Recent Acute Myocardial Infarction Research Articles

Omega-3 Ethyl Ester Concentrate Decreases Total Apolipoprotein CIII and Increases Antithrombin III in Postmyocardial Infarction Patients

This study investigated whether an ethyl ester preparation of fish oil (w-3) could normalise raised plasma concentrations of triglycerides, apolipoprotein CIII on apolipoprotein B-containing particles (LP CIII:B) found in patients with recent acute myocardial infarction. We also studied the effect of fish oil on antithrombin III levels. Out of 75 patients with a plasma triglyceride value >/=2.0 mmol/L, 22 normalised their triglycerides during diet and were therefore not randomised. The remaining patients were randomly assigned to 12 weeks' treatment with a daily dose of 4g w-3 or placebo. Mean plasma triglyceride concentrations were reduced by 24% from 3.10 +/- 1.15 (SD) to 2.53 +/- 0.94 mmol/L (p < 0.001) on w-3 (p < 0.001 vs placebo). The reduction was due to decreases in very low density lipoprotein concentrations. Total apolipoprotein CIII decreased significantly. This was due to reductions in LP CIII:non B concentrations, but the ratio LP CIII:non B/LP CIII:B was unaffected because of a slight insignificant decrease in LP CIII:B. The plasma triglyceride decreasing effect of w-3 could therefore not be due to redistribution of CIII between lipoproteins. Low density lipoprotein (LDL) cholesterol increased significantly with w-3 by 7%, and antithrombin III increased significantly with fish oil. In conclusion, w-3 had a moderate plasma triglyceride lowering effect and increased LDL cholesterol slightly, while antithrombin III increased in patients with hypertriglyceridaemia who had recently experienced a myocardial infarction.

Percutaneous transluminal coronary angioplasty experience in qatar: an analysis of more than 600 consecutive procedures

The present study describes the indications and results of 636 Percutaneous Transluminal Coronary Angioplasty (PTCA) procedures that were carried out in 596 patients. Of these, 366 (61.4 %) patients had Single Vessel Disease (SVD), 183 (30.7%) had Two Vessel Disease (2VD) and 47 (7.8%) had all Three Vessels Diseased (3VD). Dilatation of a single lesion was carried out in 564 (93.5%) patients. In another 41 (6.5%) patients, more than one vessel was dilated. The patients were predominantly male (562/596,93%) with a mean age of 46 (7.9 years. The indication for angiography was angina in 65.8% and for recent Acute Myocardial Infarction (AMI) in 34.2%. The number of procedures increased from 106 in 86-89 to 320 in 92-96 (an increase of 280%). PTCA was carried out in the same session as the angiography in 113/596 (19%). In the remaining 81%, PTCA was planned as an elective procedure with a similar success rate (85% and 87% respectively, p=N.S). Females and Qatari patients had the highest success rates (97.6% and 90.5%) respectively. The Left Anterior Descending (LAD) was the most frequently tackled vessel (53% of cases), Left Circumflex (LCX) in 20% and Right Coronary Artery (RCA) in 27%. For coronary stenoses, the overall success rate was 89%, being highest in the LAD (89.5%), lowest for LCX (82%) and moderate for RCA (88%). When faced with a total occlusion the overall success rate was 71% and was highest in RCA (84% success) and lowest in LCX (43%) and moderate in LAD (74%). Major complications were rare with only one mortality (1/596, 0.16%) and four emergency CABG is (4/596, 0.7%). Intracoronary stents were used as a bailout device in five patients and to obtain an optimal result in one patient. Stents were technically successful in all but one case.

American Heart Association Prevention Conference IV: prevention and rehabilitation of stroke: executive summary.

