METHODS AND SYSTEMS FOR TREATING HEART INSTABILITY
A system and method for assessing risk associated with a suspected heart rhythm disorder includes at least one sensor for generating a signal received from a beating human heart over a plurality of time segments, and an analytic engine that receives the signal and calculates a change in the signal among at least a first time segment and a second time segment in response to a change in at least one of rate and regularity induced in the beating human heart. The analytic engine generates a risk score for the heart rhythm disorder based at least in part on the change in the signal. The system may further be configured to control modification of tissue of the beating human heart based on the risk score.
1 . A method for assessing a risk associated with a suspected heart rhythm disorder in a beating heart, the method comprising:
detecting, using one or more sensors, one or more signals from the beating heart for a plurality of time segments;
pacing the beating heart for a portion of the plurality of time segments to modify at least one of rate or regularity of the beating heart;
calculating, via a computer processor, fluctuations in at least one of signal shape, duration of signal components, signal amplitude and signal characteristics between a first time segment and a second time segment of the plurality of time segments, wherein the second time segment is selected from the portion of the plurality of time segments during which pacing occurs;
generating, via the computer processor, a risk score for the heart rhythm disorder determined based at least in part on the fluctuations; and
displaying on a display device in communication with the computer processor a clinical representation based at least in part on the risk score.
2 . The method of claim 1 , wherein the signals comprise action potentials and the fluctuations comprise changes in a slope of an action potential restitution curve.
3 . The method of claim 2 , wherein the action potential duration restitution curve is defined by action potential durations corresponding to preceding diastolic intervals associated with the one or more signals
4 . The method of claim 2 , wherein the slope of the action potential duration restitution curve exceeds a threshold.
5 . The method of claim 4 , wherein the threshold is a value of one.
6 . The method of claim 1 , further comprising detecting conduction slowing.
7 . The method of claim 6 , wherein the conduction slowing affects at least one of the fluctuations calculated in response to the pacing.
8 . The method of claim 1 , wherein pacing comprises progressively increasing pacing to determine oscillations in atrial signals prior to onset of atrial fibrillation.
9 . The method of claim 1 , wherein pacing is increased or decreased to prevent a beat from initiating atrial fibrillation.
10 . The method of claim 1 , wherein pacing is applied by one or more of an implanted pacemaker electrode, an implanted cardioverter-defibrillator electrode, and an ablation catheter.
11 . The method of claim 1 , further comprising ablating tissue of the beating heart to modify the at least one of the tissue structure and function.
12 . The method of claim 11 , further comprising, after ablating, repeating the steps of pacing, calculating, generating and displaying until the fluctuations are attenuated or abolished.
13 . The method of claim 11 , wherein ablating tissue comprises one or more of applying radiofrequency, infrared, cryoablation, microwave radiation, or other energy to tissue of the beating heart.
14 . The method of claim 1 , wherein the fluctuations are calculated between alternate beats of the beating heart.