Hemodynamic and autonomic effects of smokeless tobacco in healthy young men
Robert Wolk, MD, PhD*,
Abu S.M. Shamsuzzaman, MBBS, PhD*,
Anna Svatikova, BA*,
Christine M. Huyber*,
Corey Huck, BA*,
Krzysztof Narkiewicz, MD, PhD and
Virend K. Somers, MD, PhD, FACC*,*
* Mayo Clinic, Rochester, Minnesota
Medical University of Gdansk, Gdansk, Poland
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Figure 1 Changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), and peripheral vascular resistance (PVR) during the placebo and tobacco sessions. *p < 0.001. Despite a 10-mm Hg increase in blood pressure, HR increased strikingly during tobacco use, with no change in PVR.
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Figure 2 Changes in muscle sympathetic nerve activity (MSNA), plasma norepinephrine (Norepi), and epinephrine (Epi) during the placebo and tobacco sessions. Despite increased arterial pressure during tobacco use (Fig. 1), there was no difference in MSNA or Norepi, but a clear increase in Epi.
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Figure 3 Systolic blood pressure (SBP), heart rate (HR), and muscle sympathetic nerve activity (MSNA) responses after snuff tobacco (n = 10) as compared to phenylephrine infusion (in the absence of chewing tobacco) (n = 8). Heart rate increased during tobacco, but decreased with phenylephrine. Despite increased blood pressure during tobacco, there was no significant decrease in MSNA, although MSNA was virtually eliminated during phenylephrine. Faster HR and minimal MSNA suppression, despite the similar blood pressures with spit tobacco use compared to phenylephrine, suggest a potent cardiac and vascular excitatory effect of spit tobacco, which overcomes the cardiac and sympathetic inhibitory influences of baroreflex activation in response to the rise in blood pressure.
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Figure 4 (A) Recordings of electrocardiogram (EKG), blood pressure (BP), muscle sympathetic nerve activity (MSNA), and respiration at baseline and after spit tobacco. Despite increased BP with tobacco use, heart rate (HR) increases, and MSNA is not suppressed. Contrast this with panel B showing the same measurements at baseline and after raising blood pressure using phenylephrine. With phenylephrine, there is a slowing of HR and a complete elimination of MSNA because of baroreflex activation.
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