Search PubMedSearch

Biomedical subjects

M Linzer

Publications and source records attributed to M Linzer.

29 records · Page 2Linked to original sources

Predicting the outcomes of electrophysiologic studies of patients with unexplained syncope: preliminary validation of a derived model.

PURPOSE: To develop and validate a predictive model that would allow clinicians to determine whether an electrophysiologic (EP) study is likely to result in useful diagnostic information for a patient who has unexplained syncope. PATIENTS: One hundred seventy-nine consecutive patients with unexplained syncope who underwent EP studies at two university medical centers comprised the training sample. A test sample to validate the model was made up of 138 patients from the clinical literature who had undergone EP studies for syncope. DESIGN: Retrospective analysis of patients undergoing EP studies for syncope. The data collector was blinded to the study hypothesis; the electrophysiologist assessing outcomes was blinded to clinical and historical data. Clinical predictor variables available from the history, the physical examination, electrocardiography (ECG), and Holter monitoring were analyzed via two multivariable predictive modeling strategies (ordinal logistic regression and recursive partitioning) for their abilities to predict the results of EP studies, namely tachyarrhythmic and bradyarrhythmic outcomes. These categories were further divided into full arrhythmia and borderline arrhythmia groups. RESULTS: Important outcomes were 1) sustained monomorphic ventricular tachycardia (VT) and 2) bradyarrhythmias, including sinus node and atrioventricular (AV) conducting disease. The results of the logistic regression (in this study, the superior strategy) showed that the presence of organic heart disease [odds ratio (OR) = 3.0, p less than 0.001] and frequent premature ventricular contractions on ECG (OR = 6.7, p less than 0.004) were associated with VT, while the following abnormal ECG findings were associated with bradyarrhythmias: first-degree heart block (OR = 7.9, p less than 0.001), bundle-branch block (OR = 3.0, p less than 0.02), and sinus bradycardia (OR = 3.5, p less than 0.03). Eighty-seven percent of the 31 patients with important outcomes at EP study had at least one of these clinical risk factors, while 95% of the patients with none of these risk factors had normal or nondiagnostic EP studies. In the validation sample, the presence of one or more risk factors would have correctly identified 88% of the test VT patients and 65% of the test bradyarrhythmia patients as needing EP study. CONCLUSION: These five identified predictive factors, available from the history, the physical examination, and the initial ECG, could be useful to clinicians in selecting those patients with unexplained syncope who will have a serious arrhythmia identified by EP studies.

Arrhythmias, Cardiac

Quantitative analysis of the outpatient oral case presentation: piloting a method.

OBJECTIVE: To measure the content of oral outpatient case presentations and to assess the correlation of objective assessments of this content with subjective ratings provided by the clinic attending physician. DESIGN: Blinded assessment via audiotape of 36 oral case presentations of new patient evaluations by 23 medical residents. SETTING: Outpatient general medical clinic. PARTICIPANTS: Duke University Medical Center medical residents during their outpatient rotation. MEASUREMENTS AND MAIN RESULTS: Important deficiencies were found in oral case presentation content. Specifically, psychosocial data were often missing (employment history) was mentioned in 28% of presentations; illicit drug use, in 17%; household social structure, in 11%; sexual history, in 6%). An assessment and a plan were mentioned only 56% and 69% of the time, respectively. No correlation was seen between an objective "content score" and the attending physician's subjective rating of the quality of the presentation (r = 0.09). CONCLUSIONS: 1) The outpatient care presentation can be quantitatively assessed in a simple, straightforward manner; 2) outpatient case presentations have important deficiencies in content; and 3) preceptors' evaluations of case presentations may be based upon factors other than content of the presentation.

Ambulatory Care

Acute cardiac ischemia in patients with syncope: importance of the initial electrocardiogram.

OBJECTIVE: To determine the prevalence of acute cardiac ischemia in emergency department (ED) syncope patients without chest pain and to determine which of these patients are at high risk for acute cardiac ischemia. DESIGN: Data were collected prospectively during a study of ED triage of patients who had had possible acute cardiac ischemia. Supplemental retrospective review of records was performed to differentiate syncope from dizziness. SETTING: Six hospital EDs in New England (two primary teaching hospitals in urban locations, two medical-school-affiliated teaching hospitals, and two nonteaching hospitals in rural settings). PATIENTS: 5,762 patients had presented to the ED with chief complaints consistent with acute cardiac ischemia, including chest pain, shortness of breath, dizziness, and syncope. The study sample consisted of 251 patients who had had syncope and no chest pain. RESULTS: The prevalence of acute cardiac ischemia among the syncope patients was 7% (18 of the 251 patients). Univariate analysis revealed the following to have significant association with acute cardiac ischemia: ischemic abnormalities on the electrocardiogram (ECG) obtained in the ED (p less than 0.001), arm or shoulder pain on presentation (p less than 0.05), rales (p less than 0.1), and prior history of exercise-induced angina (p less than 0.05) or myocardial infarction (p less than 0.1). All 18 patients with acute cardiac ischemia had ischemic abnormalities (pathologic Q waves, ST-segment elevation or depression, or T-wave abnormalities) on their presenting ECGs. CONCLUSION: For syncope patients who have no chest pain or ischemic abnormality on the presenting ECG in the ED, acute ischemia appears to be unlikely. Admission to the cardiac care unit for these patients for possible myocardial ischemia is probably unnecessary. However, patients who have syncope and ischemic abnormalities on the ECG are at risk for acute cardiac ischemia, even in the absence of chest pain. Hospital admission to rule out myocardial infarction for these patients is prudent.

Acute Disease