Table 1.

Inclusion and exclusion criteria.

Inclusion criteria were:

1.Participant aged 16 years or over.

2.Participant presenting with an episode of palpitations or pre-syncope with no obvious cause.

3.Participant's underlying ECG rhythm during these episodes remains undiagnosed after clinical assessment.

Exclusion criteria were:

1.Prior diagnostic ECG.

2.Palpitations or pre-syncope present during an admission ECG.

3.Frequent episodes (i.e. at least once a day).

4.Participants under 16 years of age.

5.Previous participation in the study.

6.Alcohol/illicit drugs/seizure/stroke/transient ischaemic attack/head trauma/hypoglycaemia as presumptive cause.

7.Inability or unwilling to give informed consent.

8.Participants with recent (i.e., within 3 months) myocardial infarction, severe heart failure (New York Heart Association class 4) or unstable angina.

9.Participants unwilling or unable to use the AliveCor Heart Monitor and AliveECG app.

10.Participants without a compatible smartphone or tablet.

11.Participants with cardiac pacemakers or other implanted electronic devices.

12.No telephone number for follow-up.

13.Participant in custody.