The unusual case of a woman who regularly fainted while eating sandwiches or fizzy drinks is explored in a Case Report in this week's edition of The Lancet, written by Dr Christopher J Boos, and Dr Howard Marshall, Department of Cardiology, University Hospital Birmingham, UK, and colleagues.
The 25-year-old woman was seen at the hospital in January this year. She presented with episodes, typically lasting 10 second or less, of feeling suddenly and alarmingly light headed, and nauseous. She had collapsed on more than one occasion, but had no movements typical of epilepsy. Sometimes she would have several episodes a week. The problem first began when she was 15 and remained unexplained despite hospital admissions between 2001 and 2007. A full battery of blood and other tests had, more than once, revealed everything to be normal. However, an electrocardiogram (ECG) test had shown a pause of 2.5 seconds. She then had external-loop ECG tests, in which she was asked to press a button to record 1-2 minutes of the ECG each time she felt faint. At times of light-headedness, she was found to have complete atrioventricular block (a slowing of intracardiac conduction), with beat-to-beat pauses lasting up to 2.5 seconds.
On questioning, the patient revealed no history of note – she did not smoke, drank little alcohol and had never used illicit drugs. Her episodes tended to occur when she ate certain types of food, particularly sandwiches and fizzy drinks — and she had last collapsed when eating a sandwich while driving (in stationary traffic). Despite weighing only 46.5 kg, she had no symptoms of anorexia and her pulse rate and blood pressure were normal. Dr Boos and colleagues offered the woman a sandwich, which caused rapid onset of atrioventricular block and an associated 'heart pause' lasting two seconds – causing her to feel light headed again. She was diagnosed with 'swallow syncope'. This is a condition caused by alterations in the vagal nervous reflex arc — whereby the action of swallowing leads to vagal hyperstimulation and abnormal feedback along these nerves causing the heart to stop temporarily, leading to light-headedness or fainting. The woman was fitted with a pacemaker to overcome this, and, when last seen in June 2008, was free of fainting.
The authors conclude: "Cardiac pacing, when necessary, has been shown to be effective in an increasing number of case reports…Patients with swallow syncope can languish for years because the diagnosis is little known — although a case report on it was published in The Lancet, 50 years ago."
Dr Christopher J Boos, Department of Cardiology, University Hospital Birmingham, UK contact by e-mail only E) christopherboos@hotmail.com
Dr Howard Marshall, Department of Cardiology, University Hospital Birmingham, UK T) +44 (0) 121 627 1627 E) howard.marshall@uhb.nhs.uk also u.martin@bham.ac.uk
Full Case Report: http://press.thelancet.com/sandwichesfinal.pdf
Journal
The Lancet