Indications for implantable cardioverter-defibrillators 

In patients with structural heart disease, a LVEF>35% and no history of heart failure, Dr Almendral also proposed non-ICD therapies, mainly RFCA, although he stressed no RCT were available. RFCA for stable VT has a success rate (in experienced hands) of 75%, and although there are recurrences they are usually not life-threatening since the sudden death rate is 1.7%/yr. Dr Almendral discussed various RFCA techniques to approach non-mappable VTs. Dr Schalij made a presentation in favour of the ICD. He referred to the AVID Registry where haemodynamically stable VT was shown to have a poor prognosis, with a similar mortality to that of unstable VT. In addition, many patients with structural heart disease and stable sustained VT have a low LVEF and/or heart failure. Finally, patients that today present with a stable VT, may develop an unstable VT in the future.

Both contenders were right in the areas of the topic that they elected to discuss. When the LVEF is low, and particularly if the patient has a past history of heart failure, monomorphic stable VT is only part of the problem. Even if the VT is approached successfully with RFCA, the risk of sudden death is determined by the underlying clinical problem, systolic left ventricular dysfunction and heart failure, and under those circumstances an ICD (or an ICD + CRT if appropriate) has to be offered as a primary prevention indication independently of the stable monomorphic VT. Ablation in such a patient may reduce the number of shocks. By itself this will not only improve the patient’s tolerance of the device, but might also improve life expectancy - should some recent claims about a possible deleterious effect of discharges on the myocardium prove to be true. In patients with a preserved LVEF (>40%), RFCA should be recommended with antiarrhythmic drugs being used if the latter fails.

Dr P. Brugada (Aalst, BE) and Dr G. Steinbeck (Munich, DE) discussed the topic Primary prevention ICD indications solely based on the LVEF. Dr Brugada believed that the LVEF is still the most important risk stratifier as to total mortality and sudden death in patients with structural heart disease with/without heart failure and that, in the recent guidelines of the ACC/AHA/ESC, it is the only class I indication that has an A level of evidence. He made a few exceptions, such as patients that are to be revascularized (CABG PATCH data), those that have a very recent AMI (DINAMIT data) or may be those that are in class III of the NYHA (subanalysis of SCD HeFT).

Dr Steinbeck was more critical and stated that although the efficacy of the ICD is high, its efficiency is very limited. He discussed a recent cost-effectiveness analysis and stressed that most studies make extrapolations for follow-ups of 5-12 years to dilute the cost of therapy, a fact that is possibly not realistic since the life span after an appropriate discharge does not seem to be that long. The USA is implanting >600 ICD/CRT devices/million people/year, whereas the average in the EU is 125/million/yr. However, should MADIT-II and SCD-HeFT type indications be implemented, the number of implants would be much higher, something that, in his opinion, the economies of European countries could not afford. He proposed that additional risk stratification, such as microvolt T-wave alternance, must be done on top of the LVEF. In addition, Steinbeck mentioned recent data from the SCD-HeFT investigators which show that one-third of patients had an EF>35% when the latter measurement was repeated after one year, and that mortality in those that had an improved EF was much lower than in those in whom the severe systolic LV dysfunction was persistent.