<p>In general, the disclosure describes techniques for storing data corresponding to sensed high-rate non-sustained episodes that occur close in time to detection of a lead integrity condition. A method comprises detecting a first high-rate non-sustained episode, activating a data storage operation for storing data associated with high rate non-sustained episodes in response to detecting the first episode, and storing data associated with the first episode in an episode log in response to activating the data storage operation. Another method comprises detecting a lead integrity condition, and activating a data storage operation for storing data associated with high rate non-sustained episodes in response to detecting the condition.</p>