The American Heart Association Prevention Conference IV, “Prevention and Rehabilitation of Stroke,” was held May 1-2, 1996, in Tucson, Ariz. The report of the conference presents the state of knowledge on stroke epidemiology, etiologic basis, treatment, and rehabilitation. The conference report in its entirety is published in the July 1, 1997, issue of Stroke . This executive summary appears in the July 15, 1997, issue of Circulation . Reprints of the executive summary and full text are available from the American Heart Association. Stroke results from either ischemia, due to arterial occlusion or stenosis, or hemorrhage, due to leakage or rupture of an artery. Differentiation cannot be reliably made from the history or clinical examination alone. Most—but not all—strokes have a sudden or rapid onset. Differential diagnosis of sudden change in focal neurological status includes seizures or postepileptic paralysis, hemorrhage into a tumor (itself a form of stroke), and migraine. Neuroimaging helps to differentiate between these and the cause of short-lived symptoms (transient ischemic attack [TIA]) usually due to ischemia but possibly due to new-onset infarction or hemorrhage. More precise classification of stroke into a pathogenic subtype evades the best clinical skills. ### Ischemic Stroke Mechanism Embolism to the brain. Embolism to the brain may be arterial or cardiac in origin. Commonly recognized cardiac sources include atrial fibrillation (AF), sinoatrial disorder, recent acute myocardial infarction (AMI), marantic or subacute bacterial endocarditis, cardiac tumors, and valvular disorders, both native and artificial. Myocardial infarction. Stroke is an important complication in patients with AMI, occurring in 1% to 3% of all infarctions and in 2% to 6% of patients with anterior wall infarctions. Atrial fibrillation . Pooling of blood in the dysfunctional atrium leads to clots and emboli. AF increases risk of thromboembolism up to 18 times. Risk of stroke in patients with AF can be reduced …

American Heart Association Prevention Conference. IV. Prevention and Rehabilitation of Stroke. Etiology of stroke.

The diagnosis of arterial stroke differentiates ischemia from hemorrhage. The former may be due to arterial occlusion or stenosis, the latter to leakage or rupture of an artery. Computed tomography (CT) and magnetic resonance imaging (MRI) have shown that this basic differentiation cannot be reliably made from the history and clinical examination alone. Of the clinical stroke syndromes, only Wallenberg’s syndrome has not been reported to be due to hemorrhage. When CT or MRI is not available for diagnosis, spinal tap is reliably positive only when the aneurysm or arteriovenous malformation has ruptured into the subarachnoid space; the results are often normal when a small hemorrhage occurs in the parenchyma. For some therapies, notably neuroprotective agents, the potential benefits for ischemia do not seem to be offset by potential harm in the case of hemorrhage. However, because fibrinolytics, antithrombotic agents, or surgery are treatment options, diagnostic certainty is essential to avoid harming the patient. Most—but not all—strokes have a sudden or rapidly evolving onset. Differential diagnosis of sudden change in focal neurological status includes seizures or postepileptic paralysis, hemorrhage into a tumor (itself a form of stroke), and migraine. Neuroimaging helps to differentiate between these and the cause of short-lived symptoms (transient ischemic attack [TIA]) usually presumed due to ischemia but possibly due to new-onset infarction or hemorrhage. More precise classification of stroke into a pathogenic subtype (embolism, thrombosis, decreased perfusion or “lacunar” infarction, leakage, or rupture) evades the best clinical skills. The classification of stroke mechanism depends on the presence of risk factors for stroke (preexisting condition or circumstance epidemiologically related to stroke) and etiologies (disease directly causing the mechanism) that implicate the cause of stroke in a given patient. However, more than one risk factor and etiology are frequently present in the same patient and may be related …

Death, mode of death, morbidity, and rehospitalization after coronary artery bypass grafting in relation to occurrence of and time since a previous myocardial infarction.

To describe the prognosis during 2 years after coronary artery bypass grafting (CABG) in relation to occurrence of and time since a previous acute myocardial infarction (AMI), data of all patients in western Sweden who underwent CABG without simultaneous valve surgery in the period June 1988-June 1991 were evaluated. In all, 2120 patients were included in the analyses. Of these, 1296 (61%) had a history of AMI and 127 (6%) had suffered an AMI within the last month before CABG. Mortality during the first 30 days after CABG was for patients with no previous AMI, previous AMI > 30 days prior to CABG, and previous AMI < or = 30 days prior to CABG 2.4%, 4.1%, and 5.5%, respectively (p < 0.05). The corresponding figures for the period between 30 days and 2 years after CABG were 3.6%, 4.4%, and 3.4% respectively (NS). In a multivariate analysis among patients with a previous AMI, a recent infarction (< or = 30 days prior to CABG) did not turn out as an independent predictor of death during 2 years of follow-up. A history of AMI was associated with increased mortality during the first 30 days but not thereafter, but recent AMI was not an independent predictor of total 2-year mortality.

