Systems and methods for detecting atrial tachyarrhythmia using heart sounds

A method, comprising:

• determining, using a first signal metric generator circuit, a first beat-to-beat cardiac cycle length or heart rate and a second beat-to-beat cardiac cycle length or heart rate in a patient;
• generating, using the first signal generator circuit, a cardiac timing variation between the first beat-to-beat cardiac cycle length or heart rate and the second beat-to-beat cardiac cycle length or heart rate;
• generating, using a second signal metric generating circuit, an S4 heart sound metric using heart sound information of the patient, the S4 heart sound metric including an indication of absence of S4 heart sound in a cardiac cycle;
• and
• detecting, using an atrial tachyarrhythmia (AT) detector circuit, an AT event of the patient using the generated cardiac timing variation and the S4 heart sound metric.

A system, comprising:

• a first signal metric generator circuit configured to determine a first beat-to-beat cardiac cycle length or heart rate and a second beat-to-beat cardiac cycle length or heart rate in a patient, and to generate a cardiac timing variation between the first beat-to-beat cardiac cycle length or heart rate and the second beat-to-beat cardiac cycle length or heart rate;
• a second signal metric generator circuit configured to generate an S4 morphology matching score with reference to an S4 template, and to determine a presence of S4 heart sound if the S4 morphology matching score exceeds an S4 metric threshold, or an absence of S4 heart sound if the S4 morphology matching score falls below the S4 metric threshold;
• and
• an atrial tachyarrhythmia (AT) detector circuit configured to detect an AT event of the patient in response to (1) the generated cardiac timing variation satisfying a first condition, and (2) the determined absence of S4 heart sound.