US 11,730,441 B2
Methods and devices for detecting heart sounds to monitor cardiac function
Xiaoyi Min, Simi Valley, CA (US); Kyungmoo Ryu, Palmdale, CA (US); and Stephanie C. Sun, Simi Valley, CA (US)
Assigned to Pacesetter, Inc., Sylmar, CA (US)
Filed by PACESETTER, INC., Sylmar, CA (US)
Filed on Aug. 7, 2018, as Appl. No. 16/57,650.
Prior Publication US 2020/0046312 A1, Feb. 13, 2020
Int. Cl. A61B 7/04 (2006.01); A61B 5/00 (2006.01); A61N 1/365 (2006.01); A61B 7/02 (2006.01); A61B 5/0205 (2006.01); A61N 1/02 (2006.01); A61B 5/08 (2006.01); A61B 5/113 (2006.01); A61N 1/39 (2006.01); A61N 1/372 (2006.01)
CPC A61B 7/04 (2013.01) [A61B 5/0205 (2013.01); A61B 5/686 (2013.01); A61B 5/725 (2013.01); A61B 5/7282 (2013.01); A61B 7/023 (2013.01); A61N 1/36514 (2013.01); A61N 1/36585 (2013.01); A61B 5/0809 (2013.01); A61B 5/0816 (2013.01); A61B 5/113 (2013.01); A61B 2562/0219 (2013.01); A61B 2562/0247 (2013.01); A61N 1/025 (2013.01); A61N 1/37211 (2013.01); A61N 1/39622 (2017.08)] 18 Claims
OG exemplary drawing
 
1. An implantable medical device (IMD), comprising:
one or more sensors configured to be implanted in a subject and to sense heart sound signals of the subject;
a respiration sensor configured to sense respiration signals of the subject;
a memory configured to store program instructions; and
a processor that, when executing the program instructions, is configured to:
identify S2 signal segments from the heart sound signals;
analyze the S2 signal segments to identify corresponding pulmonary valve signals (P2 signals) and aortic valve signals (A2 signals);
identify expiration and inspiration phases from the respiration signals;
determine an expiration time interval between the corresponding A2 and P2 signals during the expiration phase;
determine an inspiration time interval between the corresponding A2 and P2 signals during the inspiration phase;
characterize the S2 signal segments to exhibit a first type of S2 split based on a relation between the expiration and inspiration time intervals; and
identify a cardiac condition based on the first type of the S2 split, where the cardiac condition is utilized to determine at least one of a therapy or change in therapy for the subject.