Usefulness of seismocardiography for the diagnosis of ischemia in patients with coronary artery disease.

BACKGROUND: Seismocardiography (SCG) is a useful method for the detection of exercise-induced changes in cardiac muscle contractility which may occur during myocardial ischemia. The aim of this study was to compare the diagnostic accuracy of SCG with electrocardiographic exercise test (ETT) for diagnosis of ischemia in patients with angiographically proved coronary artery disease (CAD).
METHODS: Seventy-seven male patients with CAD without myocardial infarction (MI), mean age 51+/-9 years, were subjected to SCG and ETT. A gender-matched control group consisted of 30 healthy volunteers aged 34+/-7 years. SCG was done simultaneously with resting supine 12-lead electrocardiography before and immediately after a symptom-limited ETT. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of SCG were compared with ETT. Moreover, the diagnostic accuracy of both the methods was compared, with coronary angiography being the reference for the analysis.
RESULTS: SCG was more sensitive (61.1% vs 44.2%, P<0.05) and accurate (70% vs 61%, P<0.05) method for detecting ischemia caused by coronary stenosis>or=50%, at least in one coronary artery compared to the ETT. However, ETT had better specificity than SCG (82.4% vs 76%, P<0.05). The PPV and NPV of SCG were significantly better than those obtained with ETT (77.9% vs 76%, P<0.05 and 63.4% vs 53.8%, P<0.05, respectively). Moreover, the concordant results of SCG and ETT improved the diagnostic accuracy of both methods.
CONCLUSIONS: SCG appeared to be more sensitive for detecting ischemia caused by more than>or=50% stenosis of the main coronary artery compared to an electrocardiographic stress test. SCG was a useful ETT adjunct for selecting patients requiring coronary angiography.