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PubMed1994

ST segment depression detected by continuous electrocardiography in patients with acute ischemic stroke or transient ischemic attack.

BACKGROUND AND PURPOSE: Forty percent of patients with a history of ischemic stroke or transient ischemic attack (TIA) have concomitant coronary artery disease. ST segment depression, detected by continuous electrocardiography, is associated with increased cardiac morbidity and mortality in patients with known coronary artery disease. While electrocardiographic changes have been associated with acute stroke, the etiology and significance of these changes remain unclear. In this pilot study we report the prevalence of ST segment depression and ventricular arrhythmias in patients with acute ischemic stroke or TIA monitored by continuous electrocardiography. Clinical predictors of ST segment depression and ventricular arrhythmia are also identified. METHODS: Consecutive patients presenting with acute ischemic stroke or TIA were enrolled within 72 hours of hospital admission and monitored by continuous electrocardiography for 48 hours. The electrocardiographic results were analyzed for periods of ST segment depression and ventricular arrhythmias. RESULTS: Of 51 patients with ischemic stroke or TIA, 15 (29%) had episodes of ST segment depression (95% confidence interval, 15% to 43%), and 18 (35%) had ventricular arrhythmias (95% confidence interval, 21% to 49%). In logistic regression analysis, increasing age (P < .02) and a left-sided neurological event (P < .01) were significant predictors of ST segment depression. Increasing numbers of atherosclerotic risk factors, a history of cardiac disease, and increasing or decreasing mean arterial pressure were not predictive of ST segment depression. CONCLUSIONS: Patients with acute ischemic stroke or TIA have a 29% prevalence of ST segment depression within the first 5 days after their event. In comparison, the prevalence of ST depression is 2.5% to 8% in asymptomatic adults and 43% to 60% in patients with symptomatic coronary artery disease. The association of ST segment depression with left-sided neurological events suggests that the electrocardiographic changes are in part neurologically mediated. Further study is necessary to better define the brain-heart interaction and to determine whether ST segment depression in patients with ischemic stroke or TIA reflects underlying coronary artery disease.

Acute Disease↗

PubMed1991

Open access exercise electrocardiography: a service to improve management of ischaemic heart disease by general practitioners.

An initial study of the use of open access exercise electrocardiography by general practitioners (GPs) in South East Kent showed that patient selection and interpretation of test results was frequently incorrect. After issuing guidelines, modifying the request form and instituting registrar review of all requests, significant improvements in both referral pattern, result interpretation and patient management have resulted. Forty-nine GPs requested 110 exercise tests during 1988/89. Twelve per cent were not undertaken after discussion with the referring practitioner. Eighty-four per cent of those tested would have been referred to the district general hospital cardiology outpatient department in the absence of open access exercise electrocardiography service. Six per cent of patients were referred directly for invasive investigation. Thirty-five per cent were referred to the district general hospital cardiology outpatient department, whilst 42% were spared hospital referral based on the result of the investigation. Better use of the modified service was suggested by: referral of fewer patients with non-cardiac chest pains (P = 0.002); more patients with a moderate pre-test probability of ischaemic heart disease (P less than 0.05); fewer inappropriate requests (P less than 0.01); and fewer inappropriately undertaken tests (P less than 0.001) than in the previous study. All patients with strongly positive test results were appropriately managed. Open access exercise electrocardiography in the format investigated is potentially a cost-effective and useful tool to improve diagnosis and management of heart disease by GPs.

Adolescent↗

PubMed2006

Accurate placement of the right atrial air aspiration catheter: a descriptive study and prospective trial of intravascular electrocardiography.

Appropriate positioning of the right atrial air aspiration catheter is critical to successful aspiration of air. The intravascular electrocardiography patterns currently used to position the right atrial air aspiration catheter have not been validated by echocardiography. In 10 patients, using simultaneous transesophageal echocardiography and intravascular electrocardiography, we found that the largest monophasic P wave without a biphasic component correlated with the right atrial-superior vena cava junction. Using this pattern, we performed a prospective trial on 10 subjects and demonstrated appropriate positioning in only 8. This preliminary study suggests that intravascular electrocardiography may not yield appropriate positioning in all patients.

