New Study Demonstrates Clinical Utility of iRhythm’s ZIO® Service to Rule In and Rule Out Cardiac Arrhythmias in Discharged Emergency Department Patients

SAN FRANCISCO – March 28, 2014

– iRhythm Technologies, a healthcare information services company, today announced new study findings that demonstrate the clinical utility of the ZIO Service for ruling in and ruling out cardiac arrhythmias in patients suspected of having the condition, following their discharge from the hospital emergency department (ED). The new findings appear in the March issue of the Western Journal of Emergency Medicine.

"Each year, millions of patients present at hospital emergency departments with infrequent and nonspecific symptoms such as heart palpitations or dizziness that may or may not be caused by cardiac arrhythmia. The challenge is knowing which of these patients have cardiac arrhythmias and which do not to enable appropriate, timely treatment and prevent unnecessary medical visits down the road," said Dr. Donald Schreiber of the Division of Emergency Medicine at Stanford UniversitySchool of Medicine and lead author of the new study. "Our findings suggest that the ZIO Service may provide a more effective and potentially cost-efficient option compared to other approaches for use in patients discharged from the ED. Other methods, such as the 60-year-old Holter monitor, are often challenging for patients to use or tolerate and are limited in the amount of heart beat data they can capture, which reduces their clinical utility."

The ZIO Service enables long-term continuous monitoring using the noninvasive, small, wearable ZIO Patch, combined with proprietary algorithms and a physician report, to detect cardiac arrhythmias. These heart rhythm disturbances often occur infrequentlyand without symptoms, and may lead to serious complications if not detected and treated properly. The ZIO Patch enables continuous monitoring for up to 14 days, and features an event trigger button for patients to push when they feel symptoms to help correlate symptoms with heart rhythm status.

In the study, 174 patients with symptoms of possible arrhythmia began wearing the ZIO Patch upon their discharge from three academic EDs. All ZIO Patcheswere returned following monitoring and the ZIO Service had a diagnostic yield of 63%, compared to a previously demonstrated diagnostic yield of 15% for the Holter monitor. Additionally, the median time to the first triggered arrhythmia for ventricular tachycardia and sinus pauses – potentially serious types of arrhythmias – was 3.1 and 4.2 days, respectively, which is outside of the detection window of traditional Holter monitoring. Importantly, in 53% of instances where the patient pushed the event trigger button, the ZIO Service did not detect any heart rhythm abnormality, suggesting the ZIO Service's ability to rule out cardiac arrhythmias.

About the ZIO Service

The ZIO Service is increasingly recognized as the new standard for ambulatory cardiac monitoring of patients with suspected arrhythmia. The ZIO Patch is a noninvasive, water-resistant monitor that is easy to use and discrete to wear, and is worn for up to 14 days, prompting high patient compliance and a higher diagnostic yield. Proprietary algorithms analyze the vast amounts of captured heart beat data and a concise report is provided to the patient's physician. A recent study by Scripps Translational Science Institute, published in the American Journal of Medicine, found that the ZIO Service detected 57% more arrhythmia events compared to use of the Holter monitor, primarily due to prolonged monitoring. Since its commercial launch in 2011, the ZIO Service has been used with more than 200,000 patients at nearly 800 institutions nationwide. The ZIO Service is covered for most Medicare patients and by leading private payers nationwide, representing approximately 180 million covered lives.

About iRhythm Technologies, Inc.

iRhythm is a healthcare information services company that aspires to be the world leader in the management of cardiac arrhythmia information, a large and growing unmet clinical need. Its flagship solution, the ZIO Service, offers a proven approachto long-term continuous monitoring that enables diagnosis earlier in the clinical pathway to improve patient outcomes and reduce healthcare costs. For more information, please visit