Optimization of Cardiac Resynchronization Devices Using Acoustic Cardiography: A Comparison to Echocardiography

Abstract

Optimization of pacemaker settings for cardiac resynchronization therapy (CRT) remains challenging and problematic. Several noninvasive methods are offered to customize the programmed parameters for individual patients, but so far only echocardiographic imaging has established itself as an accepted method. The authors examined the value of acoustic cardiography as a fast and more cost‐efficient alternative to established echocardiographic imaging techniques for the optimization of CRT devices. The atrioventricular delay in 22 subjects with implanted CRT devices was independently optimized using echocardiography (Doppler transmitral flow) as well as acoustic cardiography, and the recommended settings from each method were later compared. Doppler echocardiography and acoustic cardiography recommendations matched within a mean value ± SD of 17±16 milliseconds and gave a correlation coefficient of r=0.90 (p<0.001). In 17 of the 22 cases (77.3%), the difference between echocardiographic and acoustic cardiogram CRT optimization results was ≤20 milliseconds. Furthermore, the echocardiographic transmitral flow pattern was not significantly different for the setting independently chosen by the echocardiographic expert and the acoustic cardiographer for the cases with a difference of >20 milliseconds (22.7%). In addition, it took less time for the acoustic cardiogram to collect sufficient information to make a recommendation, and it was found that the acoustic cardiogram data trend is easier to interpret.

Noninvasive Imaging in Cardiac Resynchronization Therapy—Part 2: Follow‐up and Optimization of Settings

“…The EMAT interval reflects the time required in ms for the LV to generate sufficient force to close the mitral valve. EMAT has been used successfully to optimize A‐V delays 61,62 . Since EMAT is a measure of contractility, the delay exhibiting the shortest EMAT is considered optimal.…”

Estimation of left ventricular function using a novel acoustic‐based device

“…Notably, the acoustic parameters were not useful for the diagnosis of LV diastolic dysfunction in the subgroup of patients with preserved LVEF [12]. Preliminary studies have attempted to use the Audicor device for optimisation of programming of biventricular pacemakers [11,16,17] with encouraging, yet nonconclusive results.…”

The role of AV and VV optimization for CRT

“…Changes in each parameter can indicate worsening heart failure: an increase in S3 suggestive of increased left ventricular filling pressure, prolongation of EMAT indicative of reduced LV contractility, and a reduced LVST suggestive of reduced systolic function. An AV delay tailored to optimize these parameters in 22 CRT patients was comparable to the mitral inflow method [31].…”