Ballistocardiography to identify high left atrial pressure in patients with heart failure

BACKGROUND Due to a high prevalence and morbidity rate, heart failure (HF) constitutes an immense economic burden on the global health care system. An increase in left atrial pressure (LAP) precedes the occurrence of any HF symptoms. In this study, we applied a novel non-invasive method of ballistocardiography (BCG) to extract early diastolic ventricular vibration waves [the BCG-B3 index, which corresponds to the third heart sound (S3) at the end of the rapid filling phase of diastole]. This study evaluated the predictive value of the BCG-B3 index for LAP in HF patients. METHODS A total of 83 HF patients and 20 patients with underlying diseases were prospectively enrolled, and their cross-sectional BCG and echocardiography (ECHO) data were collected. BCG obtains a signal through a high-precision fiber-optic sensor placed on the patient's back. LAP or pulmonary capillary wedge pressure (PCWP) was estimated by the ratio of mitral inflow peak early diastolic velocity to the early diastolic velocity of the mitral annulus (E/e') or the Nagueh equation (LAP = 1.24 × E/e' + 1.9). To evaluate the diagnostic efficacy of the BCG-B3 index, a receiver operating characteristic (ROC) curve was plotted, and the area under the ROC curve (AUC) was calculated. The best cutoff value for the BCG-B3 index was determined by the maximum Youden index. RESULTS The correlation coefficient between the BCG-B3 index and E/e' ratio was 0.51 (P<0.01). Under an optimal cutoff value of 55.13, the BCG-B3 index showed a positive consistency value of 0.93, a negative consistency value of 0.53, and an overall consistency value of 0.82 for identification of significantly elevated LAP. CONCLUSIONS The BCG-B3 index derived by noninvasive BCG using a built-in fiber-optic sensor has important diagnostic value for identifying significantly elevated LAP in HF patients with high accuracy. BCG examination is not limited by place or the doctor's experience. Therefore, BCG can provide timely assessments for HF patients, enabling early diagnosis and treatment.