Diagnostic and prognostic criteria of chronic left ventricular failure obtained during exercise-201Tl imaging

Coronary artery disease detection - limitations of stress testing in left ventricular dysfunction

Incidental diagnosis of left ventricular systolic dysfunction (LVD) is common in clinical practice. The prevalence of asymptomatic LVD (Ejection Fraction, EF < 50%) is 6.0% in men and 0.8% in women and is twice as common as symptomatic LVD. The timely and definitive exclusion of an ischemic etiology is central to optimizing care and reducing mortality in LVD. Advances in cardiovascular imaging provide many options for imaging of patients with left ventricular dysfunction. Clinician experience, patient endurance, imaging modality characteristics, cost and safety determine the choice of testing. In this review, we have compared the diagnostic utility of established tests - nuclear and echocardiographic stress testing with newer techniques like coronary computerized tomography and cardiac magnetic resonance imaging and highlight their inherent limitations in patients with underlying left ventricular dysfunction.

The use of thallium-201 lung/heart ratios

This survey gives an overview of the methodology of thallium-201 lung/heart uptake ratios often used as an independent factor in the assessment of patients with coronary artery disease undergoing myocardial perfusion scintigraphy. Different techniques have been used in the past. The most sensitive method is one which calculates a lung/heart ratio from scintigraphy obtained immediately after cessation of exercise. If single photon emission tomography (SPET) is routinely performed the anterior projection of the data set obtained during tomographic acquisition should be used in preference to a separate planar anterior static images recorded before or after the SPET procedure. The lung/heart ratio is useful as a prognostic indicator of outcome as it accurately mimics the degree of left ventricular dysfunction. With the increasing popularity of pharmacological stress testing there is evidence that this ratio still offer valid information. Additional work in this field is nevertheless required to further confirm this observation. In routine clinical practice, the lung/heart ratio should help and enable physicians to prioritise patients for urgent intervention.

Spatial distribution and temporal changes of pulmonary thallium uptake in myocardial perfusion studies

Spatial distribution and temporal changes in pulmonary thallium uptake were assessed in 24 normal subjects and 35 patients with coronary artery disease (CAD). In studies carried out directly after stress and 3 h later, pulmonary Tl uptake was assessed as body surface area corrected absolute pulmonary uptake in the upper, middle and lower right lung regions, and in the total right lung and upper left lung. Pulmonary/myocardial (PM) uptake ratios for these 5 regions were calculated as mean pulmonary/mean background-corrected myocardial uptake. Additionally, wash-out was assessed for each region and for the myocardium. In normal subjects, the initial pulmonary Tl uptake, the PM ratios and Tl wash-out were greater in the lower lung regions than in the upper. In the late studies, no significant differences in Tl content or PM ratios were found among the regions. In patients with CAD, initial pulmonary Tl uptake and PM ratios were greater in the lower than in the upper regions, and higher than for the normal subjects in all pulmonary regions (P less than 0.001). Tl wash-out was significantly higher in the low and middle regions versus the upper region (P less than 0.001) and higher in all regions than in normal subjects (P less than 0.001). In the late studies no significant differences in Tl content or PM ratios were found between any pulmonary regions. Pulmonary Tl content was, in all regions, higher in CAD than in normal subjects (P less than 0.01), as were the PM ratios (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)