A cardiac pacing system comprising: a pulse generator including a housing , the pulse generator configured to generate pacing pulses to a heart of a patient; at least one lead , wherein a proximal end of the at least one lead is configured to electrically couple with the pulse generator, the at least one lead including an electrode; a first sensor configured to monitor a physiological characteristic of the patient; a second sensor configured to monitor a second physiological characteristic of the patient; an accelerometer configured to monitor mechanical movement of the heart; and a controller configured to: determine a pacing vector based on variables including signals received from the first sensor and the second sensor; cause the pulse generator to deliver the therapeutic electrical pulses according to the determined pacing vector; identify mechanical heart deflections following delivery of a pacing pulse using an accelerometer signal; gradually reduce energy levels of the pacing pulses until a mechanical heart deflection is no longer identified and loss of cardiac capture is suspected; increase energy levels of the pacing pulses until cardiac capture is regained; set a new determined energy level with a specific safety margin of additional energy, as a new default pacing pulse energy level. a pulse generator including a housing , the pulse generator configured to generate pacing pulses to a heart of a patient; at least one lead , wherein a proximal end of the at least one lead is configured to electrically couple with the pulse generator, the at least one lead including an electrode; a first sensor configured to monitor a physiological characteristic of the patient; a second sensor configured to monitor a second physiological characteristic of the patient; an accelerometer configured to monitor mechanical movement of the heart; and a controller configured to: determine a pacing vector based on variables including signals received from the first sensor and the second sensor; cause the pulse generator to deliver the therapeutic electrical pulses according to the determined pacing vector; identify mechanical heart deflections following delivery of a pacing pulse using an accelerometer signal; gradually reduce energy levels of the pacing pulses until a mechanical heart deflection is no longer identified and loss of cardiac capture is suspected; increase energy levels of the pacing pulses until cardiac capture is regained; set a new determined energy level with a specific safety margin of additional energy, as a new default pacing pulse energy level. determine a pacing vector based on variables including signals received from the first sensor and the second sensor; cause the pulse generator to deliver the therapeutic electrical pulses according to the determined pacing vector; identify mechanical heart deflections following delivery of a pacing pulse using an accelerometer signal; gradually reduce energy levels of the pacing pulses until a mechanical heart deflection is no longer identified and loss of cardiac capture is suspected; increase energy levels of the pacing pulses until cardiac capture is regained; set a new determined energy level with a specific safety margin of additional energy, as a new default pacing pulse energy level. <EOS>