Adjuvant therapy in patients with acute myocardial infarct

Besides the thrombolytic therapy several adjuvant therapeutic measures were identified which significantly improve the prognosis of patients with acute myocardial infarction (AMI). These measures include the treatment by means of acetylsalicylic acid (ASA), beta-blockers and ACE inhibitors. Early administration of ASA and beta-blockers are indicated in all patients with AMI who have no contraindications for this therapy. They are especially the patients with manifest heart failure or asymptomatic left ventricular dysfunction who benefit from ACE inhibitors. The effectivity of routine administration of other medicaments such as anticoagulants, nitrates, calcium channel blockers and magnesium, have not been convincingly proved. However, some selected patients with AMI can benefit from these medicaments. Intravenous administration of heparin is unambiguously justified only in thrombolysis with t-PA. Thrombolyses with streptokinase, urokinase, and anistreplase are justified only at high risk of thromboembolic complications. Their prevention and therapy include also the necessity to restrict the administration of pelentan. The use of nitrates is indicated in patients with AMI in case of sustaining stenocardia, arterial hypertension and manifest heart left ventricular failure. Until the definitive standpoint is gained regarding the effect of magnesium in patients with AIM, its administration remains especially indicated in cases of arterial hypertension, tachycardiac disturbances of the heart rhythm and states of assumed or proved hypomagnesiemia. In AMI cases when magnesium is used in order to protect the patient from reperfusion lesion, it must be administered prior to the reperfusion therapy. An intensive research in the field of therapeutical measures in patients with AMI still continues. It is certain that it will soon bring further knowledge which will in turn improve the prognosis and quality of life of patients with AMI. (Tab. 4, Ref. 133.)     

Congestive heart failure and ventricular arrhythmia in relation to magnesium, potassium and sodium in serum and erythrocytes

The aim of this study was to determine magnesium, potassium and sodium in plasma and erythrocytes in patients (14 male, 12 female; the average age 60.3) with congestive heart failure (CHF) (NYHA class II/III, III, IV) who were treated with digitalis, diuretics and vasodilators. All patients were subjected to 24 h ECG monitoring and ventricular arrhythmias classified according to LOWN, were analyzed in relation to electrolyte contents in erythrocytes and serum. Control group consisted of 20 persons (17 male; 3 female: the average age 58.7 years). Plasma and erythrocyte K and Na were determined by flame spectrophotometer; Mg was assayed by atomic absorption spectrophotometer. Statistical analysis was made by t-Student test. Results obtained suggest that patients with CHF require supplementation K+ with Mg2+ (tab. I). Our study has not revealed expected interrelationships between ventricular arrhythmias and electrolyte disturbances in patients with CHF. It should be stressed, however, that the small numbers of patients in the subgroups in our study might have blurred the possible relationship.     

Early and long-term results of direct PTCA in patients with acute myocardial infarct

A review of the literature suggests that direct PTCA for acute myocardial infarction is indicated and feasible in 90-95% of unselected, consecutive patients; direct PTCA is reported to be successful in > 90% of procedures. This results in a hospital mortality of 3-7% for unselected patients and a 4% re-infarction rate. A recent meta-analysis of direct PTCA vs i.v. thrombolysis in patients with acute infarction demonstrates a lower mortality after PTCA (4.4% vs 6.5%, p = 0.02) as well as lower mortality/re-infarction rate (7.2% vs 11.9%, p < 0.001). Mortality in the 1st year after discharge is < 5% with about half of the fatalities being due to cardiac causes. Patients presenting with or developing cardiogenic shock in the acute infarct phase experience a 20-50% acute mortality. Mortality rests at < 10% in these patients in the first year after discharge. In conclusion, (1) direct PTCA is feasible without additional risks in patients with acute myocardial infarction, (2) angiographic and clinical success rates of direct PTCA are favorable and superior to i.v. thrombolysis in the hands of expert operators, and (3) referral to an institution providing the option of immediate, direct PTCA must be considered in the patient with acute infarction but contraindication(s) to i.v. thrombolysis.     

