Impact of Rater Training on Residents Technical Skill Assessments: A Randomized Trial

OBJECTIVE

The ACS/APDS Resident Skills Curriculum's Objective Structured Assessment of Technical Skills (OSATS) consists of task-specific checklists and a global rating scale (GRS) completed by raters. Prior work demonstrated a need for rater training. This study evaluates the impact of a rater-training curriculum on scoring discrimination, consistency, and validity for handsewn bowel anastomosis (HBA) and vascular anastomosis (VA).

DESIGN/ METHODS

A rater training video model was developed, which included a GRS orientation and anchoring performances representing the range of potential scores. Faculty raters were randomized to rater training or no rater training and were asked to score videos of resident HBA/VA. Consensus scores were assigned to each video using a modified Delphi process (Gold Score). Trained and untrained scores were analyzed for discrimination and score spread and compared to the Gold Score for relative agreement.

RESULTS

Eight general and eight vascular surgery faculty were randomized to score 24 HBA/VA videos. Rater training increased rater discrimination and decreased rating scale shrinkage for both VA (mean trained score: 2.83, variance 1.88; mean untrained score: 3.1, variance 1.14, p = 0.007) and HBA (mean trained score: 3.52, variance 1.44; mean untrained score: 3.42, variance 0.96, p = 0.033). On validity analyses, a comparison between each rater group vs Gold Score revealed a moderate training impact for VA, trained κ=0.65 vs untrained κ=0.57 and no impact for HBA, R1 κ = 0.71 vs R2 κ = 0.73.

CONCLUSION

A rater-training curriculum improved raters' ability to differentiate performance levels and use a wider range of the scoring scale. However, despite rater training, there was persistent disagreement between faculty GRS scores with no groups reaching the agreement threshold for formative assessment. If technical skill exams are incorporated into high stakes assessments, consensus ratings via a standard setting process are likely a more valid option than individual faculty ratings.

Implementation of the ACS/ APDS Resident Skills Curriculum reveals a need for rater training: An analysis using generalizability theory

BACKGROUND

The American College of Surgeons (ACS)/Association of Program Directors in Surgery (APDS) Resident Skills Curriculum includes validated task-specific checklists and global rating scales (GRS) for Objective Structured Assessment of Technical Skills (OSATS). However, it does not include instructions on use of these assessment tools. Since consistency of ratings is a key feature of assessment, we explored rater reliability for two skills.

METHODS

Surgical faculty assessed hand-sewn bowel and vascular anastomoses in real-time using the OSATS GRS. OSATS were video-taped and independently evaluated by a research resident and surgical attending. Rating consistency was estimated using intraclass correlation coefficients (ICC) and generalizability analysis.

RESULTS

Three-rater ICC coefficients across 24 videos ranged from 0.12 to 0.75. Generalizability reliability coefficients ranged from 0.55 to 0.8. Percent variance attributable to raters ranged from 2.7% to 32.1%. Pairwise agreement showed considerable inconsistency for both tasks.

CONCLUSIONS

Variability of ratings for these two skills indicate the need for rater training to increase scoring agreement and decrease rater variability for technical skill assessments.

Feasibility and Perceived Usefulness of Using Head-Mounted Cameras for Resident Video Portfolios

BACKGROUND

There is limited guidance on how to longitudinally administer simulation materials or to incorporate video recordings into assessment portfolios of simulated surgical skills.

MATERIALS AND METHODS

We launched a longitudinal weekly simulation curriculum for PGY1-PGY3 surgical residents based on the ACS/APDS Curriculum. Residents underwent monthly objective structured assessment of technical skills (OSATS) while wearing head-mounted cameras. Videos of OSATS performance accrued into individual online video portfolios. Residents were surveyed about their attitudes toward video recording.

