Footnotes

• Contributors IRM, OP and BB-O conceptualised and designed the study, analysed data, drafted the initial manuscript, reviewed and revised the manuscript and approved the final manuscript as submitted. BM supervised and interpreted the retinal findings, reviewed and revised the manuscript and approved the final manuscript as submitted. OK, HM, EM and CY performed and interpreted the retinal findings, reviewed and revised the manuscript and approved the final manuscript as submitted. IU and TS  designed the data collection instruments, collected the data, carried out the initial analyses, reviewed the manuscript and approved the final manuscript as submitted. AK and AL supervised safety of propranolol therapy and interpreted ECG findings and reviewed and revised the manuscript, and approved the final manuscript as submitted. SB coordinated and supervised data collection, reviewed the manuscript and approved the final manuscript as submitted.

• Competing interests None.

• Patient consent Obtained.

• Ethics approval Institutional Helsinki Committees at the two participating centres, Rambam Medical Center, Haifa; and Hadassah Medical Center, Jerusalem; and also by the Israeli Ministry of Health.

• Clinical trial registration number ClinicalTrials.gov Identifier: NCT012384.

• Provenance and peer review Not commissioned; externally peer reviewed.