Long-term electrocardiographic monitoring of patients after acute myocardial infarct

The authors present an account on detailed electrocardiographic follow-up of a patient for 12 months after an inferior myocardial infarction. The patient died 14 months after the IM due to arrhythmia after previous remodelling of the left ventricle. The results assembled by means of superstandard methods of signal averaging electrocardiography (method of cumulative amplitudes, RMS signal and frequency analysis) and electrocardiographie body surface mapping (isointegral maps) are confronted with detailed clinical examinations and repeated echocardiographic investigations. The assembled results indicate that the applied superstandard methods make it possible to extract electrocardiographic parameters (presence of pathological high frequency peaks, raised values of partial cumulative amplitudes at the end of the QRS complex at higher frequencies, negative correlation coefficients from comparisons of integral maps with controls) which are a signal that the patient's life is threatened.     

High-resolution electrocardiography in acute myocardial infarct

The author starts by highlighting the importance of risk stratification in patients who have survived a myocardial infarction. High resolution electrocardiography, also called signal-averaged electrocardiography (SAECG), appears in this setting as a diagnostic tool that, by providing important information about the way the intraventricular conduction of the electrical impulse is made, contributes to the characterization of the arrhythmogenic substrate, which is the basis of ventricular tachycardia and fibrillation. By resorting to the averaging of the electrocardiographic signal, SAECG enables us to detect ventricular late potentials whenever the analysis of that signal is made in time-domain. Further details, which will enrich the information on ventricular activation, can be obtained if the analysis is made in the frequency-domain (spectral analysis). The importance of detecting abnormalities in the SAECG recordings lies in the fact that those abnormalities are related to the occurrence of ventricular tachycardia and fibrillation, which are responsible for arrhythmic death. After referring to the criteria of positivity of SAECG and its reproducibility, the author approaches the most important part of the paper: the clinical applications of SAECG. After focusing on the interest of the method in noncoronary conditions, its usefulness in patients with acute myocardial infarction is pointed out. The author then mentions the prevalence of abnormalities in SAECG in patients with acute myocardial infarction and emphasizes the interest of the method in risk stratification. The author then presents the results of his Group in what concerns prevalence and prognosis. Finally, the author refers to the application of SAECG in other forms of coronary artery disease besides myocardial infarction.     

Nutritional problems in acute myocardial infarct

Hypocaloric nutrition in patients during the first days of myocardial infarction cannot be suggested any longer. Because of several reasons the minimum calory uptake should be about 2000 kcal/per day. Patients with enddiastolic pulmonary artery pressures above 20 mm Hg which is especially a high risk group should be treated parenterally with solutions of carbohydrates, insulin, and potassium. This regimen appears to be of a special importance at beginning shock or during cardiogenic shock.     

Biochemical markers in acute myocardial infarct

Exact and early diagnosis of acute myocardial infarction is essential for the subsequent routine management of this frequent cardiovascular disease. At present, the clinical biochemistry possesses a set of more or less cardiospecific protein markers for early detection of myocardial ischemic damage. After the admission of patient to the hospital, serial estimations of rather non-specific enzyme activities (creatine kinase, its MB-izoenzyme, lactate dehydrogenase, hydroxybutyrate dehydrogenase) are currently used for the detection of acute myocardial infarction and for the further monitoring of the patient and managing his therapy. In the past decade, many cardiospecific biochemical markers were discovered and gradually introduced into the routine clinical practice. The most perspective markers are some molecules of contractile proteins of heart myofibrils (troponins, myosin chains) as well as "rediscovered" myoglobin. The aim of this review article is to inform about the commonly used, as well as about the new biochemical markers, to discuss some problems of diagnostic strategy in the early and exact detection of ischemic myocardial damage and to attract attention to the difficulties. However its disadvantage resides in its presence in both myocardium and skeletal muscles which arise when the diagnosis of acute myocardial infarction is prematurely excluded from consideration and such patients are discharged too soon from hospital. (Fig. 1, Tab. 1, Ref. 72.)     

The apexcardiogram in acute myocardial infarct

The relation between intracardial haemodynamics and apicocardiogram (ACG) parameters is explained. A wave (amplitude and duration), A/H ratio, true and total TCI, total systole, total expulsion, RIV, RFW, TE/TCI (total) and TE/TCI (true) findings in 22 patients with acute myocardial infarct are presented. Attention is also given to clinical and radiological signs of cardiac insufficiency and the infarct site. Constant and significant increases in the A wave, A/H ratio and RIV, together with a decrease in total expulsion, were noted, particularly in cases with clinical evident insufficiency. In the pre-expulsive stage, ACG Data could not be taken as a reliable index of myocardial contractility in cases where insufficiency was not manifest. It is felt, therefore, that ACG may be of assistance in the evaluation of changes in myocardial performance, even where clinical and radiological signs of decompensation are absent.     

