5 mcg/Kg/min for three hours. The hemodynamic measurements were repeated: in Group A 2-5-30-60-120 min. after the end of the bolus; in the Group B at the same time as Group A, at the end of infusion (180 min) and 60 min after the end of infusion. Diltiazem induced no significant changes of HR, CVP, WP, CI, LVSWI and Triple product, in both groups of pts., at any time. Systolic and diastolic blood pressure decreased significantly (P less than 0.01) only 2 min. after Diltiazem administration (Group A: SBP 125.0 +/- 15.8----114.0 +/- 16.0 mmHg, DBP 85.4 +/- 6.5----76.6 +/- 10.5 mmHg; Group B: SBP 123.0 +/- 20.0----113.0 +/- 11.0 mmHg, DBP 78.1 +/- 7.0----75.0 +/- 4.9 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of hemodynamic studies in evaluating left ventricular insufficiency in acute myocardial infarct

Left ventricle (LV) disfunction is the main cause of death in patients suffering from acute myocardial infarction (AMI) who are admitted to Coronary Care Units. Therefore, it is easily understandable that the study of LV performance is of paramount importance in the choice and evaluation of the efficacy of therapy, as well as in the prognosis of patients with AMI. In the first section of this paper, the authors analyze the physiopathology of LV disfunction during AMI; in the second section, based upon a study of 480 patients, they value the contribution of hemodynamic examination with the Swan-Ganz catheter in the evaluation of the cardiac function and in the prognosis of patients with AMI.     

Behavior of arterial pressure during administration of intravenous streptokinase, in patients with acute myocardial infarct

OBJECTIVE: To evaluate the effect on blood pressure (BP) of intravenous (IV) streptokinase (SK) in patients (PTS) with acute myocardial infarction (AMI). DESIGN: Retrospective study with analysis of BP registers ten minutes before and during SK infusion. SETTING: PTS admitted to the Coronary Care Unit (CCU) of Santo António Hospital, Oporto. PATIENTS: Thirty-eight male PTS, average ages of 54, ranging from 38 to 67, AMI confirmed, and criteria to thrombolytic therapy. One patient was excluded on account of persistent hypotension since admission. MATERIAL AND METHODS: IV infusion of 1,500,000 U of SK over 60 minutes, preceded by 200 mg IV of prednisolone. BP and heart rate (HR) were evaluated with a Datascope Accutorr 1A set. The lowest value of the systolic BP (SBP) recorded ten minutes before SK infusion was considered the baseline value. We valued the reduction of SBP above 15%, defining its fall as the difference between the baseline value and the minimum value of SBP recorded during the infusion. Hypotension was defined to SBP values below 90 mmHg. MAIN RESULTS: The SBP fall was 40.4 +/- 22.1 mmHg (range 9 to 102), having been recorded the minimum value at 22.9 +/- 10.9 minutes. It was accompanied by diastolic BP (DBP) fall of 30.6 +/- 18.9 mmHg (range -2 to 76) and by a HR increasing from 76.2 +/- 13.7 beats/min. to 80.8 +/- 14.1 beats/min. (p less than 0.01). In 86% of the PTS this fall was transient, lasting 8.9 +/- 6.3 minutes, and was corrected by slowing or stopping the infusion for a few minutes and placing the patient in Trendelenburg position. Two PTS needed sympaticomimetic amines because of persistent BP reduction despite the previous measures. 92% of the PTS had a SBP fall higher than 15% in relation to the baseline value. The SBP was kept over 90 mmHg in 20 PTS (54%); hypotension was recorded in the remaining 14 PTS (38%), and in 10 (27%) of these the SBP fell below 80 mmHg. We couldn't prove that the infarction location and the extension of the ischemic lesion had influenced this BP fall. CONCLUSION: The BP reduction during treatment with high doses of SK deserves some attention because, although transient and easily reversible, it is frequent and sometimes significative. It demands then careful monitoring in order to avoid the hypoperfusion to the ischemic myocardium, that could jeopardize the potential benefits of reperfusion in the reduction of infarction area, the main objective of the thrombolytic treatment.     

Importance of the early intravenous administration of streptokinase in acute myocardial infarct

To evaluate the importance of early initiation of fibrinolytic therapy with intravenous streptokinase (IVSK), we studied 34 consecutive patients, within less than six hours of the onset of acute myocardial infarction, who were treated with 1.5 million units of intravenous streptokinase. All the patients had coronary angiograms in the first seventy two hours. We correlated the angiograms with the time of onset of the IVSK. The patients were divided into 3 groups: Group num. 1: From zero to two hours (twelve patients); Group num. 2: From two to four hours (13 patients); and Group num. 3: From four to six hours (nine patients). We had angiographic reperfusion in twenty-four patients (70.2%) P less than 0.05. We observed reopening in the patients of group num. 1 (83.3%); in group 2, nine patients (69%) and in group num. 3, five patients, (55.5%), with statistical significance only in group num. 1 (p less than 0.05). We also demonstrated the utility of the electrocardiographic and enzymatic criteria to predict reperfusion. No mortality was related to the procedure. We concluded that a higher percentage of reperfusion is obtained the sooner intravenous streptokinase therapy is initiated.     

Clinical aspects of reperfusion arrhythmia following intravenous thrombolysis in acute myocardial infarct

In accordance with the majority of the reports in the literature reperfusion arrhythmias were observed in more than 30% of the patients with acute myocardial infarction (n = 25) under or immediately after a highly dosed short-term infusion with streptokinase. With reference to indirect signs the recanalisation rate was assumed with 75%. Only one third of the reperfusion arrhythmias had haemodynamically significant characteristics and required an influence. Though in literature from animal experimental findings directive conclusions for the therapy are to be derived, the procedure in practice is still vastly empirical. In the ventricular tachycardia lidocaine, procainamide and ajmalin may be recommended. In ineffectiveness or particularly threatening situations the electrotherapy (cardioversion, DC-shock) is to be preferred. The concept inaugurated by Corr and Witkowski apply alpha-adrenoreceptor blockers has not yet entered the clinical practice. Possible problems in the treatment of reperfusion arrhythmias in the prehospital phase should at present still be a reason not to antedate the thrombolytic therapy into this phase.     

Reperfusion syndrome during thrombolytic therapy of myocardial infarct

Infarct-related coronary artery occlusion was found in 90 out of 97 patients with myocardial infarction and intracoronary thrombolytic therapy was performed by using streptokinase. Electrocardiographic, clinical, and hemodynamic manifestations of the reperfusion syndrome were assessed when the coronary artery became patent. It was concluded that arrhythmic manifestations of the syndrome were the most life-threatening as they might lead to fatal arrhythmias. It was demonstrated that prognostically unfavorable reperfusion-induced arrhythmias might be abolished by a preventive administration of mexitil and, to a lesser degree, isoptin. Good mexitil tolerance and certain limitations of isoptin therapy were also underlined.