Correlación angiográfica del descenso del segmento ST con el ejercicio en derivaciones precordiales después de un infarto agudo de miocardio inferior

This study was aimed to establish the angiographic correlation of the exercise-induced ST segment depression in precordial leads after an uncomplicated inferior wall myocardial infarction. We studied retrospectively 67 patients with a recent inferior wall acute myocardial infarction who took an exercise stress test following Bruce protocol and a coronary angiography within 3 months. Four groups were defined according to the ST segment response to exercise: group I, no ST segment changes; group II, ST depression in leads V1-V4; group III, ST depression in leads V5-V6; and group IV, ST depression in leads V1-V6. There were no significant differences among the groups for clinical and exercise variables, except for age (groups I and II were significantly younger than groups III and IV). The prevalence of multivessel coronary artery disease (two- and three-vessel disease) was 21%, 18%, 52% and 72% for group I to IV respectively (p = 0.007). The prevalence for left anterior descending coronary artery disease was 5%, 9%, 35% and 50% for group I to IV respectively (p = 0.01). By multivariate logistic regression analysis, only age > 60 years (p = 0.002) and exercise group III and IV (p = 0.02) were independent predictors for the presence of multivessel coronary disease. Whereas an ST exercise response type I or II in a patient < or = 60 years virtually excluded the presence of multivessel disease (negative predictive value, 0.90), an ST exercise response type III or IV in a patient > 60 years strongly suggested the presence of multivessel disease (positive predictive value, 0.72). Age and exercise-response of ST segment in precordial leads are useful variables for predicting the presence or absence of multivessel coronary artery disease after an uncomplicated inferior wall acute myocardial infarction.

Changes in blood pressure and heart period variability in patients with recent acute myocardial infarction.

1. A decreased heart period variability and baroreflex sensitivity in patients with acute myocardial infarction have already been documented. Since one of the major determinants of heart period variability is blood pressure variability, it would be important to know the characteristics of blood pressure regulation in this setting. The changes in blood pressure variability during the acute phase of myocardial infarction have not yet been studied. 2. We investigated the blood pressure variability and the heart period variability in 11 patients with acute myocardial infarction 3 to 5 days after their admission. Thirteen age matched patients with no evidence signs of ischaemic heart disease or previous myocardial infarction served as controls. We used the frequency domain indexes of short term measurements of finger blood pressure variability and heart period variability. The spectral powers for both heart period variability and blood pressure variability were divided into three major components: total frequency (0.01-0.4 Hz), low frequency (0.04-0.15 Hz) and high frequency (0.15-0.4 Hz). 3. All of the frequency-domain components of the heart period variability were significantly decreased in patients with recent acute myocardial infarction compared to the controls: Ln(total power): 5.68 +/- 0.24 vs. 7.21 +/- 0.29, Ln(low-frequency power): 4.31 +/- 0.28 vs. 7.05 +/- 0.53, Ln(high-frequency power): 3.50 +/- 0.33 vs. 5.48 +/- 0.32. Acute myocardial infarction patients showed a significantly reduced blood pressure variability in all frequency components compared to the controls: Ln(total power): 4.21 +/- 0.18 vs. 6.79 +/- 0.48, Ln(low-frequency power): 2.40 +/- 0.24 vs. 4.36 +/- 0.21, Ln(high-frequency power): 3.31 +/- 0.25 vs. 5.66 +/- 0.38. 4. We hypothesize that the reduced blood pressure variability in the acute phase of myocardial infarction could be related to a relative invariance of stroke volume. The underlying mechanism is the reduced left ventricular compliance.

Differences in 4-Year Health Outcomes for Elderly and Poor, Chronically III Patients Treated in HMO and Fee-for-Service Systems

To compare physical and mental health outcomes of chronically ill adults, including elderly and poor subgroups, treated in health maintenance organization (HMO) and fee-for-service (FFS) systems. A 4-year observational study of 2235 patients (18 to 97 years of age) with hypertension, non-insulin-dependent diabetes mellitus (NIDDM), recent acute myocardial infarction, congestive heart failure, and depressive disorder sampled from HMO and FFS systems in 1986 and followed up through 1990. Those aged 65 years and older covered under Medicare and low-income patients (200% of poverty) were analyzed separately. Offices of physicians practicing family medicine, internal medicine, endocrinology, cardiology, and psychiatry, in HMO and FFS systems of care. Types of practices included both prepaid group (72% of patients) and independent practice association (28%) types of HMOs, large multispecialty groups, and solo or small, single-specialty practices in Boston, Mass, Chicago, Ill, and Los Angeles, Calif. Differences between initial and 4-year follow-up scores of summary physical and mental health scales from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) for all patients and practice settings. On average, physical health declined and mental health remained stable during the 4-year follow-up period, with physical declines larger for the elderly than for the nonelderly (P<.001). In comparisons between HMO and FFS systems, physical and mental health outcomes did not differ for the average patient; however, they did differ for subgroups of the population differing in age and poverty status. For elderly patients (those aged 65 years and older) treated under Medicare, declines in physical health were more common in HMOs than in FFS plans (54% vs 28%; P<.001). In 1 site, mental health outcomes were better (P<.05) for elderly patients in HMOs relative to FFS but not in 2 other sites. For patients differing in poverty status, opposite patterns of physical health (P<.05) and for mental health (P<.001) outcomes were observed across systems; outcomes favored FFS over HMOs for the poverty group and favored HMOs over FFS for the nonpoverty group. During the study period, elderly and poor chronically ill patients had worse physical health outcomes in HMOs than in FFS systems; mental health outcomes varied by study site and patient characteristics. Current health care plans should carefully monitor the health outcomes of these vulnerable subgroups.

