BACKGROUND: This study was performed in attempt to draw a correlation between the percentage of myocardial infarction across the left ventricular wall and changes in the QRS complex in the epicardial ECG in a primate model of ischemia-reperfusion injury. METHODS: Myocardial infarction was induced in six baboons by ligating the ...

The magnetic field produced by the fetal heart magnetocardiogram (FMCG) was measured by a single channel SQUID biogradiometer in an unshielded environment. FMCG amplitude ranged from 1 to 4 pT. Instantaneous fetal heart rate and averaged FMCG waveforms were computed. Spectral analysis was used to quantify fetal heart rate variability, ...

To analyze the paradox of acute myocardial infarction (AMI) with an initially normal electrocardiogram (ECG), we reviewed the records of 732 patients discharged with a final diagnosis of AMI over a 2-year period. Twenty-one patient were identified whose initial ECG was normal and who underwent coronary arteriography during the index ...

Original cohort members of the Framingham Study were studied to determine prognosis associated with unexplained (gradual-onset) Q wave patterns detected on routine electrocardiograms (ECGs). Biennial ECGs were obtained on subjects beginning in 1948. The index ECG was read independently and then serially in relation to all previous tracings for evidence ...

STUDY OBJECTIVE: To compare the value of ECG measurements from lead aVR with the QRS-interval duration in predicting seizures and ventricular arrhythmias due to acute tricyclic antidepressant (TCA) toxicity. DESIGN: Prospective cohort series of referral cells from hospitals to a regional poison control center. PARTICIPANTS: Seventy-nine patients (mean age, 30 ...

A retrospective study of patients with possible acute myocardial infarction was conducted over a 2-year period to evaluate the clinical characteristics, angiographic findings, and in-hospital prognosis in patients with normal total creatine kinase (CK) activity and increased MB isoenzyme activity (CK-MB). Thirty-nine cases were identified (study group) and compared with ...

We examined the relation of Q-wave regression to left ventricular (LV) indexes in acute anterior wall myocardial infarction (AMI) in relation to reperfusion therapy. A total of 94 patients with their first anterior wall AMI (segment 6 or 7 occlusion according to the American Heart Association classification) were examined. The ...

Electroconvulsive therapy (ECT), regarded as safe, well tolerated, and one of the most effective treatments for depression, is used frequently in patients with underlying coronary artery disease. ECT has been associated with ST depression and arrhythmias probably due to increased myocardial demand in patients with coronary artery disease. This report ...

The aim of this study was to use the vectorial information in the conventional 12-lead electrocardiographic (ECG) recording and to investigate whether this information, in combination with well-known ECG criteria, could increase the diagnostic performance for healed anterior or inferior myocardial infarction. A total of 1,458 subjects were included in ...

Statistically-based smoothing techniques are described which have been applied to the existing framework of the Glasgow ECG Analysis program. These methods have been designed with the aim of improving repeatability in the computer interpretation of ECGs which have been recorded either several minutes or 24 hours apart from patients in ...

BACKGROUND: There are few data comparing clinical outcome and potential indications for routine post-myocardial infarction cardiac catheterization and revascularization of patients who sustain a non-Q-wave versus Q-wave infarct after thrombolytic therapy. METHODS AND RESULTS: A secondary analysis of 2634 patients enrolled in the TIMI II trial with a first myocardial ...

Ventricular late potentials detected at the end of the QRS complex by the signal-averaged ECG have been shown to predict arrhythmic events after acute myocardial infarction. Spectral turbulence analysis is a novel technique for detecting abnormalities of cardiac electric activation inside the QRS complex. The purpose of this study was ...

Atrial fibrillation occurs commonly after coronary artery bypass surgery. However, despite numerous attempts at prediction, no accurate and generally accepted method exists to predict its occurrence. P-wave-triggered P-wave signal averaging was performed on 54 patients before coronary artery bypass surgery to evaluate the utility of this method to predict atrial ...

The objectives of this study were to examine the serial vectorcardiographic changes following acute myocardial infarct and to assess the relationship between QRS loop changes and infarct size. Fifty adult male Long-Evans rats of 250-350 gm body weight were used to study experimental acute myocardial infarction induced by coronary artery ...

Studies assessing dobutamine stress (DS) echocardiography (echo) have included 12-lead electrocardiograms (ECG) in their protocol. We retrospectively reviewed the records of 76 patients who were referred for DS echo and coronary angiography to assess the incremental diagnostic value of DS ECG beyond the results of the echocardiographic images of the ...

OBJECTIVES: The purpose of this study was to determine the time course of the appearance of abnormal Q waves on the electrocardiogram (ECG) over the first 6 h of symptoms of myocardial infarction and to determine what implications, if any, such Q waves have for the efficacy of thrombolytic therapy. ...

To evaluate whether the site of occlusion/stenosis in the left anterior descending coronary artery (LAD) could be diagnosed by noninvasive techniques, thallium-201 myocardial scintigraphy (TMS), 12-lead electrocardiography (ECG), and coronary arteriography were performed in 33 patients with anterior acute myocardial infarction (AMI). The subjects were divided into two groups according ...

