Seismocardiography - a non-invasive method of assessing systolic and diastolic left ventricular function in ischaemic heart disease

Abstract

Background: Seismocardiography (SCG) is a new non-invasive method which can assess left ventricular function (LVF) during exercise testing based on cardiac time intervals (CTI). There are no data assessing cardiac time intervals during exercise ischaemia in patients with coronary artery disease. The aim of the study was to assess systolic and diastolic CTI in patients after myocardial infarction (MI) with ischaemia during the exercise tolerance test (ETT).
Material and methods: Sixty post-MI patients were included in the study and subdivided into two groups, A and B. Group A consisted of 30 patients aged 61.7 ± 6 with normal left ventricular systolic function and left ventricular diastolic dysfunction based on Echo. Group B consisted of 30 patients aged 60.1 ± 6 with normal left ventricular systolic and diastolic function. During SCG the following parameters were analysed: pre-ejection period (PEP) in ms, left ventricular ejection time (LVET) in ms, PEP/LVET, myocardial performance index (MPI) and isovolumetric relaxation time (IVRT) in ms at rest and immediately after exercise. During ETT the following parameters were analysed: ETT duration in minutes, blood pressure (BP), heart rate (HR) and ST depression in mm.
Results: In group A on SCG exercise-induced ischaemia changed PEP from 115 ± 13 to 116 ± 17 ms, LVET from 298 ± 22 to 290 ± 26 ms, PEP/LVET from 0.39 ± 0.05 to 0.40 ± 0.08, MPI from 0.39 ± 0.1 to 0.42 ± 0.1, IVRT from 67 ± 21 to 72 ± 21 ms and MO-RF from 115 ± 39 to 85 ± 20, p < 0.001, which suggests a deterioration of the left ventricular systolic and diastolic function. In group B on SCG exercise-induced ischaemia changed PEP from 116 ± 18 to 118 ± 15 ms, LVET from 305 ± 25 to 294 ± 27, PEP/LVET from 0.38 ± 0.07 to 0.40 ± 0.07, MPI from 0.37 ± 0.8 to 0.40 ± 0.09, IVRT from 59 ± 14 to 66 ± 17 and MO-RF from 112 ± 39 to 85 ± 28, p = 0.001, also suggesting a deterioration in left ventricular systolic and diastolic function in spite of the normal function at rest. There were no intergroup differences in ETT duration, HR and BP; only ST depression in group B was longer, 1.7 vs. 1.4 mm (p = 0.027).
Conclusion: Seismocardiography is a helpful method of assessing left ventricular systolic and diastolic function in patients with exercise-induced ischaemia.