Operator independent left ventricular function monitoring during pharmacological stress echo with the new peak transcutaneous acceleration signal

Abstract

Background - As the myocardium contracts isometrically, it generates vibrations that can be measured with an accelerometer. The vibration peak, peak endocardial acceleration (PEA), is an index of contractility. Objective - To evaluate the feasibility of PEA measured by the cutaneous precordial application of the accelerometer sensor; and to assess the usefulness of PEA monitoring during pharmacological stress echocardiography. Design - Feasibility study. Setting - Stress echo laboratory. Patients - 34 consecutive patients underwent pharmacological stress (26 with dipyridamole; 8 with dobutamine) and PEA monitoring simultaneously. Interventions - A microaccelerometer was positioned in the precordial region and PEA was recorded. Dipyridamole was infused up to 0.84 mg/kg in 10 minutes, and dobutamine up to 40 μg/kg/min in 15 minutes. Results - A consistent PEA signal was obtained in all patients. Overall mean (SD) baseline PEA was 0.26 (0.15)g (g = 9.8 m/s2), increasing to 0.5 (0.36)g at peak stress (+0.24 g, 95% confidence interval (CI) 0.14 to 0.34 g; p < 0.01). PEA increased from 0.26 (0.16) to 0.37 (0.25) g in the dipyridamole group (+0.11 g, 95% CI 0.08 to 0.16 g; p < 0.01), and from 0.29 (0.1) to 0.93 (0.37) gin the dobutamine group (+0.64 g, 95% CI 0.37 to 0.91 g; p < 0.01). Conclusions - Using precordial leads this method offers potential for diagnostic application in the short term monitoring of myocardial function. PEA monitoring is feasible during pharmacological stress and documents left ventricular inotropic response quantitatively in a non-invasive and operator independent fashion.