BACKGROUND: Comprehensive data based on single-beat analysis of the ventricular activation sequence during sinus rhythm in infarcted hearts are currently not available. It was the aim of our study (1) to measure and analyze these activation sequences on the epicardial surface of the right and left ventricles and on the ...

We evaluated the time course of development of positive signal-averaged electrocardiograms (SA-ECGs) by time-domain and Spectral Temporal Mapping (STM) analyses after myocardial infarction in 88 patients without bundle branch block. The incidence of positive SA-ECGs by time-domain analysis peaked at 4 to 8 weeks postinfarction whereas the peak incidence by ...

Postoperative electrocardiographic (ECG) changes are frequently present after insertion of implantable cardioverter-defibrillators (ICD) and may mimic perioperative myocardial infarction (MI). The purpose of this study was to assess the incidence and clinical significance of postoperative ECG changes in relation to clinical, laboratory, and implantation data. In 25 (16%) of 156 ...

The diastolic function of left and right parts of the heart using left and right mechanocardiogram method was investigated in 69 male patients with coronary artery disease and preceding myocardial infarction and in 18 normal patients. Nine patients were in angina class I, 28 were in class II, 32 were ...

An approach for an all-embracing ECG signal analysis is introduced. Self organizing maps are applied to spatial high resolution multilead ECG (body surface ECG) recorded during the acute phase of myocardial infarction to detect characteristic changes. The algorithm deals with the measurement of similarity between different pathological signal types. In ...

The diagnostic information contained in the standard 12-lead electrocardiogram was assessed by comparing the classification results produced by the standard leads for various clinical settings, such as normal versus myocardial infarction or versus left ventricular hypertrophy to those achieved by 120-lead data or body surface potential maps (BSPMs). Separately, optimal ...

The purpose of this experiment is to study the possibility of intra-QRS high-frequency electrocardiographic (HFECG) changes for the evaluation of and recovery from myocardial ischemia in both the time-domain and spectral-turbulence analyses on the signal-averaged ECG using the Holter ECG monitoring (Holter SAECG) system. A balloon catheter was inserted into ...

Exercise testing (ET) and adenosine testing (AT) coupled with ECG were applied in 25 patients with old myocardial infarction. ET was positive in 8 (32%) and AT in 10 (40%) patients, the sensitivity of the latter being slightly superior to the former but inferior to the sensitivity reported in the ...

A 53-year-old man who had no chest pain and no family history of heart disease demonstrated a rapid T wave change on an electrocardiogram, from a positive T wave to a giant negative T wave, within 1 year. Echocardiography showed no left ventricular hypertrophy before or after the T wave ...

BACKGROUND: Patients recovering from myocardial infarction are frequently evaluated by non-invasive tests for evidence of myocardial ischemia before returning to work or full activity. The purpose of this study was to evaluate the prognostic significance of clinical and non-invasive ischemic test variables assessed in 549 stable, convalescing patients (median 2 ...

BACKGROUND: This study followed up the natural history of T-wave inversion and assessed the short-term prognosis associated with the condition. METHODS: Forty patients with acute ischemic syndrome, without infarction, and with postischemic T-wave inversion (group 1) were followed during the persistence (inverted T-wave period) and after the resolution of T-wave ...

The purpose of the present study was to clarify the characteristic findings of electrocardiogram (ECG) in 11 patients with acute myocarditis. ST elevation without reciprocal ST depression was one of the conspicuous findings in the acute stage. Total QRS amplitudes at the acute stage were significantly decreased as compared to ...

This study examined the effects of intravenous mexiletine on the time-domain and spectrotemporal signal-averaged ECG (SAECG). SAECGs were recorded in 60 postmyocardial infarction (MI) patients with more than 100 premature ventricular beats per hour, before and after a constant infusion of mexiletine, 7 mg/kg, given over 1 hour. Spectrotemporal analysis ...

The addition of sodium to nonionic contrast media has reduced the incidence of arrhythmias in animal models. The influence on cardiac function and safety of sodium addition to the nonionic contrast medium iohexol (Omnipaque) was studied in a randomized, double-blind trial in patients undergoing cardioangiography. Fifty-nine patients received iohexol 350 ...

BACKGROUND: Patients recovering from myocardial infarction are frequently evaluated by non-invasive tests for evidence of myocardial ischemia before returning to work or full activity. The purpose of this study was to evaluate the prognostic significance of clinical and non-invasive ischemic test variables assessed in 549 stable, convalescing patients (median 2 ...

OBJECTIVES: This study was designed to evaluate the presence or absence of atypical T wave evolution in patients with a postinfarction pericardial effusion but without clinically recognized postinfarction pericarditis. A second purpose was to evaluate the frequency of atypical T wave evolution in a previous study of postinfarction pericarditis. BACKGROUND: ...

The presence of prominent left atrial v-waves following interventricular septal rupture in acute myocardial infarction have been reported in the past. Hemodynamic profile obtained in one particular case highlighted some of the varying aspects of pressure wave, oxygen saturation, and compliance abnormalities that may also be present in such cases. ...

