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HRS2019 Study recommends extending cardiac monitoring for 72 hours if micro-AF is detected

The new study presented at the 2019 Heart Rhythm Society Annual Scientific Sessions not only strengthened the link between micro-AF and clinical AF but also found that the probability of an episode of clinical AF occurring within 72 hours after detecting micro-AF was very high (82%). Using one year of data, researchers evaluated cardiac telemetry reports from 26,567 people in the United States (42% men, median age 71 years) who recorded a long-term ECG (up to 30 days) with the PocketECG full disclosure mobile cardiac telemetry device.

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Current guidelines define atrial fibrillation (AF) as a ⩾30s episode of irregular cardiac rhythm without p-waves. As the disease progresses, the duration of AF episodes becomes longer and longer, and the impact on patient’s health increases as well. The objective of the research was to study association between micro-AF episodes (4 beats – 29s) and clinical AF in subjects with up to 30-day PocketECG device full-disclosure telemetry monitoring.

The research has the potential to underline how significant it is to recognize short episodes of arrhythmia, such as Micro-AF, in order to prevent it from turning into clinically classified atrial fibrillation, a heart disease which can lead to stroke.

Research Methodology

The study population: 26,567 individuals (42% men, median age 71 years, inter-quartile range (IQR) 62-78 years) who recorded a long-term ECG (median duration 15.7 days, IQR 16 days).

Study duration: January 1-December 31, 2017

Technology used: PocketECG device. The device records a three-lead ECG and detects AF (even short Micro-AF episodes) using an algorithm based on heart rhythm and beat morphology, with manual confirmation of all events by certified technicians.

Results

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The study shows either micro-AF or clinical AF was identified in 17% of all patients (4610 patients). Roughly half of these patients (2 327) had only clinical AF, 9% had only micro-AF and 41% had episodes of both micro-AF and clinical AF.

82.7% of patients diagnosed with micro-AF also experienced at least one episode of clinical AF. The study indicates a very high probability (82%) of clinical AF following an episode of micro-AF.

In fact, 74% of all patients who experienced an episode of micro-AF also experienced clinical AF within the next 72 hours.

The probability of capturing Clinical AF after an episode of micro-AF varies in age and gender groups, however in all these groups micro-AF were very likely to be followed by clinical AF.

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Results in particular age and gender groups
   Age groups   
Under 5050 - 6060 - 7070 - 8080 - 9090 - 100
Men: AF only16
(32.7%)		54
(42.2%)
291
(49.4%)
520
(54.1%)
333
(65.8%)
47
(71.2%)
Men: micro-AF and AF28
(57.1%)
64
(50%)
256
(43.5%)
362
(37.6%)
142
(28.1%)
11
(16.7%)
Men: micro-AF only5
(10.2%)
10
(7.8%)
42
(7.1%)
80
(8.3%)
31
(6.1%)
8
(12.1%)
   Age groups   
Under 5050 - 6060 - 7070 - 8080 - 9090 - 100
Women: AF only11
(40.7%)		23
(33.3%)
155
(34.8%)
437
(43.8%)		370
(55.6%)		76
(71.7%)
Women: micro-AF and AF13
(48.2%)

39
(56.5%)		238
(53.5%)		472
(47.3%)		239
(36.0%)		26
(24.5%)
Women: micro-AF only3
(11.1%)		7
(10.2%)
52
(11.7%)
89
(8.9%)
56
(8.4%)
4
(3.8%)