Cardiac arrhythmias are tricky. While some of these heart rhythm irregularities are perfectly normal, in more severe cases they can indicate heart disease and/or cause horses to collapse. But what makes them especially complex is detecting them in the first place. Most of these heart rhythm irregularities are impossible to identify definitively with a stethoscope alone, especially in the resting horse, and owners rarely know if their horses are affected. Veterinarians can diagnose arrhythmias with an electrocardiograph (ECG) machine, but it’s impractical to carry these cumbersome instruments in their trucks. So what’s a vet to do on a farm call?

Bill Gilsenan, VMD, Dipl. ACVIM (LAIM), a practitioner at Rood & Riddle Equine Hospital, in Lexington, Kentucky, offered up an option at the 2017 American Association of Equine Practitioners convention, held Nov. 17-21 in San Antonio, Texas. He described a smartphone-based heart monitor veterinarians can use in the field.

The AliveCor Veterinary Heart Monitor is a handheld wireless portable ECG device that veterinarians can use to evaluate cardiac rhythm. Gilsenan described it as essentially an iPhone case with electrodes on it that transmits an ECG-compatible signal to a phone.

In 2013 Kraus et al. performed a study to validate the monitor in 46 dogs, 23 cats, and 18 horses. All horses’ heart rates were accurate and identical to those measured on a traditional ECG machine