Increased Ion Temperature and Neutron Yield Observed in Magnetized Indirectly Driven D_{2}-Filled Capsule Implosions on the National Ignition Facility.

The application of an external 26 Tesla axial magnetic field to a D_{2} gas-filled capsule indirectly driven on the National Ignition Facility is observed to increase the ion temperature by 40% and the neutron yield by a factor of 3.2 in a hot spot with areal density and temperature approaching what is required for fusion ignition [1]. The improvements are determined from energy spectral measurements of the 2.45 MeV neutrons from the D(d,n)^{3}He reaction, and the compressed central core B field is estimated to be ∼4.9 kT using the 14.1 MeV secondary neutrons from the D(T,n)^{4}He reactions. The experiments use a 30 kV pulsed-power system to deliver a ∼3 µs current pulse to a solenoidal coil wrapped around a novel high-electrical-resistivity AuTa_{4} hohlraum. Radiation magnetohydrodynamic simulations are consistent with the experiment.

Assessment of a rapid liquid-based cytology method for measuring sputum cell counts.

Differential sputum cell counting is not widely available despite proven clinical utility in the management of asthma. We compared eosinophil counts obtained using liquid-based cytology (LBC), a routine histopathological processing method, and the current standard method. Eosinophil counts obtained using LBC were a strong predictor of sputum eosinophilia (≥3%) determined by the standard method suggesting LBC could be used in the management of asthma.

The influence of corporate structure and quality improvement activities on outcome improvement in residential care homes.

OBJECTIVE: To examine the impact of corporate structure and quality improvement (QI) activities on improvements in client-reported and professional indicators between 2007 and 2009. DESIGN: A cross-sectional study using organizational survey and indicator multilevel modelling to test relationships between corporate structure, QI activities and performance improvements on indicators. SETTING: In total, 169 residential care homes for the elderly in the Netherlands. MAIN OUTCOME MEASURES: Change between 2007 and 2009 in client-reported and professional indicators. RESULTS: A middle-size corporate structure was associated with QI. The QI activity 'multidisciplinary team meetings' was positively correlated with the indicator 'safety environment' for somatic and psycho-geriatric care. The QI activities 'educational material' and 'direct work instructions' were associated negatively with the indicator 'availability of personnel' for somatic clients, but positively for psycho-geriatric clients. QI activities such as 'health plan activities', 'clinical lessons' and 'financial activities' had no relationship to improved performance. For psycho-geriatric clients mainly organizational QI activities were positively associated with QI. The mediating role of the corporate structure for performing QI activities appeared stronger for the change in client-reported than for professional indicators. CONCLUSION: This study reveals associations between QI activities and corporate structure and changes in indicator performance. A corporate structure was associated with improvement in client-reported indicators, but less on professional indicators, which assumes a central policy at corporate level with impact on client-reported indicators, in contrast to a more local level approach towards activities that result in QI on professional indicators. Tailoring QI activities at the right managerial level may be important to achieve improvement.

Value of subtraction MRI in assessing treatment response following image-guided loco-regional therapies for hepatocellular carcinoma.

AIM: To compare contrast-enhanced subtraction magnetic resonance imaging (MRI) with contrast-enhanced standard MRI in assessing treatment response following loco-regional therapies for hepatocellular carcinoma (HCC). METHOD AND MATERIALS: Institutional review board approval was obtained and informed consent was waived for this retrospective study. All patients were analysed from our institution's liver tumour database that had loco-regional HCC therapy and the following: (1) a contrast-enhanced MRI ≤6 weeks post-treatment, (2) an unenhanced T1-weighted high-signal treatment zone (TZ) ≥1 cm, (3) follow-up contrast-enhanced MRI performed ≥6 months post-treatment. Randomized standard and subtraction TZ datasets were independently assessed by three blinded radiology readers for either complete treatment necrosis or residual disease. The standard of reference (SOR) comprised a consensus read by two radiologists with knowledge of the follow-up MRI and all available clinical data. Statistical analyses were performed using receiver operating characteristics (ROC), t-test, and kappa statistic. RESULTS: Twenty-six patients (19 male and seven female patients; mean age 60 years, standard deviation 10.9 years, range 46-88 years) had a total of 45 corresponding HCCs and TZs. For ROC, the area under the curve (AUC) was 0.93 (subtraction protocol) versus 0.90 (standard protocol; p = 0.49). For the t-test, the mean reader confidence level was 4.4, 3.6, and 4.4 (subtraction protocol) versus 3, 3, and 3.7 (standard protocol; p ≤ 0.011). The kappa statistic for reader-to-SOR agreement was 0.83, 0.63, and 0.71 (subtraction protocol) versus 0.51, 0.36, and 0.64 (standard protocol). CONCLUSION: Subtraction MRI significantly improves the reader confidence level in the assessment of treatment response following loco-regional therapies for HCC.