Adult↗

PubMed1995

Is ambulatory electrocardiography useful in the evaluation of patients with recent stroke?

This study was designed to determine whether ambulatory electrocardiography in patients with recent stroke would lead to a change in clinical management or outcome and to express these findings in terms of cost benefit. A prospective, consecutive sample of patients (n = 100) with recent stroke referred from the neurology or medical services for ambulatory electrocardiography was identified. Ambulatory electrocardiograms were reviewed to identify patients with potentially important bradyarrhythmias, tachyarrhythmias, or atrial fibrillation. Patients were then followed up without interference with ongoing care to determine whether these findings led to changes in clinical management that might influence patient outcome. Of the 100 patients, 16 had an index "important" arrhythmia. No significant bradyarrhythmias were noted. Nonsustained ventricular tachycardia (> or = 6 complexes) in two patients and supraventricular tachycardia (> or = 10 complexes) in seven patients did not lead to management changes. Four patients had a history of atrial fibrillation who were in sinus rhythm; anticoagulation had been addressed in three; the fourth patient died before the issue could be addressed. Of three patients in atrial fibrillation, there was a history of atrial fibrillation and a decision regarding anticoagulation in each before monitoring. The cost of these 100 ambulatory electrocardiograms was about $55,000. In conclusion, these findings do not support the routine use of ambulatory electrocardiography in the evaluation of patients with stroke.

Aged↗

PubMed2001

Atrial activation during sinus rhythm in patients with rheumatic and non-rheumatic paroxysmal atrial fibrillation. Frequency-domain analysis using signal-averaged electrocardiography.

OBJECTIVE: Using P-wave signal-averaged electrocardiography, we assessed the patterns of atrial electrical activation in patients with idiopathic atrial fibrillation as compared with patterns in patients with atrial fibrillation associated with structural heart disease. METHODS: Eighty patients with recurrent paroxysmal atrial fibrillation were divided into 3 groups as follows: group I - 40 patients with atrial fibrillation associated with non-rheumatic heart disease; group II - 25 patients with rheumatic atrial fibrillation; and group III - 15 patients with idiopathic atrial fibrillation. All patients underwent P-wave signal-averaged electrocardiography for frequency-domain analysis using spectrotemporal mapping and statistical techniques for detecting and quantifying intraatrial conduction disturbances. RESULTS: We observed an important fragmentation in atrial electrical conduction in 27% of the patients in group I, 64% of the patients in group II, and 67% of the patients in group III (p=0.003). CONCLUSION: Idiopathic atrial fibrillation has important intraatrial conduction disturbances. These alterations are similar to those observed in individuals with rheumatic atrial fibrillation, suggesting the existence of some degree of structural involvement of the atrial myocardium that cannot be detected with conventional electrocardiography and echocardiography.

Adult↗

PubMed1997

Diagnosing syncope. Part 1: Value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians.

