Implantation of a dual-chamber, rate-adaptive pacemaker in a horse with suspected sick sinus syndrome.

The research focuses on the treatment of a horse suffering from a suspected case of sick sinus syndrome, a condition affecting the rhythm of the heart. The study details the successful implementation of a dual-chamber, rate-adaptive pacemaker that eliminated symptoms of the syndrome and facilitated the horse’s return to normal activity.

Introduction and Symptoms

• The study revolves around a five-year-old gelding horse that experienced fainting spells or syncope, specifically following a session of physical exercise. These incidences led to a suspicion of a health problem related to the rhythm of the horse’s heart.

Diagnosis

• The diagnostic tool used in this investigation was a 24-hour electrocardiogram recording. This measurement assists with the detection of irregularities in heart rhythmic pattern or sinus rhythm.
• The electrocardiogram in this context revealed the occurrence of intermittent pauses in the sinus rhythm of the gelding, lasting up to 10 seconds. These periods of inactivity implied a disorder of the sinus node, the heart’s natural pacemaker which initiates heart beats.
• These pauses, signaling a case of sick sinus syndrome, were frequently recorded post-exercise. Sick sinus syndrome is a collection of heart rhythm disorders or arrhythmias.

Treatment

• Treatment involved the implantation of a dual-chamber, rate-adaptive pacemaker in the horse. This kind of pacemaker can simultaneously manage the pace of both the upper and lower chambers of the heart, adjusting the heart rate depending on the body’s needs. This device is regularly used in human patients diagnosed with similar health issues.
• The pacemaker regulated the heart rhythm, preventing the excessive slowing of the heart rate or bradycardia, and resultant syncope the horse had been experiencing following exercise.

Conclusion

• The treatment was considered successful as after the implantation of the pacemaker, the gelding horse was able to return to its routine physical activity. This indicates that the pacemaker was effective in managing and eliminating the observed symptoms of the sick sinus syndrome.