RESULTS

Twenty-seven general surgical residents participated, completing 161 OSATS encompassing 11 distinct skills and generating 258 videos of simulated skills performance. The overall survey response rate was 88%. Residents viewed the curriculum favorably overall, and 36.4% of residents accessed their videos. Of those who did not watch their videos, 78.6% cited not having enough time, whereas 28.6% did not think the videos would be useful. Over 95% of surveyed residents expressed interest in having a video library of attending-performed procedures, 59.1% were interested in having their own operations recorded, and 45.5% were interested in video-based coaching.

CONCLUSIONS

Residents viewed longitudinal administration of the ACS/APDS Curriculum positively. Although video recording in simulation is feasible, resident interest may be higher for intraoperative recordings than for simulated skills.

Biographical disruption of injured workers in chronic pain

PURPOSE

This research explored how injured workers living with work-related chronic pain rethink and reconstruct their biographical experience.

METHOD

This qualitative study used a grounded theory approach to data collection and analysis. Semi-structured focus groups were conducted to gather data and analysis was performed by the coding of emergent themes.

RESULTS

Analysis of the focus groups revealed the impact that chronic pain has on the social components of an injured worker's life; particularly their sense of self, their relationship to others and how they perceive themselves in social situations.

CONCLUSIONS

Injured workers experienced changes (physical, psychological and social transformations) that led to biographical disruption; a change in self-identity, which in turn contributed to changes in important relationship dynamics. Injured workers spoke of repeated losses - loss of self, relationships and of the life imagined. Understanding the meaning of these losses could improve the conditions surrounding the injured worker's biographical reconstruction and facilitate the rehabilitation process.

Predicting dysglycaemia in patients under investigation for acute coronary syndrome

AIMS

To examine methods for the identification of previously undetected dysglycaemia [diabetes and impaired glucose tolerance (IGT)] in patients investigated for possible acute coronary syndrome. Specifically, we wished to examine whether the recently advocated use of glycosylated haemoglobin (HbA1c) would enhance detection rates for diabetes in these patients.

METHODS

Patients (n = 200) investigated for possible acute coronary syndrome and not previously known to have diabetes were recruited and anthropometric data collected. Random plasma glucose concentrations followed by oral glucose tolerance tests, HbA1c, fasting lipids, high sensitivity C-reactive protein and homeostatic modular assessment-insulin resistance were obtained during admission. Following discharge, the fasting plasma glucose (FPG) was repeated to determine the importance of sequential fasting levels. The accuracy of individual tests, combinations and sequential testing was assessed using receiver operating characteristic curves. A predictive index (PI) was generated using stepwise logistic regression models.

RESULTS

The prevalence of diabetes and IGT were 21 and 32%, respectively. FPG >6.0 mmol/l and HbA1c ≥ 6.0% had specificities of 94.9% and 93.6% but sensitivities of only 31.7 and 39.0%, respectively. Combination and sequential testing provided little additional benefit. Use of a PI comprising FPG, HbA1c and age provided the best overall performance (75.6% sensitivity, 77.1% specificity, negative predictive value 92.4%).

CONCLUSION

Our data confirm the high prevalence of dysglycaemia in this cohort. The commonly advocated screening tools have significant limitations if used in isolation, combination or sequentially. Our approach using a PI offers improved performance partly as it uses continuous data rather than arbitrary cut-off values.

Couple-friendly services in a metropolitan sexually transmitted disease clinic: views of clients and providers

CONTEXT

Clients making clinic visits related to reproductive health might benefit from participation with their partner. There is little information available, however, on whether either clients themselves or clinic staff would feel comfortable with such a possibility.

METHODS

The Multnomah County Health Department Sexually Transmitted Disease Clinic in Portland, Oregon, conducted a survey of 237 new clients in June 1994 to assess clients' and providers' responses to the idea of offering couple visits.

