Search

Given the enormous symptom relief benefit seen with cardiac myosin inhibitors, there is renewed focus to correctly identify hypertrophic cardiomyopathy (HCM) patients as obstructive versus non-obstructive. Overall, two thirds of HCM patients have clinically significant obstruction of blood flow out of the left ventricular outflow tract (LVOTO). A third of HCM patients, however, will only experience obstruction during challenging provocative maneuvers such as Valsalva, during volume depletion, or with exercise. Patients with "masked obstruction" are frequently mislabeled and subsequently mismanaged as non-obstructive. This study aims to identify features seen on cardiac magnetic resonance imaging (CMR) and on transthoracic echocardiography (TTE) that should heighten awareness that occult obstruction may be present, potentially prompting physicians to obtain exercise stress echocardiography. This study utilized retrospective data analysis from a large, single-center cohort over a six-month period. Subjects were included if both stress echocardiography and CMR were available. LVOTO was defined as peak LV outflow tract gradient ≥30 mmHg. Subjects were divided in to 1) Absent, 2) Masked and 3) Overt LVOTO. CMR was used to assess anatomical differences between groups. Continuous data was compared using ANOVA analysis, with secondary multiple comparison tests. Sixty one patients (30:31 M:F)(Age = 57.1 ± 14.4 yrs.) were included; Absent (n = 27), Masked (n = 21), Overt (n = 13). CMR data with ANOVA analysis is provided in Table 1. Multiple comparison testing of the Zone of Coaptation Length was significant between the Absent v. Masked groups (mean = 7.8 v. 10.1, 95% CI: -4.6 to -0.1, p = 0.04). (Figure 1) The height of the zone of coaptation is best understood as the length of contact between the anterior and posterior mitral leaflets in the basal to apical axis during systole. In this cohort, longer zone of coaptation lengths were more likely to associate with masked LVOTO than overt or absent LVOTO. During hyperdynamic contractility, this highly mobile region of the sub-valvular apparatus is likely pushed into the LVOT due to the Venturi Effect and/or from apical displacement of the papillary heads. Once in the LVOT, drag force is exerted on the apparatus resulting in obstruction. Anterior mitral length, a feature thought to predict obstruction from the echocardiography literature, did not predict masked or overt obstruction. Further investigation is warranted to better understand how cardiac MRI could prompt physicians to look for masked obstruction, as stress echocardiography is commonly underutilized. [ABSTRACT FROM AUTHOR]

We report 2 clinically characteristic and serologically positive cases of Ross River virus infection in Canadian tourists who visited Fiji in late 2003 and early 2004. This report suggests that [...]

Provides information regrading an experiment to determine the reactions of radical cations generated form 9-cyclopropylanthracene in the presence of methanol with the use of electrochemistry. Detailed information on this experiment; Discussion on the importance of radical cations to this experiment; Results form this experiment.

Several recent reports have described an association between human immunodeficiency virus (HIV) infection and porphyria cutanea tarda (PCT). We describe two HIV-infected patients who developed PCT and review 29 other reported cases of coexistent PCT and infection due to HIV. Recognized porphyrinogenic factors were identified in our patients and in 27 of the 29 cases described in the literature. Even in the two cases that lacked obvious precipitant factors for PCT, the possibility of hepatitis C was not excluded. This fact suggests that the cooccurrence of PCT and infection due to HIV may reflect the coexistence of risk factors for the two diseases rather than a causal association. Despite concern that exposure to sulfonamides might exacerbate porphyria, one of our patients and three patients described in the literature were safely treated with sulfonamides. [ABSTRACT FROM PUBLISHER]

Three cases of plague, all with pneumonic involvement, occurred in a small village in northwestern Zambia. Initial recognition of the diagnosis was delayed, but the outbreak was terminated by rapid intervention with insecticides and with the use of chemoprophylaxis for individuals with high-risk exposures to case-patients. [ABSTRACT FROM PUBLISHER]