Carotid sinus syndrome
A condition primarily affecting elderly people, in which the carotid sinus, a structure within the common carotid artery of the neck that regulates blood pressure, is particularly sensitive.
The carotid sinus is a pocket in the artery at the point where the vessel divided to form two branches. It contains sensors that continually monitor blood pressure. When the blood pressure is raised, the sinus sends messages to the brain, which signals blood vessels to widen and the heart rate to slow, thus lowering the pressure.
In carotid sinus syndrome, the sinus reacts too readily: simply coughing or turning the neck swiftly can trigger the sensors. As a result, the brain slows the heart rate and lowers blood pressure excessively, causing the affected person to faint. This problem may be avoided by the insertion of a pacemaker, which will help to uphold a normal heart rate, overriding any inapt message from the carotid sinus.