Analysis of the Safety of Bronchoscopy After Recent Acute Myocardial Infarction

Acute myocardial infarction (AMI) is generally considered to increase the risk of flexible fiberoptic bronchoscopy (FFB). Currently, to our knowledge, no data in the literature support or challenge this concept. We conducted a retrospective chart review for the years 1986 to 1994 of 20 patients (14 men) who underwent 21 FFBs while hospitalized for an AMI. The mean age was 63.8 years (range, 38 to 83 years). Ten patients underwent revascularization procedures (eight coronary artery bypass grafting and two percutaneous transluminal coronary angioplasty) before FFB. The mean period between the AMI and FFB was 11.7 days (range, 1 to 30 days). Indications for FFB were pulmonary infiltrate (n = 10), hemoptysis (n = 6), atelectasis (n = 4), and to localize a suspected bronchopleural fistula (n = 1). Procedures performed included airway examination (21), BAL (12), transbronchial biopsy (2), endobronchial biopsy (3), and endobronchial brushing (4). No procedure was interrupted as a result of an adverse event, and five patients died during the same hospitalization. Four of the deaths occurred 6 to 15 days postprocedure; 1 patient (who had active ischemia at the time of FFB) died 4 h postprocedure. We conclude that FFB is safe in the immediate post-AMI period as long as the patient does not have active ischemia at the time of the procedure.

Intravenous propafenone in paroxysmal atrial fibrillation: A randomized, placebo‐controlled, double‐blind, multicenter clinical trial

Pharmacological conversion of paroxysmal atrial fibrillation is frequently necessary. The aim of this study was to compare intravenous propafenone, a class Ic antiarrhythmic agent, with placebo in paroxysmal atrial fibrillation (AF) of recent onset (< 72 h). We randomly allocated 75 patients, aged 18 to 70 years, with paroxysmal AF to receive intravenous propafenone (2 mg/kg in 15 min followed by 1 mg/kg in 2 h) or the matching placebo. Patients were followed for 3 h. Exclusion criteria were the presence of one of the following: clinical heart failure, recent acute myocardial infarction, hypotension, atrioventricular block, Wolff-Parkinson-White syndrome, or current treatment with antiarrhythmic agents or digitalis. No sign of heart disease was found in 74.7% of the patients. Echocardiographically determined left atrium diameter was similar in the two groups. Conversion to sinus rhythm occurred in 24 of 41 patients allocated to propafenone and in 10 of 34 patients allocated to placebo (odds ratio 3.2, 95% confidence intervals 1.3-7.9; p < 0.01). Mean conversion time was 34 +/- 29 and 71 +/- 55 min, respectively, for propafenone and placebo. Mean heart rate in nonconverters decreased from 146 to 109 beats/min in patients treated with propafenone while it remained virtually unchanged in those treated with placebo. Only minor side effects were noted. Intravenous propafenone is an effective therapeutic option for restoring sinus rhythm in patients with paroxysmal AF of recent onset.

Usefulness of redistribution images in viability detection after acute myocardial infarction

We undertook this study to evaluate the importance of redistribution images in thallium 201 single-photon emission computed tomography (Tl-201 SPECT) assessment of myocardial viability after acute myocardial infarction. Stress-redistribution-reinjection Tl-201 SPECT was performed in 55 consecutive patients with recent (within 1 month) acute myocardial infarction. The myocardium was divided into 16 segments and activity assessed visually with a score from 0 to 3 on stress-redistribution and stress-reinjection images. A defect was considered moderate if the stress score was 2 and severe if the stress score was 0 or 1. All moderate defects were considered viable, regardless of score on redistribution or reinjection images. Severe defects were considered viable if they were reversible (improvement of 1 score) on redistribution or reinjection images. Stress-redistribution and stress-reinjection images were visually analyzed and compared in terms of viability classification. On visual analysis, 461 segments (52%) were abnormal. One hundred eleven stress defects were moderate; of these, 28 were reversible on reinjection images only and 15 on redistribution images only. However, all of these segments were viable, regardless of the analysis chosen. Of 350 severe stress defects, 48 were reversible on reinjection and irreversible on redistribution images, and 4 were reversible on redistribution and irreversible on reinjection images. Therefore, in viability assessment, 48 segments were misclassified with stress-redistribution analysis, whereas only 4 segments were misclassified using stress-reinjection analysis. Although the usefulness of Tl-201 reinjection imaging is confirmed, redistribution images seem to be of little interest in postmyocardial infarction viability assessment.

