McInnes 1985.

Methods	Randomized, double‐blind, placebo‐controlled, cross‐over study. After 4 weeks of washout period, participants were randomized to 4 × 4‐week treatment periods. BP was measured at the end of each period
Participants	14 participants Inclusion criteria: DBP 95‐110 mmHg with single‐drug therapy
Interventions	Verapamil 120 mg 3 times daily, propranolol 80 mg 3 times daily, verapamil 120 mg plus propranolol 80 mg 3 times daily, placebo
Outcomes	SBP, DBP, HR, PR interval, end systolic dimension, end diastolic dimension, fractional shortening
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The order of treatment is systematically varied to minimize any effect of sequence"
Allocation concealment (selection bias)	Unclear risk	No information
Blinding (performance bias and detection bias) All outcomes	High risk	No information
Incomplete outcome data (attrition bias) Primary and secondary outcomes	Unclear risk	No information
Selective reporting (reporting bias)	High risk	WDAE was not reported