Mickelsen 2004.

Study characteristics
Methods	RCT with crossover design
Participants	11 participants (No info available on how many patients in the treatment and the comparison group), Adults (> 18)
Interventions	Intervention: DDDwith anAVinterval at 30 ms (DDD30), and DDD with the AV interval “optimised” using aortic Doppler echocardiography (DDDop) Control: Placebo (AAI)
Outcomes	Exercise time (treadmill) quality of life (SF‐36) left ventricle outflow obstruction gradient.
Notes	Its data is unusable for this review. Author was contacted and there was no reply.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	randomised single‐blinded crossover trial
Allocation concealment (selection bias)	Unclear risk	No information given
Blinding (performance bias and detection bias) Self‐reported outcomes	High risk	Single blinded
Blinding (performance bias and detection bias) Objective outcomes	High risk	Single blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information given the study
Selective reporting (reporting bias)	Low risk	All outcomes were reported
Other bias	Low risk	No other bias could be found