RESULTS

Twenty-six percent of female clients and 16% of male clients were accompanied by their partner on their visit to the clinic. Eighty-seven percent of all clients favored the clinic's offering couple visits, 5% opposed the concept and 8% were undecided. Fifty-four percent would have wanted their partner to be with them during their present visit if this choice had been offered, and 62% would want their partner to join them in follow-up couple visits if this were recommended by their provider. Seventy-one percent had already discussed with their partner the reason for their immediate clinic visit, and 88% expected to discuss the visit with their partner afterward. Attitudes toward couple services were similar for male and female clients and did not vary by race or ethnicity. For more than one-fifth of clients, clinic staff reported that they would not recommend couple visits; however, many of these clients reported that they would prefer being accompanied by their partner.

CONCLUSIONS

Appropriately designed couple-friendly options are likely to be generally accepted and moderately utilized by clients of varying backgrounds. Clinic staff may be more reluctant to involve clients' partners than the clients are themselves, however.

Radiographic calculation of anteversion in acetabular prostheses

The position of the acetabular prosthesis is critical for preventing dislocation following total hip arthroplasty. The reliability of a mathematical model for radiographically calculated acetabular cup version was examined. A porous-coated anatomic acetabular prosthesis was mounted in a mold. Anteroposterior radiographs were taken with the cup in five different positions of anteversion. These were reviewed by five orthopaedic surgeons, and measurements were taken from each radiograph. From these measurements, the mathematically derived degree of version was calculated. The results were examined for accuracy and intraobserver reliability. It was concluded that intraobserver reliability was very good and that the accuracy was within a clinically acceptable range. This technique could be useful in studying the "safe zone" for acetabular prostheses.

Comparison of age-related changes in short-wavelength-sensitive cone thresholds between normals and patients with primary open-angle glaucoma

PURPOSE

To establish the effect of aging upon short-wavelength-sensitive cone (S-cone) sensitivity for both normals and patients with primary open-angle glaucoma (POAG).

METHODS

S-cone thresholds were established for the detection of blue test spots on a bright yellow adapting background. Detection thresholds for combined medium- and long-wavelength-sensitive cones (M/L-cones) were also established for a yellow test spot upon a yellow background. A group of 177 normal subjects (age range 20 to 80 years) and 46 glaucoma subjects were examined.

RESULTS

The rate of decline of S-cone sensitivity with increasing age was found to be similar in patients with POAG and age-matched normals (approximately 0.2 log units/decade), although S-cone sensitivity in the POAG population was significantly lower (p < 0.05) than that in age-matched normals by approximately 0.3 log units.

CONCLUSIONS

The results of the present investigation show an age-related decline in S-cone sensitivity for both normals and patients with POAG. The decline in S-cone sensitivity within the POAG population is similar to that occurring in normal subjects when the two populations are matched for age.

Antibodies to islet 37k antigen, but not to glutamate decarboxylase, discriminate rapid progression to IDDM in endocrine autoimmunity

Apart from islet cell antibodies (ICAs), antibodies to glutamate decarboxylase (GAD), insulin autoantibodies (IAAs), and a novel islet antigen (37k antigen) are potential markers for insulin-dependent diabetes mellitus (IDDM). GAD is also an antigen in stiff-man syndrome (SMS), and both SMS and IDDM are associated with ICAs and autoimmunity to other endocrine organs. We investigated possible links between antibody responses to islet antigens with autoimmunity to other endocrine organs and determined which specific antibodies can identify individuals who progress to IDDM. Antibodies to GAD were detected in > or = 90% of both diabetic and nondiabetic patients with ICAs and other endocrine autoimmunity, in 59% of ICA-positive IDDM patients without endocrine autoimmunity, in all patients with SMS, but in only 1-3% of healthy (nondiabetic) and autoimmune disease control subjects. GAD antibody levels were increased in ICA-positive IDDM patients with polyendocrine autoimmunity compared with those without. In contrast, antibodies to 37k antigen were only detected in patients who developed acute-onset IDDM. IAAs were also associated with IDDM. Thus, certain factors enhance antibody responses to GAD in polyendocrine autoimmunity, but this does not necessarily lead to development of IDDM or SMS. Antibodies to 37k antigen are strongly associated with acute-onset IDDM and are useful serological markers for disease.

