An 18-year-old man presented with a spontaneous right pneumothorax. An initial electrocardiogram (ECG) showed an S wave in lead I, a Q wave in lead III, and an inverted T wave in lead III. This ECG pattern, S1Q3T3, has been most often associated with pulmonary embolus. These changes resolved with ...

OBJECTIVE: To define the clinical value of the signal averaged P wave (SAPW) and to compare it with the standard electrocardiogram (ECG), echocardiogram, and clinical assessment for the prediction of atrial fibrillation after coronary bypass grafting (CABG). DESIGN: Prospective validation cohort study. SETTING: Regional cardiothoracic centre. PATIENTS: 201 unselected patients ...

We studied the ability to predict depressed left ventricular ejection fraction (LVEF) from clinical and exercise test findings prior to surgery in consecutive patients who underwent coronary artery bypass grafting (CABG) from 1988 to 1991 (n = 663). Multivariate analysis showed a history of myocardial infarction, pathological Q-wave in resting ...

We explored the relationship between body surface recovery time (RT), the interval between the QRS onset and the time of maximum derivative in the T-wave on a 16 precordial lead system electrocardiogram (ECG), and monophasic action potential (MAP) duration of the left ventricular endocardium in 9 patients in whom electrophysiologic ...

The Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) reported a greater risk of non-Q-wave myocardial infarction (MI) with directional atherectomy (DCA), although the specific mechanism was unclear. To assess the possible role of microvascular spasm in creatinine phosphokinase (CPK) elevation (> 2x normal) following DCA, 193 consecutive patients were given ...

BACKGROUND: Q waves developed in the subacute and persisting into the chronic phase of myocardial infarction (MI) usually signify myocardial necrosis. However, the mechanism and significance of Q waves that appear very early in the course of acute MI (< 6 h from onset of symptoms), especially if accompanied by ...

Acute coronary syndromes are defined as unstable angina, non-Q-wave myocardial infarction, and Q-wave myocardial infarction. These entities remain among the commonest life-threatening illnesses in industrialized nations. Prompt recognition of a patient with an acute coronary syndrome is important since appropriate therapy can markedly improve the patient's prognosis. Reperfusion strategies for ...

This study was conducted to clarify the clinical significance of negative U waves in the precordial leads during anterior wall acute myocardial infarction (AMI). In all, 141 patients with first anterior wall AMI (< or = 6 hours) were classified into 2 groups according to the presence (group A, n ...

Giant negative U waves transiently appeared in a patient with acute myocardial infarction (AMI). During hospitalization, these giant negative U waves (0.3-0.5 mV) were observed in leads V2 through V4 of the electrocardiogram (ECG). The waves disappeared 10 days after hospitalization, but reappeared during a treadmill exercise test 3 weeks ...

The electrocardiogram (ECG) of a 40-year-old woman with an old inferolateral myocardial infarction revealed, in the course of an exercise treadmill/thallium test, gradual disappearance of infarctional Q waves, which reappeared gradually during recovery from exercise. The patient had evidence of exercise-induced myocardial ischemia both by the ECG and by thallium-201 ...

We analyzed signal-averaged electrocardiograms (ECG) obtained in 50 patients with recent myocardial infarction (RMI: 25 anterior and 25 inferior) and 20 normal subjects to determine the relationship between the initial portion of the signal-averaged QRS complex and cardiac function and infarct size. We examined (1) the root mean square voltage ...

OBJECTIVES: We assessed the outcomes of patients with a first myocardial infarction with ST segment elevation, with and without the development of abnormal Q waves after thrombolysis. BACKGROUND: Prethrombolytic era studies report conflicting short-versus long-term mortality in the overall non-Q wave population, probably related to its heterogeneity. METHODS: Patients with ...

OBJECTIVES: This study sought to examine the management and subsequent outcomes of patients with a prehospital electrocardiogram (ECG) in a large, voluntary registry of myocardial infarction. BACKGROUND: The prehospital ECG has been proposed as a means of rapidly identifying patients with acute myocardial infarction who might be eligible for reperfusion ...

