Wireless ECG Monitoring: There’s an App for That

Introduction

Palpitations are one of the most common symptoms in all of cardiology.¹ The challenge of this condition lies in the fact that the spectrum of underlying diagnoses can range from benign to life threatening. For the electrophysiologist, electrocardiographic (ECG) documentation of the heart rhythm during symptoms is of the utmost importance as the myriad therapeutic options, including conservative management, drugs and invasive procedures, differ dramatically depending on the diagnosis. 

A common dilemma in trying to make a diagnosis is selection of the appropriate monitoring device, especially when symptoms are fleeting or infrequent. The array of available remote monitoring devices ranges from external wearable monitors to long-term, implanted cardiac monitors.² Unfortunately, patients often complain about the size and inconvenience of external monitors and may be reluctant to undergo invasive procedures. Compliance with long-term monitoring has been shown to be as low as 53% over a six-month period.³ With nearly 60% of the U.S. population using smartphones, there is increasing interest in applying this technology to remote ECG monitoring.⁴ Recently, we had the opportunity to trial a smartphone-based wireless ECG monitor, which resulted in a high level of physician and patient satisfaction.

About the Technology

The AliveCor^© Heart Monitor is an FDA-approved remote monitoring device that has previously been described in EP Lab Digest^®.⁵ The monitor (Figure 1) comes in the form of a smartphone case or mobile device attachment that is compatible with Apple iOS as well as Android devices. It consists of two electrodes which make contact with the user’s fingertips and convert the electrical impulses into ultrasound signals transmitted to the microphone of the mobile device. In combination with the App that comes free with the device, the monitor provides remote, real-time single-lead ECG monitoring for up to 30 seconds which can be recorded during a symptomatic episode. These tracings can be reviewed on the mobile device or stored as a PDF, and printed or emailed for review by the patient’s provider. The high fidelity of the monitor to produce ECGs and detect arrhythmias has been documented in a number of small studies.^{6, 7}

Example Cases at Northwestern

Case 1: A healthy, athletic 17-year-old male presented to clinic with a complaint of palpitations associated with dizziness. He was an active cross country runner and generally felt symptomatic during the cool down phase of exercise. A stress echocardiogram was normal with no documentation of arrhythmia. As the patient did not want to wear a monitor during his runs, he was provided with an AliveCor Heart Monitor. Figure 2 shows a supraventricular tachycardia that was recorded during an episode of palpitations at the end of a run. Based on this tracing, he was offered catheter ablation.

Case 2: A 49-year-old man with hypertension presented to clinic with infrequent palpitations (1-2 episodes per month) which lasted from minutes to hours in duration. He was offered an event monitor, but was concerned about the cost due to the lack of health insurance coverage. Therefore, he was provided an AliveCor Heart Monitor as an alternative. Figure 3 shows the single-lead ECG obtained during an episode of palpitations. There is clear documentation of atrial fibrillation. Based on these tracings, the patient was treated with an antiarrhythmic drug with a reduction in symptoms.

Case 3: A 34-year-old man with a history of paroxysmal supraventricular tachycardia (PSVT) presented to clinic for further management. The patient was diagnosed with PSVT three years prior, when he was told by paramedics he had a heart rate of 240 bpm and was cardioverted. There was no documentation of this episode. He had been started on AV nodal blocking agents and flecainide by his cardiologist after a negative stress test. He continued to experience palpitations every 1-2 months. An EP study with possible ablation was recommended, but he was also given an AliveCor Heart Monitor to document any tachycardia during his palpitations prior to the procedure. Figure 4 shows the PSVT recorded by the device. 

Case 4: A 60-year-old woman with a history of atrial fibrillation (AF) developed symptomatic sinus node dysfunction while taking flecainide. The antiarrhythmic dose was decreased. The patient purchased an AliveCor Heart Monitor due to repeated episodes of fatigue and dizziness that remained undocumented. The tracings showed that her symptoms were due to recurrent, paroxysmal AF refractory to medical therapy. She underwent cryoablation for her AF.

Conclusion

We believe the AliveCor Heart Monitor is an easy to use, convenient option for remote monitoring in patients with suspected arrhythmia. With increasing familiarity of smartphone technology, our patients have enthusiastically embraced this monitor and found it easy to carry as well as intuitive to use. As these brief case presentations demonstrate, it has been very useful in documenting arrhythmias in a number of otherwise challenging situations. There are, however, several limitations to the monitor. It is expensive, costing nearly $200 per device. Since it is patient triggered, there is little role in asymptomatic individuals and limited opportunity to record the onset of the arrhythmia. Often, there is documentation of a supraventricular tachycardia without insight into its mechanism. This is not an appropriate choice for use in patients with syncope, another common indication for remote monitoring. In addition, the monitor has not been validated for the documentation of AF recurrence after ablation. Despite these caveats, we have found the AliveCor Heart Monitor to be a reliable remote rhythm monitor for the appropriate patient population. 

Disclosures: The authors have no conflicts of interest to report regarding the article herein. Outside the submitted work, Dr. Passman reports grants and personal fees from Medtronic.

References

1. Zimetbaum P, Josephson ME. Evaluation of patients with palpitations. N Engl J Med. 1998;338(19):1369-1373.
2. Zimetbaum P, Goldman A. Ambulatory arrhythmia monitoring: choosing the right device. Circulation. 2010;122(16):1629-1636.
3. Vasamreddy CR, Dalal D, Dong J, et al. Symptomatic and asymptomatic atrial fibrillation in patients undergoing radiofrequency catheter ablation. J Cardiovasc Electrophysiol. 2006;17(2):134-139.
4. Saxon LA. Ubiquitous wireless ECG recording: a powerful tool physicians should embrace. J Cardiovasc Electrophysiol. 2013;24(4):480-483.
5. AliveCor^™ Heart Monitor for iPhone^®, a Breakthrough for Community Screening, AF Detection, and Stroke Prevention, Now Available for Sale to U.S. Medical Professionals. Available from: https://www.eplabdigest.com/news/AliveCor%25E2%2584%25A2-Heart-Monitor-iPhone%25C2%25AE-Breakthrough-Community-Screening-AF-Detection-and-Stroke-Preven.
6. Paul Garabelli, MD, David Albert, MD, Dwight Reynolds, MD. Accuracy and Novelty of an Inexpensive iPhone-based Event Recorde. Heart Rhythm Scientfic Sessions, 2012.
7. Lau JK, Lowres N, Neubeck L, et al. iPhone ECG application for community screening to detect silent atrial fibrillation: a novel technology to prevent stroke. Int J Cardiol. 2013;165(1):193-194.