An intact transmembrane helix 9 is essential for the efficient delivery of the diphtheria toxin catalytic domain to the cytosol of target cells

To investigate structure/function relationships involved in the delivery of the diphtheria toxin (DT) catalytic (C) domain to the cytosol of target cells, we have constructed and characterized internal in-frame deletion mutants in the transmembrane (T) domain of the fusion toxin DAB389IL-2. This fusion protein is composed of the C and T domains of DT to which human interleukin-2 (IL-2) has been genetically fused. The mutant fusion toxins were compared to DAB389IL-2 with respect to cytotoxic potency, receptor binding affinity, channel formation in planar lipid membranes, and sensitivity to proteolytic digestion. We demonstrate that genetic fusion of human IL-2 sequences to a diphtheria toxin-related fragment that contains less than full-length transmembrane helix 9 results in a fusion protein that binds to the high affinity IL-2 receptor, but has lost > or = 3 logs of cytotoxic potency and has decreased ability to insert into planar membranes and form stable channels. These observations are consistent with the hypothesis that an intact transmembrane helix 9 is essential for the formation of stable channels that are required for the efficient delivery of the C domain to the cytosol of target cells.

Antibodies to GAD and tryptic fragments of islet 64K antigen as distinct markers for development of IDDM. Studies with identical twins

Insulin-dependent diabetes mellitus (IDDM) is associated with antibodies to a 64,000-M(r) islet cell protein, at least part of which is identified as glutamic acid decarboxylase (GAD). These antibodies are detected as two distinct antibody specificities to 50,000-M(r) and 37,000/40,000-M(r) tryptic fragments of the autoantigen (50K and 37K antibodies, respectively). We determined the frequencies of antibodies to intact GAD, tryptic fragments of islet 64,000-M(r) antigen, islet cell antibodies (ICAs), and insulin autoantibodies (IAAs) in sera from 58 nondiabetic identical twins of patients with IDDM, of whom 12 subsequently developed diabetes. ICA, antibodies to intact GAD, and those to tryptic fragments were detected at similar frequencies in prediabetic twins (67-75%), but only 25% had IAA. Of 46 twins who remain nondiabetic, GAD antibodies, 50K antibodies, and ICA were detected in 6 (13%), 7 (15%), and 5 (11%), respectively, whereas only 1 (2%) possessed 37K antibodies and 2 (4%) had IAA. Eight of 9 twins with 37K antibodies and all 6 twins with ICA greater than 20 Juvenile Diabetes Foundation U have developed diabetes. Antibodies to GAD are sensitive markers for diabetes development but may also be present in genetically susceptible individuals who are unlikely to develop disease. Antibodies to 37,000/40,000-M(r) fragments of the 64,000-M(r) antigen or high-titer ICA were the best markers for diabetes development in these twins.

Binding of antibodies in sera from Type 1 (insulin-dependent) diabetic patients to glutamate decarboxylase from rat tissues. Evidence for antigenic and non-antigenic forms of the enzyme

An islet protein of M(r) 64000, identified as the gamma-amino butyric acid (GABA)-synthesizing enzyme, glutamate decarboxylase, is a major target for antibodies in Type 1 (insulin-dependent) diabetes mellitus. This enzyme is also expressed in brain and in some other tissues and may exist in multiple forms. The aim of this study was to determine the ability of antibodies from diabetic patients to recognize glutamate decarboxylase from rat islets, brain and other normal rat tissues. Glutamate decarboxylase was detected at high activity levels in brain and at lower levels in islets, kidney, liver, pituitary gland, thyroid gland, adrenal gland, testis and ovary. The ability of antibodies in sera of diabetic patients to immunoprecipitate enzyme activity from detergent extracts of tissues was determined. Antibodies in sera from diabetic patients were found to bind the enzyme from islet and brain extracts, but bound less than 20% of the activity from other tissues. The ability of antibodies to immunoprecipitate the brain enzyme was significantly correlated with the presence of antibodies to the islet 64 kilodalton antigen. These studies show that the glutamate decarboxylase activity expressed in brain shares antigenic determinants with the islet 64 kilodalton antigen. Isoforms of the enzyme expressed in other non-neuronal tissues may be antigenically distinct and may lack determinants recognized by diabetes-associated antibodies.

