Effects of Intravenous Propranolol on Human Ventricular Strength Interval Curves

摘要: BACKGROUND Prior studies on the effects of propranolol human ventricular refractoriness have yielded occasionally inconsistent results. Most prior examined refractory periods at a single stimulus intensity and without using continuous pacing; thus, repolarization may not been completely defined. The purpose present study was to reevaluate beta blockade effective period. METHODS Strength-interval curves were performed in duplicate group 10 patients demonstrate their reproducibility. before after intravenous administration second who had no evidence structural heart disease. RESULTS Propranolol increased absolute period from 208 +/- 9 milliseconds 212 (p = 0.01). However, decreased coupling interval which strength-interval curve began show an increase required for capture 236 8 232 milliseconds. This resulted decrease width 28.0 5.1 20.4 5.5 < 0.005). also significantly slope logarithmic fit curves. CONCLUSION exerts complex refractoriness. decreases increases curve, rather than increasing or decreasing These results potential implications antiarrhythmic propranolol.