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Background: Sudden cardiac death and myocardial infarction have a circadian variation with a peak incidence in the early morning hours. Increased dispersion of repolarization facilitates the development of conduction delay necessary to induce sustained arrhythmia. Both QT-dispersion and T-wave peak to T-wave end (TpTe) have been proposed as markers of dispersion of myocardial repolarization., Methods: Forty healthy adults (20 women), age 35-67 years old, with normal EKGs, echocardiograms, stress tests, and tilt-table tests were analyzed during a 27-hour hospital stay. EKGs were done at eight different time points. QT-intervals, QT-dispersion, and TpTe were measured at each time point. Harmonic regression was used to model circadian periodicity, P < 0.05 was considered significant., Results: The composite QT-interval was longer in women than in men (416 + or - 17 msec vs 411 + or - 20 msec, respectively, P = 0.006). The QT-dispersion among all leads was greater in men than women (37 + or - 13 msec vs 30 + or - 11 msec, respectively, P < 0.0001); a similar difference was found in the precordial leads. Harmonic regression showed that QT-dispersion had a significant circadian variation, primarily in men. In men, the maximum QT-dispersion occurred at 6 AM (45 + or - 15 msec). TpTe also had a significant circadian variation that was not affected by gender in the majority of leads., Conclusions: A circadian variation exists in the dispersion of myocardial repolarization, as measured by both TpTe and QT-dispersion. Men and women have a different circadian variation pattern. Further studies regarding the mechanisms and clinical implications are needed.

Objectives: This study sought to determine whether the time from diagnosis to randomization was related to outcome in a clinical trial of implantable cardioverter-defibrillator (ICD) insertion in nonischemic cardiomyopathy., Background: Whether the duration of nonischemic cardiomyopathy is related to arrhythmic risk and the possible benefit of ICD insertion is unknown., Methods: The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial randomized 458 patients with nonischemic dilated cardiomyopathy and a left ventricular ejection fraction <36% to receive standard medical therapy with or without an ICD. Patients were randomized regardless of the duration of known cardiomyopathy as long as a reversible cause of left ventricular dysfunction was not present. Patients were divided into recently and remotely diagnosed nonischemic cardiomyopathy groups based on the time from diagnosis of cardiomyopathy to randomization. To categorize patients, cut points of three and nine months were used., Results: Patients with recently diagnosed cardiomyopathy who received an ICD had better survival than those treated with standard therapy at both cut points. This difference in survival was significant at three months (p < 0.05) and was borderline significant at nine months (p = 0.058). Patients with remotely diagnosed cardiomyopathy did not have a significant survival benefit with ICD insertion, but there were no significant differences between ICD benefit in the recent and remote diagnosis groups (p = 0.17 and 0.25)., Conclusions: Patients who have a recent cardiomyopathy diagnosis do not have any less ICD benefit than those with a remote diagnosis. Thus, ICD therapy should be considered in such patients as soon as they are identified as long as a reversible cause of left ventricular dysfunction is excluded.

The benefit of beta blockade has been well established in acute myocardial infarction for several decades, and its benefit in chronic heart failure has been proven since the early 1990's. Several large retrospective analyses suggested the benefit of beta blockers in post-MI systolic dysfunction. Only recently has the benefit of beta blockers been proven in addition to ACE inhibitors, antiplatelet agents, and reperfusion therapy. In the year 2000, CAPRICORN became the first randomized trial to directly address beta blockade in patients with post-infarction systolic dysfunction. The trial showed a 23% reduction in all-cause mortality with carvedilol, in patients already receiving ACE inhibitors, antiplatelet agents, and reperfusion therapy. This is a review of the literature on the administration of beta blockade in patients after acute myocardial infarction with left ventricular systolic dysfunction, as well as a comment on other current treatment modalities for this subset of patients.

Background and Objectives: Neisseria gonorrhoeae MS11mkC harbors 11 independently expressed opacity (Opa) protein genes with distinct in vitro expression frequencies. In experimental infections in which human male volunteers were inoculated with transparent (Opa), piliated (P+) strains, the authors associate onset of symptoms with recovery of opaque (Opa+) gonococci., Goals: In vitro and recovered (Opa) protein expression rates were compared to determine if the human host influences Opa expression., Study Design: Opa expression was determined using Western immunoblot analysis; Opa sizes were determined using a scanning densitometer., Results: Seven of 10 Opa proteins were identified in gonococci recovered from all of the volunteers at frequencies consistent with in vitro results (Opa C, 29.5 kDa; Opa K, 30 kDa; Opa G, 31 kDa; Opa I, 32 kDa; Opa J, 33 kDa; Opa D, 34 kDa; and Opa H, 37 kDa) (P > or = 0.01, Fisher exact test). Opa B (30.5 kDa) was identified at lower than expected frequencies, whereas Opa E (31.2) and F (31.5) were identified at higher' than expected frequencies. When recovered gonococci were reanalyzed for in vitro expression frequencies, they were consistent with preinfection frequencies., Conclusions: The host may influence the prevalence of some Opa proteins.