Patent ID: 8478402

Claim:
A method comprising: propagating a modulated signal across a myocardium; detecting an outputted modulated signal from the myocardium; using at least one circuit to reduce the influence of process noise in the outputted modulated signal, wherein the at least one circuit reduces the influence of process noise by at least: amplifying the outputted modulated signal to produce a second outputted modulated signal; demodulating the second outputted modulated signal to produce a third outputted modulated signal; and passing the third outputted modulated signal through an integrator to produce a fourth outputted modulated signal; determining an amplitude and phase of the fourth outputted modulated signal, the amplitude and the phase indicating a complex impedance of the myocardium; monitoring the indication of complex impedance for complex impedance patterns of the myocardium; and based on changes in complex impedance patterns of the myocardium, providing an indication of cardiac function, wherein the cardiac function is at least one of contractility, capture detection, atrium-ventricle optimization, right ventricular function, left ventricular function, cardiac output, or right to left ventricular synchronization.