OBJECTIVES: The purpose of this study was to use an electrocardiographic (ECG) algorithm, derived from the results of radiofrequency ablation, to discriminate atrioventricular node reentrant tachycardia (AVNRT) from atrioventricular reciprocating tachycardia (AVRT) and to localize a concealed accessory pathway, prospectively. BACKGROUND: Information about ECG criteria for differentiating AVNRT from AVRT ...

The ECG diagnosis of ischemic heart disease is made more difficult in the setting of left bundle branch block (LBBB). The ECG diagnosis of prior or remote myocardial infarction (MI) is extremely difficult in this setting. Furthermore, the associated--and expected--ST-segment--T-wave abnormalities of LBBB may mimic acute ischemic change. However, ECG ...

The electrocardiography study of atrial arrhythmias has been hindered by the frequent occurrence of a "hidden". P wave in standard lead recordings. We present a modified method of surface electrocardiography that proved helpful in our prospective study of 26 consecutive patients in whom traditional surface recordings did not show the ...

The purpose of this evaluation was to determine if a prehospital 12-lead electrocardiogram (ECG) led to a delay in transportation when compared to non-12-lead ECG, and if it led to improved "door to drug" time. A quasi-experimental design was used to compare on-scene times for suspected acute myocardial infarction (AMI) ...

OBJECTIVE: The primary end point of the Emory Angioplasty versus Surgery Trial was a composite of three events: death, Q-wave infarction, and a new large defect on 3-year postoperative thallium scan. This study examines the clinical significance of Q-wave infarction in the surgical cohort (194 patients) of the Emory trial. ...

A prominent U wave induced by exercise testing in patients with anterior wall myocardial infarction is a highly specific but insensitive marker for the narrowing of the left circumflex or right coronary artery, although a U-wave increase alone with or without ST-segment depression may help better identify these coronary artery ...

OBJECTIVES: We attempted to determine the correlation between the presence of postextrasystolic changes in the STU segment and a history of sustained ventricular arrhythmias. BACKGROUND: Postextrasystolic U wave augmentation (a marked increment in U wave amplitude after premature ventricular complexes [PVCs]) is an adverse prognostic sign in the "pause-dependent long ...

OBJECTIVES: We sought to study the pathologic implications of restored positive T waves and persistent negative T waves in the chronic stage of Q wave myocardial infarction. BACKGROUND: Some inverted T waves (coronary T waves) become positive after acute myocardial infarction; others retain their negative T wave component for a ...

The normal shape of the T wave on the standard 12-lead electrocardiogram (ECG) is asymmetrical. The spatial velocity electrocardiogram (SVECG) is a method of recording the slope of the wave of the ECG and makes it possible to quantify the symmetry of the ECG-T wave. The aim of this study ...

BACKGROUND AND METHODS: To diagnose early acute cardiac rejection, we evaluated high-resolution electrocardiography in rats. Heterotopic heart transplantations were performed in allogeneic animals, either treated with cyclosporine or untreated, and in syngeneic animals. High-amplification electrocardiograms were recorded daily, under anesthesia, with two intra-abdominal leads. After amplification (x 5000 to 20,000), ...

Electrocardiography results were used to assess diagnosis and evolution of arrhythmogenic right ventricular disease. The initial ECG presentation and long-term changes were analysed in 74 consecutive patients with symptomatic ventricular tachycardia and arrhythmogenic right ventricular disease. On first available tracings, a left axis deviation of the QRS was found in ...

To determine the prevalence of various electrocardiographic (ECG) abnormalities among asymptomatic individuals in a rural population of India we performed a 12-lead ECG during a comprehensive cardiovascular survey in three randomly selected villages in Rajasthan. Twenty four of 3148 individuals with a past diagnosis or symptoms suggestive of coronary heart ...

