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Borderline indications in implantable cardioverter-defibrillator

ESC Congress Report

  • A new risk calculator for SD in hypertrophic cardiomyopathy allows better prediction of arrhythmic events (on the  ESC website).
  • Upgrades at the time of battery replacement are associated with a very high event rate.

View the Slides from this session in ESC Congress 365

Dr P. Maury (Toulouse, F) covered the topic of congenital heart disease (CHD): GUCH patients now usually reach the adult age and can  present with sudden death (SD) in 25%, of which 75% is probably caused by arrhythmia (also heart block). The problem is that new approaches for surgery have changed the substrate, and that old data are no longer representative for the actual situation. CHD is only 1% of the total number of ICD implantations, and no randomized trial has ever been done. It is clear that in this young population many complications occur over time, and sudden death remains present in up to 50% despite an ICD. In Tetralogy of Fallot the SD rate is 0.15% per year, increasing 20 years after the correction, according to several studies.  Inducibility, and, even more so, spontaneous VT seem to be predictive of events. In TGA the decline in RV function relates to overall mortality; the SD rate is low. Late sudden death is important in aortic stenosis and complex CHD.

Dr. P. Elliott (London, GB) suggested reconsidering the implant criteria for hypertrophic cardiomyopathy (HCM). Stratifying the risk for ventricular arrhythmia has been based upon a small number of risk factors (RF) in the past and in more recent guidelines. However, other tests can be informative: coronary blood flow, fractionation, enhancement on MRI , specific mutations, outflow tract obstruction. The presence of two or more RF is associated with increased risk, but the predictive power remains modest.  O’Mahoney performed a meta-analysis of all published trials and identified a risk calculator, with familial history, age and morphological data, usually to be obtained with echocardiography, and the presence of non sustained VT as relevant predictors.
Dr. Elliott illustrated how an intermediate risk group of 4% SD, and a high risk group of 6% at 5 years can be defined for prophylactic implantation, with the numbers needed to treat and save lives at 3 and 5 years. He strongly suggested to use the sudden death risk calculator and which is available on the ESC guidelines pages.

Finally, N. Sadoul (Nancy, FR) reflected on the question whether we should replace the defibrillator at the time of its technical end-of-life.  A battery change is not harmless: some data indicate that at 5 years the lead system can be damaged, just by the replacement. Furthermore, in the Replace Study, changes in the lead system caused in 14% of patients, as major complication or event, compared to 4% with just a battery exchange.
The indication for the ICD may have been changed as well – this should be reassessed. However, in those without a persistent indication 3 to 7% receive a shock per year respectively for primary and secondary intervention. The same discussion exists for responders to CRT: should a CRT-D be given at the time of replacement, as CRT-P is associated with less complications. Maybe a risk stratisfaction tool such as the Goldenberg score could help in taking decisions.  His main message was that we desperately need guidelines for deactivation and replacement.

To conclude, this session was quite interesting with experts presenting the state of the art on ICD therapy in these areas at a very high level.




Borderline indications in implantable cardioverter-defibrillator

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.