Thomas M. Bashore

Although the sensitivity and specificity of the Duke criteria for the diagnosis of infective endocarditis (IE) have been validated by investigators from Europe and the United States, several shortcomings of this schema remain. The Duke IE database contains records collected prospectively on >800 cases of definite and possible IE since 1984. Databases on echocardiograms and on patients with Staphylococcus aureus bacteremia at Duke University Medical Center are also maintained. Analyses of these databases, our experience with the Duke criteria in clinical practice, and analysis of the work of others have led us to propose the following modifications of the Duke schema. The category "possible IE" should be defined as having at least 1 major criterion and 1 minor criterion or 3 minor criteria. The minor criterion "echocardiogram consistent with IE but not meeting major criterion" should be eliminated, given the widespread use of transesophageal echocardiography (TEE). Bacteremia due to S. aureus should be considered a major criterion, regardless of whether the infection is nosocomially acquired or whether a removable source of infection is present. Positive Q-fever serology should be changed to a major criterion.

To examine the risk of ventricular fibrillation in patients with the Wolff-Parkinson-White syndrome, we compared patients who had this syndrome and a history of ventricular fibrillation related to preexcitation with patients who had the syndrome without this history. Ventricular fibrillation occurred during atrial fibrillation, with rapid conduction over the accessory pathway, and these patients had a higher prevalence of both reciprocating tachycardia and atrial fibrillation (14 of 25 vs. 18 of 73, P = 0.004) and multiple accessory pathways (five of 25 vs. four of 73, P = 0.012). The shortest preexcitation R-R interval during atrial fibrillation was less in the group with ventricular fibrillation (mean shortest R-R, 180 vs. 240 milliseconds, P less than 0.0001) as was the average R-R interval (mean average R-R, 269 vs 340 milliseconds, P less than 0.0001). Patients with Wolff-Parkinson-White syndrome who are most susceptible to ventricular fibrillation have a history of atrial fibrillation and reciprocating tachycardia, demonstrate rapid conduction over an accessory pathway during atrial fibrillation and have multiple accessory pathways.