Usefulness of antioxidant vitamins in suspected acute myocardial infarction (the Indian experiment of infarct survival-3)

In a randomized, double-blind, placebo-controlled trial, the effects of combined treatment with the antioxidant vitamins A (50,000 IU/day), vitamin C (1,000 mg/day), vitamin E (400 mg/day), and β-carotene (25 mg/day) were compared for 28 days in 63 (intervention group) and 62 (placebo group) patients with suspected acute myocardial infarction. After treatment with antioxidants, the mean infarct size (creatine kinase and creatine kinase-MB gram equivalents) was significantly less in the antioxidant group than in the placebo group. Serum glutamic-oxaloacetic transaminase decreased by 45.6 IU/dl in the antioxidant group versus 25.8 IU/dl in the placebo group (p < 0.02). Cardiac enzyme lactale dehydrogenase increased slightly (88.6 IU/dl) in the antioxidant group compared with that in the placebo group (166.5 IU/dl) (p < 0.01). QRS score in the electrocardiogram was significantly less in the antioxidant than in the placebo group. The following levels increased in the antioxidant group versus the placebo group, respectively: plasma levels of vitamin E increased by 8.8 and 2.2 μmol/L (p < 0.01), vitamin C increased by 12.6 and 4.2 μmol/L (p < 0.01), β-carotene increased by 0.28 and 0.06 μmol/L(p < 0.01), and vitamin A increased by 0.36 and 0.12 μmol/L(p < 0.01). Serum lipid peroxides decreased by 1.22 pmol/ml in antioxidant versus 0.22 pmol/mf in the placebo group (p < 0.01). Angina pectoris, total arrhythmias, and poor left ventricular function occurred less often in the antioxidant group. Cardiac end points were significantly less in the antioxidant group (20.6% vs 30.6%, respectively). These results suggest that combined treatment with antioxidant vitamins A, E, C, and β-carotene in patients with recent acute myocardial infarction may be protective against cardiac necrosis and oxidative stress, and could be beneficial in preventing complications and cardiac event rate in such patients.

Variations in the Utilization of Coronary Angiography for Elderly Patients with an Acute Myocardial Infarction

This article reports a study of variations in the utilization of angiography for Medicare recipients who had an acute myocardial infarction. The study cohort consisted of 1987 Medicare beneficiaries who had a recent acute myocardial infarction. Variations were examined from three perspectives: patient characteristics, regional practice patterns, and on-site availability of the procedure. Factors associated with variation within and among states were incorporated into the analysis using hierarchical logistic regression models. The probability of angiography during the first 90 days after an acute myocardial infarction was estimated as a function of patient age, gender, race, and comorbidity for patients in 51 states (including the District of Columbia). Interstate differences were examined in relation to geographic region and on-site availability of angiography. Observed rates of angiography ranged between 13.8% and 38.3% (median, 24.7%). Variation was nearly threefold based on estimated state probabilities of angiography for a patient with characteristics set at the national average. Observed and estimated rates were lower in northeastern states than in other parts of the United States. States with more extensive onsite availability of angiography tended to have higher angiography rates after adjusting for patient characteristics and geographic region. Adjusted angiography rates were on average higher for younger patients, males, and nonblacks. There was substantial interstate variation in race differences, with states in the Southeast generally having the largest differences. The adjusted black-to-nonblack odds ratio ranged from a low of 0.41 to a high of 0.94. Interstate variation in age and gender differences was moderate. The work reported in this article illustrates the potential of hierarchical regression modeling as a framework for the analysis of variations and some methodologic issues connected with its implementation. Our results show that large variations in the utilization of procedures can exist, despite uniform insurance coverage and a relatively homogeneous patient cohort. Aggressive use of angiography was highly variable across states as was the degree of access to the procedure for blacks and nonblacks. The state rate of on-site availability of angiography facilities was an important predictor of utilization. Increased on-site availability of angiography, however, was not associated with a reduction of differences in access to the procedure.

