Novel ICD Arrhythmia Detection Algorithm

Implantable cardioverter defibrillators (ICD) are used to treat life-threatening heart rhythm disturbances (arrhythmias). They have been proven to reduce the risk of sudden cardiac death; however, there are limitations with current ICDs. Firstly, they may deliver inappropriate therapies (therapies delivered in the absence of life-threatening arrhythmias). Secondly, slower life-threatening arrhythmias may be left untreated because current programming recommendations, designed to minimise inappropriate therapies, rely predominantly on heart rates. Therefore, there is considerable potential to make ICDs safer with more sophisticated ICD algorithms. In this research study the investigators will collect data from participants with newly implanted or existing ICDs whilst they are in induced or spontaneously occurring abnormal rhythms. The data will come from sensors placed on the skin that can measure blood flow or electrical properties of the body. In addition, in 20 participants, the investigators will also collect further data from a small loop recorder implanted under the skin. The investigators will use this data to help develop and validate new methods of reliably identifying life-threatening arrhythmias so that future ICDs deliver therapies when only needed. The research is funded by the British Heart Foundation, and will take place at Hammersmith Hospital over 3 years. The investigators aim to recruit 100 patients in total.