Jason M. Lazar

Relationship between QT Interval Dispersion in Acute Stroke and Stroke Prognosis: A Systematic Review

BACKGROUND QT dispersion (QTd) has been proposed as an indirect electrocardiography (ECG) measure of heterogeneity of ventricular repolarization. The predictive value of QTd in acute stroke remains controversial. We aimed to clarify the relationship between QTd and acute stroke and stroke prognosis. METHODS A systematic review of the literature was performed using prespecified medical subjects heading terms, Boolean logic, and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Eligible studies included ischemic or hemorrhagic stroke and provided QTd measurements. RESULTS Two independent reviewers identified 553 publications. Sixteen articles were included in the final analysis. There were a total of 888 stroke patients: 59% ischemic and 41% hemorrhagic. There was considerable heterogeneity in study design, stroke subtypes, ECG assessment time, control groups, and comparison groups. Nine studies reported a significant association between acute stroke and baseline QTd. Two studies reported that QTd increases are specifically related to hemorrhagic strokes, involvement of the insular cortex, right-side lesions, larger strokes, and increases in 3,4-dihydroxyphenylethylene glycol in hemorrhagic stroke. Three studies reported QTd to be an independent predictor of stroke mortality. One study each reported increases in QTd in stroke patients who developed ventricular arrhythmias and cardiorespiratory compromise. CONCLUSIONS There are few well-designed studies and considerable variability in study design in addressing the significance of QTd in acute stroke. Available data suggest that stroke is likely to be associated with increased QTd. Although some evidence suggests a possible prognostic role of QTd in stroke, larger and well-designed studies need to confirm these findings.

Echolucency of the Carotid Artery Intima‐Media Complex and Intima‐Media Thickness Have Different Cardiovascular Risk Factor Relationships: The Women's Interagency HIV Study

Background Adults infected with HIV have increased atherosclerosis potentially associated with both HIV and non‐HIV associated factors. We characterized risk factors for atherosclerosis as measured by noninvasive vascular imaging. Methods and Results We used B‐mode ultrasound to examine levels and correlates of echogenicity and vessel wall thickness of the carotid artery intima‐media complex in 1282 HIV‐infected and 510 HIV‐uninfected women of the Womens Interagency HIV Study. Levels of gray scale median (GSM, a measure of echogenicity) did not vary between HIV infection groups. In both groups, smokers had increased GSM, whereas age, diabetes, elevated blood pressure, and high BMI were associated with lower (rather than higher) GSM. Each of these non‐lipid CVD risk factors, especially age and blood pressure, was also associated with higher levels of carotid artery intima‐media thickness (cIMT). Higher serum triglyceride levels were associated with lower GSM in both HIV‐infected and HIV‐uninfected groups. Additional lipid risk factors for low GSM including high LDL cholesterol and low HDL cholesterol levels were identified in HIV uninfected but not in HIV infected women. In contrast to findings for GSM, among the lipid parameters only LDL cholesterol level had an association with cIMT, which was observed only in the HIV uninfected group. Conclusions Lipid and non‐lipid risk factor associations with echolucency of the carotid artery and the thickness of the common carotid artery intima‐media layer suggest that these measures capture different aspects of atherosclerosis.

Native aortic valve enterococcal endocarditis with myocardial paravalvular abscess

INTRODUCTION Enterococcal endocarditis accounts for 10 to 20% of all cases of bacterial endocarditis. Organisms belonging to the genus Enterococcus are the third most common cause of endocarditis after Streptococcus viridans and Staphylococcusaureus. Enterococcus faecalis causes approximately 90% of all enterococcal infections, and Enterococcus faecium about 10%. Enterococcal infections are most common in older men after a genitourinary tract manipulation or in women of childbearing age. Enterococcal endocarditis may affect both native and prosthetic valves. The aortic valve is affected more often than the mitral valve, and enterococcal endocarditis may be complicated by abscess. Enterococcal endocarditis is most often left sided, even in intravenous drug users, and most commonly presents subacutely. Fever and elevated erythrocyte sedimentation rate (ESR) are present in 90% of patients. Fatality rates average less than 20% and relapse occurs in less than 10%. Complications include stroke, congestive heart failure, and subarachnoid hemorrhage. The occurrence of a paravalvular abscess in the course of an acute endocarditis of the aortic valve indicates an advance stage of the infection and complicates endocarditis in 20 to 30% of cases. In one report, 27 of 95 patients at autopsy, with a native valve endocarditis had paravalvular abscess. Myocardial abscess occurs in approximately 5% of cases of enterococcal endocarditis. We report a case of an enterococcal endocarditis complicated by a large posterior aortic cusp paravalvular abscess, diagnosed by transesophageal echocardiogram (TEE).