Importance of Fungicide Seed Treatment and Environment on Seedling Diseases of Cotton.

The importance of fungicide seed treatments on cotton was examined using a series of standardized fungicide trials from 1993 to 2004. Fungicide seed treatments increased stands over those from seed not treated with fungicides in 119 of 211 trials. Metalaxyl increased stands compared to nontreated seed in 40 of 119 trials having significant fungicide responses, demonstrating the importance of Pythium spp. on stand establishment. Similarly, PCNB seed treatment increased stands compared to nontreated seed for 44 of 119 trials with a significant response, indicating the importance of Rhizoctonia solani in stand losses. Benefits from the use of newer seed treatment chemistries, azoxystrobin and triazoles, were demonstrated by comparison with a historic standard seed treatment, carboxin + PCNB + metalaxyl. Little to no stand improvement was found when minimal soil temperatures averaged 25°C the first 3 days after planting. Stand losses due to seedling pathogens increased dramatically as minimal soil temperatures decreased to 12°C and rainfall increased. The importance of Pythium increased dramatically as minimal soil temperature decreased and rainfall increased, while the importance of R. solani was not affected greatly by planting environment. These multi-year data support the widespread use of seed treatment fungicides for the control of the seedling disease complex on cotton.

Uncertain in the face of change: Lack of contingency shift awareness during extinction is associated with higher fear-potentiated startle and PTSD symptoms in children.

Intolerance of uncertainty is a transdiagnostic risk factor for fear-related disorders and is associated with higher levels of anxiety in children and adolescents. It is unclear how uncertainty relates to development of psychopathology in children who have experienced trauma in early life. The present study used a fear-potentiated startle paradigm in children to examine associations between uncertainty (assessed as unawareness of a change in reinforcement during fear extinction) and symptoms of anxiety and posttraumatic stress disorder (PTSD), as well as startle potentiation to threat and safety cues. Results showed that unaware children had strong positive associations between trauma exposure and PTSD symptoms, whereas aware children did not. Uncertainty interacted with anxiety in that children who were both unaware and had higher anxiety displayed higher fear-potentiated startle to safety cues and did not show discrimination between threat and safety during fear conditioning. These results suggest that anxious children who persist in associating a threat cue with an aversive event during extinction, after repeated presentations of the no longer reinforced conditioned stimulus, may express psychophysiological phenotypes related to PTSD.

A 2-4 keV multilayer mirrored channel for the NIF Dante system.

During inertial confinement fusion experiments at the National Ignition Facility (NIF), a capsule filled with deuterium and tritium (DT) gas, surrounded by a DT ice layer and a high-density carbon ablator, is driven to the temperature and densities required to initiate fusion. In the indirect method, 2 MJ of NIF laser light heats the inside of a gold hohlraum to a radiation temperature of 300 eV; thermal x rays from the hohlraum interior couple to the capsule and create a central hotspot at tens of millions degrees Kelvin and a density of 100-200 g/cm3. During the laser interaction with the gold wall, m-band x rays are produced at ∼2.5 keV; these can penetrate into the capsule and preheat the ablator and DT fuel. Preheat can impact instability growth rates in the ablation front and at the fuel-ablator interface. Monitoring the hohlraum x-ray spectrum throughout the implosion is, therefore, critical; for this purpose, a Multilayer Mirror (MLM) with flat response in the 2-4 keV range has been installed in the NIF 37° Dante calorimeter. Precision engineering and x-ray calibration of components mean the channel will report 2-4 keV spectral power with an uncertainty of ±8.7%.

Vaccination against experimental allergic encephalomyelitis with T cell receptor peptides.

Experimental allergic encephalomyelitis (EAE) is an autoimmune disease of the central nervous system mediated by CD4+ T cells reactive with myelin basic protein (MBP). Rats were rendered resistant to the induction of EAE by vaccination with synthetic peptides corresponding to idiotypic determinants of the beta chain VDJ region and J alpha regions of the T cell receptor (TCR) that are conserved among encephalitogenic T cells. These findings demonstrate the utility of TCR peptide vaccination for modulating the activity of autoreactive T cells and represent a general therapeutic approach for T cell-mediated pathogenesis.

