Thrombolytic reperfusion of coronary arteries and the function of the left ventricle in acute myocardial infarction

Left-ventricular myocardial contractility was assessed in thrombolytically-treated patients with acute myocardial infarction. General and local left-ventricular activity was shown to deteriorate progressively in patients with "late" or altogether absent recovery of coronary flow, whereas patients with early recovery of coronary flow demonstrated intact general contractility parameters and better contractility in the affected area. Coronary reperfusion within 5-6 hours helps to maintain functional capacity, which is less marked than the one in patients with early reperfusion.     

Total and segmental contractile function of the left ventricle in acute myocardial infarction studied by angiography

An angiographic study of 50 patients with acute myocardial infarction was carried out in order to assess total and segmental left-ventricular contractility. The comparison of left-ventricular activity in patients with transmural vs. nontransmural anterior myocardial infarction demonstrated no differences, related to the type of lesion. The type of affection of the infarction-linked artery largely influences left-ventricular activity. Nontransmural diaphragmatic myocardial infarction was associated with the least left-ventricular dysfunction. Various functional left-ventricular disorders corresponded to definite central hemodynamic patterns, associated with myocardial infarction.     

Coronary circulation and left ventricular function in patients with transmural myocardial infarct

Hemodynamics and left-ventricular segmental contractility were examined in 72 patients, subjected to selective coronarography and ventriculography. Forty-six patients had a history of anterior, and 26, posterior, transmural myocardial infarction (MI). Atherosclerotic stenosis of coronary arteries (more than 75% of vascular diameter) was revealed in 67 of 72 patients. Residual occlusion was shown to occur more commonly in the right coronary artery. Collateral flow was more commonly associated with a history of myocardial infarction affecting the posterior wall of the left ventricle, while segmental contractility disorders, even aneurysms, and generalized disturbance of left-ventricular contractility, as manifested in reduced mean rate of myocardial circular fibre shortening, were more typical for the affection of the anterior wall of the left ventricle.     

Total and segmental left ventricular ejection fraction of acute myocardial infarct patients during serial determination using 2-dimensional echocardiography

Ultrasonic scanning of the heart was carried out on days 1, 10, 20 and 30 of uncomplicated myocardial infarction (MI) in 46 patients whose total and segmental ejection fraction (EF) (5 segments by a two-chamber projection from the apex) were then calculated. Total left-ventricular EF was moderately reduced on day 1 (48.6 +/- 1.8%) and increased significantly by day 30 (55.4 +/- 2.3%, p less than 0.01). All patients showed impaired segmental contractility in infarcted areas. Segmental EF was essentially reduced in segments 3, 4 and 5 in anterior MI, and in segments 1 and 2 in posterior MI. Recovery was associated with increasing EF in asynergic segments, that nevertheless remained diminished on day 30, as compared to unaffected areas. The rise in left-ventricular total EF is attributed to better contractility of asynergic segments.     

Function of the heart chambers in acute myocardial infarct

A study of 87 patients, admitted to hospital within the first day of acute myocardial infarction (AMI) identified 3 groups of patients on the basis of their pulmonary capillary occlusion pressure (OP) values. Sixteen normal subjects made up the control group. Myocardial contractility and volume characteristics obtained by sectoral scanning were reviewed. It was demonstrated that the contractility of the left and right heart chambers had different patterns of change in relation to the magnitude of pressure: left-atrial and right-ventricular ejection fraction (EF) gradually declined, and normal pressure values were associated with right-ventricular hyperfunction. Right-ventricular EF also decreased as the OP grew, yet it did not reach the critical values as observed with the left-ventricular EF. The predominance of the right-ventricular function over the left-ventricular one might be one of the mechanisms underlying the development of insufficiency in the lesser circulation. Contractility unbalance was also shown to exist between the right and left atria. A rise in the end systolic volume in the presence of unchanged end diastolic volume is the earliest manifestation of reduced left-ventricular contractility in acute myocardial infarction.     

