Post date: 09-sep-2014 9:16:04

Ttitle: Physiological Feature Analysis in Heart Rate Turbulence using LASSO Model

Date: 15-Nov-2013

Speaker: Óscar Barquero Pérez (URJC)

Abstract: Background. Heart Rate Turbulence (HRT) is a relevant cardiac risk stratification criterion. It is usually assessed by turbulence slope (TS) and turbulence onset TO parameters. HRT is known to be affected by several physiological factors, mainly heart rate (HR) and coupling interval (CI). Baroreflex source of the HRT is the physiological hypothesis accepted. However, several studies showed different results about the relationship between CI and HRT.

Objective. Our aim was to propose a LASSO model using CI and sinus cardiac length (SCL), their powers and an interaction term as explanatory variables to account for the physiological dynamic of the TS parameter. Methods. We used a database of 61 recording holters from acute myocardial infarction (AMI) patients (Hospital Universitario Virgen de la Arrixaca de Murcia, Spain). The database was split into two groups; low-risk patients (TS > 2.5 & TO < 0), and high-risk patients (TS < 2.5 & TO > 0). We performed a feature analysis by means of LASSO paths, in which the regularization parameter is changed from high values, where all weights of the explanatory variables are zero, to small values where all the weights are different from zero. The first variable with a coefficient different from zero were SCL on low-risk patients and the two following were related to CI. Whereas the first variable activated on high-risk was CI and the two following were relate to SCL.

Conclusions. Results from LASSO paths suggest that the influence of physiological variables on HRT is broken on AMI high-risk and completely different from low-risk. Also, the features selected by LASSO model on AMI low-risk are in agreement with baroreflex hypothesis as source of the HRT, in which SCL is the most important variable, and CI has a negative correlation with TS, so that premature VPC implies higher TS values.