An apparatus for monitoring cardiac function, the apparatus comprising: (a) a plurality of Integrated Cardio Respiratory, orICR, acoustic sensors configured to be positioned on the chest of a patient; (b) a processor coupled to the plurality of ICR acoustic sensors; and (c) a non-transitory memory storing instructions executable by the processor; (d) wherein said instructions, when executed by the processor, perform steps comprising: (i) receiving a phonocardiogram, or PCG, acoustic signal from the plurality of ICR acoustic sensors; (ii) extracting one or more frequency characteristics from the PCG signal with AM-FM decomposition of S1 and S2 events within the PCG acoustic signal to yield a carrier signal with unit amplitude; (iii) calculating R PCSA from the AM-FM decomposition, R PCSA being the ratio between the energy content contained in a high frequency band of the carrier signal relative to that contained in a low frequency band; (iv) segmenting the PCG acoustic signal to locate one or more cardiac events in the PCG acoustic signal; (v) extracting one or more of temporal and amplitude characteristics from the PCG acoustic signal; (vi) classifying the extracted temporal, amplitude and frequency characteristics into one or more subgroups; and (vii) computing ejection fraction, or EF, based on the classified characteristics and calculated R PCSA. (a) a plurality of Integrated Cardio Respiratory, orICR, acoustic sensors configured to be positioned on the chest of a patient; (b) a processor coupled to the plurality of ICR acoustic sensors; and (c) a non-transitory memory storing instructions executable by the processor; (d) wherein said instructions, when executed by the processor, perform steps comprising: (i) receiving a phonocardiogram, or PCG, acoustic signal from the plurality of ICR acoustic sensors; (ii) extracting one or more frequency characteristics from the PCG signal with AM-FM decomposition of S1 and S2 events within the PCG acoustic signal to yield a carrier signal with unit amplitude; (iii) calculating R PCSA from the AM-FM decomposition, R PCSA being the ratio between the energy content contained in a high frequency band of the carrier signal relative to that contained in a low frequency band; (iv) segmenting the PCG acoustic signal to locate one or more cardiac events in the PCG acoustic signal; (v) extracting one or more of temporal and amplitude characteristics from the PCG acoustic signal; (vi) classifying the extracted temporal, amplitude and frequency characteristics into one or more subgroups; and (vii) computing ejection fraction, or EF, based on the classified characteristics and calculated R PCSA. (i) receiving a phonocardiogram, or PCG, acoustic signal from the plurality of ICR acoustic sensors; (ii) extracting one or more frequency characteristics from the PCG signal with AM-FM decomposition of S1 and S2 events within the PCG acoustic signal to yield a carrier signal with unit amplitude; (iii) calculating R PCSA from the AM-FM decomposition, R PCSA being the ratio between the energy content contained in a high frequency band of the carrier signal relative to that contained in a low frequency band; (iv) segmenting the PCG acoustic signal to locate one or more cardiac events in the PCG acoustic signal; (v) extracting one or more of temporal and amplitude characteristics from the PCG acoustic signal; (vi) classifying the extracted temporal, amplitude and frequency characteristics into one or more subgroups; and (vii) computing ejection fraction, or EF, based on the classified characteristics and calculated R PCSA.