The sixteen-lead ECG chest wall mapping was used to investigate the significance of inverted U waves during exercise in diagnosing occult coronary artery disease (CAD) in asymptomatic high-risk subjects. For this purpose 100 patients with various types of hyperlipidemia and 33 patients with diabetes mellitus were studied. None of these ...

OBJECTIVES: This study aimed to assess the causes and clinical implications of isolated T wave inversion in adults and to evaluate electrocardiographic (ECG) differentiation of these causes. BACKGROUND: There are few previous reports on isolated T wave inversion in adults, which is a paradoxic observation in normal adults and in ...

Our objective was to construct from readily available components a system that would allow determination of P-wave to P-wave intervals in fetuses with congenital heart block. Using a fetal monitor, bedside patient monitor, spiral electrode, and a special cable described herein, we obtained direct fetal electrocardiograms from two fetuses with ...

OBJECTIVE: The aim was to examine the regional specificity of T wave alternans and the value of precordial ECG monitoring for non-invasive tracking of cardiac vulnerability during acute coronary artery occlusion and reperfusion in animals and humans. METHODS: The left ventricular ECG was monitored during two acute occlusions of the ...

OBJECTIVES: This study was undertaken to test the hypothesis that early inversion of T waves after thrombolytic therapy for acute myocardial infarction predicts patency of the infarct-related artery with high Thrombolysis in Myocardial Infarction (TIMI) perfusion flow and better in-hospital outcome. BACKGROUND: Although numerous studies have demonstrated a strong association ...

Chemical necrosis was produced with the infiltration of 96 degrees alcohol on the middle anterosuperior segment 5 (nomenclature of the International Society for Computerized Electrocardiology) of the free left ventricular (LV) wall in 45 dogs and on the apical segment 10 and middle posterolateral segment 11 in 30 others. In ...

In 50% of cases of myocardial infarction, the 12-lead electrocardiogram (ECG) is not diagnostic of the infarction. Critical care nurses, aware of subtle ECG changes coupled with patient complaint of chest pain, may improve recognition of myocardial infarction. Expanding the 12-lead ECG to include right ventricular precordial leads and posterior ...

The effects of amplitude resolution in the signal-averaged ECG are studied in relation to the analysis of cardiac late potentials. The statistical properties of ECG signals from 22 patients after myocardial infarction were investigated in terms of amplitude distribution and noise level for the material. It was found that unbiased ...

Artificial neural networks are computer-based expert systems that learn by example, in contrast to the currently used rule-based electrocardiographic interpretation programs. For the purpose of this study, 1,107 electrocardiograms (ECGs) from patients who had undergone cardiac catheterization were used to train and test neural networks for the diagnosis of myocardial ...

OBJECTIVE: To investigate the possible mechanical associations of the presence or absence of the septal q wave. STUDY DESIGN: Retrospective and prospective study of 63 patients with various left ventricular diseases and 10 controls by electrocardiography, echocardiography, and pulsed Doppler recordings. SETTING: Tertiary cardiac referral centre. PATIENTS: 73 subjects were ...

The present study was undertaken to determine the value of abnormal late ventricular potentials on signal-averaged electrocardiograms (ECG) in identifying patients at risk of developing ventricular tachycardia or ventricular fibrillation in the early postoperative period after coronary artery bypass grafting. Signal-averaged ECGs were recorded immediately after operation in 72 patients. ...

OBJECTIVES: The study evaluates the association between T wave alternans and the risk of cardiac events (syncope, aborted cardiac arrest or cardiac death) in a large population of patients with idiopathic long QT syndrome. BACKGROUND: T wave alternans is an infrequently recorded electrocardiographic (ECG) finding in patients with delayed repolarization, ...

OBJECTIVES: This study was performed to determine electrocardiographic (ECG) features that could distinguish first diagonal branch occlusion from left anterior descending coronary artery occlusion. BACKGROUND: The ECG findings associated with first diagonal branch obstruction have not previously been compared with those of left anterior descending coronary artery obstruction. METHODS: The ...

Substantial evidence indicates that T wave alternans is an intrinsic property of ischemic myocardium. The electrophysiologic basis appears to be spatial and temporal heterogeneity of repolarization resulting from changes in action potential morphology rather than in activation sequence. Ischemia-induced changes in postrepolarization refractoriness and depressed electrical restitution of action potential ...

Indwelling pulmonary arterial catheters are often used to monitor and to guide therapy in critically ill patients. The magnitude of the V wave recorded from the pulmonary arterial wedge (PAW) position is sometimes used to assess the presence and severity of mitral regurgitation (MR). The present study was performed to ...

BACKGROUND: The high-frequency contribution (i.e. 60-120 Hz) within the QRS complex of the surface ECG is supposed to be related to the arrhythmogenic substrate underlying sustained ventricular tachycardia in patients with coronary artery disease. One of the factors that prevents a wider clinical application of spectral analysis based on the ...