Lumbar motion trends and correlation with low back pain. Part I. A roentgenological evaluation of coupled lumbar motion in lateral bending

OBJECTIVE

A radiographic study was undertaken to describe the relationship between coupled lumbar motion in lateral bending and the presence of low back pain symptomatology, evaluate trends of coupled motion and determine if these trends were attributable to chance confluence of independent motions.

DESIGN

Survey.

SETTING

Chiropractic college student health center and private chiropractic clinic.

PARTICIPANTS

249 subjects: 114 with low back pain, 29 asymptomatic with no history and 106 asymptomatic with history. Of these, 194 were freshman volunteers and 55 were new private clinic low back pain patients.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Lumbar segmental coupled motion categories according to the scheme of Cassidy and Grice, as well as a modified scheme.

RESULTS

Statistical analysis demonstrated no significant relationship (p = .01) between coupled lumbar motion and low back pain. When viewed intersegmentally, approximately half of all lumbar motion was type II; symmetric motion was rare and attributable to chance confluence of individual segmental motion.

CONCLUSIONS

This study suggests that back pain is not an indication for the routine use of lateral bending films for the identification of abnormal coupled motion. Furthermore, each segmental categorization appears to be independent of contralateral categorization as well as motion at all other segmental levels. It is also suggested that type II motion cannot be ruled out as a normal variant. Finally, the ubiquity of coupled motion asymmetry suggests that symmetry must be reevaluated as a criterion for normal spinal function.

Electrophysiologic evaluation and outcome of patients with syncope of unknown origin

Electrophysiologic studies were performed in 134 patients (87 males, mean age 59 years) with unexplained syncope. Seventy-one patients had organic heart disease (ischaemic in 50). Electrophysiologic studies revealed conduction abnormalities and tachyarrhythmias that could account for syncope in 40 patients (30%). Thirty-seven (93%) of these patients received pacing or antiarrhythmic therapy compared with 23 (24%) of the remaining 94 patients who had a negative study and received empiric therapy (P less than 0.0001). Risk of having an abnormal electrophysiologic study was greater in patients with underlying heart disease (P less than 0.05). During a mean follow-up of 22 +/- 17 months, 26 patients (19%) either had recurrent syncope (22 patients) or died (four patients) suddenly. Men had a higher incidence of recurrent syncope than women (26% vs 6%, P less than 0.005). Other clinical characteristics, electrophysiologic findings, final diagnosis and therapy at discharge were not predictive of outcome. We conclude that (1) 19% of patients investigated for syncope will have a recurrent event, (2) female gender may be an independent predictor of favourable outcome.

Interrater reliability of roentgenological evaluation of the lumbar spine in lateral bending

Interrater reliability is described for the evaluation of lumbar motion and motion coupling patterns in lateral bending. Upright neutral and lateral bending lumbar films of 58 student volunteers were marked by three examiners. Segmental tilt, segmental rotation and motion categories were computed. The performance of the examiners was evaluated using the Kappa statistic and a comparison of rater discrepancy to the experimental measurement error. Although all three raters were proficient within the context of calculated measurement error, good reliability was not universally demonstrated. Concordance for rotation was moderate to good, while agreement for lateral bending was of questionable interpretation. Reliability for the segmental motion categories was good for L1-L4, but unacceptable at L5. The poor reliability at L5 resulted in unacceptable concordance for the lumbar global motion category for three raters. The use of lateral bending radiographs for categorization of the lumbar spine in clinical practice is questioned.

