Advanced auriculoventricular block of atypical presentation after acute myocardial infarct in sleep apnea syndrome

In recent years, several types of centrifugal pumps have been widely used as the main pumps for cardiopulmonary bypass (CPB) and postcardiotomy cardiac support. From April 1990 to March 1997, a percutaneous cardiopulmonary support (PCPS) system was used in 20 patients with an average age of 58 years (13 males and 7 females). They comprised 11 ischemic, 6 valvular, 2 aortic, and 1 congenital heart disease patients. Our PCPS system consists of a centrifugal pump (BioMedicus BP-80), an oxygenator, and a reservoir. The entire blood contacting surface, including that of the thin wall cannulas, is coated by heparin bonded materials. As a result of this new technology, this system can be used for the long term without systemic heparinization. No major critical thrombi were revealed inside the pumps or circuits. Of the 20 patients, 7 (35%) (Group 1) could be weaned from PCPS, and the remaining 13 (Group 2) could not. In Group 1 although 2 patients suffered from renal failure and pneumonia, respectively, both were discharged from our hospital. The long-term survival rate was 35%. In Group 2 cerebral vascular damage was recognized in 3 patients, renal failure in 4, multiple system organ failure in 4, bleeding in 2, arrhythmia in 1, and leg ischemia in 2. Pulse pressure was significantly elevated due to the recovery of the native heart in Group 1, 2 days after support. However, in Group 2, it did not elevate, and the left ventricular ejection fraction was less than 30%, associated with high left atrial pressure. In conclusion, this heparin coated PCPS system was very simple and easy to control. It demonstrated long-term biocompatibility and was very effective in recovering deteriorated cardiac function. Quicker application of this system can play an important role in preventing severe complications and obtaining better clinical results. If long-term support is necessary, a ventricular assist device (VAD), which is more powerful, durable, and biocompatible, has to be applied instead of PCPS.     

Secondary prevention of myocardial infarct

Preventive measures are the most powerful measures to treat manifestations of ischemic cardiopathy. Secondary prevention of myocardial infarction involves the following intervention areas: a) Limitation of adverse physiological and emotional consequences of the acute illness; b) Identification of the patients particularly exposed to the risk of new episodes of ischemic cardiopathy or to their consequences, namely reinfarction and sudden death; c) Institution of therapeutic attitudes, surgical or medical, that can prolong life and can oppose functional deterioration and prevent symptoms; d) Institution of measures that can oppose the progression of the initial disease that is, in almost all cases, atherosclerosis. Measures that can oppose the progression of cardiac disease and its consequences after an episode of myocardial infarction, and measures that can oppose the evolution of atherosclerosis are described in this article. The measures that can influence the risk factors after an episode of myocardial infarction are briefly commented: characteristics related to life style and physical exercise; smoking habits; plasmatic lipid levels; high blood pressure; and therapeutic substitution with estrogens after menopause. Pharmacological interventions in secondary prevention of myocardial infarction are described, namely with the following groups of substances: beta-adrenergic blocking agents; platelet active agents; anticoagulants; and angiotensin-converting enzyme inhibitors.     

Stress echocardiography in myocardial infarct

For patients with recent myocardial infarction, the main determinants of prognosis are: extent of transmural necrosis, state of the infarct-related artery and the presence and extent of myocardium at risk. The basic principle underlying the use of stress echocardiography states that myocardial ischaemia produces abnormalities of regional wall motion which are by themselves early, sensitive and specific markers of decreased perfusion. Dobutamine infusion allows for evaluation of myocardial contractile reserve by increasing inotropism. In low doses it gives us information on regional viability. In high doses, wall motion under increased oxygen demand, it becomes dependent on the ability of the coronary arteries to increase blood flow. Dipyridamole induces coronary vasodilation. In low doses it produces an increase in the blood flow. In high doses the steal effect deviates blood from the regions dependent on stenosed arteries. Ischaemia and regional wall motion abnormalities ensue. A negative stress echocardiogram, either under dobutamine or dipyridamole, has an excellent negative predictive value while a positive stress echocardiogram is predictive of an increased rate of events in the follow-up.     