Changes in the indices of central hemodynamics and myocardial metabolism as affected by plasmapheresis in patients with myocardial infarct

Gravitation plasmapheresis (PP) on PF-0.5 fractionator was used in 32 patients with acute myocardial infarction to control blood rheologic disorders. Central hemodynamics and myocardial metabolism were monitored by means of right heart probing and echocardiography. A control group of 7 patients were subjected to "mock PP" with a rheopolyglucin infusion. PP limited manifestations of heart failure, normalized the levels of compounds with high molecular weights which conditioned plasma viscosity, reduced significantly total peripheral and total pulmonary resistance, increased the cardiac index, stroke volume and ejection fraction, and improved regional left-ventricular contractility. Myocardial metabolic studies demonstrated a decline in left-ventricular myocardial ischemia, as evidenced by the arteriovenous difference in lactate levels. It is therefore suggested that PP can be effectively used as part of combined treatment for complicated acute myocardial infarction.     

Total and segmental left-ventricular myocardial function in patients with post-infarction heart aneurysm

A study of total and segmental myocardial hemodynamics and contractility has demonstrated a close relationship between segmental disorders and the type and site of postinfarction left-ventricular aneurysms. A direct close correlation was established between total and segmental hemodynamic disorders, excepting the left-ventricular aneurysm area. A close correlation was also demonstrated between myocardial contractility and ejection fraction parameters in three left-ventricular segments. Standardized trisegmental hemodynamic and contractility analysis is shown to reflect left-ventricular myocardial condition in patients with postinfarction cardiosclerosis and aneurysms of the heart.     

Left-ventricular function and physical exertion tolerance in patients with myocardial infarction with isolated lesion of the coronary arteries

Myocardial infarction area and left-ventricular myocardial contractility, determined by sectoral scanning, and exercise tolerance were assessed in 47 myocardial infarction patients with isolated coronary arterial lesions. The area under myocardial infarction was shown to be dependent on the site of the atherosclerotic process rather than the degree of stenosis in patients with isolated coronary arterial lesions. A relationship was established between the incidence of complications developing in the acute phase of infarction and the degree of stenosis. The disease was complicated more frequently in patients with coronary arterial occlusion as compared to those with severe coronary-arterial stenosis. High stress tolerance, irrespective of the site of myocardial infarction, is an evidence of great functional potentials in this category of patients.     

Rheocardiographic evaluation of left-ventricular contractility in the measured isometric pedal test

Central hemodynamic parameters were assessed by tetrapolar chest rheography during rationed isometric pedal stress exposure in 54 normal subjects and 24 angina patients. The relationship between left-ventricular contractility and the magnitude of increasing static effort at different steps of stress exposure was examined. In normal subjects, the increase in static effort was shown to affect significantly left-ventricular contractile capacity, left-ventricular performance index and left-ventricular contractile index, and has no effect on the myocardial contractility index. In anginal patients, developing myocardial ischemia in response to stress, there was a significant drop in left-ventricular contraction intensity, myocardial contractility index and left-ventricular contractile index, as compared to the pre-ischemic values. The rheographic left-ventricular contractile index is believed to be the best instrument for the assessment of left-ventricular inotropic activity in isometric stress.     

Early systolic asynergia of the left ventricle as a symptom of myocardial ischemia

Cineangiographic contraction assessment was made in 30 coronary patients with normal left-ventricular ejection fraction. Twenty-seven (90%) patients showed abnormal myocardial segmental contractility during the early phase of contraction. or the so-called early systolic asynergia. Its loci coincided with areas supplied from atherosclerotic coronary arteries, as a result of ischemia causing local impairment of left-ventricular contractility, undetectable by routine hemodynamic investigation. In this respect, early systolic asynergia may be regarded as a sensitive angiocardiographic symptom of coronary heart disease.     

