Non-invasive cardiac kinetic energy distribution: a new marker of heart failure with impaired ejection fraction (KINO-HF)

Abstract

Background: Heart failure (HF) remains a major cause of mortality, morbidity, and poor quality of life. 44% of HF patients present impaired left ventricular ejection fraction (LVEF). Kinocardiography (KCG) technology combines ballistocardiography (BCG) and seismocardiography (SCG). It estimates myocardial contraction and blood flow through the cardiac chambers and major vessels through a wearable device. Kino-HF sought to evaluate the potential of KCG to distinguish HF patients with impaired LVEF from a control group.

Methods: Successive patients with HF and impaired LVEF (iLVEF group) were matched and compared to patients with normal LVEF ≥ 50% (control). A 60 s KCG acquisition followed cardiac ultrasound. The kinetic energy from KCG signals was computed in different phases of the cardiac cycle ($i{K}_{systolic};\Delta i{K}_{diastolic}$) as markers of cardiac mechanical function.

Results: Thirty HF patients (67 [59; 71] years, 87% male) were matched with 30 controls (64.5 [49; 73] years, 87% male). SCG $\Delta i{K}_{diastolic}$, BCG $i{K}_{systolic}$, BCG $\Delta i{K}_{diastolic}$ were lower in HF than controls (p < 0.05), while SCG $i{K}_{systolic}$ was similar. Furthermore, a lower SCG $i{K}_{systolic}$ was associated with an increased mortality risk during follow-up.

Conclusions: KINO-HF demonstrates that KCG can distinguish HF patients with impaired systolic function from a control group. These favorable results warrant further research on the diagnostic and prognostic capabilities of KCG in HF with impaired LVEF.Clinical Trial Registration: NCT03157115.

Keywords: aid-to-diagnosis; ballistocardiography; e-health; heart failure; kinocardiography; point-of-care screening; reduced ejection fraction; seismocardiography.

Figure 1

Kinocardiography signals acquisition and kinetic energy computation. From linear accelerations and angular rates raw acquisition on the chest (SCG) and in the lower back (BCG) to the kinetic energy metrics as described in section 2.4. SCG, seismocardiography; BCG, ballistocardiography; K, kinetic energy; Lin, linear; Rot, rotational.

Figure 2

Kinocardiography metrics computation. Illustration of the PQ, QT, and TP phases segmented on the ECG and displayed for BCG kinetic energy (K). The time integrals of K are computed on each of these phases providing $i{K}_{PQ}$, $i{K}_{QT}$, and $i{K}_{TP}$ respectively. Based on these, $i{K}_{systolic}$ and $\mathrm{\Delta }i{K}_{diastolic}$ are computed as displayed on the figure and further described in section 2.4.

Figure 3

Systolic kinetic energy results. Systolic kinetic energy (mean and standard error of the mean) for BCG and SCG among iLVEF patients and matched controls patients with impaired left ventricular ejection fraction (*: <0.01). CTRL, control; iLVEF, patients with impaired left ventricular ejection fraction.

Figure 4

Diastolic kinetic energy results. Diastolic kinetic energy (mean and standard error of the mean) for BCG and SCG among matched controls and iLVEF patients with impaired left ventricular ejection fraction (*: <0.01). CTRL, control; iLVEF, patients with impaired left ventricular ejection fraction.

Figure 5

Kaplan–Meier probability of survival. Kaplan–Meier curves of event-free survival according to (A) SCG $i{K}_{systolic}$; and (B) heart rate.