It may be the most romantic day of the year, but for Dr Riaz Akhtar and Dr Jill Madine, today is just another day in the lab, studying a life-threatening heart condition.
The University of Liverpool researchers work jointly on a project, funded by the British Heart Foundation, which is developing a new method to assess patients when the main artery in their chest becomes dangerously enlarged, a condition known as a thoracic aortic aneurysm.
The aorta is the biggest blood vessel in the body, and is the artery which takes oxygenated blood from the heart to the rest of the body.
An aneurysm, or swelling in the blood vessel, can happen anywhere along the aorta, but a thoracic aortic aneurysm - that occurs in the section of the vessel within the chest - is of particular concern, as it is very difficult to detect, and occurs in younger patients without prior symptoms.
If it is untreated or unrecognised it can rupture and cause near instant death.