Influence of canrenoate potassium (aldactone pro injections) on hemodynamics and myocardial ischemia in experimental myocardial infarct]

The effects of the positive-inotropic drug Canrenoat-Kalium (CRK) on the extent and severity of myocardial ischemic injury and on hemodynamic parameters were studied in 17 dogs following coronary occlusion. Acute myocardial infarction causes depression of left-ventricular function. There eas a significant decrease in dp/dtmax, stroke volume and cardiac output; average values for mean arterial pressure were reduced, but not significantly. There was a significant increase in left-ventricular enddiastolic pressure. Heart rate was unchanged. In the healing phase of myocardial infarction a significant elevation of left-ventricular enddiastolic pressure and a significant decrease of arterial pressure persisted, but the other parameters had returned toward normal. Intravenous administration of CRK (20 mg/kg) one hour after coronary occlusion causes a significant increase in left-ventricular dp/dtmax, cardiac output and stroke volume, but no significant change in arterial pressure, heart rate and left-ventricular enddiastolic pressure. Four days after myocardial infarction administration of CRK causes also a significant incrrease in left-ventricular dp/dtmax and -n 4 out of 5 animals an increase in stroke volume. Heart rate, arterial pressure and left-ventricular enddiastolic pressure are unchanged. There is a continuous deterioration of all hemodynamic parameters in the control group 1 hour and 96 hours after experimental myocardial infarction. This spontaneous deterioration has to be taken into consideration estimating the effect of CRK in experimental conditions. 120 epicardial electrocardiographic recordings were used to assess the extent and severity of myocardial ischemic injury. The average ST-segment elevation and the number of sites with abnormal ST-segments were significantly reduced 20 min after CRK administration. The study suggests a beneficial therapeutic role for CRK treatment of left-ventricular failure in the acute and healing phase after myocardial infarction.     

Factors contributing to the success of intracoronary thrombolytic therapy

Intracoronary thrombolytic therapy (ICT) was used in 36 patients with acute transmural myocardial infarction. Recanalization of an infarction-dependent artery was achieved in 26 (72.2%) patients. Factors affecting the success of ICT were analysed, using Bayes' theorem. The ejection fraction (EF) is shown to have the highest predictive value as an indicator of left-ventricular pump function. The anticipated probability of ICT success is 84.9% in patients with acute myocardial infarction and a 35% EF baseline, and 25.7% in those with a 35% EF. In the absence of severe left-ventricular pumping and contractility disorders, the success of ICT is affected by patient's age, history of myocardial infarction and the site of thrombotic occlusion.     

Use of nifedipine for treating heart failure in the subacute period of myocardial infarct in patients over 60

The efficiency of nifedipine (an average daily dose of 34.7 +/- 0.2 mg) was examined in 19 patients between 60 and 81 years of age, with myocardial infarction aggravated by heart failure. Single and repeated nifedipine doses taken for 2 weeks produced a 7% drop in arterial BP, a 25% drop in peripheral resistance and a 18% rise in the cardiac index, mostly due to a 17% increase in the stroke index. A significant prolongation of left-ventricular ejection time and an improvement of myocardial contractility were due to smaller poststress and easier left-ventricular blood ejection. Nifedipine improved hemodynamic response to isometric handgrip exercise: peripheral resistance was lower, and the stroke and cardiac indices were higher at the peak of exercise after nifedipine administration, as compared to pretreatment values. Nifedipine is an effective agent for the treatment of postinfarction heart failure accompanied with high peripheral resistance.     

Prognostic significance of the area of myocardial lesion and the status of the coronary bed during restoration of work capacity in patients with a complicated course of acute myocardial infarction

The effect of heart failure and acute left-ventricular aneurysm on the recovery of working capacity was assessed with reference to the size of necrotic focus and the extent of coronary arterial involvement in 117 patients with acute myocardial infarction. The size of necrotic focus and magnitude of coronary arterial affection were shown to be the principal determinants of heart failure in acute myocardial infarction. The presence of heart failure and acute left-ventricular aneurysm in combination with multiple coronary-arterial lesions is an adverse predictive sign in the assessment of the severity of acute myocardial infarction and the recovery of patients' working capacity. On the contrary, the presence of a local aneurysm in combination with an isolated coronary-arterial lesion should not be regarded as an unequivocal indicator of disability.     

