Key result
Pharmacologic autonomic blockade with propranolol and atropine significantly shortened right ventricular monophasic action potential duration from 269 msec to 256 msec compared to baseline.
Why the study?
Does sequential administration of propranolol and atropine alter monophasic action potential duration and effective refractory period in the human ventricle and atrium?
Does sequential administration of propranolol and atropine alter monophasic action potential duration and effective refractory period in the human ventricle and atrium?
Absolute Event Rate: 256% vs 269%
p-value: p=<0.005
In the human ventricle, parasympathetic and sympathetic tones act antagonistically with parasympathetic dominance, whereas in the atrium they act in the same direction with weaker direct parasympathetic effects.
Site-specific MAPD/ERP responses to propranolol and autonomic blockade in 11 patients; leaves open any role in arrhythmia management pending larger studies.
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Shimizu et al. (1993) studied Arrhythmia undergoing electrophysiological study (n=11). Propranolol followed by atropine (autonomic blockade) vs. Baseline was evaluated on Right ventricular 90% monophasic action potential duration (RV MAPD90) (p=<0.005). Pharmacologic autonomic blockade with propranolol and atropine significantly shortened right ventricular monophasic action potential duration from 269 msec to 256 msec compared to baseline.
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