Hormone replacement therapy (HRT) is a treatment that replaces hormones (primarily oestrogen, often combined with progestogen) that decline during menopause. It is used to relieve menopausal symptoms including hot flushes, night sweats, sleep disturbance, mood changes, and vaginal dryness, and has benefits for bone density and long-term health.
For women who have had a cardiac arrest or have significant cardiovascular risk, the question of whether HRT is safe is an important one. Current evidence and NICE guidance (NG23, updated 2024) indicate that HRT started in women under 60, or within 10 years of the menopause, is not associated with increased cardiovascular risk and may in fact reduce it. The so-called ‘timing hypothesis’ suggests that oestrogen is protective to blood vessels when started early in the menopausal transition but potentially harmful if started many years after menopause when vascular changes are already established.
Transdermal HRT (patches or gel) is preferred over oral tablets in women with cardiovascular risk, as transdermal oestrogen does not increase the risk of blood clots (venous thromboembolism) in the way that oral oestrogen can. The type of progestogen used in combined HRT also matters: body-identical (micronised) progesterone carries a lower clot and breast cancer risk than older synthetic progestogens.
Women survivors of cardiac arrest who are perimenopausal or menopausal should discuss HRT with both their cardiologist and GP to weigh benefits and risks in the context of their specific cardiac history. Blanket refusal of HRT in all women with cardiac history is not supported by current evidence, and the negative impact of untreated menopausal symptoms on quality of life, sleep, and mental health is itself relevant to cardiac recovery.
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