Thérèse Walsh (right) with her three-month-old son Jack and her twin sister Mairéad Lyons, at Thérèse’s home in Rathangan, Co Kildare. Photograph: Dara Mac Dónaill

Identical twins Mairéad Lyons and Thérèse Walsh have always had a very close bond but it reached a new level when both of them suffered heart attacks in their 30s, within eight months of each other.

“It’s the most twin thing we’ve ever done,” says Thérèse, now aged 39, who is the younger, “by five minutes”, of the pair.

Sitting in the front room of Thérèse’s home in Rathangan, Co Kildare, they both turn their wrists to show matching tiny scars where a thin tube used for coronary angiograms was inserted.

The circumstances and symptoms of their heart attacks were different but they each had a relatively rare spontaneous coronary artery dissection (Scad). It’s an under-diagnosed, emergency heart condition, where a tear occurs in the artery wall, and which primarily affects women.

Symptoms of Scad are similar to those of other heart attacks, as all are due to lack of blood supply to the heart muscle, whatever the cause, says Dr Angie Brown, consultant cardiologist and medical director of the Irish Heart Foundation. Most patients present with chest pain or pain radiating to the arms or neck, nausea, vomiting, breathlessness; some may have palpitations and dizziness.

[ Heart attacks in women: ‘I really had no idea I was having one’Opens in new window ]

For Mairéad, it was a near-death experience. In the aftermath of a second heart attack that happened during a hospital procedure, she saw her father, John Lyons, who had died of cancer a year previously. He asked her if she was coming.

“That was a very scary moment. I genuinely thought I was fine up until then.”

Scad and the repercussions have been more severe for Mairéad. However, Thérèse has no doubt that she and healthcare staff reacted quicker to the warning signs she had, thanks to her twin’s experience.

There’s a twist in the tale of Thérèse’s health after that – but let’s start with Mairéad’s story.

In the autumn of 2023, she and he