PURPOSE: To review the literature on diagnostic testing in syncope and provide recommendations for a comprehensive, cost-effective approach to establishing its cause. DATA SOURCES: Studies were identified through a MEDLINE search (1980 to present) and a manual review of bibliographies of identified articles. STUDY SELECTION: Papers were eligible if they addressed diagnostic testing in syncope or near syncope and reported results for at least 10 patients. DATA EXTRACTION: The usefulness of tests was assessed by calculating diagnostic yield: the number of patients with diagnostically positive test results divided by the number of patients tested or, in the case of monitoring studies, the sum of true-positive and true-negative test results divided by the number of patients tested. DATA SYNTHESIS: Despite the absence of a diagnostic gold standard and the paucity of data from randomized trials, several points emerge. First, history, physical examination, and electrocardiography are the core of the syncope workup (combined diagnostic yield, 50%). Second, neurologic testing is rarely helpful unless additional neurologic signs or symptoms are present (diagnostic yield of electroencephalography, computed tomography, and Doppler ultrasonography, 2% to 6%). Third, patients in whom heart disease is known or suspected or those with exertional syncope are at higher risk for adverse outcomes and should have cardiac testing, including echocardiography, stress testing. Holter monitoring, or intracardiac electrophysiologic studies, alone or in combination (diagnostic yields, 5% to 35%). Fourth, syncope in the elderly often results from polypharmacy and abnormal physiologic responses to daily events. Fifth, long-term loop electrocardiography (diagnostic yield, 25% to 35%) and tilt testing (diagnostic yield < or = 60%) are most useful in patients with recurrent syncope in whom heart disease is not suspected. Sixth, psychiatric evaluation can detect mental disorders associated with syncope in up to 25% of cases. Seventh, hospitalization may be indicated for patients at high risk for cardiac syncope (those with an abnormal electrocardiogram, organic heart disease, chest pain, history of arrhythmia, age > 70 years) or with acute neurologic signs. CONCLUSIONS: Many tests for syncope have a low diagnostic yield. A careful history, physical examination, and electrocardiography will provide a diagnosis or determine whether diagnostic testing is necessary in most patients.

Algorithms↗

PubMed1978

[Comparison of 24 hours ambulatory electrocardiography and endocavitary recording in the diagnosis of heart rate disorders].

Ninety symptomatic patients aged between 16 and 90 years were investigated by ambulatory continuous 24 hour electrocardiography. 75 of these patients underwent endocavitary exploration of atrioventricular conduction and sinus node function within 48 hour of ambulatory electrocardiography. Symptoms occurred during the recording in 30% patients, enabling the mechanism of the malaise to be determined. Every time that abnormalities in the zone surrounding the Tawara node were demonstrated by endocavitary recordings, the 24 hour electrocardiogramme showed the symptoms to be due to other causes than complete heart block. In 70% patients no symptoms were experienced but 58% of them had cardiac arrhythmias and particularly sinus node dysfunction (24 out of 37 patients) on the 24 hour electrocardiogramme. Comparing the results of these two methods of investigation, continuous electrocardiography appears to be a better technique for the diagnosis of sinus node dysfunction but endocavitary study of sinus node function would seem more suited to determine its severity. Endocavitary recordings seem more reliable in the investigation of paroxysmal atrioventricular blocks. These results demonstrate the complementary nature of these two methods in determining the causes of syncope and dizziness.

Adolescent↗

PubMed1999

Laplacian electrocardiography.

This article reviews the recent development in Laplacian electrocardiography. The Laplacian electrocardiogram was proposed in the early 1990s as an alternative for mapping regional cardiac electrical activity. Considerable progress has been made in the field during the last 5 years on this emerging technique. This article attempts to cover both the basic concepts and theory for general readers in biomedical engineering, and state-of-the-art developments in forward and inverse problems of Laplacian electrocardiography, as well as Laplacian ECG mapping in an experimental setting for researchers working in the field of cardiac mapping. The article also addresses controversies regarding the feasibility of experimentally obtaining the Laplacian electrocardiogram in human subjects. The work reviewed in this article suggests that Laplacian electrocardiography merits further investigation and promises to provide an important alternative means of assessing noninvasively cardiac electrical activity.

Algorithms↗

PubMed2000

[High resolution electrocardiography of P-wave signals in clinical cardiology].

Signal-averaged electrocardiography of the QRS complex detects presence of late potentials which represent significant arrhythmogenic marker responsible for increased risk of life-threatening ventricular arrhythmias especially in post myocardial infarction patients. The P wave signal-averaged electrocardiography has been designed to predict development of atrial fibrillation in different populations of patients. Many P wave signal-averaging methodological procedures have been developed. However their common disadvantages remain lack of standardization, relatively low specificity and sensitivity, low positive predictive value as well as limited number of larger prospective clinical trials. Recent software and technological improvements of the P wave high resolution techniques as well as some new reports about the influence of antiarrhythmic drugs on the parameters of the P wave signal-averaged electrocardiography are creating new possibilities not only for the diagnosis of paroxysmal atrial fibrillation but also for the prediction of antiarrhythmic drug efficiency.