Impact of myocardial perfusion on left atrial remodeling following primary angioplasty for acute myocardial infarction

OBJECTIVES: To investigate the impact of myocardial perfusion on left atrial remodeling and its determinants after primary percutaneous coronary intervention for acute myocardial infarction. BACKGROUND: Left atrial volume is an important predictor of morbidity and mortality in acute myocardial infarction, while thrombolysis in myocardial infarction (TIMI) myocardial perfusion (TMP) grade is an angiographic index associated with infarct size and mortality. As yet, however, the relationship between TMP grade and left atrial remodeling has not been investigated. METHODS: Conventional transthoracic echocardiography was performed in 105 patients (55+/-13 years old, 92 men) with acute myocardial infarction within 24 h and after 6 months (mean 9+/-4, range 6-29 months) following successful primary percutaneous coronary intervention. Absolute left atrial volume was calculated using an elliptical model. Myocardial perfusion was evaluated, using TMP grade, by visual assessment on the coronary angiogram. Patients were divided into three groups on the basis of myocardial perfusion status, as TMP 0/1 (n=36), TMP 2 (n=36) and TMP 3 (n=33). RESULTS: No difference was observed between baseline and follow-up left atrial volumes in the overall study population (42.5+/-16.1 vs. 43.5+/-17.4 ml, P=0.519). As regards TMP grade, follow-up left atrial volume significantly increased in the TMP 0/1 group (43+/-17 vs. 54.6+/-1.1 ml, P<0.001) and significantly decreased in the TMP 3 group (42.9+/-15.7 vs. 35.5+/-12.2 ml, P=0.001) compared with initial values. No change was observed in left atrial volume in the TMP 2 group. Multivariate analysis showed that TMP grade (P<0.001) and anterior location of myocardial infarction (P<0.001) were independent determinants of left atrial remodeling. CONCLUSIONS: These results suggest that poor myocardial perfusion and anterior location of myocardial infarction can affect left atrial remodeling in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention. It appears that adequate myocardial perfusion is crucial to prevent left atrial remodeling, a poor prognostic factor in acute myocardial infarction.     

Autologous bone-marrow stem-cell transplantation for myocardial regeneration

Implantation of bone-marrow stem cells in the heart might be a new method to restore tissue viability after myocardial infarction. We injected up to 1.5x10(6) autologous AC133+ bone-marrow cells into the infarct border zone in six patients who had had a myocardial infarction and undergone coronary artery bypass grafting. 3-9 months after surgery, all patients were alive and well, global left-ventricular function was enhanced in four patients, and infarct tissue perfusion had improved strikingly in five patients. We believe that implantation of AC133+ stem cells to the heart is safe and might induce angiogenesis, thus improving perfusion of the infarcted myocardium. See Commentary page 11     

Central hemodynamic characteristics of patients with acute myocardial infarct of the right ventricle

A study of central hemodynamic parameters and clinical patterns of acute right-ventricular myocardial infarction (ARVMI) is reported. Thirty-nine patients with acute inferior left-ventricular myocardial infarction were divided into 2 groups: 28 patients with electrocardiographic signs of ARVMI (group 1) and 11 patients showing no such signs (group 2). All patients were subjected to catheterization of the heart's right compartments, and their minute blood volumes were measured by thermodilution. Three patterns of ARVMI were identified on the basis of the mean pulmonary arterial blood pressure: hypo-normo- and hypertensive ones. All the three were associated with the development of prevailing right-ventricular insufficiency in group 1.     

