Abstract 18991: Mechanism of False Positive Exercise Electrocardiographic Testing: An Investigation by Advanced Echocardiography
Introduction: Treadmill exercise electrocardiography (TEE) is the classical method for initial assessment of coronary artery disease (CAD). However, a significant number of patients reveal false positive with this method. The mechanism of false positive TEE remains unclear. Global longitudinal strain (GLS) by speckle tracking echocardiography (STE) was reported to detect early left ventricular (LV) dysfunction.
Methods: The present study included 755 patients with suspected CAD who underwent TEE. Patients with depressed LVEF (EF<50%), atrial fibrillation, or valvular heart disease were excluded. Of the study patients, 30 patients (3.9%) were false positive for TEE, which was identified by coronary artery angiography (n=19, 63%) or 64-slice multidetector coronary computed tomography (n=11, 37%). The present study also included aged-matched 20 healthy controls. Conventional echocardiographic parameters were obtained within 2 days after TEE. Speckle tracking echocardiography (STE) was also performed for evaluation of global longitudinal strain (GLS) and circumferential strain (GCS). GLS was defined as the averaged longitudinal strains at end-systole in 18 segments from three apical views. GCS was defined as averaged circumferential strain at end-systole in 18 segments at short-axis views.
Results: No differences in the clinical characteristics, exercise indices, LV mass index, LV volume and LV ejection fraction were found between the false positive TEE patients and controls. GLS and the early mitral annular velocity (E') were significant reduced in the false positive TEE patients than controls (-20.3±2.0 vs -22.9±2.9%, p=0.034; -5.5±3.8 vs -8.3± 2.3 cm/s, p=0.005), while GCS was comparable (-20±3.8 vs -21±4.7% p=0.37). Multivariate analysis showed E' and GLS were independent factors associated with false positive TEE (p = 0.001 and p=0.027, respectively).
Conclusions: Speckle-tracking and tissue Doppler echocardiography detected LV diastolic and subclinical systolic dysfunction in patients with false positive TEE. This study is in agreement with the report that false positive TEE patients have poor prognosis than normal controls.
- © 2010 by American Heart Association, Inc.