RR Variability in Healthy, Middle-Aged Persons Compared With Patients With Chronic Coronary Heart Disease or Recent Acute Myocardial Infarction

The purpose of this investigation was to establish normal values of RR variability for middle-aged persons and compare them with values found in patients early and late after myocardial infarction. We hypothesized that presence or absence of coronary heart disease, age, and sex (in this order of importance) are all correlated with RR variability. To determine normal values for RR variability in middle-aged persons, we recruited a sample of 274 healthy persons 40 to 69 years old. To determine the effect of acute myocardial infarction RR variability, we compared measurements of RR variability made 2 weeks after myocardial infarction (n = 684) with measurements made on age- and sex-matched middle-aged subjects with no history of cardiovascular disease (n = 274). To determine the extent of recovery of RR variability after myocardial infarction, we compared measurements of RR variability made in the group of healthy middle-aged persons with measurements made in 278 patients studied 1 year after myocardial infarction. We performed power spectral analyses on continuous 24-hour ECG recordings to quantify total power, ultralow-frequency (ULF) power, very-low-frequency (VLF) power, low-frequency (LF) power, high-frequency (HF) power, and the ratio of LF to HF (LF/HF) power. Time-domain measures also were calculated. All measures of RR variability were significantly and substantially lower in patients with chronic or subacute coronary heart disease than in healthy subjects. The difference from normal values was much greater 2 weeks after myocardial infarction than 1 year after infarction, but the fractional distribution of total power into its four component bands was similar for the three groups. In healthy subjects, ULF power did not change significantly with age; VLF, LF, and HF power decreased significantly as age increased. Patients with chronic coronary heart disease showed little relation between power spectral measures of RR variability and age. Patients with a recent myocardial infarction showed a strong inverse relation between VLF, LF, and HF power and age and a weak inverse relation between ULF power and age. ULF power best separates the healthy group from either of the two coronary heart disease groups. Differences in RR variability between men and women were small and inconsistent among the three groups. All measures of RR variability were significantly and substantially higher in healthy subjects than in patients with chronic or subacute coronary heart disease. The difference between healthy middle-aged persons and those with coronary heart disease was much greater 2 weeks after myocardial infarction than 1 year after infarction, but the fractional distribution of total power into its four component bands was similar for the healthy group and the two coronary heart disease groups. Values of RR variability previously reported to predict death in patients with known chronic coronary heart disease are rarely (approximately 1%) found in healthy middle-aged individuals. Thus, when measures of RR variability are used to screen groups of middle-aged persons to identify individuals who have substantial risk of coronary deaths or arrhythmic events, misclassification of healthy middle-aged persons should be rare.

Rebound Increase in Thrombin Generation and Activity After Cessation of Intravenous Heparin in Patients With Acute Coronary Syndromes

The abrupt cessation of heparin and other thrombin inhibitors when used to treat acute coronary syndromes has been accompanied by a clustering of thrombotic events. It is unknown whether these events are the result of inadequate antithrombin therapy or whether they represent a rebound increase in thrombin activity. This study was designed to determine whether there is a true rebound, as defined by an increase followed by a subsequent decrease, in thrombin activity after discontinuation of intravenous heparin therapy. Thirty-five patients with recent acute myocardial infarction or unstable angina who had received at least 48 hours of intravenous heparin were studied. Patients underwent ST-segment monitoring, and blood samples for determination of thrombin generation and activity were drawn at 0, 3, 6, 10, and 24 hours after heparin discontinuation. Median aPTT was 65 seconds before heparin discontinuation. Median fibrinopeptide A increased from 9.5 to 16.9 ng/mL at 3 hours (P < .0004) and returned to 10.5 by 24 hours. Prothrombin fragment 1.2 likewise transiently increased, from 0.34 to 0.51 nmol/L at 6 hours (P < .0002). Modified antithrombin III decreased over time (P < .002), and activated protein C increased from 2.3 to 4.5 ng/mL at 3 hours (P < .001). Although there were no clinical thrombotic events in the first 24 hours, 4 patients had evidence of ischemia by ST-segment monitoring at a median of 12 hours after heparin discontinuation. The degree of increase in fibrinopeptide A and prothrombin fragment 1.2 was not found to be associated with baseline diagnosis, duration of heparin therapy, baseline level of antithrombin III, or activated protein C. This study demonstrates a transient rebound increase in thrombin activity as well as in activated protein C upon abrupt discontinuation of intravenous heparin. Clinicians should be vigilant for associated thrombotic events. Further investigation of the significance, mechanism, and possible prevention of this rebound phenomenon is needed.

