title: Rapid assessment of cardiac contractility on a home bathroom scale.
abstract: Analyzing systolic time intervals-specifically the preejection-period (PEP)-is widely accepted as one of the few methods for the noninvasive assessment of cardiac contractility. In this paper, we investigated the ballistocardiogram (BCG) as a way to noninvasively measure myocardial contractility when combined with the ECG. Specifically, we derived a parameter from the BCG and ECG that we hypothesized would be highly correlated to PEP. This is the time delay between the J-wave peak of the BCG and the R-wave of the ECG, which we refer to as the RJ interval. The RJ interval was correlated to PEP (r(2) = 0.86) for 2126 heartbeats across ten subjects, with a y-intercept of 138 ms and slope of 1.05. This suggests that the RJ interval can be reliably used as a noninvasive assessment of cardiac contractility.
authors.affiliation: Division of Pediatric Surgery, University of California, San Francisco, CA, USA. mozziyar.etemadi@ucsf.edu
authors.forename: Mozziyar
authors.initials: M
authors.lastname: Etemadi
authors.forename: Omer T
authors.initials: OT
authors.lastname: Inan
authors.forename: Laurent
authors.initials: L
authors.lastname: Giovangrandi
authors.forename: Gregory T A
authors.initials: GT
authors.lastname: Kovacs
mesh_terms: D000328:Adult; D001450:Ballistocardiography / Q000379:methods*; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D001837:Body Weights and Measures / Q000379:methods; D002307:Cardiography, Impedance / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors