JG Cleland, L Buga, J Ghosh, M Nasir



In terms of engineering, clinical understanding and application, device therapy remains in its infancy. In clinical trials, implantable cardiac defibrillators (ICDs) have greatly reduced the rate of sudden death and had a modest impact on mortality in a relatively broad range of patients. They do not generally improve symptoms and may make them worse. Cardiac resynchronisation therapy (CRT) devices have been used more selectively – probably far too selectively – and have shown substantial improvement in symptoms and a large reduction in mortality both by reducing sudden death and death due to heart failure. These effects are not explained solely by improved ventricular function, and the clinical response to therapy has so far not been predicted well by any method of assessing cardiac function or dyssynchrony. Reduction in brady-arrhythmia-triggered sudden death may be an underestimated benefit of biventricular pacing. In recent trials, heart failure patients implanted with a device have had a remarkably low mortality. This forces the clinical community to contemplate universal device use for patients with heart failure, except in those who have irremediable, life-limiting, non-cardiac disease. For most patients this should be CRT or a combination of CRT and an ICD (CRT-D).

Keywords Cardiac resynchronisation therapy, heart failure, implantable cardiac defibrillators, morbidity, mortality, symptoms

Declaration of Interests Prof. Cleland has received research funding from Medtronic and Biotronik and speaker fees from both of the above as well as St Jude Medical and Boston Scientific.