Population trends in emergency cancer diagnoses: The role of changing patient case-mix.

BACKGROUND: Diagnosis of cancer through an emergency presentation is associated with worse clinical and patient experience outcomes. The proportion of patients with cancer who are diagnosed through emergency presentations has consequently been introduced as a routine cancer surveillance measure in England. Welcome reductions in this metric have been reported over more than a decade but whether reductions reflect true changes in how patients are diagnosed rather than the changing case-mix of incident cohorts in unknown. METHODS: We analysed 'Routes to Diagnosis' data on cancer patients (2006-2015) and used logistic regression modelling to determine the contribution of changes in four case-mix variables (sex, age, deprivation, cancer site) to time-trends in emergency presentations. RESULTS: Between 2006 and 2015 there was an absolute 4.7 percentage point reduction in emergency presentations (23.8%-19.2%). Changing distributions of the four case-mix variables explained 19.0% of this reduction, leaving 81.0% unexplained. Changes in cancer site case-mix alone explained 16.0% of the total reduction. CONCLUSION: Changes in case-mix (particularly that of cancer sites) account for about a fifth of the overall reduction in emergency presentations. This would support the use of adjustment/standardisation of reported statistics to support their interpretation and help appreciate the influence of case-mix, particularly regarding cancer sites with changing incidence. However, most of the reduction in emergency presentations remains unaccounted for, and likely reflects genuine changes during the study period in how patients were being diagnosed.

Leydig cell insufficiency in hypospermatogenesis: a paracrine effect of activin-inhibin signaling?

Clinical findings and a variety of experimental models indicate that Leydig cell dysfunction accompanies damage to the seminiferous tubules with increasing severity. Most studies support the idea that intratesticular signaling from the seminiferous tubules to Leydig cells regulates steroidogenesis, which is disrupted when hypospermatogenesis occurs. Sertoli cells seem to play a pivotal role in this process. In this review, we summarize relevant clinical and experimental observations and present evidence to support the hypothesis that testicular activin signaling and its regulation by testicular inhibin may link seminiferous tubular dysfunction to reduced testosterone biosynthesis.

Testosterone and estradiol are co-secreted episodically by the human testis.

In spite of a striking pulsatile pattern of luteinizing hormone (LH) secretion, testosterone (T) fluctuations in peripheral blood in normal adult men are irregular and of low amplitude. To determine whether T secretion by the human testis is episodic, T was measured in blood samples drawn at 15-min intervals for 4 h through a catheter placed in the testicular vein of six men with varicocele-associated infertility. Estradiol (E2) concentrations were also determined in each sample. Each subject released testosterone in well-defined pulses. Gonadal vein T levels ranged from 1 to 1,540 ng/ml. Mean (+/- SE) pulse amplitude was 176 +/- 42 ng/ml, with a frequency of 4.0 +/- 0.3 pulses per 4 h. Testicular vein E2 levels ranged from 0.01 to 6.8 ng/ml. E2 secretory episodes were generally coincident with T pulses, and their amplitudes were highly positively correlated (r = 0.90, P less than 0.01). These results indicate that T secretion by the adult human testis is pulsatile, and suggest a functional relationship between intermittent LH secretion and normal testicular steroidogenesis in men. The failure to appreciate these fluctuations as hormone pulses in peripheral blood may relate to their absolute amplitude and frequency. The concordance between E2 and T pulses suggests that the Leydig cell, under LH control, is the source of most of the E2 secreted by the adult human testis.

The origins of the sinus node pacemaker complex in man: demonstration of dominant and subsidiary foci.