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.     

Old myocardial infarct: echocardiographic study

A large number of patients survives many years after an acute myocardial infarction (AMI). Echocardiographic study in patients with a very old myocardial infarction (VOMI) can certainly contribute to a better understanding of anatomical and functional damage of the heart. AIM OF THE STUDY: To describe the echocardiographic pattern and to analyze differences between patients with anterior (ant.) and inferior (inf.) VOMI and subjects treated or not with a thrombolytic agent (T+ and T-). METHODS, DESIGN OBSERVATIONAL STUDY: We performed an M-B mode and color-doppler echocardiographic examination of 136 patients (M/F: 130/6), mean age 64.4 +/- 9 years, with an isolated VOMI that is least 5 years old (mean 9.5 +/- 3.1; range 5-16 years), with a good visualization of left ventricular (lv) endocardial profile and without left bundle branch block or valvulopathy is related to myocardial infarction. We established electrocardiographic site and thrombolytic treatment on a documental basis dating from AMI. End diastolic volume index (EDVi), end systolic volume index (ESVi), ejection fraction (EF), wall motion score index (WMSI), left atrial antero-posterior diameter (AD) and presence of any lv aneurysm, scar, thrombus, mitral regurgitation (MR) were assessed. Data were compared with those of 100 normal subjects (controls) with sex, age and physical settlement similar to those of the patients. RESULTS: EDVi appeared much more enlarged in patients than in controls (p < 0.0001). There was a large difference between ant. VOMI and inf. VOMI (p < 0.0001); where as a smaller increase was noticed in T+ versus (vs) T- patients (p = 0.04). In comparison with controls, a smaller difference was observed in inf. VOMI (p = 0.002). ESVi presented a similar behaviour in patients vs controls and ant. vs inf. VOMI (p < 0.0001), but there was no statistical difference between T+ and T- while a large difference was detected between inf. VOMI and controls (p < 0.0001). EF was lower in patients than in controls (p < 0.0001) and in ant. VOMI rather than in inf. VOMI (p < 0.0001); no statistically relevant difference was seen between T+ and T-, while a large difference was observed between inf. VOMI and controls (p < 0.0001). WMSI appeared to be significantly worse in patients vs controls (p < 0.0001), but there was also a great difference between ant. and inf. VOMI (p < 0.0001). T+ had a better index in comparison with T- (p = 0.02). There was also large difference between inf. VOMI and controls (p < 0.0001). AD was larger in patients than in controls (p < 0.0001), but there was no statistical difference between ant. and inf. VOMI and T+ and T-; in comparison with controls, smaller difference was seen in inf. VOMI (p = 0.04). Aneurysm was seen in 16% of patients, more prevalently in ant. (27%) than in inf. VOMI (5%) (p < or = 0.001). Scarring was seen in 45% of patients and, like aneurysms, more in ant. (69%) than in inf. VOMI (22%) (p < or = 0.001). Thrombus was rarely detected (5%) and only in ant. VOMI (12%) with aneurism (p < or = 0.01 vs inf.). MR was seen in a large number of patients (48%) and in 27% of controls (p < or = 0.001). No significant difference was pointed out between ant. and inf. VOMI. Aneurysm, thrombus and MR (21.8 and 55% respectively) were more prevalent in T- than in T+ (9.3 and 48% respectively), with no statistical significance. Scarring prevailed in T+ (48%) rather than in T- (43%), without any statistical difference. CONCLUSIONS: Patients with VOMI show increased lv volumes, decreased EF and persistence of regional wall motion abnormalities. Volumetric and kinetic modifications mainly involve ant. VOMI, but inf. VOMI also presents similar but smaller modifications. Left atrial dimensions also increase in VOMI. Aneurysms, scars, MR occur frequently; while the presence of thrombus is infrequent. Thrombolytic therapy appears to be a long-term protection from anatomical and functional damage. Echocardiography seems to be the ideal tech     

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 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.).