Table 1

Trial inclusion and exclusion criteria

Inclusion criteria

Adult patients (age 18 years or over).
Record of a Valsalva manoeuvre for presumed SVT having been delivered by an ambulance clinician assigned to a participating ambulance station cluster.

Exclusion criteria

Subsequent withdrawal of patient consent to use their data.
Existing opt-out for use of NHS data for research.
Data from patients who are prisoners at the time of treatment.
Patients with permanent lack of capacity as recorded by the treating clinician.
Patients solely treated by an SWASFT resource not from one of the included ambulance station clusters, for example, air ambulance, Hazardous Area Response Team, Tiverton Minor Injuries Unit, British Association for Immediate Care doctor.
Data from patients previously included in the study will be excluded from the primary outcome analysis but will be used in analyses of some secondary outcomes.

NHS, National Health Service; SVT, supraventricular tachycardia; SWASFT, South Western Ambulance Service NHS Foundation Trust.