Arrhythmias, Cardiac↗

PubMed2002

[Diagnosis of effort angina pectoris at rest by first derivative electrocardiography].

OBJECTIVES: First derivative electrocardiography (FDECG) records the slope of the wave of the standard 12-lead electrocardiography (ECG) and enables quantification of ECG-T wave symmetry. This study investigated the usefulness of FDECG to diagnose effort angina pectoris in patients with chest pain. METHODS: All 62 patients who visited our hospital with exertional chest pain underwent FDECG at rest, and exercise electrocardiography or stress thallium scintigraphy. Patients with possible ischemic change underwent coronary angiography, and those with significant coronary artery stenosis (> or = 75% reduction) were classified as the angina pectoris group (23 subjects). The other patients (without ischemic change or without significant coronary artery stenosis) formed the non-angina pectoris group (39 subjects). The FDECG is a simple differential wave with two peaks. The first peak of the FDECG-T wave designated as the T1 wave and the second peak as the T2 wave. The heights (the T1 and T2 wave amplitude) and the T2/T1 ratio (T2 wave heights/T1 wave heights) were calculated in the two groups. RESULTS: The T2/T1 ratios in leads I, V3, V4, V5 and V6 were significantly (I, V3, V4: p < 0.01, V5: p < 0.0001, V6: p < 0.001) decreased in the angina pectoris group. Using the criterion of a T2/T1 ratio at the V5 lead of less than 1.30, FDECG could detect effort angina pectoris patients with 65% in sensitivity, 74% specificity and 71% accuracy. CONCLUSIONS: ECG-T waves in the angina pectoris group were symmetrical. T2/T1 ratio of the FDECG-T wave is a useful index to diagnose effort angina pectoris at rest.

Angina, Unstable↗

PubMed2004

Diagnostic and therapeutic impact of ambulatory electrocardiography in acute stroke.

UNLABELLED: Detection of paroxysmal atrial fibrillation (PAF) in patients with recent ischemic stroke or TIA suggests a cardioembolic etiology and leads to initiation of oral anticoagulation in suitable candidates. We assessed the diagnostic and therapeutic impact of adding ambulatory electrocardiography (24 hr ECG) to a standardised ischemic stroke workup. METHODS: We measured the frequency of detection of PAF in consecutive stroke patients who underwent 24 hr ECG that was not diagnosed clinically or on a standard 12-lead ECG. RESULTS: One hundred forty five ischemic stroke patients were included. 24 hr ECG was obtained in 136 patients (93.8%). Clinically unsuspected PAF was detected on 24 hr ECG in 7 patients (5.1%). The secondary prevention measure changed from antiplatelet agents to oral anticoagulation in 6 of 7 patients. CONCLUSION: Our findings suggest that ambulatory electrocardiography is a valuable diagnostic tool in the workup of stroke patients. Further prospective studies are needed to identify, subtypes of patients in whom the yield of ambulatory electrocardiography is higher.

Aged↗

PubMed1992

Results of continuous ambulatory electrocardiography in a cat with hypertrophic cardiomyopathy.

An 8-year-old neutered male cat with a history of intermittent collapse and dyspnea was evaluated. Hypertrophic cardiomyopathy was diagnosed on the basis of findings from physical examination, radiography, and echocardiography. Cardiac arrhythmias were not recorded during routine electrocardiography. Continuous ambulatory electrocardiography documented severe ventricular arrhythmias (ventricular premature complexes, ventricular bigeminy, and paroxysmal ventricular tachycardia). Continuous ambulatory electrocardiography can detect intermittent and potentially life-threatening cardiac arrhythmias.

