Propagation viewer
Embodiments of the present invention disclose a method and system for visualizing the depolarization of a heart as a wave across the surface of the heart while at the same time showing the underlying electrograms associated with the depolarization. Controls are provided to: start and pause the propagation (depolarization) animation, fast forward or rewind, reduce the speed from 1× to slower speeds, and select a subset of the signal for viewing.
1 . A method for visualization of propagation of a depolarization wave in a heart, comprising:
measuring a plurality of electrograms (EGMs) using a plurality of electrodes, at a plurality of locations in contact with a surface of the heart;
extracting, from the plurality of EGMs, information corresponding to depolarization of the heart as a function of time, wherein extracting comprises:
computing a first derivative with respect to time of each of the plurality of EGMs;
determining extrema in the first derivative for each EGM;
classifying the EGM as unipolar or bipolar; and
for bipolar EGMs, selecting a local activation time and a corresponding DVIDTMIN value based on a ratio of the extrema, wherein the ratio is defined as an absolute value of a minimum dV/dt divided by an absolute value of a maximum dV/dt;
on a first portion of a display screen, recreating the depolarization of the heart as a propagation of a depolarization wave across a model of the heart;
on a second portion of the display screen, displaying the plurality of EGMs, wherein each of the plurality of EGMs includes a visual indication representing a correlation between the displayed plurality of EGMs and the propagation of the depolarization wave; and
providing a control to a user to interact with the propagation of the depolarization wave across the model of the heart.
2 . The method of claim 1 , wherein the interaction of the user with the propagation of the depolarization wave comprises:
receiving an input from the user to perform at least one of: start propagation of the depolarization wave on the display screen, pause the propagation of the depolarization wave on the display screen, control a speed of the propagation of the depolarization wave on the display screen, fast forward the propagation of the depolarization wave on the display screen, reverse the propagation of the depolarization wave on the display screen, or selection of a set of EGMs from the plurality of EGMs to display on the second portion of the display screen.
3 . The method of claim 1 , further comprising:
simultaneously displaying the propagation of the depolarization wave across the model of the heart and the plurality of EGMs including the corresponding visual indication on the display screen in a time-synchronized manner.
4 . The method of claim 1 , further comprising
on a third portion of the display screen, displaying a bar that indicates a progress of the propagation of the depolarization wave across the model of the heart.
5 . The method of claim 1 , further comprising
storing the recreated the propagation of the depolarization wave as a sequence of events in a memory device; and
controlling a display of the sequence of events on the display screen based on a first input from the user.
6 . The method of claim 5 , further comprising
controlling a speed of the display of the sequence of events on the display screen based on a second input from the user.
7 . The method of claim 1 , further comprising
illuminating a portion of the model of the heart to indicate depolarization of a corresponding region of the heart, based on a propagation of activation electrical signals to the region of the heart.
8 . The method of claim 1 , further comprising:
generating a spatial map for each of the plurality of EGMs, based on a corresponding local activation time and the extrema of the corresponding first order derivative; and
displaying the generated spatial map for each of the plurality of EGMs on the second portion of the display screen.
9 . The method of claim 1 , further comprising:
mapping values of the local activation time and the extrema of the corresponding first order derivative for each of the plurality of EGMs to corresponding one or more points of the heart;
generating an activation map for the heart based on the mapped values; and
recreating the propagation of the depolarization wave to indicate the activation map on the display screen.
10 . The method of claim 9 , further comprising
determining health of tissues underlying the one or more points of the heart based on the corresponding mapped values.
11 . The method of claim 9 , further comprising:
determining a cardiac therapy based on the mapped values of the local activation times and the extrema of the corresponding first order derivatives for each of the plurality of EGMs; and
controlling a therapy device to deliver the determined cardiac therapy.
12 . A system for visualization of propagation of a depolarization wave in a heart, comprising:
a signal acquisition module configured to measure a plurality of electrograms (EGMs) using a plurality of electrodes, at a plurality of locations in contact with a surface of the heart;
a memory configured to store computer-executable instructions; and
one or more processors configured to execute instructions to:
extract, from the plurality of EGMs, information corresponding to depolarization of the heart as a function of time, wherein extracting comprises:
computing a first derivative with respect to time of each of the plurality of EGMs;
determining extrema in the first derivative for each EGM;
classifying the EGM as unipolar or bipolar; and
for bipolar EGMs, selecting a local activation time and a corresponding DVIDTMIN value based on a ratio of the extrema, wherein the ratio is defined as an absolute value of a minimum dV/dt divided by an absolute value of a maximum dV/dt;
recreate, on a first portion of a display screen, the depolarization of the heart as a propagation of a depolarization wave across the model of the heart;
display, on a second portion of the display screen, the plurality of EGMs, wherein each of the plurality of EGMs includes a visual indication representing a correlation between the displayed plurality of EGMs and the propagation of the depolarization wave; and
provide a control to a user to interact with the propagation of the depolarization wave across the model of the heart.
13 . The system of claim 12 , wherein the one or more processors are further configured to execute instructions to display, on a third portion of the display screen, a bar that indicates a progress of the propagation of the depolarization wave across the model of the heart.
14 . The system of claim 12 , wherein the one or more processors are further configured to execute instructions to
store the recreated propagation of the depolarization wave as a sequence of events in a memory device; and
control a display of the sequence of events on the display screen based on a first input from the user.
15 . The system of claim 14 , wherein the one or more processors are further configured to execute instructions to control a speed of the display of the sequence of events on the display screen based on a second input from the user.
16 . The system of claim 12 , wherein the one or more processors are further configured to execute instructions to illuminate a portion of the model of the heart to indicate the depolarization of a corresponding region of the heart, based on a propagation of activation electrical signals to the region of the heart.
17 . The system of claim 12 , wherein the one or more processors are further configured to execute instructions to:
generate a spatial map for each of the plurality of EGMs, based on a corresponding local activation time and the extrema of the corresponding first order derivative; and
display the generated spatial map for each of the plurality of EGMs on the second portion of the display screen.
18 . The system of claim 12 , wherein the one or more processors are further configured to execute instructions to:
map values of the local activation time and the extrema of the corresponding first order derivative for each of the plurality of EGMs to corresponding one or more points of the heart;
generate an activation map for the heart based on the mapped values; and
recreate the propagation of the depolarization wave to indicate the activation map on the display screen.