ABSTRACT
All lethal rapidly acting toxins ultimately aect the function of the heart, either directly via eects on the cardiac muscle or the nerve signals controlling contraction, or indirectly by aecting the availability or utilization of oxygen. Longer-acting agents can aect the biochemistry of the body in such a manner so that the heart is no longer able to function. In either case, the cessation of the heartbeat has long (and reasonably so) been considered the hallmark of death. Many postmortem cases can be clearly related to cardiac eects, either by the actions of a toxin (in the absence of natural disease) or natural disease (in the absence of a toxin). However, the challenge the pathologist and toxicologist oen face is to understand and evaluate the role that drugs or toxins may have played in a case, against a background of some degree of underlying disease or pathologic condition. An understanding of the actions of a drug in a case, particularly those with a direct cardiac eect, can be facilitated by a corresponding appreciation for the condition of the heart. An understanding of cardiac function, as well as anatomy and physiology, disease states, and some characteristic pathology, is therefore oen useful and perhaps even essential for the toxicologist. is chapter focuses on the basic structure and function of the heart and the mechanisms of actions of a number of toxins, with consideration of the factors that toxicologists may be interested in or may nd helpful in their casework. While the toxicologist need not bring a physician-level understanding to the disease states of the heart, it is important to be able to interpret the eects of drugs or toxins in the context of any underlying disease or pathology.
