The purpose of this research was to evaluate, in human subjects, the degree to which pulse transit time (PTT) covaries with systolic (SBP) and diastolic (DBP) blood pressure, and the degree to which PTT is sensitive to sympathetic influences on myocardial performance. Six studies were performed involving 118 young adult males. In all subjects, cardiovascular activity was assessed in both the resting state and during three stressors: the cold pressor, a pornographic movie and unsignaled shock avoidance reaction time task. The studies differed with respect to where on the arterial tree the pulse wave was transduced, whether blood pressure was measured invasively or noninvasively, and whether the myocardial sympathetic innervations were intact or not. It was observed that PTT covaried quite consistently with SBP but very inconsistently with DBP. The degree of covariation was influenced by the individual's reactivity and, with DBP, by the type of stress. PTT was appreciably influenced by myocardial sympathetic excitation and to a lesser degree by vascular processes. The use of PTT as an index of blood pressure and myocardial performance is discussed.

The relationships between pulse transit time (PTT) and both systolic (SBP) and diastolic blood pressure (DBP) were evaluated in 114 human subjects during rest and stress. PTT was found to covary quite consistently with SBP, but not with DBP, when blood pressure was measured both noninvasively and invasively. Pharmacological blockade of the sympathetic innervation of the heart appreciably attenuated the relationship between PTT and SBP.

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A 34‐year‐old woman presented with an unusual and unfortunate combination of complications to a phenothiazine drug. Rhythmic protrusion of her tongue was not a problem until it became trapped outside of her oral cavity by spasm of the muscles of mastication. Massive edema with questionable viability of her tongue ensued. She presented as an airway as well as therapeutic management problem.