A technique for production of complete atrioventricular block in dogs

A simple and reliable technique for producing complete atrioventricular (AV) block in dogs by the injection of a 38% formaldehyde solution into the area of the AV node is described. This technique, a modification of previous methods utilizing formaldehyde injection for the production of complete AV block, uses the coronary sinus as the major landmark. Complete heart block was produced in 20 of 20 dogs. The technique is simple and associated with few problems, does not require special equipment, is associated with little or no hemorrhage from the injection site, and does not enter a cardiac chamber. The only side effect noted was the development of ventricular arrhythmias in 2 of 20 dogs. A detailed description of the technique is included with comparisons to previous techniques utilizing injection of a 40% formaldehyde solution.