951-73 Combined Antiplatelet Therapy without Anticoagulation: An Effective Alternative to Prevent Subacute Thrombosis After Coronary Stenting?A 3 Month Follow-up

Stent implantation is limited by the occurrence of subacute stent occlusion and local complications related to anticoagulant therapy. Subacute closure is usually delayed and may occur several weeks after stent implantation. Recent data suggest that antiplatelet therapy might be an effective alternative to classical anticoagulation. We are prospectively studying the use of a combined antiplatelet therapy without anticoagulation (heparin discontinued within 48 hours and no coumadin) in consecutive and successful stent procedures in our institution. All patients received aspirin 200 mg daily continued indefinitely, dextran infusion during the procedure and for 4 days and ticlopidine 500 mg daily begun within one hour following a successful procedure and continued for 3 months. The 3 month follow-up (range: 1–7 months) of the first 53 patients stented during the first 10 months is presented. Stent implantation was required mainly for failed PTCA (n = 50) including 41 cases for acute or threatened closure. These stent procedures represented 6.4% of total procedures during this period. PTCA indications were stable angina (n = 18), unstable angina (n = 18), recent myocardial infarction (n = 15) and acute myocardial infarction (n = 2). Sixty-seven stents were implanted (Wiktor, n = 50; Palmaz-Schatz, n = 7; Gianturco-Roubin, n = 10) in 53 arteries (saphenous vein grafts, n = 2; left anterior descending artery, n = 19; circumflex artery, n = 11; and right coronary artery, n = 21). Mean stent diameter was 3.43 ± 0.34 mm (range: 2.5–4.0 mm). There were no deaths. The dayolthe procedure, 3 patients had Q-wave MI that were ongoing at the time of stenting, 3 patients developed non Q-wave MI and 2 patients needed transfusion related to blood loss during the procedure. Between day one and discharge no patient had recurrent ischemia, no patient needed emergent revascularization, vascular repair or blood transfusion but one patient had elective CABG (2.4%). All patients were asymptomatic at discharge after 7.4 ± 3 days. During the subsequent 3 month follow-up no patient presented history of unstable angina, myocardial infarction, subacute thrombosis or emergent revascularization. One additional patient was referred for elective CABG (2.4%). Two patients developed rashes and ticlopidine was discontinued (4.9%). In regard to major clinical events, combined antiplatelet therapy using ticlopidine plus aspirin is a promising alternative to classical anticoagulant therapy to prevent delayed complications after successful stent implantation.

Extent of cardiac autonomic denervation in relation to angina on exercise test in patients with recent acute myocardial infarction

According to the current concept, anginal pain results from stimulation of sympathetic nerves within the heart. In this study, we evaluated the role of cardiac adrenergic denervation in exercise-induced angina pectoris in 15 men with recent acute myocardial infarction. Before discharge from the hospital, the patients were subjected to a symptom-limited exercise test. Three months after the infarction, cardiac scintigraphic studies using I-123 metaiodobenzylguanidine (MIBG), I-123 paraphenylpentadecanoic acid (pPPA), and Tc-99m sestamibi (MIBI) were performed in order to determine the extent of denervated myocardium, the size of infarction, and myocardium with reduced perfusion, respectively. MIBG defect (17.2 ± 7.6% of left ventricular mass) (defect defined as an activity distribution ≤30% of the maximal myocardial activity) was larger than pPPA defect (8.3 ± 8.8%, p < 0.001) In all patients, which indicates that the area of myocardial necrosis was surrounded by viable myocardium with sympathetic denervation. The extent of viable but denervated myocardium was significantly greater in patients who developed angina pectoris than in patients without angina pectoris during the early exercise test (13.3 ± 4.4% vs 5.0 ± 2.4%, p < 0.001). In addition, patients with silent ischemia tended to have smaller areas of viable but denervated myocardium than patients with painful ischemia (5.7 ± 3.8% vs 13.8 ± 5.1%, p = 0.07). Thus, contrary to expectations, the extent of viable but denervated myocardium seems to be associated with increased pain sensitivity in patients with recent myocardial infarction.