To test the hypothesis that the human sinus node is capable of demonstrating multiple sites of impulse generation, we assessed spontaneous shifts in the sinus node pacemaker complex, and shifts after overdrive atrial pacing, premature atrial stimulation and carotid sinus massage. A total of 24 patients aged 59 +/- 15 years (mean +/- SD) in whom stable sinus node electrograms were obtained were selected for the study. Ten of the 24 patients had sick sinus syndrome, whereas 14 had no sinus node dysfunction. All 24 patients had atrial pacing at cycle lengths of 1,000 to 300 ms; 9 patients had premature atrial stimulation and 12 had carotid sinus massage. Shifts in the sinus node pacemaker complex occurred spontaneously in 4 (17%) of the 24 patients; after atrial pacing at cycle lengths of 800 to 300 ms (mean 387 +/- 92) in 15 (63%) of 24 patients; after premature atrial stimulation at one or more coupling intervals in 5 (56%) of 9 patients and during carotid sinus massage in 9 (75%) of 12 patients. Shifts in the sinus node pacemaker complex lasted one to six beats and returned to the original site within two to seven beats. Spontaneous shifts in the sinus node pacemaker complex occurred in 3 of 14 patients without sick sinus syndrome and were induced in 6 (60%) of 10 patients with sick sinus syndrome and 11 (79%) of 14 patients without sick sinus syndrome. Shifts in sinus node pacemaker complex were characterized by loss of primary negativity, change in P wave morphology, significant (p less than 0.001) prolongation of sinoatrial interval and sinus cycle length.

Intracardiac electrode catheter recordings of atrioventricular bypass tracts in Wolff-Parkinson-White syndrome: techniques, electrophysiologic characteristics and demonstration of concealed and decremental propagation.

UNLABELLED: Atrioventricular bypass tract deflections were recorded in five patients with the Wolff-Parkinson-White syndrome using standard, closely spaced (5 mm) electrode catheters. Three right paraseptal and two left-sided Kent bundles were recorded at the level of the tricuspid valve on the His bundle catheter and in the coronary sinus, respectively. Characteristics of the bypass tracts were studied during atrial pacing, programmed premature atrial stimulation, induction of supraventricular tachycardias and programmed ventricular stimulation. During atrial pacing, as pre-excitation increased, the stimulus to bypass tract deflection time remained unchanged. In five patients normalization of the QRS complex coincided with loss of the bypass tract deflection during incremental atrial pacing. Two patients demonstrated fragmentation of the bypass tract deflection before block. In one patient fragmentation of the bypass deflection coincided with normalization of the QRS complex. The effective refractory periods of the bypass tracts coincided with loss of bypass tract deflections in three of the five patients. In one patient, the effective refractory period of the bypass tract at its ventricular insertion preceded that at its atrial insertion, whereas in the remaining patient, the effective refractory period of the bypass tract was not attained because of atrial refractoriness. During orthodromic supraventricular tachycardia, the bypass tract deflections disappeared in the anterograde limb in all patients. In one patient, the bypass tract deflection was recorded during atrial fibrillation with pre-excitation. IN CONCLUSION: Bypass tract deflections can be recorded with a closely spaced electrode catheter. Right paraseptal bypass tracts are located close to the His bundle. The anterograde effective refractory period of the bypass tract usually reflects its atrial insertion, but concealment through the bypass tract can occur with block at the ventricular insertion. Decremental conduction within the bypass tract can occur before block, suggesting concealed and overt Wenckebach block within the bypass tract. Recordings of bypass tract deflections increase the potential of closed chest ablation of right paraseptal and left-sided bypass tracts.

Signal averaging of the surface QRS complex predicts inducibility of ventricular tachycardia in patients with syncope of unknown origin: a prospective study.

Forty patients with syncope of unknown origin underwent quantitative signal averaging of the surface QRS complex before invasive electrophysiologic testing with programmed ventricular stimulation. Of 34 patients without bundle branch block, 12 had inducible ventricular tachycardia (Group I) and 22 did not (Group II). The duration of low amplitude signals, the root mean square voltage of the terminal 40 ms and the signal-averaged QRS vector duration were measured in each case. One or more abnormal signal averaging variables were present in 92% of patients in Group I, but in only 27% of patients in Group II (p less than 0.005). An abnormal root mean square voltage of the terminal 40 ms was the most significant distinguishing variable, being present in 83% of Group I patients and in only 14% of Group II patients (p less than 0.005). The QRS vector duration was prolonged in 58% of Group I patients, but in only 9% of Group II patients (p less than 0.05). Likewise, the duration of low amplitude signals was prolonged in 58% of Group I patients, but in only 19% of Group II patients (p less than 0.05). When compared with 24 hour ambulatory electrocardiographic monitoring, the presence of abnormal signal averaging variables was more predictive of inducible ventricular tachycardia. Seven (32%) Group II patients had greater than or equal to 10 ventricular premature beats/h, couplets or episodes of nonsustained ventricular tachycardia; however, none had abnormal late potentials recorded. In contrast, three patients (25%) in Group I had less than 10 ventricular premature beats/h, although all in that group had one or more abnormal signal-averaged variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of signal averaging of the surface QRS complex in selecting patients with nonsustained ventricular tachycardia and high grade ventricular arrhythmias for programmed ventricular stimulation.

