Myocardial infarction results in depressed baroreflex sensitivity, which has been shown to be associated with increased risk of ventricular arrhythmias and sudden death. We measured baroreflex sensitivity in 37 patients with acute myocardial infarction before hospital discharge and 3 months after the infarction to find out whether the baroreflex sensitivity ...

BACKGROUND: Early repolarization is a normal ECG variant which may resemble various pathologic conditions including acute myocardial infarction/injury and pericarditis. Some electrocardiographers believe early repolarization resolves with exercise-induced increases in heart rate. The purpose of this study was to evaluate qualitatively and quantitatively this phenomenon. METHODS: From among 3,000 consecutive ...

To date, there has been no report of temporary disappearance of right bundle branch block (RBBB) during exercise. A patient with old infero-posterior myocardial infarction is described in whom complete RBBB disappeared transiently during treadmill exercise testing. No chest pain or significant ST-T changes occurred during and after the exercise ...

BACKGROUND: The relation between heterogeneously coupled myocardium and fractionated electrograms is incompletely understood. The purpose of this study was to use a detailed computer model of nonuniformly anisotropic myocardium to test the hypothesis that spatial variation of morphology of electrograms recorded simultaneously from multiple sites increases with increasing heterogeneity of ...

In addition to new knowledge concerning the mechanisms whereby conventional risk factors act, other risk factors have been newly described, such as dietary antioxidants, lack of exercise, insulin resistance, excess iron stores, increased plasma angiotensin-converting enzyme, and left ventricular hypertrophy. An intact endothelium protects both by the formation of nitric ...

BACKGROUND: Low-dose scopolamine increases heart rate variability (HRV) in patients with a prior myocardial infarction (MI). This observation, combined with the evidence that elevated cardiac vagal activity during acute myocardial ischemia is antifibrillatory, has generated the hypothesis that scopolamine might be protective after MI. We tested low-dose scopolamine in a ...

The heart responds positively to programs of chronic dynamic exercise. Hallmark adaptations of the heart include a training bradycardia, increases in end-diastolic dimension and maximal stroke volume, and a general improvement in ventricular performance and contractile function. Of considerable clinical significance are the general observations that chronic exercise renders the ...

The study was carried out to determine the relationship between ventilatory threshold and the onset of ischaemia, as shown on the ECG (horizontal and/or descending ST depression of 0.05 mV, on average). Twenty-seven male patients (aged 58 +/- 7 years) with angiographically documented coronary artery disease (CAD) were assessed by ...

Thirty-two patients with acute myocardial infarction performed an exercise stress test one month after hospital discharge. The in vivo formation of thromboxane and prostacyclin formation before and during the exercise stress test was analyzed with gas chromatography-mass spectrometry of the in vivo formed metabolites 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha. Patients with ...

Late potentials are considered to be a marker for regional slow conduction which might predispose to reentrant ventricular arrhythmias. Since these arrhythmias may be induced by ischaemia it may be speculated that exercise-induced myocardial ischaemia may trigger late potentials. Exercise testing was performed in 53 patients early after myocardial infarction ...

We describe the occurrence of an intraparenchymal (thalamic) haemorrhage during a stress test in a hypertensive 52-year-old man who had suffered from myocardial infarction 3 months earlier. Common causes of spontaneous haemorrhage, such as arteriovenous malformation, aneurysms, neoplasm, bleeding disorders or vasculitis were excluded. This single neurological complication was observed ...

Previous studies have shown that cardiovascular patients benefit from exercise. The explanations are partly physical and partly psychological, yet evidence for the latter is contradictory, possibly because only selected samples start and maintain prolonged exercising. The authors examined psychological effects of short-term exercise started as soon as possible after myocardial ...

The significance of exercise-induced S-T elevation in aVR was studied in 57 patients with recent anterior infarction and single-vessel disease. S-T elevation in aVR was found at peak exercise in 24 patients. Although the initial defect area was similar in the groups with and without S-T elevation in aVR, the ...

More than 2 million patients are admitted to U.S. hospitals annually for clinical suspicion of acute myocardial infarction (AMI), and > 70% are found not to have had a cardiac event. This study evaluates the safety and efficacy of immediate exercise testing for patients admitted to the hospital for suspected ...

Previous studies of neurohumoral activation following myocardial infarction have concentrated on the within-hospital phase and have only made measurements at rest. The objectives of this study were to measure neuroendocrine activity in the early convalescent phase of myocardial infarction at rest and during symptom-limited maximal exercise and to study the ...

OBJECTIVES: To evaluate the prognostic value of exercise testing performed soon after acute myocardial infarction (AMI) in patients treated with thrombolytic therapy. DESIGN: A 1-year prospective follow-up of 185 subjects treated with thrombolytic therapy who survived AMI, and who performed exercise testing 3 weeks after AMI. These patients were compared ...

Neutrophil activation occurs after myocardial infarction/ischaemia. They produce the reactive oxygen species (ROS) hypochlorous acid (HOCl) and hydrogen peroxide (H2O2) which could contribute to contractile dysfunction upon reperfusion. The myofilaments of 'skinned' rat cardiac muscle were exposed to ROS in various states of activation. Isometric force was measured at controlled ...