OBJECTIVES: To examine the epicardial U-wave changes recorded in intracoronary electrocardiograms (ECGs) during anterior or inferoposterior myocardial ischaemia and the corresponding changes in precordial ECGs recorded from the body surface in humans. METHODS: 40 patients undergoing coronary angioplasty of the left anterior descending (LAD) coronary artery (22 patients) or left ...

Sudden cardiac death remains a preeminent public health problem. Despite advances in preventative treatment for patients known to be at risk, to date we have been able to identify, and thus treat, only a small minority of these patients. Therefore, there is a major need to develop noninvasive diagnostic technologies ...

We assessed the changes in plasma von Willebrand factor level concentration in 10 patients with Q-myocardial infarction and in six patients with non-Q-myocardial infarction who did not receive thrombolytic treatment. Concentrations of von Willebrand factor antigen were measured by an enzyme-linked immunoassay method in plasma samples obtained twice daily for ...

Serial electrocardiographic (ECG) changes are a critical component of the diagnostic algorithm for classification of myocardial ischemic events in large-scale clinical trials. This study describes a computerized serial ECG classification program developed at the St. Louis University Core ECG Laboratory for use in the Bypass Angioplasty Revascularization Investigation (BARI) trial, ...

A 54-year-old male experienced the Hanshin earthquake at 5:46 am on Jan. 17, 1995. He was rescued after being buried under his house for 20 h. After being treated at two hospitals, he was admitted to our hospital with acute renal failure caused by crush syndrome. The maximal serum creatinine ...

OBJECTIVES: The purpose of this study was to compare the diagnoses of healed myocardial infarction made from the 12-lead electrocardiogram (ECG) by artificial neural networks and an experienced electrocardiographer. BACKGROUND: Artificial neural networks have proved of value in pattern recognition tasks. Studies of their utility in ECG interpretation have shown ...

OBJECTIVE, DESIGN AND PATIENTS: Between August 1981 and July 1983, 5839 consecutive myocardial infarction patients were hospitalized in 13 coronary care units in Israel. The present study examines 10 year survival among 4037 consecutive patients with a first myocardial infarction with either Q or non-Q waves. Demographic and medical data ...

We sought to determine the effects of platelet glycoprotein IIb/IIIa receptor blockade on adverse outcomes, especially non-Q wave myocardial infarction, in patients undergoing directional atherectomy in the Evaluation of c7E3 for the Prevention of Ischemic Complications (EPIC) trial. Randomized trials comparing directional atherectomy with percutaneous transluminal coronary angioplasty (PTCA) have ...

OBJECTIVES: We sought to investigate the relation between signal-averaged electrocardiographic (ECG) variables and the extent of right ventricular disease, as estimated by right ventricular enlargement during detailed echocardiography, in patients with arrhythmogenic right ventricular dysplasia. BACKGROUND: In patients with ventricular tachycardia of right ventricular origin, a normal signal-averaged ECG is ...

The computed daily values of lunisolar tidal waves, the observed daily values of Ap index, a measure of the planetary geomagnetic activity, and the daily numbers of patients with epileptic attacks for a group of 28 neurology patients between 1987 and 1992 were analyzed by common, multiple and partial cross-spectral ...

The aim of this study was to analyze the ability of the multiresolution decomposition of the signal-averaged electrocardiogram (ECG) to discriminate between patients who develop life-threatening ventricular arrhythmias after myocardial infarction and those who do not and to compare the predictive values of this approach with those obtained from the ...

PURPOSE: To examine the prognostic significance of electrocardiographic (ECG) abnormalities among the elderly. MATERIALS AND METHODS: The Finnish cohorts of the Seven Countries Study involved 697 men aged 65 to 84 years at baseline in 1984. A 5-year follow-up was made from 1984 to 1989. Fatal myocardial infarction, nonfatal myocardial ...

