Methodology involving assessing, and applying therapy regarding, degree of ischemia and risk for sudden cardiac death in a therapy-device-equipped subject utilizing a Holter-type instrumentality. The methodology includes (a) gathering simultaneous ECG and heart-sound data, (b) computer processing and interrelating the gathered data to obtain one or more heart-functionality parameter(s), focusing on LDPT and % LVST, and (c), using these obtained parameters, adjusting, as necessary, the therapy device so as to minimize and counteract the likelihood of the onset or advancement of ischemia, and/or the onset of sudden cardiac death.