Use of a new electrocardiogram (ECG) technique to detect an abnormal heart rhythm called paroxysmal atrial fibrillation (PAF) has been described in Nature Scientific Reports (Alexeenko et al., 2020). PAF causes rapid, erratic heartbeats in horses and is also a major cause of stroke in humans. The abnormal rhythm is intermittent, and therefore often very difficult to diagnose, but it can impact on a horse’s racing performance and, in some cases, prove fatal.
The researchers developed a rapid and inexpensive technique to identify PAF using complexity analysis of apparently normal sinus-rhythm ECGs. Sixty-second ECG recording strips were obtained from 82 healthy horses and 10 horses with a prior diagnosis of PAF and converted to a string of computational numbers using a range of detection algorithms. ECG results recorded at rest (low heart rate of 25bpm to 60bpm) and processed by the novel detection method were found to be significantly different between horses with and without PAF. Horses with PAF were diagnosed with high accuracy. What is surprising about this study is that PAF is typically triggered by high heart rate but could be diagnosed by this method looking at low heart rate recordings of normal heart rhythms. Horses did not need to be exercised to induce the arrhythmia and the analysis could be done in minutes, using low power computers.
In humans, PAF can be dangerous as it can cause disruption of blood flow in the upper two chambers of the heart (atria), which can lead to the formation of blood clots. These clots can block blood vessels elsewhere in the body, including the brain causing a stroke. Early detection of PAF is important to prevent these serious consequences. Electrical stimulation or anti-arrhythmic drugs can be used to restore the normal heart rhythm, and anti-coagulation drugs can help prevent formation of blood clots preventing strokes or greatly reducing their effects.
Alexeenko, V., Fraser, J.A., Bowen, M. et al. The complexity of clinically-normal sinus-rhythm ECGs is decreased in equine athletes with a diagnosis of paroxysmal atrial fibrillation. Sci Rep 10, 6822 (2020). Available HERE