Biomedical subjects

J D Kirk

Publications and source records attributed to J D Kirk.

6 recordsLinked to original sources

PubMed2000

Evaluation of chest pain suspicious for acute coronary syndrome: use of an accelerated diagnostic protocol in a chest pain evaluation unit.

Management of patients presenting to the emergency department with chest pain suggestive of acute myocardial infarction (AMI) remains a continuing challenge. A low threshold for admission has been traditional because of concern for patient welfare and the litigation potential associated with the inadvertent discharge of patients with ischemic events. Because of this approach, < 30% of patients admitted for chest pain ultimately are found to have an acute coronary syndrome. To reduce unnecessary admissions, maintain patient safety, and enhance cost-effectiveness, innovative strategies have been applied to the management of patients with chest pain. It is now recognized that a low-risk group can be identified by the clinical presentation and initial electrocardiogram. Chest-pain centers have been developed to provide further risk stratification and systematic management of these patients. We employ an accelerated diagnostic protocol based on immediate exercise treadmill testing to evaluate low-risk patients. Moderate-risk patients are assessed over a 6-hour observation period with serial electrocardiograms and evaluation of cardiac-injury markers. Patients with positive evaluations are admitted. Those with negative results undergo either exercise echocardiography or rest myocardial perfusion imaging utilizing technetium-99m sestamibi. Patients with positive functional tests are admitted. Those with negative studies are discharged with outpatient follow-up. These strategies have provided a safe and accurate means of patient disposition from the emergency department with the potential for vital cost savings.

Algorithms↗

PubMed2000

Interpretation of immediate exercise treadmill test: interreader reliability between cardiologist and noncardiologist in a chest pain evaluation unit.

STUDY OBJECTIVE: To determine whether attending physicians in a chest pain evaluation unit (CPEU) can perform and interpret exercise testing with the same accuracy as cardiologists. METHODS: Between January 1996 and November 1998, immediate exercise tests were performed and interpreted by internists with additional training in exercise testing who serve as attending physicians in a CPEU at a large university medical center. For quality assurance, all tests were overread by a cardiologist. Test results were compared for each reader, and all tests with discrepant readings were reinterpreted by an independent cardiologist who was blinded to the previous results. Patients' clinical course was monitored for at least 30 days after exercise testing. RESULTS: The study group consisted of 645 patients (347 men, 298 women). Discrepant interpretations were found in 11 (1. 7%) patients. The agreement was 98.4% (kappa value 0.9618). The majority of discrepancies were insignificant and were based on subtle differences in the definition of a nondiagnostic test or the degree of ST-segment shift. Of the 11 discordant readings, the blinded cardiologist concurred with 5 (45%) of the CPEU interpretations and 4 (36%) of the cardiologist interpretations. In 2 cases, there was disagreement by all 3 interpreters. There was no cardiac morbidity or mortality of any patient with a discrepant reading. CONCLUSION: Our results suggest that noncardiologists serving as attending physicians in a CPEU can accurately interpret exercise tests and overreading by cardiologists for quality assurance is unnecessary.

Adult↗

PubMed1999

Immediate exercise testing of low risk patients with known coronary artery disease presenting to the emergency department with chest pain.

OBJECTIVES: The purpose of this study was to demonstrate the safety and utility of immediate exercise treadmill testing (IETT) of low risk patients presenting to the emergency department with known coronary artery disease (CAD). BACKGROUND: More than 70% of the two million patients admitted to U.S. hospitals annually for suspected acute myocardial infarction (AMI) are found not to have had a cardiac event. We have previously demonstrated the safety and efficacy of IETT of selected low risk patients without known CAD presenting to the emergency department with chest pain. This study extends this approach to selected patients with a history of CAD. METHODS: One hundred patients evaluated by the chest pain emergency room to rule out AMI underwent IETT using a modified Bruce protocol upon admission to the hospital (median time <1 h). RESULTS: Twenty-three patients (23%) had positive exercise electrocardiograms (ExECGs); an uncomplicated non-Q wave AMI was diagnosed in two patients. Thirty-eight patients (38%) had negative ExECGs and 39 patients (39%) had nondiagnostic ExECGs. Of these 100 patients, 64 were discharged immediately after IETT, 19 were discharged in less than 24 h after negative serial cardiac enzymes and stable electrocardiograms and 17 were discharged after further evaluation and treatment. There were no complications from exercise testing and no late deaths or AMI during six-month follow-up. CONCLUSIONS: Immediate exercise treadmill testing of low risk patients with chest pain and known CAD is effective in further stratifying this group into patients who can be safely discharged and those who require hospital admission.

