Left Atrial Volume by Echocardiography in Patients With False Positive Myocardial Perfusion Scans

Abstract

SummaryA stress-induced myocardial perfusion abnormality (MPS), in the absence of angiographically significant epicardial coronary artery disease, is considered a "false-positive" test result. We hypothesized that echocardiography would provide complementary prognostic and pathophysiologic data relevant to the management of patients with MPS and normal coronary angiograms.Accordingly, left atrial volume index (LAVi) was assessed by echocardiography in 38 patients with false positive MPS as defined by normal coronary angiograms and 26 patients with true negative MPS from a total of 1,356 patients stressed from July 2006-May 2008. Pathologically abnormal elevation of LAVi (≥ 32 mL/m 2 ) was observed in 16 of 19 women (84%) and 11 of 19 men (58%) in the false positive MPS (FPMPS) group while none of the patients in the true negative MPS (TNMPS) group had elevated LAVi. In the FPMPS group mean LAVi was significantly higher in women than men (40.64 ± 11.4 mL/m 2 versus 32.6 ± 10.5 mL/m 2 , P = 0.01). The mean LAVi in the FPMPS group was significantly different from the TNMPS group (36.6 ± 11.6 versus 21 ± 7 mL/m 2 , P = 0.000). A stepwise logistic regression determined BSA, LAV and LAVi as useful in predicting false positive and true negative MPS. All three were significant predictors (P < 0.01) and the area under the ROC curve was 0.91.Our findings in this relatively small cohort suggest that patients with false positive MPS have a greater increased LAVi. (Int Heart J 2012; 53: 18-22) Key words: Left atrial volume index, False positive myocardial perfusion scan, Echocardiography A stress-induced myocardial perfusion abnormality (MPS), in the absence of angiographically significant epicardial coronary artery disease is considered a "false-positive" test result.1) Several factors may compromise the specificity of MPS, including poor quality imaging, artifacts caused by intracardiac and/or extracardiac structures, conduction abnormalities, and cardiac structural abnormalities.2-6) Previous studies have reported associations between false positive MPS and endothelial dysfunction, elevated left ventricular end diastolic pressure (LVEDP), and occult epicardial vessel atherosclerosis. 7-9) Thus, "false positive MPS" does not preclude cardiovascular pathology.We hypothesized that echocardiography would provide complementary prognostic and pathophysiologic data relevant to the management of patients with MPS and normal coronary angiograms. In particular, left atrial (LA) enlargement is a robust predictor of adverse cardiovascular outcomes such as congestive heart failure (CHF), stroke (CVA), atrial fibrillation (AF), myocardial infarction (MI) and cardiovascular death. LA volume (LAV) provides more accurate measurement of LA size than conventional M-mode LA dimension.10,11) Accordingly, we explored an association between LAV and false positive MPS. MethodsA cohort study design was approved by the West Virginia University Institutional Review Board. Inclusion criteria were patients with provocable ischemia by MPS, and the ...