A system, comprising: sensor circuits including sense amplifier circuits (212, 214) to sense a first physiological signal and a second physiological signal different from the first physiologic signal; a signal processor circuit configured to generate a first signal metric from the first physiological signal and a second signal metric from the second physiological signal; a risk stratifier circuit configured to produce a risk indication indicating a cardiac risk of the patient; a detector circuit coupled to the signal processor circuit and the risk stratifier circuit, the detector circuit configured to: generate a primary detection indication of a presence or absence of a worsening cardiac event using at least the first signal metric; modulate the second signal metric using the risk indication; generate a secondary detection indication of a presence or absence of the worsening cardiac event using at least the modulated second signal metric; and detect the worsening cardiac event using the primary and secondary detection indications; and an output circuit configured to generate an alert in response to the detection of the worsening cardiac event; wherein the first signal metric includes a heart sound signal metric and the second signal metric includes a respiratory signal metric, wherein the heart sound signal metric includes a third heart sound intensity or a ratio of a third heart sound intensity to a reference heart sound intensity; and wherein the respiratory signal metric includes a respiration rate measurement, a tidal volume measurement, or a ratio of the respiration rate to the tidal volume measurement. sensor circuits including sense amplifier circuits (212, 214) to sense a first physiological signal and a second physiological signal different from the first physiologic signal; a signal processor circuit configured to generate a first signal metric from the first physiological signal and a second signal metric from the second physiological signal; a risk stratifier circuit configured to produce a risk indication indicating a cardiac risk of the patient; a detector circuit coupled to the signal processor circuit and the risk stratifier circuit, the detector circuit configured to: generate a primary detection indication of a presence or absence of a worsening cardiac event using at least the first signal metric; modulate the second signal metric using the risk indication; generate a secondary detection indication of a presence or absence of the worsening cardiac event using at least the modulated second signal metric; and detect the worsening cardiac event using the primary and secondary detection indications; and generate a primary detection indication of a presence or absence of a worsening cardiac event using at least the first signal metric; modulate the second signal metric using the risk indication; generate a secondary detection indication of a presence or absence of the worsening cardiac event using at least the modulated second signal metric; and detect the worsening cardiac event using the primary and secondary detection indications; and an output circuit configured to generate an alert in response to the detection of the worsening cardiac event; wherein the first signal metric includes a heart sound signal metric and the second signal metric includes a respiratory signal metric, wherein the heart sound signal metric includes a third heart sound intensity or a ratio of a third heart sound intensity to a reference heart sound intensity; and wherein the respiratory signal metric includes a respiration rate measurement, a tidal volume measurement, or a ratio of the respiration rate to the tidal volume measurement.