Houston Heart Care Blog | Memorial Katy Cardiology Associates

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Apple Heart Study: Assessment of Wristwatch-Based Photo-Plethysmography to Identify Cardiac Arrhythmias

Apr 2, 2019 11:49:00 AM

Apple Heart Study

This research study assessed whether the Apple Heart Study App can effectively use data collected on the Apple Watch to detect irregular heart rhythms, along with those from potentially serious heart conditions such as atrial fibrillation. 419,093 people participated in the study.

Apple is conducted this research study in collaboration with Stanford Medicine to improve the technology used to detect and analyze irregular heart rhythms, like atrial fibrillation - a leading cause of stroke.

Key Findings

  • Primary endpoints:
    • Irregular pulse detected in 0.52% of wearers (low rates). These received an ECG patch to wear for up to 7 days.
    • 34% of those were determined to have AF. AF > 30 seconds during up to 8 days of ambulatory ECG monitoring with irregular pulse watch notification (IPWN).
    • Confirmed AF by ECG monitoring during up to 8 days of ambulatory ECG monitoring after app detection.
  • Other Endpoints:
    • Notification positive predictive value was 0.84 (84% of notifications also had an ECG showing AF). At 90 days, only 57% of those who received notification contacted their provider. Irregular pulse notifications happened more in those ≥ 65 years old (3.2%) and in men (0.7% vs 0.26% in women).

Abstract

Purpose: To evaluate whether the Apple Heart Study Watch app has the potential to be used to identify arrhythmias such as AF.

Trial Design: 419,093 participants, ≥ 22 years old; single-arm; series 1 or later Apple watch with OS version 4.0 or later paired with iPhone 5S or later. Interventional, prospective, unmasked, single-arm, screening trial. Virtual screening; and data collection and telehealth physician study visits by video chat. The Apple Watch uses photo plethysmography which measures blood flow and changes that may suggest irregular rhythms.

Primary Endpoints: AF > 30 seconds during up to 8 days of ambulatory ECG monitoring for patients ≥ 65 years old. Confirmed AF by up to 8 days of ambulatory ECG monitoring after app detection.

Results: Irregular pulse detected in 0.52% of wearers (low rates). These received an ECG patch to wear for up to 7 days. 34% of those were determined to have AF. Notification positive predictive value was 0.84 (84% of notifications also had an ECG showing AF). At 90 days, only 57% of those who received notification contacted their provider. Irregular pulse notifications happened more in those ≥ 65 years old (3.2%) and in men (0.7% vs 0.25% in women).

Conclusions: In this population, there were a low number of irregular pulse notifications. PPV of 0.84 suggests the ability for correct identification of these irregularities in these people.

Apple Heart Study Watch app irregular pulse notification results

AF > 30 seconds

0.52%

Confirmed AF on ambulatory ECG

34%

Provider Contact by 90 days

57%

Age of irregular pulse notification receivers

3.2% ≥ 65 years old

Men vs women - irregular pulse notification receivers

0.7% men vs 0.26% women

Positive predictive value for notification

Irregular pulse notifications:
AF detected on ECG patch: 72 
Positive notifications: 86
PPV: 0.84


Topics: Heart Health

Orville Caval
Written by Orville Caval

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