@article{3117735,
    title = "Identifying sudden cardiac death risk and specifying its occurrence time
by analyzing electrocardiograms in natural time",
    author = "Varotsos, P. A. and Sarlis, N. V. and Skordas, E. S. and Lazaridou, M. and S.",
    journal = "Applied Physics Letters",
    year = "2007",
    volume = "91",
    number = "6",
    publisher = "AMER INST PHYSICS",
    issn = "0003-6951, 1077-3118",
    doi = "10.1063/1.2768928",
    abstract = "Sudden cardiac death (SCD) is a frequent cause of death and may occur
even if the electrocardiogram seems to be similar to that of a healthy
individual. A method which not only identifies the risk but also
provides an estimate of the time of an impending cardiac arrest is
proposed. Analyzing 159 electrocardiograms in natural time, the authors
find that the key quantity is the entropy change under time reversal.
After it becomes maximum at the scale of 13 heartbeats, ventricular
fibrillation starts within similar to 3 h in 16 out of 18 SCDs. The
method also distinguishes congestive heart failure patients from SCD.
(c) 2007 American Institute of Physics."
}