Those with the LQT2 form of Romano–Ward syndrome should avoid sudden loud noises such as alarm clocks as these may trigger arrhythmias. Fevers should be treated promptly with paracetamol. Grapefruit juice should be avoided as it contains a chemical which decreases IKr and further prolongs the QT interval. Medications that further prolong the QT interval such as sotalol should be avoided, lists of which can be found in publicly accessible online databases.Beta blockers such as propranolol or nadolol blunt the effects of adrenaline on the heart and thereby reduce the risk of arrhythmias. Mexiletine, flecainide and ranolazine decrease the  late sodium current and are of particular use in the LQT3 form of Romano–Ward syndrome, and mexiletine may also be of benefit in other subtypes. Potassium supplements may be used at times when potassium is being lost such as when experiencing diarrhoea or vomiting, but medications that encourage the retention of potassium such as spironolactone or amiloride may also be required.An implantable defibrillator, a small device that monitors the heart rhythm and can automatically deliver an electric shock to restart the heart, may be recommended. These devices are recommended for those with Romano–Ward syndrome who have experienced a cardiac arrest or a blackout whilst taking beta blockers. In those who experience recurrent arrhythmias despite medical therapy, a surgical procedure called sympathetic denervation can be used to interrupt the nerves that stimulate the heart. Epidemiology
Romano–Ward syndrome is the most common form of inherited long QT syndrome, affecting an estimated 1 in 7,000 people worldwide.
Certain situations are more likely to precipitate arrhythmias such as exercise or mental stress in the LQT1 subtype, sudden loud noise in the LQT2 subtype, and during sleep or immediately upon waking in the LQT3 subtype.Romano–Ward syndrome can be differentiated from other forms of long QT syndrome by Romano-Wards sole involvement of the heart. While other forms of long QT syndrome are associated with deafness (Jervell and Lange-Nielsen syndrome), intermittent weakness and bone abormailities (LQT7, Andersen–Tawil syndrome), and autism spectrum disorder (LQT8, Timothy syndrome), these extra-cardiac manifestations are not seen in Romano-Ward. Causes
Romano–Ward syndrome is a descriptive term for a group of subtypes of long QT syndrome, specifically subtypes LQT1-6 and LQT9-16. Several subtypes of Romano–Ward syndrome have been described based on the underlying genetic variant. These subtypes differ in clinical presentation and their response to treatment. There is robust evidence that the genetic variants associated with the three most common subtypes (LQT1, LQT2 and LQT3) are truly causative of the syndrome. However, there is uncertainty as to whether some of the other rarer subtypes are truly disease-causing by themselves or instead make individuals more susceptible to QT prolongation in response to other factors such as medication or low blood potassium levels (hypokalaemia). LQT1
LQT1 is the most common subtype of Romano–Ward syndrome, responsible for 30 to 35% of all cases. The gene responsible, KCNQ1, has been isolated to chromosome 11p15.5 and encodes the alpha subunit of the KvLQT1 potassium channel.