By providing measurements of O2 uptake and CO2 production during exercise, cardiopulmonary exercise testing can (1) distinguish between cardiac and pulmonary limitations in patients with dyspnea; (2) measure disability and provide an accurate exercise prescription; (3) provide physiologically relevant endpoints for assessing interventions; (4) define low-risk patients after uncomplicated myocardial ...

OBJECTIVES: (1) To examine the effects of exercise alone and the additional benefit of a teaching-counseling program with exercise when compared with usual medical and nursing care on the rate of return to previous activities, and (2) to describe the rates of return to former activities of daily living after ...

The value of exercise testing in patients with right bundle branch block (RBBB) is uncertain. A retrospective review of 3609 patients who underwent exercise testing identified 163 (4.5%) with preexisting RBBB. After excluding those with coronary artery bypass graft(s), 133 patients remained and 48 (36%) had a prior myocardial infarction. ...

This study evaluated long-term effects of 12 weeks of supervised training, of at least 45 minutes duration with two sessions per week, on physical performance and psychological well-being after myocardial infarction (MI). Sixty-nine patients were randomized to either an exercise or a nonexercise group. Maximum exercise capacity 6 weeks post-MI ...

OBJECTIVES: The aim of this study was to investigate the prognostic significance of peak oxygen uptake in patients with coronary artery disease who had an exercise test that could be sustained to exhaustion without limiting symptoms. BACKGROUND: Many studies have reported an inverse association between the level of exercise reached ...

The myocardial uptake kinetics of 14(R,S)-[18F]fluoro-6-thia-heptadecanoic acid (FTHA) were evaluated in humans with PET. The relationship between human myocardial FTHA uptake kinetics and the rate-pressure product (RPP) as an index of myocardial oxygen consumption was investigated in seven normal subjects under fasting conditions. METHODS: Seven studies were performed at rest ...

We assessed the effects of age and endurance exercise training (treadmill running at 75% maximal running capacity, 1 h/day, 5 days/wk for 10 wk) on the total concentration of insulin-regulatable glucose transporters (GLUT-4) and GLUT-4 mRNA levels in the myocardium of male Fischer 344 rats aged 7, 15, and 25 ...

BACKGROUND: Remodeling of infarcted and noninfarcted ventricular regions, infarct expansion, shape distortion, and global left ventricular (LV) dilation influence LV performance and survival. The effect of chronic exercise, initiated early or later after infarction, on remodeling, hemodynamics, and survival has not been studied. METHODS AND RESULTS: A total of 156 ...

OBJECTIVES: This study was conducted to determine the diagnostic yield and risks of a symptom-limited treadmill exercise test before hospital discharge. BACKGROUND: Currently, predischarge low level and 6-week symptom-limited exercise treadmill tests are recommended for risk stratification after myocardial infarction. However, few data exist on the safety and value of ...

OBJECTIVE: To determine whether a group programme of light exercise could improve quality of life in patients after acute myocardial infarction to the same extent as a high intensity exercise training programme. SETTING: Australian teaching hospital. PATIENTS: 224 men from a consecutive series of 339 men under 70 admitted to ...

Clinical, exercise, and angiographic variables, and long-term follow-up were compared in patients, who, during maximal Bruce exercise testing after a first acute myocardial infarction (AMI), had positive responses to exercise testing (n = 116, 38% of 303) with (n = 23, group I) or without (n = 93, group II) ...

The purpose of this investigation was to define, with radionuclide technique, the variation on left ventricular filling rate in patients with coronary artery disease, and to determine the effects of dynamic exercise on this variation. The study was carried out on 91 subjects, 46 patients with anterior and 30 with ...

BACKGROUND: Studies examining the relative value of clinical, exercise test, and angiographic data in the prediction of further clinical events after a first acute myocardial infarction (AMI) have produced conflicting results. METHODS: We examined the relative value of clinical, exercise test, and angiographic data as predictors of death, recurrent infarction, ...

Increased myocardial fatty acid uptake during acute exercise could adversely affect myocardial O2 consumption in lambs with left-to-right shunts, which would be unfavorable in view of their decreased coronary blood flow reserve. Therefore, we studied myocardial substrate uptake (glucose, lactate, pyruvate, free fatty acids, triglycerides, beta-hydroxybutyrate, and acetoacetate) in 10 ...

We tested the hypothesis that early plasma atrial natriuretic factor (ANF) values are related to subsequent functional capacity in patients with acute myocardial infarction (MI). Blood for ANF determination was sampled from 90 male patients (age 66.5 +/- 9.5 (mean +/- SD) years) day 3 post MI. Exercise testing on ...

The prevalence and clinical significance of transient myocardial ischemia was evaluated prospectively in 43 patients with a clinical diagnosis of unstable angina. Continuous 2-channel Holter electrocardiographic monitoring was begun < 24 hours after admission. In 3,558 hours of recordings (mean 83 +/- 20 hours/patient), there were 1,671 episodes of transient ...

