The present invention provides a method for applying external counterpulsation to a patient, including detecting a blood-flow impedance signal, self-adaptive filter processing the detected blood-flow impedance signal, and adjusting inflation of an inflatable member based on the self-adaptive filter processing in order to optimize counterpulsation timing. The present invention further includes an external counterpulsation apparatus providing a high-frequency current source applied to the patient to produce an electrocardiographic signal and a blood flow impedance signal, as well as an amplifier-filter circuit to operably condition the electrocardiographic signal and a heart impedance signal amplifier receiving the blood flow impedance signal. A computer processes the signals and controls a fluid distribution device to distribute compressed fluid to a plurality of inflatable members based on said processed signals.