Fatty acid composition of clinically healthy and malignant oral epithelium

The fatty acid composition of epithelium from clinically healthy oral mucosa and or oral squamous cell carcinoma was analyzed by gas/liquid chromatography following extraction using a modified Folch technique and conversion of fatty acids to methyl esters. There were significant reductions in the relative proportions of palmitoleic and oleic acids and elevation of the relative proportions of palmitic, steric and arachidonic acids in samples from squamous cell carcinoma. These differences could reflect changes in cell membranes and/or fatty acid metabolism. Further studies are required to assess their functional, diagnostic and prognostic significance.

Effect of the hemopump left ventricular assist device on regional myocardial perfusion and function. Reduction of ischemia during coronary occlusion

The Hemopump is a new 7-mm diameter left ventricular assist device that provides as much as 3.5 l/min of nonpulsatile cardiac output after fluoroscopic placement into the left ventricle through a femoral artery cutdown. The purpose of this study was to measure the effects of Hemopump assist on hemodynamics, left ventricular function, and perfusion in the presence and absence of ischemia. Eight dogs were instrumented under pentobarbital anesthesia with left ventricular, left atrial, and aortic catheters, a loose silk ligature around the midleft anterior descending coronary artery, and sonomicrometer crystals in midwall myocardium within the left anterior descending and circumflex perfusion territories. Hemodynamic variables, regional systolic fractional shortening, and myocardial perfusion after left atrial injection of 15-microns radiolabeled microspheres were measured in the presence and absence of Hemopump assist before and after left anterior descending artery occlusion. In the absence of ischemia, Hemopump left ventricular assist resulted in reduced left ventricular end-diastolic pressure while aortic mean pressure was maintained, and there was significant reduction in regional systolic fractional shortening (reflecting systolic unloading) that correlated with an 18% decline in regional myocardial perfusion. During left anterior descending artery occlusion, left ventricular systolic and diastolic pressures were reduced during Hemopump assist while aortic mean pressure was maintained. Perfusion rose in the ischemic territory (from 13.0 +/- 8.7% to 26.2 +/- 19.8% of nonischemic flow, p = 0.045). Reduced fractional shortening was again seen in nonischemic tissue with Hemopump assist during left anterior descending artery occlusion, and this was often correlated with reduced perfusion (r = 0.67).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of the somatostatin analogue SMS 201-995 (sandostatin) on mouth-to-caecum transit time and absorption of fat and carbohydrates in normal man

1. Somatostatin analogues, such as SMS 201-995 (sandostatin), have been suggested as treatment for a variety of disease states including acromegaly, secretory gastrointestinal tumours and diabetes mellitus. 2. Somatostatin-14 has actions to prolong gastro-intestinal transit time and inhibit intestinal absorption, and we have therefore studied the effects of SMS 201-995 on these processes. Five male subjects received a test meal having been given either saline or 50 micrograms of SMS 201-995 subcutaneously 30 min before ingestion. 3. SMS 201-995 caused a delay in mouth-to-caecum transit time for lactulose assessed by breath hydrogen analysis (316 +/- 17 vs 192 +/- 14 min, mean +/- SEM, P less than 0.01), a delay (234 vs 120 min, P less than 0.05) in the plasma peak of the non-metabolizable glucose analogue 3-O-methylglucose and conversion of the expected postprandial rise in serum triglycerides (with saline 1.02 +/- 0.20 to 1.51 +/- 0.28 mmol/l, P less than 0.05) to a decrease below basal values (with SMS 201-995 0.97 +/- 0.80 to 0.79 +/- 0.11 mmol/l, P less than 0.05). 4. After SMS 201-995, an enhancement of the increase in blood glucose (8.2 +/- 0.7 vs 4.7 +/- 0.2 mmol/l, P less than 0.01) and inhibition and postponement of the postprandial rise in insulin (27.6 +/- 6.7 vs 9.9 +/- 2.1 m-units/l, P less than 0.05) occurred. Furthermore, a rise in non-esterified fatty acids, glycerol and 3-hydroxybutyrate, compared with the decline in concentrations of these metabolites after saline, was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial natriuretic factor during atrial fibrillation and supraventricular tachycardia