Supraventricular arrhythmias and disorders of atrioventricular and intraventricular conduction in patients with acute myocardial infarct

Reperfusion arrhythmias originate as a consequence of the complex of cellular and humoral reactions accompanying the opening of coronary artery. As the primary cause of their generation are considered the chemically defined substances that are produced and accumulated in myocardium during reperfusion. The key role is ascribed to free oxygen radicals but of importance are also other substances such as calcium, thrombin, platelet activating factor, inositol triphosphate, angiotensin II and others. These chemical mediators of reperfusion arrhythmias operate as modulators of cellular electrophysiology causing the complex changes at the level of ion channels. It is supposed that in the genesis of reperfusion arrhythmias unlike ischemic arrhytmias operate nonreentrant mechanisms such as abnormal or enhanced automacy and triggered activity due to afterdepolarizations. As a typical reperfusion arrhythmia is considered an early (within 6 hours after start of thrombolysis), frequent (> 30 episodes/hour) and repetitive (occurring during > 3 consecutive hours) accelerated idioventricular rhythm (AIVR). AIVR with such characteristics has a high specificity and positive predictive accuracy but relative low sensitivity as a predictor of reperfusion. Thus, in occurrence of AIVR, recanalization of infarction-related coronary artery is very probable, but in absence of AIVR, reperfusion is still not excluded. The following arrhythmias are regarded also as markers of reperfusion: frequent premature ventricular complexes (> twofold increase in frequency within 90 minutes after the start of thrombolysis), a significant increase of episodes in nonsustained ventricular tachycardia, sinus bradycardia and probably also high-degree atrioventricular blocks. At present, there is no definite evidence, as to whether sustained ventricular tachycardia and especially ventricular fibrillation can be caused by reperfusion. Reperfusion arrhythmias are an important noninvasive marker of successful recanalization of infarction-related coronary artery. However, they are also a sign of reperfusion injury and a finding which may limit the favourable effect of reperfusion. In account of that, there is a very intensive search for pharmacologic interventions which could protect or attenuate the reperfusion injury and thereby also the genesis of reperfusion arrthythmias. Although promising results were obtained with many substances antagonizing the effects of mediators of reperfusion injury, there is no definite recommendation for their use under clinical conditions. However, the results from the latest clinical trials with ACE inhibitors are very promising. These trials render relative conclusive evidence, that ACE inhibitors could have a protective effect against reperfusion arrhythmias. (Ref. 89, Tab. 1.)     

The pre-hospitalization period in acute myocardial infarct

The article reviews the possibilities of biochemical markers in coincidence with the assessment of prognosis in acute coronary syndromes and in the revealing of effectivity of their therapy. The current options of clinical biochemistry in many cases allow to supplement, confirm, or exclude the results of modern physical and other clinical examination methods and in this way to contribute to the accuracy of the diagnostic process, and enable to comment the prognosis and the risk measure of the patient. A significant progress has been achieved in the assessment of effectivity in thrombolytic therapy in acute myocardial infarction, where especially the series assessment of myoglobin levels or specific troponin cardiomarkers can facilitate the process of physician's decision as to the assessment of the subsequent procedure in the treatment of patients. The assessment of levels of both specific and partly less specific cardiomarkers becomes one of the criteria of the decision in coincidence with ischaemic episodes in the peri and postoperative periods (the diagnosis of peri-operative myocardial infarction). Specific troponin cardiomarkers acquire an extraordinary significance in the prediction of the measure of risk in patients with unstable angina pectoris where already one single assessment of the level of these markers is sufficient for hospitalization of the patient and thus enables to change the physician's strategy of further therapy. (Ref. 95.).     

Pathophysiologic and clinical basis for classification of patients after acute myocardial infarct

Non-invasive stratification of patients after AIM represents the basic procedure in identification of patients at high risk of the origin of complications after AIM. It enables to tip a group of patients at the highest risk of the development of reinfarction, sudden cardiac death (SCD) or general cardiac mortality, i.e. the patients who can benefit the most from the early therapy. The presented review describes pathophysiological and clinical aspects of stratification of patients after acute myocardial infarction.