ACTRN12612000710820.

Study name	Novel interventions in heart failure with preserved ejection fraction using ivabradine
Methods	Study design: Single‐centre, randomised, double‐blinded, placebo cross‐over pilot study Unit of randomisation: Blocking is used to ensure that comparison groups will be generated according to a predetermined ratio, usually 1:1 or groups of approximately the same size. Total duration of study: 18 weeks Intervention time: 18 weeks Follow‐up: No information Setting: Department of Cardiovascular Medicine, Flinders Medical Centre, Bedford Park, South Australia
Participants	Type of heart failure: HF‐PEF N = 20 participants Age: > 18 years Gender: Both males and females Inclusion criteria: 1. Age ≥ 18 years 2. HF‐PEF (LVEF ≥ 50% within 6 months of randomisation) 3. NYHA II‐III 4. Diastolic dysfunction on echo 5. E/A = 1, E/E’ ≥ 15, deceleration time ≤ 140 ms 6. Heart rate over 70/min 7. Stable disease, confirmed by no hospital admissions or HF medication changes within 3 months prior to randomisation 8. Informed consent 9. No other causes for exertional dyspnoea Exclusion criteria: 1. Atrial fibrillation 2. Contraindications to MRI 3. Significant valvular or coronary disease as primary cause of HF 4. Hypertrophic cardiomyopathy, cardiac amyloidosis, sarcoidosis 5. GFR ≥ 45 mL/min
Interventions	Intervention: Ivabradine max. 5 to 7.5 mg Comparison: Placebo (microcellulose oral capsule twice daily) Concomitant medications: No information Excluded medications: No information
Outcomes	Outcomes and time points measured in the study: [Baseline, 8, 18 weeks] Primary outcome: Improvement in 6‐minute walk test Peak VO2 as assessed by cardio‐pulmonary exercise testing. The VO2 is calculated using the difference between the heart rate at rest and at peak exercise. The heart rate blood pressure and concentration of inspired oxygen will be monitored regularly by monitors. Secondary outcome: RV volume as assessed on cardiac magnetic resonance imaging Diastolic parameters of E/E', E/A ratio on echocardiogram
Starting date	No information
Contact information	Dr Govindarajan Srinivasan Department of Cardiovascular Medicine Flinders Medical Centre, 1, Flinders Drive Bedford Park, SA, 5042 Australia Phone: +61‐08‐82017916 Fax: +61‐08‐82017701 Email: Govindarajan.Srinivasan@health.sa.gov.au
Notes	Funding source category: Self‐funded/unfunded Primary sponsor type: Other collaborative groups Name: South Australian Health and Medical Research Institute Ethics status: Approved by Southern Adelaide Clinical Human Research Ethics Committee