Smart Phones: The Future of Cardiac Monitors?

AliveCor cardiac monitors, which record and transmit cardiac rhythms to a smart phone, are inexpensive and readily available devices that should be further explored, according to a clinical review published in JAMA Internal Medicine.

Researchers from Beth Israel Deaconess Medical Center reviewed a case study of a 62-year-old male patient with no prior medical problems. The man suddenly began experiencing episodes of exertional near syncope and syncope, though the symptoms were not linked to any prodromal symptoms. Various standard tests were unhelpful, so the patient’s primary care physician advised the purchase of the AliveCor device, which recorded up to 6 seconds of tachycardia during an episode of near syncope.

Initially, the patient’s episodes were interpreted as polymorphic ventricular tachycardia (VT) or ventricular fibrillation (VF). Later, he was thought to have idiopathic VF and was urged to consider an implantable cardioverter defibrillator (ICD). However, AliveCor was not established as an aid in clinical decisions such as these, so he decided to undergo further diagnostics. The patient avoided an implantation of the ICD; the researchers believe that the tracings recorded by the AliveCor device were runs of right ventricular outflow tract (RVOT) VT with superimposed artifact due to inconsistent contact with the device.

AliveCor — which is approved by the US Food and Drug Administration (FDA) and can be purchased without a prescription – can record up to a 30-second single lead rhythm strip, which the researchers believe can be a valuable tool. In a small study of healthy conference attendees, a quarter of the patients followed up with a physician for further evaluation due to the device’s results and 16% of patients believed the device helped them discover a new health problem.

Another study demonstrated that the device had a sensitivity of 94-100% and can correctly detect atrial fibrillation with an accuracy of 91-95%. However, detections of monomorphic VT, polymorphic VT, and VF are limited. Sometimes the results are skewed due to poor contact with the device’s electrodes, or interference if a patient’s fingertips are moistened prior to use.

One limitation of the device is that it can only be used if the patient is available to activate it — patients with short lived symptoms won’t have any significant effect on the device. In cases like these, or where monitoring with adhesive electrodes is undesirable or impractical, ICD is a better alternative, the researchers noted. One suggestion the authors had proposed for this scenario was the

Medtronic LINQ (Medtronic), a paperclip sized device implanted in the chest, which can continuously monitor patients’ cardiac rhythm for up to 3 years with various other features.

Smart phones as cardiac monitors are on the rise, the authors believed, however they cautioned that right now, current devices’ abilities are limited.