Mehta 1988.

Methods	Country: United Kingdom Randomisation method: not stated
Participants	Age: 16 to 69 years (20 male, 15 female) 5 groups with 35 participants allocated to each group Inclusion criteria: repeatedly inducible haemodynamically stable SVT (AVNRT or AVRT) Exclusion criteria: unsustainable induced SVT for > 5 minutes, tachyarrhythmias other than AVNRT or AVRT
Interventions	VM performance: 35 mmHg pressure, 15 and 30 seconds duration, supine posture Number of VM attempts: maximum of 2 attempts* for each of 3 episodes of stimulated SVT Group 1: supine VM Group 2: standing VM Group 3: right CSM Group 4: left CSM Group 5: DR
Outcomes	Reversion (in 2 out of 3 attempts). No time frame was given for length of reversion, as these SVT episodes were induced.
Notes	* A second attempt was performed if the participant failed to revert on the first attempt.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "The manoeuvres were performed in random order". "The manoeuvres were performed first during sinus rhythm or first during tachycardia in random order". Comments: Probably not done.
Allocation concealment (selection bias)	High risk	Not reported. Comment: Probably not done.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Due to the nature of the interventions participants and personnel could not be blinded. Comment: Not done.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not reported. Comment: Probably not done.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcomes reported for all interventions (35/35) and outcomes except DR in sinus rhythm (32/35).
Selective reporting (reporting bias)	Low risk	Outcomes for reversion of SVT for supine and standing VM, right and left CSM, and DR were reported. Heart rate responses in sinus rhythm for the above interventions were also reported.
Other bias	Unclear risk	N/A