Author + information
- Allyn L. Mark, MD*
- ↵*Address for reprints: Allyn L. Mark, MD, Cardiovascular Division, Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242.
The concept of depressor reflexes originating in the heart was introduced by von Bezold in 1867 and was later revived by Jarisch. The Bezold-Jarisch reflex originates in cardiac sensory receptors with nonmyelinated vagal afferent pathways. The left ventricle, particularly the inferoposterior wall, is a principal location for these sensory receptors. Stimulation of these inhibitory cardiac receptors by stretch, chemical substances or drugs increases parasympathetic activity and inhibits sympathetic activity. These effects promote reflex bradycardia, vasodilation and hypotension (Bezold-Jarisch reflex) and also modulate renin release and vasopressin secretion. Conversely, decreases in the activity of these inhibitory sensory receptors reflexly increase sympathetic activity, vascular resistance, plasma renin activity and vasopressin.
Long regarded as pharmacologic curiosities, it is now clear that reflexes originating in these inhibitory cardiac sensory receptors are important to the pathophysiology of many cardiovascular disorders. This paper reviews the role of inhibitory cardiac sensory receptors in several clinical states including 1) bradycardia, hypotension and gastrointestinal disorders with inferoposterior myocardial ischemia and infarction, 2) bradycardia and hypotension during coronary arteriography, 3) exertional syncope in aortic stenosis, 4) vasovagal syncope, 5) neurohumoral excitation in chronic heart failure, and 6) the therapeutic effects of digitalis.
The research by the author and his colleagues which is reviewed in this paper was supported by Grants HL-14388 and HL-24962 from the National Heart, Lung, and Blood Institute, by Grant MO-1RR-59 from the General Clinical Research Centers Program, National Institutes of Health, Bethesda, Maryland; by research funds from the Veterans Administration, Washington, D.C.; and by grants-in-aid from the Iowa Heart Association, Des Moines, Iowa.
- American College of Cardiology Foundation