Heart rate turbulence and fractal scaling coefficient in response to premature atrial and ventricular complexes and relationship to the degree of prematurity

Abstract

819-5 Citation: Supplement to Journal of the American College of Cardiology, March 6, 2002, Vol. 39, Issue 5, Suppl. A Heart Rate Turbulence and Fractal Scaling Coefficient in Response to Premature Atrial and Ventricular Complexes and Relationship to the Degree of Prematurity Julia H. Indik, Peter Ott, Frank I. Marcus Sarver Heart Center, University of Arizona, Tucson, Arizona. Background: Heart rate turbulence (HRT) slope following premature ventricular beats is decreased following myocardial infarction and associated with increased mortality. The fractal scaling properties of the variation in beat-to-beat (RR) intervals measured from Holter monitoring has also been shown to predict mortality in heart failure. The relationship of HRT to the type of premature beat, atrial (PAC) or ventricular (PVC), as well as to the degree of prematurity of that beat has not been reported, nor has the fractal scaling properties of the RR interval variation following a premature beat been previously described. Methods: Holter data were analyzed from 10 normal patients between the ages of 30-75 years. HRT slope was calculated from the first twenty beats. Fractal scaling coefficients, α, were computed using a detrended fluctuation analysis of the first thirty beats. The degree of prematurity was defined as the ratio of the RR interval of the premature beat to that of the preceding interval. Results: A total of 227 PACs and 171 PVCs were analyzed from 24-hour Holters. The HRT slope (mean ±SE) was 17± 1 ms/beat for PACs and 26± 2 ms/beat for PVCs (p<0.001). There was a negative correlation between HRT slope and degree of prematurity (r=-0.4, p<0.001), which was present for PVCs and PACs analyzed as separate groups. Following PACs, αPAC= 1.16±0.02 and following PVCs, αPVC = 1.19 ±0.03 (p=NS), and showed a small positive correlation for degree of prematurity of PVCs (r=0.2, p<0.001), but not for PACs. Conclusions: In normal subjects, HRT slope differs for PACs and PVCs and correlates with prematurity. The fractal properties of this variation are unaffected by the type of beat but are dependent on the degree of prematurity of PVCs. By taking into account the prematurity of the PVC and combining with a fractal scaling analysis, risk stratification may be enhanced. ACC 2002 / 51st Annual Scientific Session March 17-20, 2002, Atlanta, Georgia, USA Page 1 CONIFERTM Information System. Conifer is a trademark of Excerpta Medica Medical Communications B.V.