Abstract: Methods and apparatus for assessing cardiac risks based on heart activity data obtained during a recovery stage of an exercise test of a specific patient. An embodiment of a method comprises determining a prognostic period of the heart activity data after a time t0 after a peak heart rate of the exercise test, and ascertaining a risk indicator. The risk indicator is based on (a) the heart rate activity data during the recovery stage only after time t0 and (b) a post-exercise heart rate reserve based on a post-exercise resting heart rate. This embodiment of the method further includes providing an assessment of cardiac risk of a specific patient based on the ascertained risk indicator.

Abstract: Methods and apparatus for assessing cardiac risks in a specific patient. One embodiment of a method in accordance with the invention comprises providing heart rate activity of a specific patient including a windowed time series relating to heart rate variability during a heart rate test. This method further includes determining a frequency domain value based on energy values of frequency bands of the heart rate variability in the windowed time series, and/or determining an aggregate power for a frequency band of the windowed time series. This method further includes assessing the risk of a cardiac event based on the frequency value and/or the aggregate power.

Abstract: Methods and apparatus for determining T-wave alternan signatures (i.e., morphology and polarity) derived from a physiologic signal representative of a subject's heart activity; assessing changes in the myocardium Action Potential (“AP”) through analysis of the alternan signature derived from a physiologic signal representative of a subject's heart activity; and/or assessing spatial disassociation of alternan characteristics that are likely associated with the initiation of re-entrant arrhythmias.

Abstract: Methods and apparatus for determining T-wave alternan signatures (i.e., morphology and polarity) derived from a physiologic signal representative of a subject's heart activity; assessing changes in the myocardium Action Potential (“AP”) through analysis of the alternan signature derived from a physiologic signal representative of a subject's heart activity; and/or assessing spatial disassociation of alternan characteristics that are likely associated with the initiation of re-entrant arrhythmias.

Abstract: Methods and apparatus for determining T-wave alternan signatures (i.e., morphology and polarity) derived from a physiologic signal representative of a subject's heart activity; assessing changes in the myocardium Action Potential (“AP”) through analysis of the alternan signature derived from a physiologic signal representative of a subject's heart activity; and/or assessing spatial disassociation of alternan characteristics that are likely associated with the initiation of re-entrant arrhythmias.