Long-term use of an implantable loop recorder for ECG recording in horses.

The study investigates the effectiveness and feasibility of utilizing the Reveal XT cardiac monitor, an implantable loop recorder, for long-term monitoring of cardiac arrhythmias in adult horses. While the monitor proved to be reliable and well-tolerated in the long term, the algorithm designed for human usage could not accurately detect arrhythmic episodes in horses, necessitating manual interpretation of the ECG data.

Introduction and Methodology

• The researchers aimed to evaluate the performance of the Reveal XT cardiac monitor—a loop recorder—for long-term ECG (electrocardiogram) recording in adult horses. This tool has been used in a horse before, but its exact diagnostic capabilities remained unclear.
• The study involved implanting the monitor in 12 horses in a sedated standing position.
• The median duration for data recording was notably extensive, measured at 1,169 days.

Findings and Analysis

• The results indicated a high number of false positives for detections of asystole (absence of heart beats) and bradycardia (slow heart rate).
• The device also inaccurately identified instances of atrial fibrillation, a heart rhythm disorder, with five false positive detections and one false negative detection.
• Despite these shortcomings, the use of the monitor proved to be feasible and reliable for long-term use. Furthermore, the device was well-tolerated among the horses, with no complications recorded.

Conclusion and Implications

• The limitation arises from the device’s human-designed algorithm that failed to accurately detect arrhythmic episodes in horses, requiring manual interpretation of the ECGs.
• Considering the high incidence of false detections and failure to identify bradyarrhythmias, a slow heart rhythm, the study concludes that the monitor is not suitable for determining the causes of episodic collapse in horses.
• So while the implantable loop recorder can be safely and feasibly used for long term, its diagnostic potential for accurately identifying arrhythmias in horses is limited, affecting its broader applicability.