A vibratory attachment interface enabling transmission of oscillations generated by an oscillation source upon an external human body surface. The interface comprises a first contact node and a second contact node slideably mounted alongside the first contact node, wherein the contact nodes are each sized and shaped to enable seating within a human rib-space, and whereby upon forced engagement of the first contact node within a first rib-space, the second contact node automatically slides and conforms to the contour of a second differing rib-space thereby optimally nestling within the second rib-space. The attachment interface is for use in contoured application to preferably the anatomic left sternal border, third and fourth intercostal space, such as to enable and ensure an optimized vibratory transmission pathway from the chest wall to the base of the heart and coronary arteries thereupon.