Animals↗

PubMedDate not supplied

Limitations of esophageal electrocardiography in recording atrial rhythms after orthotopic heart transplantation.

Esophageal electrocardiography is a commonly used tool for the differential diagnosis of arrhythmias. A 39-year-old man who underwent orthotopic heart transplantation developed a narrow complex tachycardia. Esophageal electrocardiography showed a junctional tachycardia (recording native atrial activity alone), whereas atrial intracavitary electrograms showed the correct diagnosis of atrial flutter. Esophageal recording in patients who undergo orthotopic heart transplantation is a useful technique for recording native atrial activity. For arrhythmia diagnosis in these patients it is frequently necessary to record donor atrial activity with intracavitary electrograms. The limitations of esophageal electrocardiography should be recognized by physicians who care for these patients.

Adult↗

PubMed1987

Historical aspects of electrocardiography.

One hundred years ago, Augustus Desiré Waller recorded the human electrocardiogram for the first time, using a capillary electrometer. Electrocardiography only became clinically relevant in 1901 when Willem Einthoven devised his string galvanometer for this purpose. Sir Thomas Lewis was the key figure in showing the value of the electrocardiography for the diagnosis of disorders of cardiac rhythm and conduction, but many others amplified the technique to encompass the assessment of structural heart disease, especially when due to ischemia. Knowledge of their role and work gives us a better perspective when considering the development of surface electrocardiography.

Electrocardiography↗

PubMed1982

Electrocardiography, cardioenzymes and myocardial imaging to detect perioperative myocardial infarction.

Serial electrocardiography, technetium-99m pyrophosphate scintigraphy and measurement of myocardial creatine kinase (CK2) and lactic dehydrogenase isoenzyme activity (specifically the LD1 to LD2 ratio) were evaluated prospectively in 26 patients who underwent aortocoronary bypass grafting and 11 patients who underwent valvular or other thoracic surgery, as methods of diagnosing perioperative myocardial infarction. Of the 26 patients who had aorto coronary bypass grafting, 7 (group 1) had myocardial infarction perioperatively; of these, only 2 had positive results from all four diagnostic tests. The other 19 patients (group 2) had no perioperative myocardial infarction and the only diagnostic method yielding positive results was the LD1 to LD2 ratio, in 7 of the 19. In the 11 patients who did not undergo aortocoronary bypass grafting (group 3), only 1 patient had myocardial infarction perioperatively; results from the measurement of CK2 isoenzyme activity and LD1 to LD2 ratio were positive while electrocardiography and 99mTc pyrophosphate scintigraphy yielded negative results. The respective sensitivity (%) and specificity (%) of the four diagnostic methods were as follows: electrocardiography: 38, 100; 99mTc pyrophosphate scintigraphy: 88, 100; LD1 to LD2 ratio: 100, 68; CK2: 38, 100. When the CK2 criterion was redefined, using patients in group 2 as controls, the sensitivity and specificity of this method became 100 and 90 respectively. The authors conclude that 99MTc pyrophosphate scintigraphy and measurement of myocardial creatine kinase isoenzyme are of comparable value and are the most reliable indicators of perioperative myocardial infarction.

Coronary Artery Bypass↗

PubMed1983

Comparison of cardiotocograms prepared by abdominal electrocardiography and by ultrasound cardiography.

Cardiotocograms were prepared in 127 cases on 120 pregnant women, first by abdominal electrocardiography, and immediately afterwards by ultrasound cardiography. A study was made to ascertain which method yielded recordings of higher quality, and which factors influenced the quality of the cardiotocogram. It was found that the proportion of good-quality recordings was higher with ultrasound cardiography than with abdominal electrocardiography. The higher information content of the latter technique allows a more accurate assessment of the cardiotocograms. The recording quality is affected by numerous factors, the most important of which are adiposity and the duration of pregnancy. The use of abdominal electrocardiography is preferred in case of a thick abdominal wall, whereas the ultrasound technique is recommended between the 28th and 36th weeks of pregnancy.

