Effects of bee ( Apis mellifera) venom on the electrocardiogram and blood pressure

Abstract

The effects of whole bee venom on the electrocardiogram and systemic blood pressures were investigated in 14 cats and in four dogs. The effect of propranolol on venom action was determined in six animals. High doses of bee venom (above 1 mg per kg) cause an immediate fall in blood pressure to levels of irreversible shock. Three types of changes were noted in the electrocardiogram (ECG): (a) Marked shifts in the ST-T segments. (b) Appearance of various degrees of atrio-ventricular block. (c) Severe ventricular arrhythmias which usually occurred somewhat later than (a) and (b). Propranolol prevented the marked ECG changes described in (a). Following smaller doses of the venom given to the four dogs an initial phase of a significant positive inotropic effect was observed. Thus the rate of left ventricular pressure development increased. Following further doses a general hemodynamic deterioration was observed. Bee venom has a significant positive inotropic effect and enhances ventricular ectopic pacemaker activity. The ECG changes indicate direct damage by some venom components on the myocardial cell membrane. Betablockade with propranolol protects the animal from the ECG changes but leaves it undefended against the severe hemodynamic derangement.