Patent ID: 7177681

Claim:
A method comprising: detecting a thoracic impedance of a subject; lowpass filtering the thoracic impedance using a cutoff frequency that is approximately between 0.1 Hz and 0.5 Hz to obtain a resulting baseline thoracic impedance; obtaining the baseline thoracic impedance at first and second times, the second time delayed from the first time; comparing the baseline thoracic impedance at the first time with the baseline thoracic impedance at the second time; if the baseline thoracic impedance at the first time is less than the baseline thoracic impedance at the second time by a magnitude that exceeds a predetermined threshold value, then declaring a first condition to exist; and initiating or adjusting, in response to the first condition, a cardiac resynchronization therapy that coordinates a spatial nature of a depolarization associated with a heart contraction in at least one heart chamber, the cardiac resynchronization therapy comprising at least one of an interventricular delay and an intraventricular delay.