Plasma immunoreactive atrial natriuretic factor was measured in 10 patients with chronic atrial fibrillation before and after cardioversion to sinus rhythm, and in 14 patients during electrophysiologic evaluation of paroxysmal supraventricular tachycardia. The mean plasma concentration of atrial natriuretic factor in atrial fibrillation was 138 +/- 48 pg/ml and decreased to 116 +/- 45 pg/ml 1 hour after cardioversion to sinus rhythm (p less than 0.005). The mean plasma concentration of atrial natriuretic factor increased from 117 +/- 53 pg/ml in sinus rhythm to 251 +/- 137 pg/ml during laboratory-induced supraventricular tachycardia (p less than 0.005). Right atrial pressures were recorded in 12 patients; the baseline atrial pressure was 4.3 +/- 1.9 mm Hg and increased to 7.4 +/- 3.6 mm Hg during supraventricular tachycardia (p less than 0.005). A modest but significant linear relation was noted between the changes in plasma atrial natriuretic factor and right atrial pressure measurements during induced supraventricular tachycardia (r = 0.60, p less than 0.05). In conclusion, changes in atrial rhythm and pressure may be an important factor modulating the release of atrial natriuretic factor in the circulation and raised levels of this hormone may be a contributing factor for the polyuria and the hypotension associated with paroxysmal supraventricular tachyarrhythmias.

Electrophysiologic effects and long-term efficacy of bepridil for recurrent supraventricular tachycardias

Thirteen patients underwent electrophysiologic evaluation for recurrent supraventricular tachycardia (SVT). The effects of intravenous bepridil (4 mg/kg) were evaluated during the initial study in 5 patients, and 12 patients underwent repeat study 7 to 10 days later taking oral bepridil, 300 to 400 mg/day. Intravenous bepridil increased the pacing cycle length inducing atrioventricular (AV) (276 +/- 43 vs 334 +/- 31 ms, p less than 0.01) and ventriculoatrial (VA) block (268 +/- 34 vs 310 +/- 35 ms, p less than 0.001), the retrograde refractory period of the accessory pathway (251 +/- 17 vs 295 +/- 25 ms, p less than 0.05) and the ventricular refractory period (216 +/- 17 vs 226 +/- 11 ms, p less than 0.05), and prevented induction of sustained SVT in 3 patients. Oral bepridil increased the sinus cycle length (723 +/- 64 vs 800 +/- 118 ms, p less than 0.05), corrected QT (403 +/- 14 vs 431 +/- 21 ms, p less than 0.05) and the pacing cycle inducing AV (288 +/- 63 vs 353 +/- 78 ms, p less than 0.01) and VA block (271 +/- 31 vs 408 +/- 124 ms, p less than 0.01). It prolonged the refractory period of the atrium (195 +/- 29 vs 233 +/- 36 ms, p less than 0.05), AV node (264 +/- 35 vs 303 +/- 22 ms, p less than 0.05), ventricle (221 +/- 16 vs 245 +/- 21 ms, p less than 0.01), accessory pathway in the AV (290 +/- 47 vs 329 +/- 54 ms, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiologic sequelae of chronic myocardial infarction: local refractoriness and electrographic characteristics of the left ventricle