Signal averaging of the surface QRS complex was performed before programmed ventricular stimulation in 53 individuals with high grade ventricular arrhythmias or nonsustained ventricular tachycardia, or both. An abnormal signal-averaged electrocardiogram (ECG) was recorded in 22 patients and was associated with inducible ventricular tachycardia in 12 (55%) of the 22. In contrast, a normal signal-average ECG was associated with inducible tachycardia in only 1 (3%) of 31 individuals (p less than 0.005). The group with inducible tachycardia had a longer duration of the signal-averaged QRS complex (124 +/- 19 versus 96 +/- 26 ms) and of low amplitude signals (44 +/- 13 versus 29 +/- 11 ms) (p less than 0.005). In addition, the root mean square voltage of the terminal 40 ms was lower in this group (20 +/- 14 versus 48 +/- 34 microV, p less than 0.005). Twenty-seven of the 53 subjects had a prior myocardial infarction; 17 (63%) of the 27 had an abnormal signal-averaged ECG, and ventricular tachycardia was inducible in 10 (59%) of the 17. A normal signal-averaged ECG was recorded in 10 of the 27 patients and only 1 (10%) of these 10 had inducible tachycardia. An abnormal signal-averaged ECG had a 91% sensitivity and a 56% specificity with respect to subsequent induction of tachycardia. During long-term follow-up, 2 (15%) of the 13 patients with inducible ventricular tachycardia who were treated with electrophysiologically guided antiarrhythmics therapy died suddenly; the remaining 11 patients (85%) are alive 15 +/- 10 months after electrophysiologic testing.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study of frequency domain and time domain analysis of signal-averaged electrocardiograms in patients with ventricular tachycardia.

Although both time domain and frequency domain analysis of signal-averaged electrocardiograms (ECGs) may distinguish patients with and without sustained ventricular tachycardia, it remains unclear which method is superior. Both methods were assessed in 55 subjects comprising 26 patients with sustained ventricular tachycardia (Group I), 18 control patients with organic heart disease but without sustained ventricular tachycardia (Group II) and 11 normal volunteers (Group III). Time domain analysis was performed with high pass filtering of 25, 40 and 80 Hz and low pass filtering of 250 Hz. Frequency domain analysis was performed on the terminal 40 ms of the QRS complex, either alone or with 216 or 150 ms of the ST segment. Absolute summed energies of discrete frequency bands and band energy ratios were calculated. The effectiveness of discrimination between Groups I and II was evaluated in terms of group means, sensitivity, specificity and an information content index based on receiver operating characteristic curve analysis. Group I showed a uniform decrease in amplitude across all frequencies derived from the terminal 40 ms of the QRS complex (p less than 0.005). This was abolished by the inclusion of ST segment data in frequency domain analysis. No frequency band was unique for Group I. At a specificity of 78%, the best time domain sensitivity was 85%, and the best frequency domain sensitivity was 77%. The best time domain information content index was 0.156, the best index for frequency domain analysis was 0.077 using absolute band areas. It is concluded that patients with sustained ventricular tachycardia have decreased energy content across all frequencies in the terminal 40 ms of the QRS complex. Frequency domain analysis was not an improvement over time domain analysis in differentiating patients with ventricular tachycardia from those without.

Verapamil-induced polymorphous ventricular tachycardia.

A 31 year old woman who developed an atypical ventricular tachycardia after administration of intravenous verapamil for control of a recurrent supraventricular tachycardia is presented. Possible explanations for the observed arrhythmia, polymorphous ventricular tachycardia, are discussed. Verapamil must be considered one of the pharmacologic agents that can cause this arrhythmia.

A new noninvasive index to predict sustained ventricular tachycardia and sudden death in the first year after myocardial infarction: based on signal-averaged electrocardiogram, radionuclide ejection fraction and Holter monitoring.