Acute Disease↗

PubMed1998

Evaluation of chest pain in low-risk patients presenting to the emergency department: the role of immediate exercise testing.

STUDY OBJECTIVES: To determine the safety and utility of immediate exercise testing in the evaluation of low-risk patients presenting to the emergency department with chest pain and its applicability to a heterogeneous population of men and women. METHODS: We conducted a prospective study of the safety and utility of immediate exercise testing in low-risk patients, as indicated by clinical and ECG criteria. The study group was large, heterogeneous, and included patients with a history of coronary artery disease. The patients were treated at a large, university medical center. Exercise testing (immediate exercise treadmill testing) was performed by internists, and cardiac serum enzyme levels were not measured before the exercise test. RESULTS: A total of 212 patients (121 men, 91 women) underwent exercise testing with no adverse effects. Twenty-eight (13%) patients had positive results on exercise ECGs. Twenty-three of the latter had further evaluation that revealed evidence of coronary artery disease in 13 (57%). Fifty-nine percent (125/212) of patients had negative exercise test results and 28% (59/212) had nondiagnostic tests. All patients with negative test results and 93% with nondiagnostic test results were discharged directly from the ED. Thirty-day follow-up was achieved in 201 (95%) patients and revealed no mortality in any of the patients in the three groups. One patient with a positive exercise test result returned to the ED within 30 days with mild congestive heart failure. CONCLUSION: Our results in this patient population support the safety and utility of immediate exercise testing of low-risk patients who present to the ED.

Adult↗

PubMed1998

Reinforcement without awareness: I. Voice level.

Although some studies have reported that reinforcement can strengthen people's behaviour without their awareness, most studies that have incorporated adequate procedures for assessing awareness have been unsuccessful. Using rigorous procedures, we report two studies designed to provide more scope for learning without awareness by making the reinforcement contingency as unobtrusive as possible. Subjects were told that the experiment was on ESP, and that they were to say which of two words the experimenter was thinking about. In fact, reinforcement was contingent on the loudness of the subject's voice when responding. Even though subjects reported no awareness of a relationship between trial outcomes and their behaviour, the probability of the reinforced responses increased significantly over trials in both experiments. These results support the view that reinforcement can occur without awareness.

Adult↗

PubMed1998

A strategy for the use of cardiac injury markers (troponin I and T, creatine kinase-MB mass and isoforms, and myoglobin) in the diagnosis of acute myocardial infarction.

OBJECTIVE: To design a strategy for cardiac injury marker testing in the diagnosis of acute myocardial infarction. DESIGN: Prospective study. Group I (n=54 patients): evaluation of clinical performance. Specimens collected at 0, 3, 6, and 12 (+/-1.5) hours after presentation. World Health Organization criteria were used for diagnosis of acute myocardial infarction. Group II (n=57 patients): evaluation of temporal evolution. Time intervals 0 to 1.5, 1.5 to 4.5, 4.5 to 7.5, and 7.5 to 13.5 hours. Patients identified by positive creatine kinase-MB (CK-MB) mass or myoglobin. Fourteen patients in Group I qualified for Group II. Hence, the total number of patients was 97. SETTING: A team of laboratorians and clinicians at the University of California, Davis, hospital assessed the clinical performance and temporal evolution of serial CK-MB isoform, troponin I, and troponin T results in comparison to parallel CK-MB mass and myoglobin results. MAIN OUTCOME MEASURES: Group I: sensitivity, specificity, and positive and negative predictive values. Group II: the time interval of the first positive result for each cardiac injury marker. Strategy and conclusions were based on study results and a literature review. PARTICIPANTS: Emergency department patients with acute onset of chest pain and other complaints, possibly indicative of myocardial ischemia, who were under evaluation for admission. RESULTS: Twenty-seven cases of acute myocardial infarction were documented. Group I: troponin I had the highest specificity (100%) and the highest positive predictive value (100%); troponin I, troponin T, and CK-MB mass had the highest sensitivity (90.0%); and the negative predictive values of troponin I, troponin T, and CK-MB mass were comparable (97.8%, 97.6%, and 97.6%, respectively). Group II: early diagnosis (within 1.5 hours) was provided by both CK-MB isoforms and CK-MB mass, and then by myoglobin and troponins, in order of decreasing frequency. CONCLUSIONS: Creatine kinase-MB mass, myoglobin, and troponin I were selected as the cardiac injury markers of choice at our institution. The strategy calls for serial testing of myoglobin and CK-MB mass initially-and serially if warranted by heightened clinical suspicion--with troponin I added if indicated for (1) specific confirmation, (2) late presentation, or (3) risk stratification.

Biomarkers↗