Story highlights A 73-year-old woman called 911 after her fitness tracker showed an elevated heart rate

A scan revealed dangerous blood clots in both lungs

(CNN) Quick feedback from a Connecticut woman's Fitbit confirmed her suspicions that her shortness of breath and rapid heartbeat were cause for alarm.

Patricia Lauder, a 73-year-old retiree from Harwinton, knew that something was seriously wrong in mid-January after her wearable fitness tracker displayed a resting heart rate of 140 beats per minute.

Patricia Lauder, left, was cared for by Dr. JuYong Lee.

She had been battling a sinus infection and suspected a case of walking pneumonia. After several doctor visits, Lauder was awaiting the results of diagnostic tests to determine the cause of her symptoms.

"Finally, my resting heart rate got to the point where a simple chore was a big effort," she said.

Over the next few days, Lauder noticed that her resting heart rate was steadily rising from her normal 60 to 70 beats per minute to over 100. Because of the data her Fitbit had saved, Lauder knew that this was abnormally high for her.

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