Plasma MMP-9 and MMP-2 following acute myocardial infarction in man: correlation with echocardiographic and neurohumoral parameters of left ventricular dysfunction

BACKGROUND: Left ventricular dilatation and elevated plasma natriuretic peptide levels predict adverse prognosis and the development of congestive heart failure after myocardial infarction. Altered matrix metalloproteinase (MMP) activity has been implicated in the structural changes associated with development of heart failure after myocardial injury. The aims of this study were to investigate plasma MMP-2, MMP-9, and tissue inhibitor of metalloproteinase (TIMP)-1 concentrations following acute myocardial infarction and their relationships with measures of left ventricular function. METHODS AND RESULTS: Plasma MMP-2, MMP-9, TIMP-1, and N-terminal proBNP (N-BNP) were quantified on 5 consecutive days in 60 patients with acute myocardial infarction (39 anterior). N-BNP was measured on day 3. Echocardiographic assessment of left ventricular wall motion index and volumes was performed during admission and 6 weeks later. Plasma MMP-9 showed peaks on days 1 and 4. MMP-2 levels, similar on each day, were higher after inferior myocardial infarction. Plasma MMP-2 showed strong, inverse correlation with left ventricular volumes during and after admission. Plasma MMP-9 correlated directly with N-BNP (P=.022) and inversely with wall motion index during admission (P=.05). TIMP-1 levels were higher after anterior (1269, 870-1466 ng/mL) compared with inferior (1183, 856-1419 ng/mL, P=.05) acute myocardial infarction and fell from day 1 through 5 (P <.0005). CONCLUSION: Plasma MMP-9 concentration correlates with neurohormonal and echocardiographic measures of left ventricular dysfunction after myocardial infarction. Higher left ventricular volumes are associated with lower plasma MMP-2 concentrations. Circulating MMP concentrations may provide insights into left ventricular remodeling after acute myocardial infarction.     

The prognostic value of dobutamine echocardiography after an uncomplicated acute myocardial infarct

BACKGROUND AND PURPOSE: The identification of patients at risk for future events after an infarction is mandatory. The aim of this study was to assess the prognostic value of dobutamine stress echocardiography after an uncomplicated myocardial infarction. METHODS: One hundred and twenty five patients (mean age 65 +/- 11 years, males 82%) underwent dobutamine-echo within ten days after an uncomplicated myocardial infarction. Four myocardial responses were identified: a) negative; b) sustained improvement of myocardial contractility; c) initial improvement followed by worsening, and d) worsening at a distance or in the infarcted zone. RESULTS: Mean follow-up was 7.4 +/- 4.6 months. An adverse outcome occurred in 47 patients: non cardiac death in 3, cardiac death in 6, myocardial infarction in 5, angina in 21, congestive heart failure in 2, and in 10 patients revascularization. Cox regression analysis showed that worsening of contractility was the best predictor for adverse events (p < 0.0001, relative risk 2.8; 95% confidence interval: 1.7-4.5). Non-smoking and previous angina were also predictors of adverse events (p = 0.003 and p = 0.04, respectively). Similar results were obtained after excluding the revascularized patients. CONCLUSIONS: Sustained improvement of contractility in the infarcted region is not a predictor of adverse events. Asynergy at a distance or in the infarcted region during dobutamine echocardiography within ten days after an uncomplicated myocardial infarction predicts adverse cardiac events during follow-up. Therefore, dobutamine echocardiography could be used for risk stratification after acute myocardial infarction.     

Experience with 5 years of drug therapy of ischemic heart disease patients with stable angina and stenosing atherosclerosis of the coronary arteries

The results of 5-year pharmacologic treatment of 234 coronary patients with stable angina of varying functional classes are reported. Coronarography detected stenosis of major coronary arteries in all cases; ventriculography demonstrated no disorders of left-ventricular contractility. Clinical improvement and stabilization occurred in 75.2% of patients, deterioration, in 24.8%. Of the latter group, nonfatal myocardial infarction occurred in 13.7%, and signs of heart failure developed in 9.8%. Repeat bicycle ergometry demonstrated increased or unchanged physical stress tolerance in 67.1%. Working capacity was intact after five years in 61.1%. Therefore, long-term medication of coronary patients with stable angina and normal left-ventricular contractility has proved efficient.