OBJECTIVES: ECG peaked T wave appears during the early phase of myocardial ischemia, but the underlying mechanisms remain unknown. The purpose of this study was to elucidate the role of ATP-sensitive K+ channel (KATP) in this ECG change. METHODS: In 12 anesthetized, open-chest dogs, the sinus node was crushed and ...

OBJECTIVE: To determine whether acute myocardial infarction (AMI) patients who have negative ECGs on presentation have significantly lower complication rates than do those AMI patients who have positive ECGs on presentation. METHODS: Retrospective, cohort analysis comparing rates of hospital complications (ventricular fibrillation or tachycardia, shock, atrial arrhythmia or bradyarrhythmia with ...

The 12-lead ECG is extremely valuable in helping the critical care nurse detect the presence of myocardial ischemia, injury, and infarction. With an understanding of the 12-lead ECG, the nurse can relate the ECG findings to the patient's coronary artery disease and can anticipate the clinical consequences both for the ...

A 74-year-old Japanese woman with subarachnoid hemorrhage was admitted to our hospital. During her hospitalization, serial electrocardiograms showed the combination of abnormal Q waves, ST-segment elevation, and T-wave inversion, which strongly suggested acute myocardial infarction. However, postmortem examination revealed widespread focal myocytolysis of the myocardium which was unrelated to vascular ...

Conflicting results in a heterogenous patient population have been described on the functional significance of stress-induced T wave normalization in the ECG. The aim of this study was to evaluate the relationship between T wave normalization during dobutamine stress testing and stress-induced ischaemia evaluated by echocardiography and myocardial perfusion scintigraphy ...

Jugular venous pressure (measured clinically) and pulse wave form (recorded at 100 mm/s) were analysed in 44 cases of first acute myocardial infarction and 10 age-matched controls. Patients were divided into different groups according to site of infarction decided by detailed 2-D echocardiography. Raised jugular venous pressure had high specificity ...

OBJECTIVE: To investigate the value of a giant negative T wave (> or = 1.0 mV) in precordial leads of 12-lead electrocardiograms in the acute phase of Q wave myocardial infarction as a predictor of myocardial salvage. METHODS: Coronary angiographic and electrocardiographic findings, left ventricular ejection fraction in the chronic ...

We evaluated the time course of QT intervals and the amplitude of T waves, and their relationship to subsequent left ventricular regional wall motions in 88 patients with successfully reperfused acute myocardial infarction (MI). The QTc intervals and the amplitude of inverted T waves of lead V3 in patients with ...

We prospectively examined 45 patients with serial echocardiography to measure left ventricular end-diastolic volume index within 1 week and at 6 weeks after infarction. Left ventricular volume increased in patients with Q-wave infarction but not in those with non-Q or in control patients without recent infarction. Peak creatine phosphokinase levels ...

OBJECTIVES: This study sought to evaluate the prognostic value of wavelet correlation functions of the signal-averaged electrocardiogram (ECG) for arrhythmic events in patients after myocardial infarction. BACKGROUND: Wavelet transform of the signal-averaged ECG has been shown to be a nonstationary analysis technique describing the time evolution of frequency spectra throughout ...

OBJECTIVES: To estimate interobserver, within-patient and between-patient variation of the signal-averaged P wave. To determine whether demographic, clinical, conventional ECG information, and coronary angiographic data are associated with the signal-averaged P wave duration in patients with documented coronary artery disease. BACKGROUND: A prolonged signal-averaged P wave may indicate the presence ...

Though absence of the septal q wave on a standard ECG was recognised by Willem Einthoven, this abnormality has received little attention. Nevertheless it is common in patients with coronary artery disease, and strongly associated with fibrosis of the septum with or without infarction. Furthermore, the associated disturbance of ventricular ...

Consecutive electrocardiographic (ECG) analysis is very useful in acute coronary ischemia, but it is known that ECG patterns can be misleading in subjects with left ventricular hypertrophy, mainly during the repolarization phase. An automated system was developed to collect, store, and follow-up all heterogeneous data concerning a cohort of 1,898 ...