Complications of percutaneous transluminal coronary angioplasty in patients convalescing from acute myocardial infarction

Disagreement exists with regard to the role of percutaneous transluminal coronary angioplasty (PTCA) in patients convalescing from acute myocardial infarction (AMI). Routine PTCA within the tist few days after thrombolytic therapy offers no benefit beyond that resulting from thrombolysis. 1–3 Nevertheless, many physicians believe that even patients in stable condition are best served by diagnostic angiography and appropriate revascularization at some later point in their convalescence. 4 However, there is evidence that the risk of death and major complications in such patients is greater than is true for PTCA performed outside the setting of AMI. 5,6 The Treatment of Post Thrombolytic-Stenoses Study Group encountered a mortality of 2.1% in stable patients treated electively with PTCA 4 to 14 days after AMI, 7 a figure substantially greater than that in patients with no recent AMI. 5,6 Few data are available comparing the procedure-related morbidity and mortality associated with PTCA in contemporaneously treated patients with and without recent AMI. To provide insight into this issue, we compared results in those with AMI within 30 days of the PTCA with those with no such history.

Effects of late percutaneous transluminal coronary angioplasty of an occluded infarct-related coronary artery on left ventricular function in patients with a recent (

The effect of late percutaneous transluminal coronary angioplasty (PTCA) of an occluded infarct-related artery on left ventricular ejection fraction was studied in patients with a recent, first Q-wave myocardial infarction in a prospective, randomized study. Forty-four patients (31 men and 13 women, mean age 58 ± 12 years) with an occluded infarct-related coronary artery were randomized to FrCA (n = 25) or no PTCA (n = 19). Patients received acetylsalicylic acid, a β blocker and an angiotensinconverting enzyme inhibitor unless contraindicated. Left ventricular ejection fraction was determined at baseline and 4 months. Coronary angiography was repeated at 4 months. Baseline ejection fraction measured 20 ± 12 days after myocardial infarction was 45 ± 12% in both groups. PTCA was performed 21 ± 13 days after the event. The primary PTCA success rate was 72%. One patient in each group died before angiographic follow-up, which was completed in 37 of the remaining 42 patients (88%; 21 with and 16 without PTCA). At 4 months, the infarct-related artery was patent in 43% of FrCA patients and in 19% of no PTCA patients (p = NS). Reocclusion occurred in 40%A of patients after successful PTCA. Secondary analyses showed that the change in left ventricular ejection fraction was significantly greater in patients with a patent infarct-related artery (+9.4 ± 6.2%) than in those with an occluded artery (+1.6 ± 8.8%; p = 0.0096). Baseline ejection fraction also independently predicted improvement in left ventricular ejection fraction (p = 0.0001). Sustained potency of the infarct-related artery, even when achieved late, may improve left ventricular ejection fraction of patients with a recent Q-wave myocardial infarction. The efficacy of PTCA in this setting is limited by a high reoclusion rate. Further studies are needed to examine methods to minimize reocclusion and to investigate the effect of PTCA on ventricular function, analyzed on an Intention-to-treat basis, in patients with persistent occlusion of the Infarct-related artery after the acute phase of myocardial infarction.

Influence of transdermal scopolamine on cardiac sympathovagal interaction after acute myocardial infarction

In 41 survivors of acute myocardial infarction (AMI) a prospective study was performed In 2 sequential phases. In phase 1, the role of beroreflex sensitivity and heart rate variability as predictors of Inducible and spontaneous sustained ventricular tacryarrhythmias was evaluated. In phase 2, the effects of trarurdenmal scopolamine on baroreflex sensitivity, spectral and nonspectral measures of heart rate variability were investigated. At a mean follow-up of 10 ± 3 months after AMI, 5 of 41 patients (12%) developed a late arrhythmic event. Of these, all (100%) had inducibility of sustained monomorphic ventricular tachycardia at programmed stimulation compared with 3 of 36 patients (8%) without events (p -0.0001). At multivariate analysis, baroreflex sensitivity had the strongest relation to both Inducibility of sustained monomorphic ventricular tachycardia (p <0.0001) and occurrence of arrhythmic events (p <0.0001). Of 41 patients, 28 (68%) consented to undergo phase 2 of the investigation. Baroreflex sensitivity significantly (p <0.00001) increased after transdermal scopolamine as well as heart rate variability indexes. Of these, the mean of 8Ds of normal RR Intervals for 5-minute segments (p <0.0001) and the total power (p <0.0001) had the most significant improvement after scopolarnine. The present investigation confirms that assessment of autonomic function is an essential part of arrhythmic risk evaluation after AMI. Transdenmal scopolamine, administered to survivors of a recent AMI, reverses the autonomic indexes that independently predict arrhythmic event occrurence. On the basis of these data, transdennal scopolamine could be a potential useful tool in the prophylaxis of life-threatening ventricular arrhythimias after AMI.