Crowd-Sourcing Syncope Diagnosis: Mobile Smartphone ECG Apps
A 76-year-old gentleman with a history of hypertension, on low-dose lisinopril, had a witnessed syncopal episode. He fainted from a standing position with no prodrome. He was unresponsive for 15 seconds without epileptiform activity or loss of sphincter control. He quickly regained consciousness with mild disorientation, without additional symptoms or focal deficits. A cardiologist at the event had just purchased the AliveCor (San Francisco, Calif.) smartphone portable electrocardiogram (ECG) device and quickly applied it. It showed a single limb lead (II) with sinus tachycardia, complete heart block, and a narrow escape rhythm of 54 beats per minute. En route to the hospital, the relevant team members on call were identified via the Amion app (Amion, Newton, Mass.), and the tracing was e-mailed from the AliveCor app. At the Emergency Department, the ECG had normalized and all investigations were normal, including an echocardiogram. He underwent dual-chamber pacemaker placement with no further issues.
Syncope is one of the most common presentations to the Emergency Department. Underlying diagnoses can range from benign to life threatening. Often, the application of expensive diagnostic tests is fruitless and leads to protracted attempts at outpatient diagnosis. During this period, limitations to patients’ activity are often recommended, with potential occupational implications. A 12-lead ECG and telemetry monitoring is standard of care. Obtaining an ECG when the patient is symptomatic is critical, as the presence of an arrhythmia usually suggests causality and quickly guides therapy. However, the ability to capture an offending arrhythmia is a rare phenomenon, with the physician commonly resorting to monitoring devices. The array of available clinically prescribed monitoring devices ranges from external wearable to long-term, implanted monitors. Unfortunately, the cost and inconvenience of these monitors are significant, and patients may be reluctant to undergo invasive procedures. Compliance with long-term monitoring has been shown to be as low as 53% over a 6-month period.
With nearly 60% of the US population using smartphones, there is increasing interest in applying this technology to remote ECG monitoring. The AliveCor Heart Monitor is a US Food and Drug Administration-approved portable ECG monitoring device that comes in the form of a smartphone case or attachment and is compatible with Apple and Android devices. It is an easy-to-use, convenient option and consists of 2 electrodes that the user contacts with their fingertips. The electrical impulses are converted into ultrasound signals, transmitted to the microphone of the smartphone. In combination with the app that comes free with the device, real-time single-lead ECG monitoring up to 30 seconds can be recorded during a symptomatic episode. These tracings can be reviewed on the device or stored and e-mailed for interpretation. The high fidelity of the monitor and arrhythmia detection capability has been documented in several studies. Because it is primarily patient triggered, it is difficult to capture asymptomatic arrhythmias, and has a limited role in syncope without warning symptoms, unless captured by bystanders, as illustrated in this case. It costs < $100 USD per device. With such a low price point, the potential of widespread use may usher in a new era of democratized, crowd-sourced, syncope diagnostic capability.
Without the use of the app, our patient would likely not have had a definitive diagnosis and undergone low-yield, high-cost investigations. Our case illustrates the power of such an app and hints at the future disruptive paradigm shift in syncope diagnosis. We should embrace this brave, new world.
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-Iwan Nyotowidjojo, MD, Robert P. Erickson, MD, Kwan S. Lee, MD
This article originally appeared in the April 2016 issue of The American Journal of Medicine.