OBJECTIVES: The goal of this study was to create a nomogram, based on maximal exercise capacity (in metabolic equivalents [METs]) and age, for assessing a patient's ability to perform dynamic exercise to quantify the level of physical disability or relative capacity for physical activity. BACKGROUND: Providing an estimation of exercise ...

To assess the difference in left ventricular performance during exercise between anterior (11 patients) and inferior (10 patients) myocardial infarction (MI) of equivalent size, patients performed a supine bicycle exercise 6 to 8 weeks after the first acute MI. All patients had negative exercise test results and despite no significant ...

After stabilization of symptoms by medication a predischarge exercise test was performed in 855 men admitted with suspected unstable angina (54%) or non-Q-wave myocardial infarction (46%). Multiple logistic regression analysis demonstrated that the number of leads with ST-depression at exercise, low maximal work load, increasing age and ST-elevation in electrocardiogram ...

To evaluate the effect of different bicycle exercise programmes on estimates of functional capacity in cardiac patients, the cumulated exercise capacity, physiologic and gas exchange responses were measured in eleven men 5-10 weeks after an acute myocardial infarction. The patients were not limited by angina and all were treated with ...

A lack of the QTc ratio decrease at maximal exercise is considered as an index of exercise-induced ischemia in patients with coronary artery disease. The authors studied 51 patients with recent myocardial infarction in order to evaluate the QTc changes with exercise in assessing the presence of remaining ischemic myocardium. ...

To predict exercise tolerance in the chronic phase of myocardial infarction (MI), cardiopulmonary exercise testing was performed using a ramp treadmill protocol in 25 patients at 1 and 3 months after the onset of MI. Oxygen uptake, heart rate and O2 pulse were estimated at rest, during a warm-up period, ...

BACKGROUND: beta-Adrenergic blockade is known to improve the survival of patients after acute myocardial infarction and to reduce myocardial infarct size in experimental coronary occlusion. However, the effects of beta-blockade on global and regional left ventricular (LV) remodeling have not been characterized after coronary occlusion with reperfusion. In rats subjected ...

The present study was conducted to determine whether or not there is diurnal variation in the hemodynamic responses to stimuli that increase myocardial oxygen demand, and the effects of such variation on electrocardiograms (ECG). Fifteen patients with angina pectoris, 17 patients with old myocardial infarction, and 8 healthy controls were ...

Twenty-one male patients with a history of myocardial infarction underwent bicycle cardiopulmonary exercise testing. The onset of leg pain or dyspnea, which reflects anaerobic metabolism, was termed anaerobic exercise symptom threshold (AEST). Our aims were (1) to evaluate the temporal relationship between AEST and the ventilatory anaerobic threshold (VAT) and ...

To evaluate the influence of acute beta-blockade on the ability of predischarge exercise test data to predict long-term prognosis in patients admitted for suspected acute myocardial infarction, patients randomized at hospital admission to intravenous metoprolol or placebo were studied. Among 190 patients discharged alive, total 4-year mortality was 20.5% (n ...

The concept of cardiac rehabilitation following myocardial infarction is not a new one but is now at last gaining acceptance as an essential part of the service to the coronary patient. Its aim is to restore the effectiveness of post-infarct patients by ensuring that they are well adjusted, well educated ...

We performed exercise testing in 236 of 289 survivors of acute myocardial infarction to test the hypothesis that exercise-related parameters contribute to cardiac prognosis. Beta-blockers and/or calcium antagonists were used by 50% and 55% respectively of the study population. Of the 236 patients 67 had received thrombolytic therapy during the ...

OBJECTIVE: The purpose of this study was to determine myocardial infarct size and scar dimensions in experimentally infarcted rats that were randomly assigned to a moderate, mild, or no exercise condition after infarction. DESIGN: Pretest-posttest control group design (experimental). SUBJECTS: 57 male Harlan Sprague Dawley rats between 62 to 64 ...

To investigate the prognostic value of exercise-induced changes in R-wave amplitude and their relation to other exercise and angiographic variables, 303 consecutive patients who underwent maximal exercise testing and coronary angiography within 2 months of a first acute myocardial infarction were studied. R-wave amplitude at peak exercise increased or was ...

Although thrombolytic therapy reduces mortality in patients with acute myocardial infarction (AMI), it is associated with a greater incidence of successive coronary events, and there is still no ideal diagnostic and therapeutic strategy for such patients. The present study verifies the value of negative predischarge exercise testing in identifying low-risk ...

In order to investigate whether thrombolysis affects residual myocardial ischaemia, we prospectively performed a predischarge maximal exercise test and early out-of-hospital ambulatory ST segment monitoring in 123 consecutive men surviving a first acute myocardial infarction (AMI). Seventy-four patients fulfilled our criteria for thrombolysis, but only the last 35 patients included ...

BACKGROUND: Reentrant ventricular arrhythmias can occur in the surviving muscle fibers of the epicardial border zone of the canine heart 5 days after coronary artery occlusion. To understand the cellular basis of these arrhythmias, we developed a method of dispersing myocytes (IZs) from the epicardial border zone. METHODS AND RESULTS: ...