Cardiac performance monitoring system for use with mobile communications devices
Described herein are apparatuses (e.g., devices, systems, software), and methods for monitoring the cardiac health of a patient. The apparatuses and methods may include a smartphone or hand held computing device having an accelerometer. The apparatus may also include a device with a plurality of electrodes integral with or attached to the smartphone. The devices can be placed on a patient's chest to measure electrical signals and vibrations on the chest caused by the heartbeat. The measurements can generate a seismocardiogram (SCG) and in some variations an electrocardiogram (ECG). The apparatuses and methods can analyze the data in the SCG to produce a measure of the cardiac function. Changes in such measures can provide an early warning for potential cardiac problems and signal the need for the patient to seek treatment prior to a fatal cardiac event.
1. A non-transitory computer-readable storage medium storing a set of instructions capable of being executed by a smartphone having an accelerometer, that, when executed by the smartphone, causes the smartphone to record both a seismocardiogram (SCG) from the smartphone's accelerometer by detecting vibrations on a patient's chest corresponding to heart motion for a first time period and to detect an electrocardiogram (ECG) from the patient's chest, further wherein the set of instructions, when executed by the smartphone, cause the smartphone to do at least one of: analyze the SCG to determine an index of cardiac function, display the SCG, transmit the SCG, store the SCG, display the ECG, transmit the ECG, or store the ECG.
2. The non-transitory computer-readable storage medium of claim 1 , further wherein the set of instructions, when executed by the smartphone, causes the smartphone to concurrently record the SCG and detect the ECG from the patient over the first time period.
3. The non-transitory computer-readable storage medium of claim 1 , further wherein the set of instructions, when executed by the smartphone, causes the smartphone to analyze the SCG to determine the index of cardiac function by determining a Tei index or a modified Tei index.
4. The non-transitory computer-readable storage medium of claim 1 , further wherein the set of instructions, when executed by the smartphone, causes the smartphone to determine an index using an interval between cessation and onset of the mitral inflow and an ejection time (ET) of the left ventricular outflow.
5. The non-transitory computer-readable storage medium of claim 1 , wherein the set of instructions, when executed by the smartphone, causes the smartphone to identify two or more characteristic regions of the SCG from the regions consisting of: mitral valve closure, isovolumetric contraction, aortic valve opening, rapid ejection, aortic valve closure, mitral valve opening, and rapid filling.
6. The non-transitory computer-readable storage medium of claim 1 , wherein the set of instructions, when executed by the smartphone, causes the smartphone to identify two or more characteristic regions of the SCG using an electrocardiogram (ECG) that is taken over the first time period.
7. The non-transitory computer-readable storage medium of claim 1 , wherein the set of instructions, when executed by the smartphone, causes the smartphone to instruct the patient to position the smartphone against the patient's chest prior to recording the SCG.
8. The non-transitory computer-readable storage medium of claim 1 , wherein the set of instructions, when executed by the smartphone, causes the smartphone to verify the orientation of the smartphone and notify the user if the orientation of the smartphone during the first time period was incorrect.
9. The non-transitory computer-readable storage medium of claim 1 , wherein the set of instructions, when executed by the smartphone, causes the smartphone to identify multiple SCG cycles taken during first time period and to average the multiple SCG cycles.
10. The non-transitory computer-readable storage medium of claim 1 , wherein the set of instructions, when executed by the smartphone, causes the smartphone to identify multiple SCG cycles using an electrocardiogram (ECG) that was taken over the first time period.
11. A method of determining an index of cardiac function for a patient using a smartphone having an accelerometer, the method comprising:
placing the smartphone on the patient's chest;
recording a seismocardiogram (SCG) for a first time period using the smartphone's accelerometer;
detecting an ECG using the smartphone;
analyzing the SCG and to determine an index of cardiac function; and
performing one or more of: displaying the SCG, transmitting the SCG, storing the SCG, displaying the ECG, transmitting the ECG, or storing the ECG.
12. The method of claim 11 , further wherein recoding the SCG and detecting the ECG are both performed over the first time period.
13. The method of claim 11 , wherein placing the smartphone on the patient's chest comprises the patient placing the smartphone on the patient's own chest.
14. The method of claim 11 , further comprising using the smartphone to verify the orientation of the smartphone on the patient's chest before or during the first time period.
15. The method of claim 11 , further comprising transmitting the SCG and ECG to a processor remote to the smartphone for analysis.
16. The method of claim 11 , wherein analyzing the SCG to determine an index of cardiac function comprises analyzing the SCG using the smartphone to determine one or more characteristic times including one or more of: mitral valve closure (MC), aortic valve opening (AO), Aoritc valve closure (AC) and mitral valve opening (MO), isolvolumetric contraction time (ICT) rapid ejection (RE), rapid filling (RF).
17. The method of claim 11 , wherein analyzing the SCG to determine an index of cardiac function comprises identifying multiple SCG cycles taken during first time period and averaging the multiple SCG cycles.
18. The method of claim 11 , wherein analyzing the SCG to determine an index of cardiac function comprises identifying multiple SCG cycles taken during the first time period using the ECG.
19. The method of claim 11 , wherein analyzing the SCG to determine an index of cardiac function comprises using an interval between cessation and onset of the mitral inflow and an ejection time (ET) of the left ventricular outflow to determine an index.
20. The method of claim 11 , wherein analyzing the SCG to determine an index of cardiac function comprises determining a Tei index or a modified Tei index.