ECG signal in green line (record 108 containing several abnormal shapes, noise and artifacts).

<p>Left: MAP decision in red line based on M( = 3)-ary LRT. Right: A real time implementation of the matched filter-based method <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110629#pone.0110629-Sornmo1" target="_blank">[15]</a>.</p

Hypothesis considered for the derivation of the approximate M-ary LRT and its expected value.

<p>Left: Example of ECG segment (blue line) and its observation window composed of QRS (red line) and noise (black line) frames (<i>M</i> = 5 and <i>r</i> = 1). Right: The most probable hypotheses in and for a transition as shown in left figure.</p

Operation points for the MAP based QRS detectors. Average and deviation of and (, ).

<p>Operation points for the MAP based QRS detectors. Average and deviation of and (, ).</p

Area Under Curve (AUC) of the ROC curves obtained by averaging all the tapes in the database.

<p>Area Under Curve (AUC) of the ROC curves obtained by averaging all the tapes in the database.</p

Zoom on the ROC curves by averaging all the tapes in the database.

<p>Results using the same observation interval are plotted for the two MAP strategies. The dependence of the operation point on the noise level affects the performance of all detectors.</p

ECG synthetic signal generated for the calculation of <i>a priori</i> probabilities [26].

<p>Note HB: heartbeats.</p

Patient 101 of the MIT-BIH arrhythmia database [20] sampled with .

<p> In both cases a 25% overlap between observation windows is selected. The M-ary LRT test is performed with M = 5, order <i>L</i> = 2. Left: <i>r</i> = 0. Right: <i>r</i> = 1 Note how the false alarm in in the last T segment is removed.</p

Patient 101 of the MIT-BIH arrhythmia database [20] sampled with

<p>Patient 101 of the MIT-BIH arrhythmia database <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110629#pone.0110629-Goldberger1" target="_blank">[20]</a> sampled with </p

Expected value for the M-ary LRT vs the <i>a priori</i> SNR in the detection of a step change.

<p>Expected value for the M-ary LRT vs the <i>a priori</i> SNR in the detection of a step change.</p