A prospective study of the prognostic significance of the signal-averaged electrocardiogram (ECG), left ventricular function and 24 hour Holter ECG monitoring was performed in 102 patients (age 63 +/- 11 years) after myocardial infarction. The signal-averaged ECG (40 Hz high pass bidirectional filtering) was obtained 10 +/- 6 days after the acute myocardial infarction and all three tests were performed within 72 hours of each other. Ejection fraction was determined by radionuclide ventriculography. An abnormal signal-averaged ECG was seen in 44% of patients; abnormal ejection fraction (less than 40%) in 52% and high grade ectopic activity (greater than or equal to 10 ventricular premature depolarizations/h or couplets, or nonsustained ventricular tachycardia, or a combination of these) in 62%. During a 12 +/- 6 month follow-up period, 15 patients (14.7%) had an arrhythmic event defined as sustained ventricular tachycardia or sudden cardiac death, or both. The event rates were higher in patients with an abnormal versus a normal signal-averaged ECG (29 versus 3.5%, p = 0.003), an abnormal versus a normal ejection fraction (24 versus 6%, p = 0.001) and the presence versus the absence of high grade ectopic activity (23 versus 9%, p = 0.09). Patients with an abnormal signal-averaged ECG and an abnormal ejection fraction had a significantly higher (p = 0.0007) event rate than did patients in whom both the tests were normal (36 versus 0%; odds ratio 30.1).(ABSTRACT TRUNCATED AT 250 WORDS)

The role of silent ischemia, the arrhythmic substrate and the short-long sequence in the genesis of sudden cardiac death.

To study the role of silent ischemia and the arrhythmic substrate in the genesis of sudden cardiac death, 67 patients were studied (mean age 62 +/- 12 years). Of these, 14 patients (Group 1) had an in-hospital episode of ventricular tachycardia or fibrillation while wearing a 24 h Holter ambulatory electrocardiographic (ECG) monitor, 33 (Group II) had a documented episode of sustained ventricular tachycardia or fibrillation, or both, and 20 (Group III) had angina pectoris but no ventricular tachycardia or fibrillation. Eight Group I survivors underwent programmed electrical stimulation or ECG signal averaging, or both. All Group II patients underwent 24 h Holter monitoring and ECG signal averaging to detect late potentials before programmed electrical stimulation. Group III patients underwent both 24 h Holter recording and coronary angiography. The 24 h ECG tapes were analyzed for ST segment changes, prematurity index and characteristics of ventricular premature depolarizations. Any ST depression greater than or equal to 1 mm for greater than 30 s was considered to be a reflection of silent ischemia, and the induction of ventricular tachycardia or fibrillation by programmed electrical stimulation or the presence of late potentials, or both, was considered to be a reflection of the arrhythmia substrate. Silent ischemia preceded ventricular tachycardia in only 2 (14%) of the 14 Group I patients. The prematurity index was less than 1 in only 18% of ventricular tachycardia episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

The prognostic significance of quantitative signal-averaged variables relative to clinical variables, site of myocardial infarction, ejection fraction and ventricular premature beats: a prospective study.

A prospective study was undertaken of the prognostic significance of quantitative signal-averaged electrocardiographic (ECG) variables relative to clinical variables, site of myocardial infarction, left ventricular ejection fraction and characteristics of ventricular premature beats in 115 patients (mean age 62 +/- 12 years) studied 10 +/- 6 days after myocardial infarction. Signal-averaged variables included the root mean square voltage of the terminal 40 ms, the duration of the filtered signal-averaged QRS complex and low amplitude signals less than 40 microV determined at 25 and 40 Hz high pass filtering in all patients. Of the 115 patients, 51 (44%) had an abnormal signal-averaged ECG (one or more abnormal signal-averaged variables), 51 (44%) at 25 Hz and 48 (42%) at 40 Hz high pass filtering. A higher proportion of patients with an inferior wall infarction had an abnormal signal-averaged ECG as compared with patients with anterior wall infarction (58% versus 31%). Over a 14 +/- 8 month follow-up period 16 patients (14%) had an arrhythmic event. An abnormal signal-averaged ECG at 40 Hz high pass filtering had a higher sensitivity (81% versus 75%) and specificity (65% versus 61%) than at 25 Hz high pass filtering. The predictive value of the signal-averaged ECG was superior to that of the ejection fraction (40% versus 20%) in anterior wall myocardial infarction, whereas in patients with inferior wall infarction, the predictive values of the two tests were equivalent. The prognostic power of 27 clinical and noninvasive variables was determined with the Cox proportional hazards regression model.(ABSTRACT TRUNCATED AT 250 WORDS)