Ventricular tachycardia (VT) has been shown to arise from ischemically damaged left ventricular myocardium, which possesses heterogeneity of refractoriness and activation. Catheter techniques were used to study left ventricular refractoriness using the strength-interval relation and activation by local electrographic characteristics in 8 patients with and 6 patients without previous myocardial infarction (MI). Noninfarcted myocardium in patients with and without previous MI was similar overall with respect to refractoriness and excitability, whereas local electrographic duration in MI patients was longer (66 +/- 2 vs 52 +/- 3 ms, p less than 0.005) and amplitude lower (3.9 +/- 2.1 vs 6.1 +/- 2.0 mV, p less than 0.05). Comparisons of infarcted and noninfarcted regions in MI patients revealed an increased threshold of excitability at infarct sites (e.g., 1.9 +/- 1.0 vs 0.7 +/- 0.4 mA, p less than 0.05) and prolongation of refractory periods (375 +/- 118 vs 275 +/- 13 ms, p less than 0.05) at the lowest level of stimulating current. Shortening of refractory period as a result of change in pacing cycle length was not affected by infarction. The local electrographic duration (95 +/- 17 ms) was significantly longer in infarcted regions than at noninfarcted sites (p less than 0.005), but the electrographic amplitude (3.4 +/- 3.0 mV) differed significantly only in noninfarct patients. It is concluded that considerable electrophysiologic disparity exists between infarcted and noninfarcted myocardium. Whether or not arrhythmogenic tissue possesses unique alterations in electrophysiologic characteristics remains to be established.

Relation of late potentials to site of origin of ventricular tachycardia associated with coronary heart disease

Signal-averaged electrocardiograms and endocardial catheter mapping were performed in 41 patients with coronary artery disease and sustained ventricular tachycardia (VT) to determine the relation between signal-averaged late potentials (SA-LPs) and catheter-mapped late activity (CM-LA) to the site of origin of VT. The 41 patients had 79 morphologically distinct VTs. Either CM-LA or SA-LP was present during sinus rhythm in 37 of 41 patients (90%). Twenty-two out of 30 patients (73%) had CM-LA corresponding to SA-LP during normal sinus rhythm. Patients with SA-LP had a significantly greater number of sites of CM-LA, which were later and longer in duration than patients without SA-LP present during sinus rhythm. In a select group of patients, those with both SA-LP and CM-LA, the site of origin of VT was located at or adjacent to a site of CM-LA during sinus rhythm in 38 of 44 (86%); however, 36 of 78 sites (46%) of CM-LA were clearly distant from the site of origin of VT. In conclusion, CM-LA corresponding to SA-LP in patients with VT is sensitive but not specific for the site of origin of VT.

Unusual clinical signs complicating tension haemothorax

We describe a patient in whom a haemothorax produced ipsilateral Horner's syndrome, inequality of the carotid and radial pulses and superior vena caval obstruction.

Right ventricular tachycardia: clinical and electrophysiologic characteristics

This report describes the clinical and electrophysiologic characteristics of 30 patients without myocardial disease who had ventricular tachycardia with the morphologic characteristics of left bundle branch block and inferior axis. The tachycardias were nonsustained in 24 patients, sustained (greater than 30 sec) in six patients, and provocable by exercise in 14 of 23 patients undergoing a standard Bruce protocol. Ventricular tachycardia was induced during electrophysiologic study in 22 of 30 patients. Programmed stimulation induced tachycardia in 10 of 30 patients, most frequently by rapid atrial or ventricular pacing. Isoproterenol infusion facilitated tachycardia induction in 13 of 23 patients. Endocardial activation mapping, performed in 10 patients, confirmed that earliest ventricular activation during tachycardia occurred at the right ventricular outflow tract on the interventricular septum. These tachycardias were unique in their responsiveness to a wide variety of antiarrhythmic drugs, including type I drugs and propranolol. During a mean follow-up of 30 months, no patient has died or experienced cardiac arrest. Two patients appear to be in spontaneous remission, and no patient has developed additional signs of cardiac disease.