Implantation of a permanent transvenous pacing catheter in a horse with complete heart block and syncope.

The researchers were able to successfully implant a permanent pacing system in a horse with a severe heart condition. This allowed the horse to return to its regular activities.

Objective of the Study

The objective of the study was to establish the feasibility of implanting a permanent, transvenous, atrioventricular, sequential pacing system in a horse with complete heart block. The researchers aimed to test if this method could help restore the horse’s normal heart function, allowing it to resume its competitive career.

Study Methodology

• The study used a 7-year-old Quarter Horse gelding that was suffering from a complete heart block, a severe condition where the electrical signal is entirely blocked from reaching the heart’s lower chambers (the ventricles).
• The researchers performed surgery on the horse to implant a transvenous atrial and ventricular electrodes. This was a delicate process that required the use of real-time, two-dimensional echocardiography. Echocardiography is a type of ultrasound that uses sound waves to create detailed pictures of the heart, allowing the surgical team to accurately place the electrodes in their respective positions in the heart.

Results of the Study

• After the successful surgery, the permanent pacing system started sending electrical signals to stimulate the horse’s heart, effectively bypassing the blockage and imitating the normal pulsing of the heart.
• The researchers saw an improvement in the horse’s condition as its heart could now beat effectively and pump blood throughout its body.
• Following recovery from the surgery, the horse was able to return to its competitive activities as a show horse. This successful return to activity suggests that not only did the pacing system effectively fix the heart block but it didn’t impact the horse’s performance or quality of life.

Implications of the Study

• This successful experiment sets a precedent in veterinary medicine – it shows that it is indeed possible to treat complete heart block in horses through an implantable pacemaker system.
• It opens the field to further studies on how permanent pacing systems can be applied to other large animals with similar heart problems, possibly improving their lifespans and quality of life.