Roberta Barone

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1 INTRODUCTION The concept of a frequency-based positive inotropic response of the heart (Bowditch effect, staircase phenomenon, or Treppe phenomenon) was first explained in 1871 by the physiologist, Henry Pickering Bowditch after he stimulated a resting frog's ventricular apex.1 An increase in heart rate (HR) leads to positive inotropic and lusitropic effects, with an increase in peak tension and abbreviation of relaxation time in a normal cardiac muscle.

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