Echocardiography↗

PubMedDate not supplied

Signal-averaged electrocardiography and Doppler echocardiographic study in predicting acute rejection in heart transplantation.

BACKGROUND AND METHODS: In a prospective protocol for noninvasive diagnosis of acute cardiac rejection, 83 routine endomyocardial biopsies, followed each time by the analysis of signal-averaged electrocardiography and by a cardiac Doppler echocardiographic study, were performed in 18 heart transplant recipients. The follow-up time was 5 +/- 3.6 months. To detect noninvasively acute cardiac rejection, we compared biopsy findings with the presence of late potentials at signal-averaged electrocardiography and with two diastolic indexes, pressure half-time, and isovolumic relaxation time obtained from Doppler echocardiographic study. RESULTS: Thirteen acute rejection crises requiring modification of immunosuppression were diagnosed by means of endomyocardial biopsy. This clinically relevant acute cardiac rejection was associated with the presence of late potentials in 69% of cases and with the presence of pressure half-time < or = 55 msec and isovolumic relaxation time < or = 60 msec in 69% and 62% of cases, respectively. Sensitivity and specificity were as follows: for late potentials, 69% and 71%; for pressure half-time < or = 55 msec, 69% and 76%; for isovolumic relaxation time < or = 60 msec, 62% and 83%, respectively. The presence in a single patient of at least one abnormal parameter showed a sensitivity of 100% and a specificity of 60% in detecting important rejection. CONCLUSIONS: These data support the use of combined signal-averaged electrocardiography and Doppler echocardiographic study of the left ventricular diastolic function in the screening of acute cardiac rejection. Such results can suggest when endomyocardial biopsy should be performed, with the reliance that a normal noninvasive study highly excludes the presence of acute cardiac rejection requiring intensified immunosuppression.

Adult↗

PubMed2003

Feasibility of simultaneous application of fetal electrocardiography and fetal pulse oximetry.

BACKGROUND: Fetal pulse oximetry measures arterial oxygen saturation during delivery. The fetal electrocardiogram STAN S21 analyzes the repolarisation segment of ECG (ST) waveform, which is altered by the intramyocardial potassium release resulting from metabolic acidemia. This study aimed to evaluate the feasibility of a simultaneous application of pulse oximetry and fetal electrocardiography and to estimate any agreement between both methods indicating fetal compromise. METHODS: In an observational trial 35 fetuses were simultaneously monitored by pulse oximetry (OBS-500) and electrocardiography. The evaluation focused on signal output and on the coincidence of desaturation in fetal pulse oximetry and on ST events. Desaturation was defined as a drop of at least 20% of oxygen saturation from base line level occurring within 1 min (steep desaturation) or duration of time (s) with oxygen saturation below the threshold of 30%. Statistical analysis was performed with the Mann-Whitney U-test for continuous variables. RESULTS: Signal output of the simultaneous application of both sensors was not significantly reduced in the electrocardiogram and in pulse oximetry (8% vs. 12% reduction). In 15 of the 35 fetuses, ST events indicating fetal hypoxia occurred. In these cases, pulse oximetry showed significantly more episodes of desaturation in comparison with fetuses without ST events. Median saturation during the ST events was significantly lower than in the recordings without ST events (60% vs. 74%, p < 0.05). In the umbilical artery these neonates showed significantly lower pH (7.19 vs. 7.33, p < 0.001), significantly higher lactate (5.1 vs. 3.4 mmol/l, p < 0.05) and significantly lower base deficit (-9.4mmol/l vs. -4.0 mmol/l, p < 0.001) levels. CONCLUSIONS: The combination of fetal pulse oximetry and fetal electrocardiography appears feasible and indicates signs of intermittent hypoxia. These findings may encourage the development of technology that combines these different methods of monitoring.

Adult↗