Comparison of linear–stochastic and nonlinear–deterministic algorithms in the analysis of 15-minute clinical ECGs to predict risk of arrhythmic death

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Authors: James E Skinner, Michael Meyer, Brian A Nester, et al

Published Date August 2009 , Volume 2009:5 Pages 671 - 682 DOI 10.2147/TCRM.S5568

James E Skinner¹, Michael Meyer², Brian A Nester³, Una Geary⁴, Pamela Taggart⁴, Antoinette Mangione⁴, George Ramalanjaona⁵, Carol Terregino⁶, William C Dalsey⁴

¹Vicor Technologies, Inc., Boca Raton, FL, USA; ²Max Planck Institute for Experimental Physiology, Goettingen, Germany; ³Lehigh Valley Hospital, Allentown, PA, USA; ⁴Albert Einstein Medical Center, Philadelphia, PA, USA; ⁵North Shore University Hospital, Plainview, NY, USA; ⁶Cooper Medical Center, Camden, NJ, USA

Objective: Comparative algorithmic evaluation of heartbeat series in low-to-high risk cardiac patients for the prospective prediction of risk of arrhythmic death (AD).

Background: Heartbeat variation reflects cardiac autonomic function and risk of AD. Indices based on linear stochastic models are independent risk factors for AD in post-myocardial infarction (post-MI) cohorts. Indices based on nonlinear deterministic models have superior predictability in retrospective data.

Methods: Patients were enrolled (N = 397) in three emergency departments upon presenting with chest pain and were determined to be at low-to-high risk of acute MI (>7%). Brief ECGs were recorded (15 min) and R-R intervals assessed by three nonlinear algorithms (PD2i, DFA, and ApEn) and four conventional linear-stochastic measures (SDNN, MNN, 1/f-Slope, LF/HF). Out-of-hospital AD was determined by modified Hinkle–Thaler criteria.

Results: All-cause mortality at one-year follow-up was 10.3%, with 7.7% adjudicated to be AD. The sensitivity and relative risk for predicting AD was highest at all time-points for the nonlinear PD2i algorithm (p ≤ 0.001). The sensitivity at 30 days was 100%, specificity 58%, and relative risk >100 (p ≤ 0.001); sensitivity at 360 days was 95%, specificity 58%, and relative risk >11.4 (p ≤ 0.001).

Conclusions: Heartbeat analysis by the time-dependent nonlinear PD2i algorithm is comparatively the superior test.

Keywords: autonomic nervous system, regulatory systems, electrophysiology, heart rate variability, sudden cardiac death, ventricular arrhythmias, ECG, HRV, PD2i, nonlinear, nonlinear, chaos

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