Johanna A. Higgins

Stress-induced abnormalities in myocardial perfusion imaging that are not related to perfusion but are of diagnostic and prognostic importance

IntroductionCertain stress-induced ancillary findings on myocardial perfusion scintigraphy increase the likelihood that the patient has coronary artery disease (CAD); furthermore, among CAD patients, they indicate more severe and extensive disease, placing these patients at higher risk for future cardiac events. Indeed, in studies with no obvious perfusion defect yet with serious CAD—for example, balanced ischemia—it can be these high-risk findings that necessitate invasive intervention.DiscussionBesides reversible perfusion defects, such findings include increased pulmonary radiotracer uptake, transient cavity dilatation, increased end-diastolic or end-systolic volume, decreased post-stress ejection fraction, and increased right ventricular tracer uptake on stress images. The pathophysiology underlying these findings is clearly different as they do not always occur together, and each independently predicts more severe and extensive CAD. In the current review, these findings are defined and their significance in diagnosing patients with suspected or known CAD is discussed.

Chlamydia pneumoniae and coronary artery disease: legitimized linkages?

Chlamydia pneumoniae (Cp) infection in early life may accelerate atherosclerosis over ensuing decades, leading to cardiovascular complications. Cp promotes endothelial dysfunction and may modulate inflammation underlying atherosclerosis. It represents a biologically plausible candidate for the causation of atherosclerosis. Other infections simultaneously occurring with Cp may result in a synergistic effect to promote atherosclerosis. Studies on the treatment of Cp with antibiotics indicates decreased rates of infection, modulation of inflammation and in some settings, fewer cardiovascular complications.