Treatments for<unk>  aim to prevent lethal abnormal heart rhythms from occurring, and to rapidly restore a normal rhythm if they do occur. As the arrhythmias in<unk>  generally occur at times when the heart is exposed to high levels of adrenaline or other similar chemical messengers (catecholamines), many treatments for<unk>  aim to lower the levels of catecholamines the heart is exposed to or block their effects on the heart. The first-line treatment for those with<unk>  involves lifestyle advice. This includes avoiding competitive sports, very strenuous exercise and highly stressful environments, as high levels of adrenaline can occur in these settings, which can provoke arrhythmias. Medication Several medications can be useful for those with<unk> . The mainstays of treatment are beta blockers, which block the effects of adrenaline and other catecholamines on the heart, reducing the chance of abnormal heart rhythms developing. Of all the beta blockers, Nadolol has been proven to be the most effective for treating<unk> . This drug lowers the heart rate to a greater extent than other beta blockers and only needs to be taken once daily, reducing the risk of missed doses. Nadolol may be difficult to obtain and is not available in all countries, and an alternative beta blocker suitable for use in<unk>  may be Propranolol, which however has a more complex dosing regimen. Recently published data suggest that the use of selective beta blockers, such as atenolol, bisoprolol, or metoprolol, is associated with very high treatment failure rates. Flecainide is a class 1c antiarrhythmic drug that is recommended for those with<unk>  who experience abnormal heart rhythms despite taking a beta blocker. Flecainide reduces the risk of arrhythmias in those with<unk> , but it remains uncertain how Flecainide achieves this. Some have suggested that Flecainide directly interacts with the cardiac ryanodine receptor, which is frequently abnormal in those with<unk> , while other suggest that the anti-arrhythmic effects of Flecainide rely entirely on its sodium channel blocking effects. Verapamil is a calcium channel antagonist that, when combined with a beta blocker, may reduce the risk of arrhythmias in patients with<unk> . Propafenone is another antiarrhythmic that may reduce the risk of arrhythmias, potentially through direct effects on the ryanodine receptor. Sympathetic denervation The sympathetic nervous system Some persons with<unk>  continue to experience life-threatening arrhythmias despite pharmaceutical therapy. In this case a surgical procedure can be used to affect nerves supplying the heart that communicate using catecholamines. A collection of nerves known as the sympathetic nervous system supply the heart as well as other organs. These nerves, when activated, encourage the heart to beat harder and faster. The sympathetic nervous system uses noradrenaline, a catecholamine, as a chemical messenger or neurotransmitter, which can promote arrhythmias in those with<unk> . To prevent this, a region of the sympathetic nervous system can be intentionally damaged in an operation known as cardiac sympathetic denervation or sympathectomy. While the sympathetic nervous system feeds into the heart from both sides, often only the left sided nerves are targeted during sympathectomy, although destruction of the nerves on both sides may be required. Through this process, sympathectomy is effective at decreasing, but not abolishing, the risk of further life-threatening arrhythmias. Implantable cardioverter-defibrillator Chest x-ray of a patient with an implantable defibrillator (components labelled) While medication and sympathectomy aim to prevent abnormal heart rhythms from occurring in the first place, an implantable defibrillator (ICD) may be used to treat arrhythmias that medication has failed to prevent and restore a normal heart rhythm. These devices, usually implanted under the skin at the front of the chest below the shoulder, can continuously monitor the heart for abnormal heart rhythms. If a life-threatening arrhythmia is detected, the device can deliver a small electric shock to terminate the abnormal rhythm and restart the heart. Implantable defibrillators are often recommended for those with<unk>  who have experienced blackouts,<unk>  arrhythmias or cardiac arrest despite taking appropriate medication. These devices are life-saving, as it has been shown that their use confers a significant survival benefit in patients with<unk> . It has been suggested that the resulting surge of adrenaline caused by the pain of an electric shock from the device could theoretically bring on a cycle of recurrent arrhythmias and shocks known as an electrical storm, and therefore it is strongly recommended that those with an ICD implanted for<unk>  take a beta blocker to dampen the effects of adrenaline.
Catecholaminergic polymorphic ventricular tachycardia
Benign early repolarization
Junctional ectopic tachycardia
Brugada syndrome
Pre-excitation syndrome
Long QT syndrome
Wandering atrial pacemaker
Andersen–Tawil syndrome