Ventricular arrhythmias in cardiac anaphylaxis

Area of Science:

• Cardiovascular Physiology
• Pharmacology
• Immunology

Background:

• Anaphylaxis can cause cardiac arrhythmias.
• Histamine is a key mediator in anaphylaxis and may contribute to cardiac effects.

Purpose of the Study:

• To investigate the arrhythmogenic effects of anaphylaxis and histamine on cardiac electrophysiology.
• To determine the mechanisms underlying histamine-induced arrhythmias.

Main Methods:

• Studied guinea pig papillary muscles to measure transmembrane potentials.
• Induced anaphylaxis via antigenic challenge in sensitized animals.
• Administered exogenous histamine and various pharmacological agents.

Main Results:

• Antigenic challenge induced ventricular automaticity in 1/3 of experiments.
• Exogenous histamine reproduced the arrhythmogenic effects of cardiac anaphylaxis.
• Histamine shortened the effective refractory period and increased arrhythmias at high Ca2+.
• Histamine H2-receptor antagonist burimamide and prajmalium bitartrate inhibited spontaneous ventricular activity.

Conclusions:

• Histamine plays a significant role in the arrhythmogenic effects of cardiac anaphylaxis.
• Specific H2-receptor antagonism and certain antiarrhythmic drugs can mitigate histamine-induced arrhythmias.